Grid Integration of
Electric Vehicles
A manual for policy makers
INTERNATIONAL ENERGY
AGENCY
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Grid Integration of Electric Vehicles Abstract
A manual for policy makers
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Abstract
This policy makers manual is prepared under the framework of the Global
Environment Facility programme aimed at supporting low- and middle-income
economies in their transition to electric mobility. It aims to serve as a guide for
policy makers to effectively integrate electric vehicle charging into the grid, thereby
supporting road transport electrification and decarbonisation. The key steps can
be summarised as preparing institutions for the shift to electric mobility, assessing
the impacts on the grid, deploying measures for grid integration and improving
power system planning. Each of these steps is informed by insights from various
studies and inputs from international stakeholders, with recommendations based
on best practices from around the world.
Grid Integration of Electric Vehicles Acknowledgements
A manual for policy makers
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Acknowledgements, contributors
and credits
Luis Lopez is the lead author of this manual under the guidance of Jacques
Warichet and Cesar Alejandro Hernandez Alva, former Head of the Renewable
Integration and Secure Electricity Unit. IEA colleagues Juha Köykkä and Julia
Guyon also contributed to the analysis. Alejandra Bernal, Joerg Husar, Rebecca
McKimm and Zhiyu Yang from the IEA Global Energy Relations Office, former IEA
colleagues Woan Ho Park and Daniela Quiroga Vergara, and IEA-Latin America
consultant Luiz de Oliveira also contributed to this report.
Keisuke Sadamori, Director of the Energy Markets and Security Directorate,
provided valuable feedback. Valuable comments and feedback were also provided
by Pauline Henriot, Zoe Hungerford, Aditya Ramji, Cornelia Schenk, Jacob Teter
and Per-Anders Widell.
Adam Majoe edited this report. Thanks go to the Communications and Digital
Office – especially to Jad Mouawad, Head of the Communications and Digital
Office, Astrid Dumond and Therese Walsh – for their help with production and for
providing website materials. Anna Kalista also provided essential support.
An online webinar
on managing the grid integration of electric vehicles was held
on 15 March 2022. The speakers and participants provided valuable inputs for this
report.
This report benefited greatly from comments and feedback from many external
experts, including:
Doris Agbevivi (Energy Commission Ghana), Arina Anisie (IRENA), Molly Blatchly-
Lewis (WBCSD), Victor Bonilla (EBRD), Karima Boukir (Enedis), Jaap Burger
(Regulatory Assistance Project), Francisco Cabeza (Element), Francois Cuenot
(UNECE), Shyamasis Das (Independent Consultant), Thomas Deloison
(WBCSD), Michael Drtil (Hitachi Energy), Aaron Fishbone (Green Way), Nikos
Hatziargyriou (National Technical University of Athens), Harini Hewa Dewage (4R
Digital), Nishi Hidetaka (METI), Julia Hildermeier (RAP), Antonio Iliceto
(ENTSO-E/Terna), Chaitanya Kanuri (WRI), Tarek Keskes (ESMAP World Bank),
Yanchao Li (World Bank), Mattia Marinelli (DTU), Indradip Mitra (GIZ), Sajid
Mubashir (Bureau of Indian Standards), Hiten Parmar (uYilo eMobility
Programme), Luis Felipe Quirama (UNEP), Chris Rimmer (Cenex), Sacha
Scheffer (Rijkswaterstaat), Sudhendu Jyoti Sinha (NITI Aayog), Urska Skrt
(WBCSD), Chris Vertgewall (RWTH Aachen), Lulu Xue (WRI) and Zifei Yang
(ICCT).
Grid Integration of Electric Vehicles Acknowledgements
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The report was prepared by the International Energy Agency under the Global E-
Mobility Programme funded by the Global Environment Facility. The work could
not have been achieved without the financial support provided by the Global
Environment Facility and inputs from many of the partners and experts highlighted
above. In particular, we would like to acknowledge the United Nations Environment
Programme as the lead implementing agency under the programme and all their
efforts in co-ordinating the preparations, planning and roll-out of its activities.
Comments and questions on this report are welcome and should be addressed to:
[email protected]
Grid Integration of Electric Vehicles Executive summary
A manual for policy makers
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Executive summary
The electrification of road transport is a major driver of decarbonisation in the IEA’s
Net Zero Emissions by 2050 Scenario
, and providing charging solutions will be
crucial for supporting this transition. The power sector plays a key role in ensuring
a secure supply of electricity for electric vehicle (EV) charging, and in taking
advantage of EV flexibility through seamless integration with the power system.
This manual is intended to support policy makers in assessing and mitigating the
impacts of electric mobility on the power sector and designing strategies to
leverage the flexibility of EVs. It provides key recommendations in four main areas:
the readiness of institutions, impact assessment of EV charging, design of
operational measures to integrate EVs as an energy resource, and power system
planning.
Summary of policy recommendations to integrate EV charging into the grid
IEA. CC BY 4.0.
① Prepare institutions for the electric
mobility transition
1. Engage electric mobility stakeholders
2. Break silos in planning and policy making
② Assess the power system impacts
1. Define an electric mobility strategy
2. Gather data and develop insights
3. Assess the grid impacts under mobility
scenarios
③ Deploy measures for grid
integration
1. Accommodate all charging solutions but
encourage managed charging
2. Facilitate aggregation by enforcing standards
and interoperability
3. Value the flexibility of EVs
4. Co-ordinate EV charging with renewables
5. Incentivise smart-readiness
④ Improve planning practices
1. Conduct proactive grid planning
2. Reflect the full value of EV charging
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Preparing institutions for the shift to electric mobility
While electric mobility is accelerating in many locations around the world,
preparing institutions can help ensure that the shift to electric mobility happens
efficiently by taking advantage of various synergies. Electric mobility is cross-
sectoral and requires institutions to engage with a wide variety of stakeholders
from the mobility and power sectors as well as the building and real estate sectors.
To engage efficiently across sectors and support planning, silos in ministries as
well as in the industry need to be broken down.
Policy makers can start preparing institutions by engaging electric mobility
stakeholders by creating multidisciplinary working groups. Working groups serve
as focal points where stakeholders can learn about the concerns and motivations
of others, and where common frameworks can be developed to help push electric
mobility forward.
Policy makers can break silos by establishing co-operation at the policy-making
level and designating contact persons to be in charge of cross-sectoral
co-ordination so they can maximise synergies.
Assessing the impacts of electric mobility on the power
sector
Like any other electric load, EVs will impact the power system based on their
power and energy requirements and on the grids from which they are charging.
Depending on the degree of uptake, line or transformer loading or power quality
problems may not be encountered when EVs charge simultaneously or fast charge
in commercial or industrial areas but may be encountered in residential areas.
Moreover, even with sufficient network capacity, the coincidence of EV charging
with peak electricity consumption will increase marginal generation requirements
and result in additional system costs.
The vehicle segments electrified and their corresponding charging solutions, along
with user preferences and local mobility patterns, determine how and where these
impacts take place. Regular commuters with personal EVs mainly recharge in the
evening at home or during the day at work if the charging infrastructure is
available. Meanwhile, e-buses and e-trucks require high charging power for
overnight charging at depots and even higher power for mid-travel stops. Hence,
it is important for policy makers to develop an electric mobility strategy to
consider all of these factors and determine the vehicle electrification priorities and
the charging solutions that accompany them.
Obtaining data on travel needs and charging patterns through travel surveys,
global positioning system (GPS) technologies and charging databases can
provide insights for policy makers and aid in modelling EV uptake and charging
profiles. To account for forecasting uncertainties, policy makers can use mobility
scenarios when assessing the impacts on the grid to ensure that decisions on
grid investments can adapt to possible changes in the landscape.
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Due to variations in local mobility and power system contexts, dedicated studies
are necessary to adequately assess the grid impacts and deploy comprehensive
plans. In this respect, an upcoming interactive tool
on EV charging under the
Global Environment Facility’s electric mobility programme, along with this policy
manual, aims to support policy makers in these endeavours.
Deploying measures for the grid integration of EVs
While electric mobility can have significant impacts on the grid, several measures
exist to mitigate the impacts and turn them instead into opportunities for flexibility.
This manual provides a simple framework for EV grid integration to help policy
makers prioritise charging strategies according to the conditions of their EV uptake
and power system needs. The framework is structured around four phases
corresponding to increasing volumes of flexible EV load and increasing system
demand for flexibility.
Framework for grid integration of electric vehicles
IEA. CC BY 4.0.
The main strategy is to maximise the amount of managed charging, as opposed
to unmanaged charging. Cost-effective charging solutions that help accelerate the
shift to electric mobility should be accommodated by the grid, but opportunities to
maximise the share of managed charging should be pursued when possible.
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Measures to mitigate unmanaged charging and encourage managed charging
include providing locational signals, making connections non-firm at certain power
levels or at certain times of the day, requiring storage or storage fees, and making
the connection fee dependent on power demand or the controllability of the
connected EV charger.
In order to unlock the technology and business models necessary to provide
flexibility through managed charging, the flexibility needs to be valued and
remunerated. Policy makers can use tools such as tariff design, contracts and
markets for flexibilities, and participation in wholesale markets to reward managed
charging.
Individual EVs may be too small to participate in most power markets, but this can
be resolved through standardisation and interoperability measures, thereby
aggregating sufficient numbers of vehicles.
Electric mobility is also an unprecedented opportunity to grow the share of variable
renewables in the power system. EV charging can be co-ordinated with
variable renewable energy generation through incentives and measures to allow
the contracting of renewables capacities.
Finally, with all of the potential benefits of managed charging, policy makers
should incentivise the smart-readiness of ecosystems through minimum
communication and control requirements.
Improving power system planning
The rate of electrification of transport and other loads, and the potential cost
savings they provide, calls for a fundamental improvement in planning practices
to ensure the power system is ready to accommodate and take advantage of them
as distributed energy resources.
Co-ordinated and integrated planning practices are becoming essential. These
ensure that power sector plans are well co-ordinated within the power sector and
with other sectors. In particular, grid planning needs to be proactive and
anticipate various needs for expansion rather than respond to new requests for
connection. Mandated time windows of interconnection and the publication of
hosting capacity maps can help streamline interconnection processes. Meanwhile,
capacity building to develop modelling capabilities and regulatory incentives tied
to supporting electric mobility can help grid operators proactively plan for EV
charging demand.
Finally, the scenarios and plans for the power sector need to properly reflect the
full value of EV charging. Revisiting regulatory design to reduce bias on capacity
expenditure helps grid operators put more focus on leveraging available flexibility
and reducing costs for everyone. Likewise, revisiting criteria for grid expansion
and system planning can help ensure that the cost savings from EV charging
flexibility are recognised and accounted for when developing grids.
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Introduction
Context
The electrification of road transport is a key pillar of the IEA’s Net Zero Emissions
by 2050 Scenario for reducing transport emissions. Emissions could be reduced by
around 94% if electric mobility were ramped up from 11 million vehicles today to 2
billion in 2050.
1
By eliminating tailpipe emissions, EVs would also improve local air
quality and result in health improvements for cities and communities.
Electric mobility can also be a tool for energy security. By 2030, the global uptake
of EVs could displace oil demand from 2 million barrels per day
in the IEA’s Stated
Policies Scenario to about 4.6 million barrels per day in the IEA’s Announced
Pledges Scenario.
2
For many countries that are highly dependent on oil imports,
electrifying transport could allow them to diversify and use domestic primary energy
resources, such as hydro, solar and wind. The energy demand on the power
systems would be significant but would only constitute a minor share of the
countries’ electricity consumption. According to the Stated Policies Scenario
,
approximately 709 TWh of final electricity demand globally would be needed in
2030, equivalent to the total power generation of Canada and the Netherlands in
2019, but on average would only constitute 2.7% of individual countries’ total
electricity generated.
On the other hand, local constraints on grid capacity are expected to be the main
challenge due to the high power levels associated with the simultaneous charging
of EVs. For example, in the Netherlands, about 3 000 neighbourhoods with at least
100 EVs are expected to exceed network capacity by 2025
due to faster-than-
expected growth in EV uptake. In California, a local distribution system would need
to
upgrade five times more feeders than originally planned to accommodate EVs by
2030. Moreover, the concurrent electrification of heating and acquisition of air
conditioning and distributed PV could pose challenges to network capacities, in
some cases exacerbating or exceeding the impact of EVs.
Despite these challenges, electric mobility offers opportunities for flexibility due to
its storage capabilities. Total battery capacity from EVs could be as high as 29 TWh
by 2030 and 186 TWh by 2050 in the Net Zero Emissions by 2050 Scenario
,
providing a high potential for flexibility while the EVs are charging. Taking advantage
1
A comparison of the life cycle emissions of EVs and internal combustion engine vehicles is relevant for policy discussions,
especially when considering battery extraction, manufacturing and recycling. However, this is not within the scope of this
report. For more details, see the International Council on Clean Transportation’s (ICCT) report on the life cycle emissions
of
combustion engines and electric passenger cars.
2
The Announced Pledges Scenario is based on the different countries’ announcements of their 2030 targets and longer-term
net zero pledges, regardless of whether they are anchored in legislation or in updated nationally determined contributions.
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of this opportunity would require investments in communications and digital
infrastructure as well as changes in market design and regulation.
Policy makers hence need to ensure that their power systems are ready, and the
preparation must be done immediately and proactively. Electric mobility is already
becoming mainstream, representing 5%, 16% and 17% of total
light-duty vehicle
sales in 2021 in the United States, the People’s Republic of China (hereafter,
‘China’) and Europe and up to 30% of LDV sales in the Netherlands. It is also
taking hold in emerging economies, such as India, where electric three-wheelers
constituted
46% of total sales between April 2021 and March 2022.
One key aspect of policy intervention relates to EV charging. While adapting EV
charging to the demands of EV users can help accelerate the uptake of electric
mobility, shaping its deployment to minimise impacts on the grid can reduce costs
and contribute to sustainability goals. Co-ordinating the planning and deployment
of charging infrastructure with the planning of the power system grids can help
ensure the timely delivery of charging solutions to support the shift to electric
mobility.
Purpose
Given the increasing role of electric mobility in many countries, the IEA, as one of
the implementing agencies of the Global Environment Facility-funded
Global
Programme to Support Countries with the Shift to Electric Mobility, has produced
this manual for policy makers to help facilitate the grid integration of EV charging
and renewables and outline important considerations for a secure, clean and
affordable energy system. It is also a deliverable under the Clean Energy
Ministerial’s
Electric Vehicles Initiative.
This manual is primarily targeted at policy makers in the power sector, highlighting
the key intersections with other stakeholders, especially those in the transport and
building sectors. It aims to serve as a guide for policy makers on how to prepare
for the shift to electric mobility and effectively take advantage of the opportunities
from EVs.
The manual organises the technical and policy insights from grid integration
practices around the world and is arranged in four chapters corresponding to the
key steps recommended to policy makers:
• Step/Chapter 1 is about preparing institutions for the shift towards electric
mobility. It introduces the key stakeholders who need to be rallied to support
this shift and the need to break silos between sectors, in particular between
mobility, the power sector and buildings/real estate.
• Step/Chapter 2 is about understanding and assessing the grid impacts of
electric mobility. It introduces the dynamics of EV charging and explains how
vehicle electrification patterns and local conditions affect the power system. It
highlights the need to develop robust scenarios for grid planning and
operations.
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• Step/Chapter 3 is about deploying measures for grid integration. It explains
the policies, standards and regulations that aim to reduce the impact of EV
charging and even turn them into an opportunity for the power system, helping
balance the system and integrate more renewables.
• Step/Chapter 4 is about improved planning practices. It explains how proactive
grid planning can help accommodate future charging needs, and the need to
reflect the full value of EV charging flexibility in planning.
Grid Integration of Electric Vehicles
1. Prepare institutions for the electric mobility transition
A
manual for policy makers
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1. Prepare institutions for the
electric mobility transition
Authorities can play a significant role in the shift to electric mobility through policies
that enable and accelerate the uptake of electric vehicles (EVs). Therefore, the
shift to electric mobility starts from the institutions.
1.1 Engage electric mobility stakeholders
The electric mobility ecosystem involves a wide range of stakeholders, some of
which may have had limited interactions among themselves until recently. Given
the imperative of maintaining the power system’s supply-demand balance at all
times, providing charging solutions for EVs entails a high degree of co-ordination
among stakeholders. To do so, understanding their concerns and motivations is
important.
From the perspective of the power system, stakeholders can be classified into
operational stakeholders – those directly involved in the charging operations – and
planning stakeholders – those involved in planning and enabling the conditions for
vehicle-grid integration to happen.
The engagement of operational stakeholders focuses on accelerating EV uptake
by addressing prospective users’ range anxiety.
3
Original equipment
manufacturers (OEMs) provide portable chargers and charging point operators
(CPOs) install public charging infrastructure in collaboration with network
operators and retailers to ensure that energy can be sufficiently supplied. Charging
programmes may exist, provided by electric mobility service providers (EMSPs) to
help reduce costs for EV users by co-operating with aggregators or network
operators.
3
Range anxiety is the driver’s concern that there will not be enough battery storage in the EV to cover the distance required
to reach the destination or to find the next charging station. Range anxiety poses as a barrier in the shift from conventional
internal combustion engine vehicles to EVs. “Charger confidence” is a term used to demonstrate the ability to address range
anxiety.
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Operational stakeholders for vehicle-grid integration
Operational
stakeholders
Typical concerns and motivations
EV users
• Vehicle drivers
• Fleet managers
• Concerns: finding an available and functional charger and having
enough autonomy for the next trip; privacy and security
• Motivation: charging convenience and lower energy bills
• Programmes to manage EV charging are welcome, but the ability to
opt out of the programmes is necessary
EV manufacturer or
vehicle original
equipment
manufacturer (OEM)
• Manufactures vehicles and provides warranties for components
(batteries may be manufactured by a separate entity)
• Dimensions the maximum charging capacities of the vehicles to
ensure safety
• Can install basic control and communication functionalities in the
vehicle
• Concerns: handling warranty claims; charging convenience of clients
• May engage in some programmes to support charger deployment
•
Motivation: sales and market share
Charge point operator
(CPOs) or battery-
swap station operator
• Operates and often also owns the charging infrastructure
• Concerns: securing grid interconnection and land acquisition;
network tariffs
• Motivation: business model to increase charge point utilisation and
revenue streams
Electric mobility
service provider
(EMSP)
• As the interface between the EV user and the CPOs, ensuring
accessibility to electricity recharging
• EMSPs may be associated with a CPO or have arrangements with
several CPOs to expand access for the user
• Some original equipment manufacturers may have extended services
similar to that of an EMSP
• Concern: interoperability of charge points for users
• Motivation: business model to maximise share of subscribers
Network/system
operators
• Regulated monopolies operating the transmission grid (transmission
system operators, transmission network operators or transmission
network service providers) and the distribution grid (distribution
system operators, distribution network operators or distribution
network service providers); distribution companies are also in charge
of metering
• Concerns: maintaining grid security and quality of electricity supply
• Motivation: obtaining revenue from public service provision under
regulatory constraints
Electricity suppliers
and retailers*
• Companies supplying electrical power systems; suppliers offer
electricity to the wholesale market while retailers in turn buy the
offered energy and sell electricity directly to the consumers
• Concerns: retailers have concerns about balancing their portfolios
and ensuring that retail rates pay for the purchased energy; suppliers,
especially of variable renewable energy, have concerns about
securing a buyer/off-taker to help reduce financial risk
Aggregators
• Third-party entities that help aggregate various distributed resources,
through EMSPs or CPOs, to act as middlemen to provide services to
the power system; some retailers can also act as aggregators
• Motivation: obtaining access to services where they can offer their
contracted resources
* In most advanced economies, the power sector is unbundled and restructured, and companies such as generators and
retailers compete in the market. In other countries or subnational systems, regulated vertically integrated monopolies
remain the norm. These vertically integrated markets conduct similar activities of generation, transmission, distribution and
retail but may be organised in a different manner within a company.
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For planning stakeholders, a main focus on co-ordination is needed. Given that
most EVs are recharged while they are fully parked, the planning of locations for
public charging infrastructure will involve local authorities, urban and transport
planners, and the building sector. Moreover, charging programmes that shift
charging to more favourable times in a 24-hour period to reduce the peak load or
increase the consumption of renewables will require the co-operation of electric
vehicle supply equipment (EVSE) manufacturers, battery manufacturers,
researchers and regulators to establish technical requirements.
Planning stakeholders for vehicle-grid integration
Planning stakeholders Typical concerns and motivations
National and local
authorities
• Deploy policies to enable and support the shift to electric mobility
• Facilitate access to public spaces for charging in municipalities or at
highways, and to private spaces through building regulations for
charging provision
• Can serve as focal points for co-ordination with network operators,
urban and transport planners, and charge point operators
• Local authorities may not always have expertise in EV charging
Energy regulators
• Agencies tasked with regulating network monopolies and ensuring
competition in non-monopolistic activities; even though independence
is preferred, these can exist as functions under the energy ministry
• Motivation: ensuring consumer welfare through fair tariffs and
service reliability
Battery manufacturers
• Develop and innovate on battery technology; they possess expertise
in battery handling and safety, power limits and degradation dynamics
• Concern: availability of materials, especially for lithium-ion batteries
• Motivation: battery sales to vehicle original equipment manufacturers
or subscriptions via battery-as-a-service
EV supply equipment
manufacturers
• Provide the equipment for charging: portable or fixed electric vehicle
supply equipment to EV users and charge point operators
• Concern: compatibility of electrical and communications features with
vehicles, charge point operators, electric mobility service providers
and the power system
Urban and transport
planners
• Identify mobility needs for people and goods and routes to efficiently
fulfil these needs; may have the expertise to determine locations for
installing charging points from the user perspective
• Motivation: providing efficient solutions for transporting people and
goods that may go beyond electric mobility
Building sector
• Real estate
• Construction
• Similar to local authorities, may be instrumental in giving access to
spaces for EV charging to complement the current role of providing
space for vehicle parking
• Concern: determining electrical connection requirements for EV
charging that may exceed their typical allocated capacity or increase
their typical network tariff
Research institutes
and think tanks
• Conduct research on key technological and business aspects of
electric mobility
• Can conduct pilot studies and demonstrations to help inform policy
and business models
• Can develop expertise in modelling EV uptake and determining
system impacts
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Create multidisciplinary working groups on electric mobility
The first step for policy makers is to create working groups on electric mobility to
bring together different stakeholders to arrive at common objectives, such as
supporting EV uptake or minimising the total energy system cost. For example,
supporting EV uptake by developing right-to-charge laws
that allow tenants in
multi-unit-dwelling households to install charging points, or the expansion of
rights-to-connection that can allow parking lots to request connections from the
grid, will require engagement with these different stakeholders.
Working groups help gather working-level officials from the sectors involved and
create a focal point for knowledge sharing and capacity building, as well as
identifying the relevant contact persons. The development of robust EV uptake
scenarios can also take place, along with assessments of alternative solutions
under commonly agreed holistic economic frameworks.
Specific working groups related to vehicle-grid integration, such as in California
,
can also provide further insights into effective ways of obtaining value from EV
flexibility.
1.2 Break silos in planning and policy making
In addition to engaging stakeholders, policy makers also need to co-ordinate
planning and policy making across different sectors of the government. There are
several opportunities for synergies, especially in the transport and energy sectors:
• Synchronising the increase in targets for EV uptake and variable renewable
energy generation. Variable renewable energy generation can be increased
if additional flexibility from EV batteries is leveraged. Likewise, EV uptake
can be accelerated if revenue sources exist when providing flexibility for the
power system.
• Co-ordinating the roll-out of charging infrastructure with transmission
expansions to support the high-powered charging expected along highways.
Transmission expansion along highways could also be linked to local variable
renewable energy generation to reduce grid losses.
• Anticipating potential land use issues from grid extension by co-ordinating
planning for grids and bus or truck depot electrification. For example, a depot
of 90 electric buses requires about 4 MW of charging power and entails co-
ordination between e-bus procurement and infrastructure planning, especially
for additional substation needs due to the high costs of financing and risk
.
• Alignment and rationalisation of incentives. Co-ordinating the taxation of
internal combustion engine vehicles or fuels with electricity taxation and
electric mobility incentives or charging programmes can improve the overall
cost of ownership for users and accelerate the shift to electric mobility.
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Alignment to be pursued among policy-making silos
IEA. CC BY 4.0.
Note: End users include consumers, self-generation and storage.
Source: Reproduced from Clean Energy Ministerial (2020),
Electric Vehicle and Power System Integration: Key Insights
and Policy Messages from CEM Initiatives.
Establish co-operation at the policy-making level
Co-ordination on setting high-level targets for power system and transport
development by senior policy makers in government departments and ministries
can help set the precedent for co-ordinated planning in their respective sectors.
Co-operation can also be formalised at the institutional level. For example, the
Joint Office on Energy and Transportation in the United States has been created
to co-ordinate planning between the energy and transport departments to ramp up
electric mobility. It was created as part of the country’s
Bipartisan Infrastructure
Law in 2021 to boost investment in infrastructure. By utilising the transport
department’s rights-of-way,
4
the necessary grid expansions to power charging
corridors could be accelerated through streamlined permitting and construction.
Designate contact persons in charge of cross-sectoral co-ordination
In situations where formal co-operation may not be possible, policy makers can
designate contact persons to facilitate co-ordination among the different sectors.
Training can ensure that these contact persons have an understanding of the
4
A right-of-way is a right to establish and use a pathway over a piece of land for transport purposes without necessarily
owning the land itself.
Transport and infrastructure
stakeholders
Overarching
policies
EV uptake targets
Transport emission reductions
Energy efficiency targets
Overarching
policies
Variable renewable energy
penetration targets
End-use electrification targets
Energy efficiency targets
Countrywide
infrastructure
Charging infrastructure roll-out
programmes
Accepted charging standards
Roaming and long-haul travel
arrangements
Bulk power
system and
transmission
network
Need to reduce peak-demand
increase
Balancing variable renewable
energy
Rising transmission cost
Mobility, land use
and urban
planning
Charging depot requirements
Local mobility plans (e.g. public
and active transport)
Distribution
network and
local utilities
Local network reinforcement
Substation or city
-level
infrastructure
End users
Fuel prices including taxes and
levies
End users
End-user electricity rates
including taxes and levies
Smart energy offerings
Energy and power sector
stakeholders
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planning and policy-making practices of the other sectors and can leverage the
synergies in their own sectors.
Joint Office on Energy and Transportation, United States
The United States has established an institutional means to break the silo between the
Department of Transportation and the Department of Energy. With a USD 300 million
budget, the joint office is expected to carry out work within nine focus areas:
technical assistance on the deployment, operation and maintenance of zero
emissions charging and refuelling infrastructure; renewable energy generation; and
vehicle-to-grid integration
data sharing of installation, maintenance and utilisation for the charging and
refuelling network build-out
national and regional study on charging and refuelling needs and deployment factors
for community resilience and EV integration
training and certification programmes
programmes to promote renewable energy generation, storage and grid integration
high voltage and medium voltage transmission pilots in the rights-of-way of the
interstate highway system
research, strategies and actions to further reduce transport emissions
development of streamlined utility accommodations policy for high voltage and
medium voltage transmission rights-of-way
other areas that the Department of Energy and Department of Transportation may
jointly deem as necessary.
Source: Joint Office of Energy and Transportation.
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2. Assess the power system
impacts
Electric vehicles (EVs) interact with the power system whenever they are
connected to a charging point. Like many other electrical loads, EV charging can
cause operational challenges and require upgrades based on the power drawn
from the system and the specific location from which the power is drawn. The
impacts can be classified as those affecting the capacity limits of the different
components of the network, those that affect the power quality for the end users
and those that affect the larger power system.
• Line, transformer, and feeder loading: sustained loading beyond the
physical capacity of the components of the grid can lead to premature ageing
or permanent damage. Operating limits on current, voltage, frequency,
temperature and losses are placed in order to reduce the likelihood of this
problem. The components must be upgraded or reinforced if loading is
expected to regularly exceed these limits.
• Power quality: the current drawn for EV charging may lead to imbalances
5
in
the network voltage if EV charging is done on a single phase and may also
lead to harmonic distortions. Lower power quality could lead to the eventual
damage of other nearby electrical appliances, and hence distribution utilities
are subject to power quality indicators, such as contractual voltage limits and
harmonic distortion limits.
6
• Systemwide impacts: charging during peak periods can exaggerate the peak
demand and the subsequent need for peak generation capacity.
The extent to which these grid impacts manifest depends on the charging use
cases that develop and where they occur, which in turn are based on the
electrification of vehicles. Defining an electric mobility strategy is the first step in
assessing the grid impacts resulting from transport electrification.
2.1 Define an electric mobility strategy
Vehicle segments provide insights into charging needs
Countries have differing existing vehicle types due to a complex set of factors
involving their geography, structures, purchasing power, local economic activities
5
To maximise the efficient use of the equipment, power systems are made of three symmetrical phases. The network
operator ensures that the phases remain more or less symmetrical by avoiding the current drawn from one phase significantly
exceeding that of the others.
6
Recommendations to resolve power quality issues are increasingly being addressed in international technical standards
that policy makers can directly implement. The policy manual would focus on the wider techno-economic impacts of EV
charging that involve decisions on network and generation capacity.
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and local mobility preferences, among other factors. Policy makers can conduct a
first-level classification based on the broad vehicle type to understand the
expected power system impacts of charging.
• Two-wheelers and three-wheelers generally have small battery capacities
(0.5-20 kWh). They can be charged using a regular socket through a portable
charger, or their batteries can be swapped. They usually do not have
active
cooling systems, so high-power charging is limited. The power demand is
comparable to washing machines (0.5-1.5 kW) and room air conditioners
(3-4 kW).
• Light-duty vehicles have a wide range of battery capacities (10-100 kWh)
and comprise different sub-classes, such as plug-in hybrid electric vehicles
and full-battery electric vehicles.
• Light commercial vehicles are vans and small pickup trucks with battery
capacities in a similar range as light-duty vehicles
(35-76 kWh).
• Buses have a range of battery capacities (50-550 kWh) depending on the
specific vehicle use, with smaller batteries being associated with trolleybuses
where certain sections can be
connected by catenary wiring.
• Trucks have high battery capacities (100-800 kWh) due to the long distances
and high power requirements.
Stock share of all vehicles (left) and EVs (right) by vehicle type in selected countries
IEA. CC BY 4.0.
Note: Four-wheelers or quadricycles are small car-like vehicles. They are grouped with three-wheelers and separated from
larger-volume passenger light-duty vehicles or sedans.
Source: IEA analysis from IEA Mobility Model.
0% 20% 40% 60% 80% 100%
United States
France
Mexico
Brazil
South Africa
Japan
China
India
Viet Nam
Stock share
All vehicles
Two-wheelers Three- and four-wheelers Passenger light-duty vehicles Buses and minibuses
Light commercial vehicles
Medium trucks
Heavy trucks
0% 20% 40%
60%
80% 100%
Stock share
EVs only
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Note that there can be considerable variation across markets in battery capacity,
vehicle power and energy efficiency that can change the power and energy
requirements of different vehicle classes. However, a more significant factor to
consider is the vehicle use case.
Classifying v
ehicles according to the vehicle use case or vehicle segments can
reveal route patterns and dwelling times. These are used as guides for battery
sizing and charging infrastructure planning, with the aim of minimising total system
costs. The resulting charging roll-out plans provide an idea of the location and
charging profile of the surrounding connected load, which then inform about the
impact on the grids.
Typical charging solutions for selected vehicle segments
Vehicle
class
Vehicle
segment
Driving patterns Charging solutions
Two-
wheelers
Personal
Regular patterns of home to
workplace with occasional travel
for leisure
Home charging and destination
charging (0.5-3.3 kW), battery
swapping
Taxi or ride-
hailing
Diverse routes with high daily
mileage and off-shift charging at
depot or home
Public charging (0.5-3.3 kW),
battery swapping
Three-
wheelers
Taxi
Diverse routes with high daily
mileage and off-shift charging at
depot or home
Depot, home and public
charging (0.5-3.3 kW)
Last-mile
delivery
Light-duty
vehicles
Personal
Regular patterns of
home/roadside to destination
(workplace or leisure) with
occasional long-distance travel
Home charging (1.9-7 kW),
destination (workplace or
leisure) charging, public
charging
(≤22k
W), en
route/highway fast charging
(50-350 kW)
Taxi or ride-
hailing
Diverse routes with high daily
mileage and off-shift charging at
depot or home
En route fast charging (50-350
kW), depot charging (≤22-
350 kW) and home charging
Car sharing
Diverse routes with regular
stops at planned locations
Public charging (≤22 kW)
Light
commercial
vehicles
Last-mile
delivery
Diverse routes with stops at
depots
Depot charging (22 kW)
Buses
Intracity or
transit bus
Fixed routes with pre-
determined schedules and short
stops during the day
Opportunity (bus stop) charging
(150 kW or more) and depot
charging (22-50 kW)
School bus
Semi-fixed routes with daytime
parking at the school
Destination (school) charging
(19-50 kW)
Regional
bus
Fixed long routes along
highways with fewer stops
En route fast charging and
depot charging (50-350 kW)
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Vehicle
class
Vehicle
segment
Driving patterns Charging solutions
Trucks
Local
distribution
Diverse routes with stops at
depots
Depot (19-125 kW)
Regional or
long-haul
delivery
Semi-fixed long routes on
highways with mid-shift stops
and off-shift charging at depots
Depot (<350kW) and en route
megawatt charging (1-3.75
MW)
Notes: Charging levels and standards vary by country and region. A detailed comparison is provided in the Annex. EV
battery charging is conducted via DC through an onboard AC-to-DC converter. The capacity of the onboard charger limits
the speed and power coming from the socket and is usually in the range of 3-22 kW. For DC charging, the battery is
charged directly from the charging infrastructure equipped with the rectifier.
Sources: IEA analysis of AEEE (2020), Charging India’s Two- and Three-Wheeler Transport
; Basma, H. et al. (2022),
Energy Consumption and Battery Sizing for Different Types of Electric Bus Service; Borlaug et al. (2022), Charging Needs
for Electric Semi-Trailer Trucks; Borlaug, B. et al. (2021), Heavy-Duty Truck Electrification and the Impacts of Depot
Charging on Electricity Distribution Systems; ChargeUp (2022), State of the Industry; ENTSO-E (2021), Electric Vehicle
Integration into Power Grids; Gao, Z. et al. (2017), Battery Capacity and Recharging Needs for Electric Buses in City
Transit Service; Link, S. and P. Plötz (2022), Technical Feasibility of Heavy-Duty Battery-Electric Trucks for Urban and
Regional Delivery in Germany—A Real-World Case Study; NACFE (2021), Box Trucks: Market Segment & Fleet Profile
Fact Sheet; NITI Aayog (2021), Handbook for Electric Vehicle Charging Infrastructure Implementation; NREL (2021),
Electrifying Transit: A Guidebook for Implementing Battery Electric Buses; RAP and ICCT (2022), Electrifying Last-Mile
Delivery; Rojas, J. et al. (2022), Caso Mi Taxi Eléctrico y las Barreras para la Electrificación del Transporte Público Menor
[The Case of Mi Taxi Eléctrico and the Barriers to the Electrification of Minor Public Transport]; SEPA (2021), The State of
Managed Charging in 2021; Turoń, K. and G. Sierpiński (2018), Electric-Car-Sharing in Urban Logistics – Analysis of
Implementation and Maintenance; UITP (2020), The Case for Electrification of Taxis and Ride-Hailing; US DOE (2022),
Electric School Bus Education; US DOT (n.d.), Electric Vehicle Charging Speeds (accessed 1 March 2022); Vosooghi, R.
et al. (2019), Shared Autonomous Electric Vehicle Service Performance: Assessing the Impact of Charging Infrastructure;
ViriCiti (2021), Opportunity Charging for E-Buses.
The charging infrastructure roll-out plans also provide an opportunity for the power
system planner to determine the eventual power and energy requirements of
vehicles that have been electrified. In the IEA’s
Policy Brief on Public Charging
Infrastructure, co-ordinated planning and collaboration are identified as important
steps, especially when identifying locations with available grid capacity.
Understand key mobility needs and challenges
The first step in defining an electric mobility strategy is to understand the mobility
needs for both passenger and freight purposes. This involves identifying the most
efficient pathways for transporting people and goods between points and through
corridors. There are several analyses and management toolkits
that exist, and
transport policy makers have the relevant expertise to conduct such analyses.
Using
avoid-shift-improve principles can help make overall transport sustainable.
An important aspect to consider is that replacing the current vehicle stock with
EVs may not always be the best solution for the challenges faced. For example,
in high population density areas with frequent congestion, shifting portions of
passenger mobility to public transport and active transport (i.e. cycling and
walking) can be a better solution for improving the traffic flow for the remaining on-
road passenger and freight vehicles. Options such as bus rapid transit can be
efficient and competitive
and can also pave the way to electrification. Electrified
public transport, such as metros, trams, and trolleybuses, are already common
and provide a solid experience base.
For example, in the electric mobility strategy of Saanich, Canada, the individual
motorised vehicle share of mobility is expected to decrease from 77% in 2017 to
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50% in 2050, while that for public transport is projected to grow from 10% to 20%,
respectively. Likewise, the London Mayor’s Transport Strategy and the
London
Environment Strategy target a mode shift to walking, cycling and public transport
from 64% in 2018 to 80% in 2041 and require vehicles to be zero emissions by
2030 for light-duty vehicles and 2040 for heavy-duty vehicles.
Determine vehicle electrification priorities
There are several ways policy makers can prioritise the electrification of vehicle
segments. These include prioritising them based on the electric mobility benefits
they wish to enable, such as GHG emissions reduction, local air quality
improvement, and fuel import reduction.
In Mexicali, Mexico, key considerations
for prioritising vehicle electrification
include the potential to reduce GHG emissions, reduce noise, and improve local
air quality. The report has also considered the prioritisation of fleets to help
generate a critical mass of charging infrastructure and identified light-duty vehicle
taxis and transit buses as candidates for electrification.
Affordability and current usage patterns can also be major considerations. In many
Latin American countries, buses form a significant part of daily travel, with
significant numbers in Colombia and Chile
. The transition towards bus
electrification has been fast as e-buses have reached cost parity with diesel buses
in certain instances as a result of lower operations and maintenance costs and
better financing availability.
Likewise, the total cost of ownership for two-wheelers for personal use, ride-hailing
and last-mile delivery is lower compared to internal combustion engine
equivalents. As such, countries with significant shares of two-wheelers have high
targets for electrification. For example, In Indonesia, the
2030 target is 13 million
electric motorcycles compared to 2 million passenger light-duty vehicles.
Chile’s electromobility strategy
Chile’s electromobility strategy sets the main strategic guidelines, actions and
targets for sustainable transport in the country. The strategy was developed
through a participatory process with stakeholders and is aligned with the broader
long-term energy policy to 2050.
The strategy contains specific outputs for the expansion of charging infrastructure;
infrastructure and regulation; R&D and capacity building; and information, co-
ordination and international co-operation. The objective is for electric mobility to
contribute 20% of the emissions reduction effort required to reach carbon
neutrality by 2050.
In the past five years, Chile has embarked on a rapid increase in deploying EVs
in the capital Santiago and has set ambitious targets for electrifying road transport
nationwide over the coming decades:
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By 2035: 100% of new additional urban public transport, 100% of new sales of
light- and medium-weight vehicles and 100% of new sales of agricultural and
industrial vehicles with power output greater than 560 kW.
By 2040: 100% of new sales of agricultural and industrial vehicles with power
output greater than 19 kW.
By 2045: 100% of new sales of land cargo transport and inter-city buses.
The strategy also outlines various requirements for the charging infrastructure,
grid integration and regulation.
Expansion of charging infrastructure
Preparation of a national plan of reference locations for charging points based
on vehicle flow and power grid availability criteria.
Preparation of a best practice guide covering technologies and business
models for local governments.
Identification and reduction of hurdles to the installation of public charging
infrastructure.
Using public tenders to leverage investment in highway charging solutions.
Shortening interconnection timelines for charging stations through a web
platform.
Grid integration
Assessment of mechanisms to encourage off-peak charging to avoid power
grid congestion and stress.
Creation of active co-ordinated planning between planning new charging hubs,
public transport and grid planning to shorten design and implementation
timelines.
Incorporation of a grid communications component into the charging
infrastructure to enable future bidirectional charging and other power system
services.
Regulatory framework
Enforcing interoperability to facilitate access and connection to the charging
network.
Development of technical standards for the charging infrastructure.
Regulation of existing and new buildings to include spaces for charging
infrastructure.
Source: Government of Chile (2022), National Electromobility Strategy.
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2.2 Gather data and develop insights
Undertake travel surveys
Determining typical vehicle use, daily travel and parking preferences through travel
surveys can give huge insights into likely EV driving behaviour. Longer daily travel,
such as for taxi segments, can require larger battery capacities and/or more
frequent charging. Travel surveys can also provide insights into whether expanding
electrified public transport, such as rail or buses, could be more cost-effective and
impactful. For example, multiple paths along common routes can be an opportunity
for public transport instead.
Household travel surveys can form a solid basis for modelling, as has been
validated for Switzerland. Such surveys can be coupled with
EV registration
databases, which take vehicle model specifications into account and provide
insights into new sales and second-hand use. Travel surveys are already deployed
in most
advanced economies and in countries such as Chile and Thailand.
As the electrification of transport progresses, however, the travel patterns of EVs
can deviate from those of internal combustion engine vehicles. More precise
information from EV users on their travel routes and charging patterns can help
develop holistic insights for policy makers. More tailored surveys targeting EV users,
such as that conducted by Enedis in France
, can provide a better understanding of
charging needs.
Leverage digital technologies
Digital technologies, such as GPS data, can give information on specific travel
routes and corridors and aid in the specific placement of charging infrastructure. In
Europe, a GPS-based study found that the share of the private fleet in motion at the
same time never exceeded 12%
, with some areas as low as 5%, indicating the
massive grid-integration potential of electrified private mobility. Likewise, in the
United States, the National Renewable Energy Laboratory created models to project
the need for
slow and fast charging, with considerable accuracy on the miles
travelled based on GPS data and travel surveys. While personal vehicle users may
have data security considerations regarding GPS, public and commercial uses,
such as buses, trucks, ride-hailing and delivery vans, could provide immediately
actionable insights for the choice of charging locations and grid development. For
example, regionwide GPS studies on
truck travel in Europe show multiple stops at
rest areas of less than 3 hours, followed by stops of 8-23 hours at logistics hubs.
Record charging session data
Analysis of charging patterns can help improve information on actual connection
and charging times, uncover flexibilities and inform charging infrastructure
deployment strategies. For example, charging patterns between plug-in hybrid
electric vehicles and battery electric vehicles vary, with higher variability observed
in the former.
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For public charging infrastructure, cities and municipal authorities can specify the
data-sharing requirements in their tenders to facilitate early access to charging
data. Opening access to collected data, especially on type, quantity, location,
availability and utilisation, can help planners and researchers determine whether
the charging points are accessible and reliable. The recording of charging
sessions can be initiated by EV associations, such as in Norway
, or collected by
public authorities, such as in Germany.
For home charging, policy makers could require onboard meters or data sharing
from vehicle telematics systems, coupled with data privacy regulations. In major
EV markets where the majority of charging occurs at home, data from public
charging sessions may miss information on the time periods of electricity use.
Obtaining information directly from vehicles can be an alternative pathway. There
are already regulations, such as the On-Board Fuel Consumption Meters
in
Europe, that aim to improve the accuracy of data on actual emissions from internal
combustion engine vehicles and plug-in hybrids by placing onboard tools for the
real-time measurement of energy consumption. Extending these regulations to
EVs can reveal time periods of connection and charging. Data from vehicle
telematics systems installed by several OEMs can already provide information on
periods of battery recharging.
Given the potential sensitivities related to personal information involved in home
charging, data collection efforts require extensive stakeholder discussions to
balance the value of gaining insights with the data-sharing risks to develop
appropriate data protection measures. General data protection regulations, such
as those developed in the European Union
, can help in establishing trust by
allowing data providers (in this case EV users) to view their personal data and
object to their use and processing when needed.
Maintain open access to public charging infrastructure data
Researchers and private companies can use open access to help leverage their
collective efforts in analysing the effectiveness of charging services. They can also
help recommend the placement of charging infrastructure in consideration of
transport corridors, municipal zones, and grid capacity.
Examples of open EV load
data in major EV markets can serve as reference for policy makers looking to
develop open datasets.
Run pilot studies
Pilot studies can help provide in-depth insights, especially for identifying specific
charging needs within local mobility contexts. Early efforts, such as the
EVI Global
EV Pilot City Programme under the Clean Energy Ministerial, offered experiences
from frontrunner cities. Ongoing pilot studies, such as SOLUTIONSplus,
incorporate integrated mobility solutions. Meanwhile, recently launched pilot
studies, such as
SCALE and EV4EU, aim to develop knowledge on vehicle-grid
integration.
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2.3 Assess grid impacts based on mobility
scenarios
Grid impacts and opportunities vary by charging use
case
Based on the charging solutions selected for the electrification of vehicle
segments, the grid impacts and opportunities can be classified according to the
charging use cases that the vehicle segments take up.
Grid impacts and opportunities for charging use cases
Charging use case Impacts Opportunities
Home charging
Overloading issues expected for
high levels of EV penetration* with
high levels of simultaneity** and
voltage issues for rural areas.
Off-peak charging or reduction of
variable renewable energy curtailment
via load shifting depending on
connection time duration and charging
time.
Workplace and
destination
charging
Lower probability of overloading
issues due to larger capacities
typical in commercial or industrial
zones.
• Potential increase of consumption of
solar generation due to typical daytime
connection.
• For the workplace: flexibility potential
can be facilitated by a fleet manager,
especially for workplaces.
• For destination charging: flexibility
potential might be limited depending
on the dwelling time.
Public roadside
charging
Similar issues to home charging,
especially with higher power
draws from three-phase charging.
Similar flexibilities possible for
destination and home charging.
However, strategies to increase
utilisation by encouraging car-switching
once fully charged may limit the
potential.
En route charging
(also called
opportunity or top-
up charging)
Potential high-power draw.
Depending on the power and
volume required, dedicated
transformer or stationary storage
serving as a buffer might be
required.
• Limited demand response flexibility
due to short or non-existent surplus
connection time.
• Higher power system participation may
be possible if buffer storage is
installed.
Depot charging
• Expected high-power draw due
to larger volumes and numbers
of vehicles served.
• Dedicated substation might be
needed, but the added cost can
remain viable due to the nature
of the commercial operation.
• Network upgrades might
encounter land use restrictions,
especially if located in dense
urban areas.
• Fleet predictability and load
management offer high potential for
load shifting, variable renewable
energy, curtailment reduction and
bidirectional charging due to larger
battery capacities and existing fleet
control.
• Flexibility potential might be limited to
a few hours depending on the parking
period and trip scheduling.
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Charging use case Impacts Opportunities
Battery swapping
• Limited overloading issues due
to charging control within the
battery-swap station.
• May require dedicated feeders
depending on the station size.
Full 24/7 bidirectional interaction with
the grid and the aggregated capacity
could facilitate renewable energy
offtake. Battery charging management
can help reduce asset ageing.
* EV penetration can be defined as the share of current vehicles converted to EVs, or the amount of EVs per dwelling.
** Simultaneity is the coincidence of EVs resulting in a higher collective charging power and is very dependent on local
conditions. In China
, studies estimate 21% coincidence for residential neighbourhoods, 15% for workplace charging and
5% for charging in leisure or commercial spaces. In Germany, the simultaneity factor can vary between 30% and 40% for a
set of 100 public charging points, meaning that for areas with 100 charging points, grid operators could expect
simultaneous charging in 30-40 charging points.
Notes: There are also proposed alternative charging techniques, such as inductive charging, catenary wiring, mobile EV
charging and automated conductive charging, which are at different stages of maturity. They are briefly discussed in the
Annex. These require further study, especially in determining the optimal investment mix given how they could be
competitive for specific use cases despite potentially higher capital costs.
Sources: US DOT (n.d.), Electric Vehicle Charging Speeds (accessed 1 March 2022); ENTSO-E (2021),
Electric Vehicle
Integration into Power Grids; Gao. Z. et al. (2017), Battery Capacity and Recharging Needs for Electric Buses in City
Transit Service; AEEE (2020), Charging India’s Two- and Three-Wheeler Transport; RAP and ICCT (2022), Electrifying
Last-Mile Delivery; Barthel, V. (2021), Analyzing the Charging Flexibility Potential of Different Electric Vehicle Fleets Using
Real-World Charging Data; Li, S. (2020), Optimizing Workplace Charging Facility Deployment and Smart Charging
Strategies; IEA (2022), Policy Brief on Public Charging Infrastructure.
The impacts of charging may vary across locations, especially due to the profiles
of other connected loads and the typical network capacities allocated to them. In
residential and commercial areas, the additional load from charging EVs could
aggravate the typical peak periods
during the evening and daytime, respectively,
due to the use of lighting, heating or air conditioning, appliances and other plug
loads during the same time periods. On the other hand, the impact of additional
load from EV charging may be minimal relative to existing industrial loads and
dedicated network capacity.
Analysis of different distribution networks would be needed to consider these
variations. In Australia, for example, analysis of urban and rural areas
shows that
80% EV uptake is possible in urban areas with robust grids but can be as low as
0% in certain rural grids where the transformers are already overloaded and due
for upgrade.
Model power system impacts based on EV uptake and charging profiles
Based on travel surveys and charging sessions, and in collaboration with fleet
operator targets, policy makers can model the impact of electric mobility on the
power system, with the help of modelling tools
. Depending on the type of
analysis, there are several models that can be used.
Distribution-level analyses can help determine specific issues with network
capacity and facilitate planning for distribution companies to anticipate the build-
out. Such analyses require more detailed information on vehicle segments, the
electrification of other loads, the transport corridor, and the distribution network
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layout. For example, in the Netherlands, forecasts of EV uptake are developed
at the neighbourhood level. These forecasts project up to the 2035 horizon and
are updated every two years.
Bulk power system-level analysis, on the other hand, can reveal more state-level
or national-level impacts of the aggregated load and flexibility opportunities or
peak-demand challenges for power system generation planning. It can also
provide a first-order estimate of the impacts of the electrified vehicle classes. In
Thailand, for example, scenario analyses
based on national EV targets estimate
18-35 million private e-motorcycles compared to 1.1-1.3 million electric light-duty
vehicles by 2036, with peak demand driven by private electric two-wheelers up to
1 400 MW and electric light-duty vehicles up to 1 250 MW.
Create mobility scenarios to address uncertainties
There are several uncertainties in the uptake of electric mobility. Historically,
shares of battery electric vehicles
compared to plug-in hybrid electric vehicles
have varied significantly, and average electric ranges have also increased,
indicating an increase in battery capacities. Charging preferences can also
change, such as when electric light commercial vehicles in Shenzhen, China,
shifted to more mid-shift fast charging compared to depot charging once the fast-
charging infrastructure was made available.
To account for these types of uncertainties, policy makers can create mobility
scenarios that aim to model the sensitivities of different trajectories. While there
are various methods that aim to incorporate varying probabilities, creating
scenarios can help create a cohesive set of factors or policy targets for which the
power system will be tested.
For example, in a vehicle-grid integration study
on France, mobility scenarios
considered varying shares of private EVs of 7-15.6 million by 2035, alongside
varying shares of rail and electrified public transport and autonomous sharing of
vehicles, corresponding to the forecasts and policy targets of the country.
These mobility scenarios also need to be coupled with projections of other
possible trends, such as heat pump uptake, air conditioning acquisition and the
uptake of distributed PV.
For example, in a US electrification futures study
, varying adoption of EVs from 30
million to 242 million light-duty vehicles is modelled alongside building and
industrial electrification trends to develop a model for the grid under different
power supply scenarios.
In the mobility scenarios, bulk power system-level analysis can provide insights
into the amount of flexibility that can be considered reliable even while considering
differences in uptake. In addition, distribution-level analyses can show the
locations of optimal network expansion and locations where measures to limit
power would be preferred.
Grid Integration of Electric Vehicles 3. Deploy measures for grid integration
A manual for policy makers
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3. Deploy measures for grid
integration
Grid integration is the process of adapting power system operations to
accommodate the entry of new energy technologies in a cost-effective manner.
For distributed energy resources such as EVs, the following characteristics help
distribution companies determine the extent to which the resource could affect or
fully participate in the system.
• Visibility: location information of the connected resource. For EV charging,
this could entail information on the charging status of electric vehicle supply
equipment (EVSE) and load profiles.
• Control: the ability to influence the operation of the connected resource. For
EV charging, this could include the ability to send signals to start and stop
charging or to modulate the power of a connected EV.
• Guidance: the ability of the network operator to provide locational guidance
on where the connection should preferably take place, taking into account the
minimisation of upgrade costs or the improvement of system performance.
Based on the needs and capabilities of the distribution company, and based on
the charging use cases, one or a combination of any of these features could be
utilised through a set of policies.
3.1 Aim to accommodate all charging
solutions but encourage managed
charging
Inflexible high-power charging, such as en route fast charging or opportunity
charging at bus stops, can strain the local distribution grid due to the high-power
requirements and can result in power quality issues
. Due to its limited flexibility, it
can also increase emissions depending on the generation mix.
Fast charging can also accelerate the degradation of lithium-ion batteries, leading
to larger concerns for battery recycling and supply chain planning in a country.
However, accommodating all charging solutions is important for facilitating the
shift to electric mobility. Encouraging en route fast charging can help
reduce range
anxiety and improve the uptake of EVs. Likewise, providing high-power
opportunity charging at bus stops can help reduce battery size requirements and
consequently the total cost of ownership,
especially for medium-distance buses.
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While public fast charging currently constitutes a minor share of total charging
sessions, it will continue to grow, with 4.7 million charging points expected around
the world by 2030 in the Stated Policies Scenario and 5.4 million in the Announced
Pledges Scenario.
In the short term, policy makers can deploy measures to mitigate the grid impacts
of high-power charging. In the medium-to-long term, policy makers should
consider proactively planning
to provide capacity in anticipation of the connection
requests.
In all of these planning horizons, policy makers should aim to maximise managed
charging to reduce reliance on top-up charging and leverage the flexibility potential
for the power system.
Managed charging strategies can unlock benefits
For charging use cases where vehicles are connected for longer periods of time,
the charging process can be managed through different strategies. Several
charging strategies, collectively termed “smart”, “managed” or “optimised”
charging, could contain one or all of these named characteristics to leverage EV
charging flexibility, as opposed to “unmanaged” charging.
The following measures are applicable for situations where the grid connection
time is typically much longer than the pure battery charging time:
• Passive measures. There is no active control of users’ decisions to charge,
but signals are given to shift load. For example, time-of-use tariffs can be
used as a signal to prompt behavioural responses from EV users to charge
during off-peak periods. Other passive measures include regulating the
start/stop and power modulation capabilities of chargers. These capabilities
allow for simple strategies to help avoid peak load, such as randomised
delay, charging as late as possible and spreading out the charging load until
the departure time.
• Active control with unidirectional charging (V1G). Direct control is
exercised by the utility with the express consent and participation of the EV
user. Charging can be stopped and started remotely and/or charging power
can be modulated. Hence, more refined load shifting can be done for valley-
filling, peak-shaving and variable renewable energy (VRE) integration. In
addition, power can also be modulated to improve local power quality. The
ability to co-ordinate with other vehicles can help avoid demand charges and
avoid or delay network upgrades by maximising utilisation.
• Active control with bidirectional charging to a building or house
(V2B/H). A vehicle can discharge energy to other consumers within its
vicinity through a connection point, typically to a house or building. Similar to
V1G, V2B/H can maximise the utilisation of the grid to which the house or
building is connected and increase the uptake of VRE, especially if there is
locally installed rooftop PV. When combined with a home/building energy
management system, EVs can reduce the peak load from electrified heating
and air conditioning, thereby avoiding steep increases in consumption and
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reducing the user’s demand charges. Finally, this measure can provide
backup electricity in case of blackouts.
• Active control with bidirectional charging to the grid (V2G). The vehicle
can discharge energy to the distribution grid through a charging point. This
can occur either through an AC- or DC-connected charger. The direct
interaction with the grid means that the vehicle can participate in the
electricity market through arbitrage, reserves, frequency response and
distribution-level services. V2G has attracted attention, with several
demonstration studies globally
.
For battery-swapping use cases, similar charging directions and control are also
applicable:
• Active control with battery stations (S2G or B2G). Battery-swapping
stations can use spare batteries to provide 24/7 bidirectional flexibility.
Swapping decisions are then balanced in terms of the additional costs of
maintaining spares and the revenue from power system participation.
Benefits and limitations of charging strategies
Strategy System benefits Examples Limitations
Passive
measures
• Simple and easy
to implement
• Can avoid
inflating the peak
load
• 15-20% of EV users shifted
out from any given hour
and 20-30% shifted into a
given hour depending on
the mix of incentives and
price signals (California)
At higher rates of EV
penetration, a lack of co-
ordination among the
connected EVs could result
in a rebound peak, as
observed in San Diego,
California*
Active control
with
unidirectional
charging
(V1G)
• More reactive
compared to
passive
measures,
without
accelerating
battery
degradation
• Load can be
shifted to times
when renewable
energy is
available
• Can also provide
upward
frequency
regulation
• Simulations show up to
USD 210-660 million in
costs could be saved due
to avoided peak capacity
and increased consumption
of renewables (California)
• Capacity of 6-13 GW could
be freed up due to smart
charging compared to
uncontrolled charging in an
average weekday scenario
in 2035 where peak
demand could reach
65 GW (France)
As the power flow is
unidirectional, the utilisation
of renewable energy is
limited to load shifting.
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Strategy System benefits Examples Limitations
Active control
with
bidirectional
charging to a
building or
house
(V2B/H)
• Increases self-
consumption of
local VRE
• Avoids steeper
changes in
consumption
• Contributes to
resilience
• Backup power of
19-600 hours could be
achieved for a V2H with
rooftop PV (United States)
• V2H models have been
offered as early as 2012 in
Japan
Bidirectional charging is
limited to the local system
of the house or building.
Hence, further participation
of EVs in the grid is limited.
Active control
with
bidirectional
charging to
the grid
(V2G)
• Contributes to
frequency
regulation and
arbitrage
• Helps expand
VRE
consumption
A range of net savings from
EUR 2 304 per EV per year
to a net cost of EUR -955
per EV per year based on
frequency regulation
remuneration and the
additional costs of a
bidirectional charger
(Denmark)
Accelerated battery
degradation occurs due to
increased charging cycles.
This needs to be accounted
for in charging algorithms.
Active control
with battery
stations
(S2G/B2G)
• Easier
aggregation
• Longer timespan
for flexibility in
the same
location
Pilot cities with battery-
swapping stations charging
during valley hours, avoiding
peak hours or lowering
charging power (100 kW per
station on average) and
discharging to the grid for a
few minutes for frequency
regulation (China)
The capacity to provide
flexibility is limited by the
trade-off between having
standby battery capacity
and reducing the
warehousing costs of
batteries.
* Rebound peaks occur when multiple deferrable loads simultaneously draw power at the first instance of an off-peak
period, causing a secondary peak period. Given the significant increase in deferrable loads, such as EVs, avoiding rebound
peaks through better tariff design is being studied. New tariff designs are also proposed
to limit the effects of the rebound
associated with the lower tariff zones of simple time-of-use tariff designs.
Each charging strategy entails a set of technological, operational and regulatory
requirements to fully activate the flexibility potential associated with it.
A framework
is proposed at the end of this chapter to contextualise these charging strategies
within the power system conditions and EV availability where they may be best
suited.
Unlocking V2G through battery degradation models and vehicle durability
regulations
A previously identified barrier to the commercial roll-out of V2G was the absence
of a consensus on how to account for accelerated battery degradation as a result
of increased cycles from bidirectional charging as well as the revocation of
warranties by most OEMs if the battery was used for reverse power flow. Recent
developments have been made since.
V2G will soon be compatible with OEM warranties. The United Nations Global
Technical Regulation No. 22 has incorporated the use of virtual mileage to
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account for the additional cycles due to V2G operations. This virtual mileage can
be considered as part of the mileage warranties by OEMs, hence avoiding issues
on warranty revocation. The regulation will come into effect after adoption by the
national legislative bodies.
Insights into battery degradation are also growing. Reviews of degradation models
suggest some common trends:
Battery degradation depends on the battery chemistry. V2G activities show an
accelerated capacity fade for lithium nickel-cobalt-aluminium (NCA) batteries
but a decelerated one for lithium-iron-phosphate (LFP) batteries compared to
regular charging and use patterns in a year.
The ambient temperature, especially high temperatures, can accelerate
degradation.
Degradation dynamics are sensitive to the type of service. In bulk energy
services, degradation accelerates due to the large energy throughputs.
Meanwhile, in fast reserve service where energy throughput is smaller, the
resulting depth-of-discharge is the main factor that accelerates degradation.
Degradation speed is a function of the state of charge. High average state-of-
charge levels accelerate degradation.
The high frequency of the V2G service is a significant contributor to battery
degradation but to a lesser extent compared to calendar ageing at high state-
of-charge levels.
Due to the sensitivities surrounding battery degradation, indicators such as state
of health or optimal state of charge can be measured and incorporated into
algorithms to reduce degradation. For example, pilot studies in the
United Kingdom used algorithms to improve battery life by 8-12% through V2G
operations compared to uncontrolled charging. Further research developments
will help address the concerns of EV users by providing fair compensation for V2G
participation.
Several measures exist to mitigate and influence
connection
Provide locational signals for available grid capacity
One way of mitigating the impacts of charging, especially for charging use cases
with high power and energy demand, is to locate stations where grid capacity is
abundant. This can be done by distribution companies by creating hosting
capacity maps or varying connection costs by location.
Publishing hosting capacity maps helps guide CPOs in determining the
optimal locations for the connection of charging stations, especially those with
a high-power demand. Hosting capacity analyses consider the impact of a
potential connection in relation to existing load profiles, network capacity, and
performance requirements for the distribution company. Hosting capacity maps
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can be enabled by geographic information systems. Overlaying existing and
planned transmission and distribution networks on interactive maps showing
urban data, such as on buildings, parking areas and transport corridors, can help
CPOs to decide on which areas to prioritise when deploying new charging stations.
Public hosting capacity maps are already used by utilities in New Jersey,
New
York and California to show locations where grid capacities are available and can
be approved. Proactively conducting the analyses and making them public allow
CPOs to prioritise the development of charging points in areas where connections
would be guaranteed, thus supporting EV uptake. Hosting capacity maps also help
streamline the interconnection pr
ocess and facilitates co-ordinated planning.
EV hosting capacity map of New Jersey, United States
IEA. CC BY 4.0.
Source: PSE&G. EV Hosting Capacity Map (
accessed 3 August 2022).
Varying local connection fees based on the available grid capacity can also
serve as a locational signal. By passing a portion of the costs on to the CPO,
they can then make a feasibility assessment of the charging station plans given
possible higher charging rates. Making the connection fees more reflective of the
needs of the grid can help avoid crowding in congested locations.
Consider non-firm connections
Non-firm connections can speed up the connection of a higher charging capacity
by allowing power modulation or even disconnection during critical periods. This
can avoid additional investment from the grid’s perspective and reduce the costs
passed on to the CPO. For example, in the north of the United Kingdom, non-firm
or “flexible” connections are offered as an option in the distribution access policy
.
The disadvantages are that this can entail lower reliability of the charging
infrastructure in general and may evoke range anxiety among EV users.
0
0.2
0.4
0.6
0.8
1
1.2
0 5
> 1 000 kW
500-1 000 kW
< 500 kW
Analysis pending
EV hosting capacity
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Consider using buffer storage requirements or storage fees to smooth
peak demand
Stationary storage can be used in charging stations to limit the impact of high
power requirements on the grid, especially during critical periods. The buffer
storage supplements the grid capacity that the charging stations need and may be
more cost-effective and faster than grid upgrades.
Depending on the charging station’s business case, CPOs can use buffer storage
as a tool to avoid high peak demand charges and as a way to participate in other
power system operations to obtain additional revenue from the investment.
The buffer storage may be located in a more optimal location for the grid, and the
connection fees for charging stations and other users may simply incorporate the
costs of the common storage component to reduce the cost burden on each user.
The use of second-life batteries
can also be explored as they can reduce the
levelised cost of electricity by 12-41%.
Provide signals to shift towards managed charging
Network charges can also be varied based on controllability and the maximum
power of EV charging. CPOs without sufficient communication with the grid could
be initially charged as if they would contribute the maximum rated power during
peak periods. Likewise, the fee could be lowered if flexibility could be
demonstrated by the CPO. These conditions would allow the charging point
installer to make an economic assessment of the cost of investing in intelligent
communication capabilities and incentivise power control.
It is important to note, though, that these measures impose costs on the CPO that
will eventually be passed down to the EV user. The additional costs could act as
a barrier to charging infrastructure deployment and EV uptake. Balancing the cost
allocation between the CPO (eventually paid by EV users only) and the grid
(eventually paid by all electricity consumers) is therefore important and must be
assessed carefully by policy makers and regulators. Connections that encourage
flexible smart charging can improve the utilisation of the grid. This is a net benefit
for electricity users, and hence a larger portion of the costs could be covered by
the grid.
Consider alternative methods to mitigate high power and energy demand
Beyond the options discussed above, there are also other proposals that can help
mitigate power and energy demand when network capacity is unavailable and
connection is urgent.
• Collective charging. Collective charging aims to gather fleet operators or
fast-charging CPOs to request connection to a higher voltage level that might
be prohibitive to individual connections due to its higher cost. Adjusting the
scheduling of charging, especially for bus fleet operators, can help lower the
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connection capacity required. The higher connection cost for inflexible en route
charging could entail higher charging costs for users.
• Charging hubs. Similar to collective charging, charging hubs can be created
to provide charging services to meet the demands of vehicles whose current
allocated grid capacity might not be sufficient. The strategy is more applicable
to fleet operations where charging can be organised and scheduled around
the available capacity of the hub. Companies can also co-operate to invest in
stationary storage to expand collective capacity without having to request a
higher voltage connection.
• Temporary local generation. Local generation can also be used to help
supply the charging needs of charging stations while waiting for the expansion
of the network capacity. Local renewable generation paired with storage can
also help reduce the carbon content of the electricity but may incur additional
costs.
Hosting capacity of a distribution grid
The hosting capacity is the amount of new energy-generating or energy-
consuming technologies that can be connected to the grid without compromising
reliability or power quality for the other connected users. Hosting capacity studies
have been commonly used by grid operators to assess and communicate the
impacts of distributed PV on performance indices and acceptable limits.
Typical metrics used are the kW of load or generation connected in relation to
performance metrics of the voltage level, safety and reliability, line loading and/or
transformer loading. The input values are often represented based on the
technology adoption rate (e.g. EV penetration or rooftop PV per household).
Several methodologies exist with varying levels of complexity that grid operators
can consider to conduct hosting capacity analyses for EVs and to convey the
capacity of the grid and the implications on performance for the rest of the users.
3.2 Facilitate aggregation through standards
and interoperability
The larger the number of EVs available for aggregation, the larger the flexibility
potential from which the power system can draw. Supporting transport
electrification and ensuring that EVs, EVSEs, and the power system use common
communication protocols are, therefore, in the interest of the power system
stakeholders.
Standardisation and interoperability are commonly thought to improve electric
mobility uptake by allowing EV users who purchase different models to maintain
access to various charging points. However, this could also be extended to
improving consumer choice
by providing access to managed charging and bill
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reduction regardless of the vehicle model choice. Likewise, for the power system,
this helps ensure a larger degree of aggregation for providing services to the grid.
Facilitating interoperability would require the use of common communication
protocols. Protocols help standardise data flow and commands. The following are
some of the main protocols needed for vehicle-grid integration:
• ISO/IEC 15118
facilitates communication between the EV and the EVSE. It
sends charging parameters based on user needs and the charging profiles
from the CPO. The latest update includes protocols for
bidirectional charging.
• CHAdeMO is a protocol originally developed in Japan that accompanies its
specific CHAdeMO plug that physically allows bidirectional DC charging.
• IEC 61850 is a group of standards defining communication protocols for
intelligent electronic devices at substations. It is a foundational standard for
smart grids.
• Open Charge Point Protocol (OCPP) communicates smart charging features,
such as grid capacity, energy prices, local supply of sustainable energy, and
user preferences. It is currently being incorporated into
IEC 63110 to establish
a regular international technical standard.
• Open Charge Point Interface (OCPI) supports connections between electric
mobility service providers and CPOs to allow EV users to access different
charging points and streamline payments across jurisdictional borders, helping
support EV uptake through roaming. Among different roaming protocols
7
OCPI supports the most functionalities
including smart charging. It is
commonly used in the European Union.
• Open Automated Demand Response (OpenADR) communicates price and
event messages between the utility and connected distributed energy
resources for the purpose of demand-side management. It is more focused on
exchanging information, whereas OCPP has
more emphasis on control. It has
a wide adoption across the globe.
• IEEE 2030.5 enables utility management of the distributed energy resources
such as electric vehicles through demand response, load control and time-of-
day pricing. It is commonly used in
California.
• Open Smart Charging Protocol (OSCP) communicates predictions of locally
available capacity to charging station operators. The current version contains
use cases with more generic terms to allow integration of solar PVs, batteries
and other devices. Currently, the use of OSCP is still limited.
7
Other common roaming protocols are Open Intercharge Protocol (OICP), Open Clearing House Protocol (OCHP) and
eMobility Interoperation Protocol (eMIP).
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Vehicle-grid integration ecosystem and communication protocols
IEA. CC BY 4.0.
Notes: CPO = charge point operator, EMSP = electric mobility service provider, eMIP = eMobility Interoperation Protocol,
EVSE = electric vehicle supply equipment (charging infrastructure), OpenADR = Open Automated Demand Response,
OCHP = Open Clearing House Protocol, OCPI = Open Charge Point Interface, OCPP = Open Charge Point Protocol, OEM
= original equipment (EV) manufacturer, OICP = Open Intercharge Protocol, OSCP = Open Smart Charging Protocol.
Sources: IEA analysis from Neaimeh and Andersen (2020),
Mind the Gap - Open Communication Protocols for Vehicle
Grid Integration; Element Energy (2019), Implementing Open Smart Charging; Klapwijk, P. (2018), EV Related Protocols;
NAL (2021), Tendering Guidelines for Open Market and Open Protocols.
It is important to have a common communication protocol between the EVSE and
the power system that is facilitated by managed charging actors. Currently, efforts
are being made towards the global harmonisation of communication protocols
,
including those between EVs and EVSE, to aid in interoperability when crossing
international borders.
Standardised communication protocols bring about systemwide benefits but can
also carry risks. Using insecure protocols that lack authentication and encryption
can create entry points for cyberattacks. While it is not in the scope of this manual,
policy makers should conduct a cybersecurity assessment and plan
for mitigation
measures for charging operations.
Use incentives and regulations to set standards and interoperability
Policy makers can use a mix of incentives and regulations to disseminate key
smart features. For example, in Belgium, tax deductions
apply to publicly
accessible charging points, and there is a EUR 1 500 incentive for residential
charging points if they can be digitally connected and managed through standard
protocols. Meanwhile, in Luxembourg, a EUR 1 200 incentive is given to OCPP-
compliant smart charging stations. In the Netherlands, OCPP and OCPI are used
as de facto standards for publicly accessible charging points based on tendering
guidelines.
EVEVSE
CPO
Distribution
Transmission
EMSP
OEM
OCPI
OCPP
ISO 15118
Proprietary
OSCP
OpenADR
IEC 61850
CHAdeMO
Proprietary
Energy
supplier
Power system
OpenADR
IEEE 2030.5
IEEE 2030.5
Roaming
Platform
OICP
eMIP
OCHP
OpenADR
IEEE 2030.5
OpenADR
IEEE 2030.5
OpenADR
IEEE 2030.5
OpenADR
IEEE 2030.5
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On the other hand, the United Kingdom’s EV (Smart Charge Points) Regulations
2021 mandated that all home and workplace charging points from Q2 2022 would
be required to have smart functionalities.
8
The regulations included a key rationale
explaining that the market would not be expected to arrive at establishing smart
interoperable standards on its own and that customers must be protected and
given access to smart charging regardless of their choice of EMSP or EVSE.
Likewise, in India’s draft battery-swapping policy
, stations are required to adopt
open standard communication protocols, such as OCPP.
Legal authority on standardisation and interoperability varies by country. They can
be enforced by the transport policy makers or by the economic and trade
authorities.
It is important to note that the minimum standards for charging points and vehicles
must make them ready to conduct smart charging but not necessarily oblige smart
charging. EV users must still have the final choice to participate in managed
charging schemes based on their specific needs.
Develop open vehicle-grid integration platforms as a supplementary
measure
Open vehicle-grid integration platforms allow electric utilities to gain visibility and
communicate demand response events to EVSEs through communication
protocols and to EVs directly through vehicle telematics systems installed by
OEMs.
Where homes remain the preferred location for charging, a significant portion of
charging profiles may not be visible to the local utility especially if the EVSE that
an EV driver uses does not have communication capabilities. In these cases,
facilitating communication and control through vehicle telematics can help
aggregate more vehicles to participate in the power system.
Open vehicle-grid integration platforms also allow OEMs to provide managed
charging programmes as the communications go through their systems. For
example, utilities in the United States, such as DTE Energy and Xcel Energy
have
adopted open vehicle-grid integration platforms and partnered with OEMs to use
OpenADR as the common communication protocol.
3.3 Value the flexibility of electric vehicles
In order to enable the technology investments and business models that facilitate
flexibility from EVs, the cost savings enabled by flexibility must be passed on to its
providers. From operational requirements, such as frequency regulation, to capital
expenditure savings, such as network capacity deferral, several mechanisms can
be used to allow the power system to turn the cost savings into remuneration for
8
Smart functionalities are defined in the regulations as the ability to send and receive information and respond to signals by
increasing or decreasing the rate of electricity flow through the charging point, shift the time at which electricity flows, and
provide demand-side response services.
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the flexibility providers. This will, in turn, allow the EV users and managed charging
actors to make the necessary investments to activate grid-interactive charging.
There are several mechanisms in the market that can be used to transmit the
remuneration to the EV user providing flexibility. The policy maker does not need
to activate all these options, but the more they are made available, the more they
can help the EV user to stack revenue from providing these services.
Market mechanisms to remunerate EV charging flexibility
Domain Service requirement Market mechanism
Distribution
Phase imbalance
N/A – enforced by grid code
compliance
Voltage regulation
No mature market mechanisms so
far
Congestion management
Tariffs
Flexible contracts
Flexibility tenders
Local flexibility markets
Fault restoration
Bilateral contracts
Flexibility tenders
Transmission
Balancing and reserves
Ancillary services markets
Energy arbitrage
Wholesale energy markets
Source: IEA analysis from Venegas (2021), Active Integration of Electric Vehicles into Distribution Grids: Barriers and
Frameworks for Flexibility Services.
Tariff design
Designing tariffs in a way that reflects the cost on the grid or system based on
specific time periods and locations can align the charging decisions to adapt and
participate in lowering the cost for the system. These tariff designs are generally
referred to as “dynamic tariffs” as opposed to flat, single-value “static tariffs”. Some
of the main designs are:
• Time-of-use (ToU) or time-of-day (ToD) tariffs. Tariff rates can be set at a
higher price to discourage load during peak periods. Rates may vary multiple
times within a day, and the metering simply needs to be at the same time
interval as the tariff settings (e.g., hourly). In Thailand, for example, off-peak
rates can be as low as 45%
of those during peak hours for connected
consumers below 12 kV. In Korea, specific static ToU tariffs exist for EVs
differentiated
by season and the voltage level of the connection. Changes can
be made more periodically – for example, using day-ahead market prices –
but this implies a substantial
loss of information and efficiency for the system.
Enhancements to the tariff design can also be made to avoid rebound peaks
while maintaining simplicity in setting up the tariff.
• Real-time pricing. Tariffs can be changed according to real-time conditions,
especially in power grids with higher shares of utility-scale and distributed-
scale variable generation where the supply-demand balance changes
throughout the day and can reflect locational signals from the grid. Setting
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tariffs based on the real-time conditions of the grid requires advanced metering
and communication infrastructure and automation systems in order to reflect
the system needs and allow the EV users to respond to the time-varying prices.
While establishing real-time pricing may incur upfront expenses, it can
increase the value for the system. For example, a study from the
European Union shows that using real-time pricing can save
up to 27% of
power generation costs and reduce VRE curtailment by 14% compared to a
baseline scenario.
• Critical-peak pricing. Tariff rates are fixed, but exceptionally high prices can
be set and communicated if a load reduction is needed at specific times of the
day or the year. This tariff structure is quite common and offered, in particular,
for EV charging in Colorado and Southern California
. Critical peak pricing in
the United States is estimated to save EV users USD 1 125-1 220 per month.
Graphical representation of the basic types of tariff structure
IEA. CC BY 4.0.
Provide dedicated connections for EVs if needed
The benefit of dynamic tariff designs is that they are technology-neutral and can
incentivise load flexibility not just for EV charging but also for different loads.
However, in certain cases, changing the tariff design can be burdensome and may
require lengthy legislative changes, especially for residential loads. In this case,
separating metering and creating specific dynamic tariffs for EVs as a new load
category can help in facilitating EV load flexibility despite maintaining static tariffs
elsewhere. In India, several states have separate EV tariffs
, with states such as
Maharashtra implementing ToD tariffs. Battery-swapping stations are required to
participate in ToD tariff regimes with dedicated connections in India’s draft battery-
swapping policy. Having EVs as a specific load category can also be useful in
times of shortage, helping to discriminate between the basic needs of households
and more flexible electricity demand.
Allow innovative business models for engaging users
It is important that EV users and EV fleet operators are given the opportunity to
contribute to power system objectives based on a set of incentives. Setting up a
fair dynamic pricing model can be costly, but dynamic load shifting can also be
achieved by allowing dynamic control by the utility during a certain period of the
Static Dynamic
Critical Peak
Price per kWh
Hour of day
Price per kWh
Hour of day
Price per kWh
Hour of year
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day and giving the fleet or EV user a rebate for enrolment or participation. Allowing
a diverse range of possible tariff structures and reward systems can help
incentivise participation from EV users.
Flexibility contracts and markets
Aside from the typical ways of accessing flexibility through network tariffs and
connection agreements, market-based procurement can also be explored.
Local flexibility markets can entail bidding based on capacity and energy and
enable the lowest cost of flexibility to be used first. An example is
the
United Kingdom, where more than 10 GW of location-specific flexible capacity
was bid through a common platform where distribution network operators could
publish their flexibility needs. Another example is the
Crowd Balancing Platform in
commercial operation in Germany, Italy, the Netherlands and Switzerland.
Bidding in wholesale markets
In countries with unbundled power markets, opening up the wholesale energy
market and balancing markets to the demand side allows for the wider
participation of flexible loads, such as EVs. Explicit demand-side responses allow
remuneration based on the actual costs of the system, compared to tariffs, which
are often fixed. However, this option may not be available, especially if the power
market is only accessible to large suppliers and retailers. Hence, opening up the
market to demand response and allowing the participation of entities such as EVs,
charging stations and stationary batteries is a necessary first step. In instances
where demand response is already allowed, the key features needed are allowing
aggregation and modifying product specifications where possible to match the
scale of EVs.
Allow third-party resource aggregation
Allowing third-party resource aggregation is a useful way for distributed resources
to meaningfully provide services in wholesale energy markets. Aggregators can
access the electricity market as participants and enter into various contracts with
smaller entities providing distributed generation or load flexibility. In the
United Kingdom, participation in balancing markets has been opened up to
aggregators – known as Virtual Lead Parties
– which allows distribution-connected
assets to provide aggregate services when needed.
Adjust product specifications when possible
Market product specifications, such as minimum sizes to participate and symmetry
of ancillary services products, can implicitly form barriers by dictating the minimum
amount of EV aggregation needed. While the size of a product needs to be large
enough to significantly influence the bulk energy system, reducing it where
feasible for the system should be encouraged. For example, in several European
countries, the minimum size to participate in primary regulation
is 1 MW. In
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Sweden, on the other hand, a minimum size of only 0.1 MW
9
is needed, meaning
only 27 EVs on 3.7 kW of charging are needed to provide the required service. In
the United States, 0.1 MW of
resource aggregation is also accepted.
3.4 Co-ordinate EV charging with renewables
Initial demand from EV charging may increase power
sector emissions
The addition of EV charging load into the power system entails a marginal
generation requirement that may be fulfilled by technologies that produce more
emissions. While EVs are generally considered cleaner than their internal
combustion engine counterparts thanks to the higher efficiency of the conversion
technology, their operating emissions are still dependent on the emissions
intensity of the electricity used to charge them.
IEA analysis
shows that life cycle emissions are lower for EVs compared to
conventional internal combustion engine (ICE) cars only if the average emissions
intensity of the electricity used to charge the EVs is less than 800 g CO₂-eq/kWh
(if larger ICE cars are displaced by EVs of equivalent sizes) or less than
450 g CO₂-eq/kWh (if smaller ICE cars are displaced).
10
Transport and electricity emissions intensity in selected countries, 2019
IEA. CC BY 4.0.
Source: IEA, World Energy Statistics and Balances
(accessed 25 October 2022).
9
For normal primary regulation (power and energy), the activation time is 63% within 60 seconds and 100% within 3 minutes,
whereas for disturbance (power only), the activation time is 50% within 5 seconds and 100% within 30 seconds.
10
Small cars include battery electric vehicles with a capacity of 36 kWh (200 km range) or 75 kWh (400 km range) and
internal combustion engines with a Worldwide Harmonised Light Vehicle Test Procedure (WLTP) fuel economy of
5.5 Lge/100 km. Large cars include battery electric vehicles with a capacity of 39 kWh (200 km range) or 80 kWh (400 km
range) and internal combustion engines with an on-road fuel economy of 8.9 Lge/100 km. For more information, see the
Global EV Outlook 2019
.
200
400
600
800
1 000
1 200
0.00
0.50
1.00
1.50
2.00
2.50
3.00
United States
China
France
Germany
Ukraine
Kazakhstan
India
Indonesia
Brazil
Chile
Egypt
South Africa
g CO₂-eq/kWh
t CO₂-eq/toe
Road transport
emissions
intensity (left axis)
Electricity
emissions
intensity (right
axis)
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Many countries have electricity mixes with average emissions intensities
11
of less
than 800 g CO₂-eq/kWh but greater than 450 g CO₂-eq/kWh, as of 2019. Hence,
despite the efficiency gains from EVs, further decarbonisation of the electricity mix
is needed to ensure that the transport sector also decarbonises. Fortunately, there
are strong potential synergies to be gained from increasing both renewables and
EVs. New electricity demand arising from electrification can be met with additional
variable renewable sources.
EV charging has strong potential synergies with
renewables
At the bulk energy level, load shifting of EV charging to more favourable times of
the day can increase consumption and reduce the curtailment of transmission-
connected renewables, leading to a better business case.
In Korea, for example, flexible EV charging of 30% of the expected EV fleet in
2035 could reduce operating costs
by USD 21/MWh and peak costs by
USD 18/MWh, corresponding to 21% and 30% of the costs, respectively. It could
also lead to a 63% emissions reduction compared to a full internal combustion
engine fleet. Matching the EV load to the availability of renewables could also
provide a better business case for renewable energy developers by reducing
curtailment.
Variable renewable energy patterns and the load-shifting potential of EVs in Korea,
2050
IEA. CC BY 4.0.
Source: IEA (2021), Reforming Korea’s Electricity Market for Net Zero
.
11
The annual average emissions intensity of the grid is referenced here as a high-level indicator. For more rigorous
accounting, the marginal emissions intensity must be considered since the exact time and location of EV charging can entail
higher emissions compared to the annual average. One example is when charging occurs during peak periods where the
marginal generation technology is diesel, and the network losses are high due to congestion.
0
10
20
30
40
50
60
70
80
90
0
2
4
6
8
10
12
14
16
0 8 16 24 32 40
Solar and wind availability (GW)
EV demand (GW)
Hour of 48-hour period
Wind
generation
(right axis)
Solar
generation
(right axis)
Unmanaged
charging
(left axis)
Smart
charging
(left axis)
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There are also potential synergies at the distribution level. Currently, areas with
significant penetration of rooftop solar PV can experience problems with high local
voltage (overvoltage) due to the injected energy not being matched with
consumption. These conditions often arise during sunny weekends
when
consumption is low and PV generation is high. On the other hand, simultaneous
EV charging in the evening when consumption is high can cause the opposite
effect of low voltage levels (undervoltage). Co-ordinating the operation of EV
charging and solar PV could increase the mutual hosting capacity within a
distribution grid by keeping delivery within the contractual voltage limits. For
example, a
modelling study in Sweden shows that the distribution grid could host
a higher penetration
12
of EVs and distributed PVs when co-ordinated with a
management system compared to when they are uncoordinated.
Given these potential benefits, policy makers should pursue the co-ordinated
integration of EV charging to ramp up both electric mobility and the deployment of
renewables. The co-ordinated plan helps ensure that the switch from ICEVs to
EVs effectively decarbonises transport activity by ensuring that the marginal load
imposed by the introduction of EVs can be supplied by clean electricity.
Encourage daytime charging
Daytime charging, even when unmanaged, can help increase the consumption of
renewables when solar-based generation is available and reduce storage
requirements and ramping costs. Vehicle segments such as personal-use vehicles
and school buses tend to be parked for long periods during the daytime at
workplaces or schools. Providing charging solutions in these locations helps
ensure that connected EVs are available during the daytime period.
Policy makers can provide specific training for building managers to install and
manage workplace chargers, as has been done in the United States
, or they can
also provide purchase and installation incentives, such as those available in the
United Kingdom.
Provide options to contract or support a clean electricity supply
In liberalised power systems, market options for obtaining power supply from
renewable sources can be developed to help increase the build-up of renewable
energy capacity. Options such as consumer power purchase agreements (PPAs),
green tariffs and energy attribute certificates are common options provided by
countries. Green tariffs can be a suitable option for individual EV users and CPOs,
whereas PPAs can be utilised by fleet managers. These options are common in
Europe and the United States.
Where the mechanism already exists, high minimum size requirements can act as
barriers to the types and numbers of EVs that can participate, such as bus depots
or large EV fleets. Lowering the size requirements to participate, as is
12
For the mentioned study, the penetration rates are based on the presence of the typical load of EV charging (3.7 kW) per
household and the typical daily rooftop PV output (11.4 kWh) per household.
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recommended for bidding in wholesale markets, can help. For example, India
recently lowered the minimum requirements for its Green Open Access
mechanism to purchase renewables from 1 MW to 0.1 MW and is awaiting
implementation of the regulation in individual states.
As the decarbonisation of the power system progresses, importance will be placed
on increasing the precision of temporal and locational matching, such as
24/7
matching. This will require a higher frequency of exchange of information on
emissions, forecasts and connected EVs. Investments in establishing a smart
electric mobility ecosystem can help support this higher demand.
Develop a framework to monitor indirect emissions from EV charging
As EV charging produces indirect emissions through the electricity sector, creating
a framework to monitor electricity emissions from EV charging can help align smart
charging algorithms and support decarbonisation options
where possible.
Obtaining charging time periods coupled with the real-time and forecasted
electricity mix can help align charging towards periods of lower emissions,
especially in cases where carbon prices do not exist or are not significant enough
to change dispatch and load-shifting decisions. Initial considerations on
developing frameworks to determine the amount and share of GHG emissions
from electric mobility have been conducted at United Nations Economic
Commission for Europe workshops.
Leverage incentives around EV charging
Incentives for charging infrastructure deployment can be tied to renewable energy
matching conditions. For example, in Belgium, to qualify for tax incentives for
residential charging, the user must show that the charging point is
supplied by
renewable electricity through either a retail contract, an on-site renewable energy
source or a mixture of both. In Hanover, Germany, between 2018 and 2021, grants
of EUR 500 were given to those planning to build charging points supplied by
renewable sources.
Incentives for the co-location of PV with EV charging stations can also be an
option, especially for cases where distributed PV would be more cost-effective
than utility-scale PV (i.e. reduced grid interconnection costs and reduced land use
costs). More importantly, co-location can reduce grid losses and can offset high
local EV charging demand.
System operators can identify and publish locations where co-located PV-EV
charging would provide grid benefits. They can also use incentives such as
rebates, special tariff structures and streamlined interconnection schedules tied to
the co-location of PV and EV charging. The use of these incentives often requires
authorisation from regulators and/or policy makers, depending on the regulatory
regime.
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3.5 Incentivise smart-readiness
Policy makers must often balance the trade-offs between instituting standards to
enjoy the benefits of scale and aggregation and allowing the market to continue to
innovate without additional restrictions.
Given the potential for flexibility of EVs, uncontrolled charging loads in situations
where they would be parked for a long period of time represent a lost opportunity.
Setting a minimum standard of communication and controllability while the EV
market is still nascent will help ensure a future-proof infrastructure.
Policy makers can set the minimum requirements based on the conditions of their
markets, both with respect to EV uptake and the state of the power system.
Institute randomised charging delays
Instituting charging delays based on known peak and off-peak periods can be a
cost-effective solution to reduce EV load during peak periods, even in situations
where EVs are connected to regular sockets. The delays should incorporate
randomness and variation to prevent simultaneous power draw at the first instance
of the off-peak hour that could lead to grid instability. In the United Kingdom, for
example, a randomised delay
of up to 10 minutes, with the remote capability of
being adjusted to 30 minutes, is required in all charge points as part of the Smart
Charge Points Regulations 2021.
Minimum communication requirements
Imposing minimum communication requirements on the charging infrastructure or
vehicles can help ensure that more co-ordinated charging strategies can be
implemented at higher levels of EV penetration.
In power systems where the grid already contains or is developing advanced
metering and communications features, requiring EV charging infrastructure to be
ready to communicate with the power system can help take advantage of these
assets. Mandating compliance with the OCPP on EVSEs and battery-swapping
stations, as has been done in the United Kingdom and India, respectively, can
help ensure that the smart charging of batteries can be conducted when the
opportunity arises.
In some cases, EVs may continue to charge using regular sockets or charge in
areas where the distribution grid does not have advanced metering and
communication infrastructure. Requiring communication features in EVs, which is
already common practice for some manufacturers using vehicle telematics
, can
help in implementing managed charging in such contexts.
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A framework for grid integration of electric vehicles
Every electricity system is unique and has specific circumstances. EVs, due to the
various vehicle segments and charging use cases, also pose different types of
impacts. While it is not possible to identify the level of EV charging load at which
various issues will arise, it is possible to categorise the context in which EVs
connect to the grid and associate measures that can be implemented to mitigate
any impacts.
Given the various possible measures to manage the EV charging process, from
simple to complex, determining when to deploy which measures can be useful.
This report provides a framework that can be used as a guide for this. The
framework summarises the key issues of grid integration:
• Volume of flexible-charging EV load. As EVs increase in uptake, the amount
of the connected flexibility resource available when they charge can increase
depending on the vehicle segment and charging use case. It is important to
recognise that since the primary use of EVs is for mobility, the connected
flexibility resource also entails an inevitable load from the system.
• Flexibility demand from the system. The flexibility demand is what
remunerates the investment in the grid integration measures. The demand for
flexibility can come from limitations in building new capacity or limitations in
power generation during the moment of demand. For example, cost-efficiency
measures on new network capacity investments can make a distribution
company consider investing instead in shifting load from EVs through V1G,
especially if the periods of excess demand occur for only a few hours of the
year.
By examining the nature of the flexibility supply from EVs and flexibility demand,
policy makers can consider the following phases to prioritise measures according
to the situations they face.
Phase one
Phase one is where the EV charging load has no noticeable impact on the grid.
Either the EV penetration levels are small, the vehicle segments electrified are
small or the loads are small relative to the capacity of the grid. Even if there is high
flexibility demand from the system, the volume of the connected storage resource
is too small and sparse to be reliably utilised.
In this case, policy makers can focus on increasing the deployment of EVs through
policies such as increasing charging infrastructure support or enforcing standards
and interoperability to help address range anxiety or improve charger confidence.
Deploying charging stations in favourable areas of the grid can be a sufficient
strategy to accommodate new stocks of EVs, especially if they turn out to have
limited charging flexibility.
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This is a period where policy makers can focus on foundational aspects, such as
developing databases for EVs and charging points and conducting data research
on travel and charging patterns. From the power system perspective, an important
component is creating frameworks to incentivise demand response.
Phase two
Phase two is where the EV charging load is significant and noticeable in system
operations, but the flexibility demand is minimal. There is a considerable number
of EVs where unmanaged charging is resulting in occasional problems in the local
load or systemwide peak load. However, the demand for flexibility can remain low,
either because there is sufficient network or peaking capacity in most periods of
the year or there is an upcoming upgrade. Note that EV penetration may not
necessarily be higher compared to phase one, but the other connected loads may
also have profiles that collectively contribute to issues with the peak load or
network capacities.
Applying passive measures to provide simple load-shifting measures can be a
cost-effective solution. If load shifting to a defined off-peak period is specifically
desired, simple signals such as time-of-use tariffs or critical-peak tariffs will be
needed to obtain a response from the EV users. The signals and the response
need to be measured by an hourly meter or through an onboard charging
measurement device.
Personal-use vehicles and fleet operations can comprise a significant amount of
the EV charging load. Hence, rallying the different entities involved in co-ordinating
the charging process, such as the aggregators, CPOs, EMSPs and OEMs, will
require common communication protocols and a common data exchange platform
where signals can be exchanged.
Policies to encourage the self-consumption of renewables
may be valuable to
incentivise homeowners and building managers to schedule their EV charging to
periods when on-site generation is available. In doing so, the EV charging load on
the distribution grid can be reduced.
An example of a system in this phase is Norway. Despite its high share of EVs,
the country can actually be classified under phase two due to its high shares of
clean and flexible hydro generation and high existing distribution grid capacity,
which have led to lower demand for additional flexibility from the power system.
The impact of EV charging is noticeable only in certain instances, such as in win
ter
periods, and other flexibility measures exist given that the country already has
dynamic tariffs (real-time pricing) and smart meters.
Phase three
Phase three is where the flexible EV charging load is significant and there is a
high demand for flexibility.
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The demand for flexibility can come from local network capacity limitations wherein
passive charging measures are not enough to shift the load in a more co-ordinated
manner. The demand can also come from the wholesale market looking to shift a
significant amount of demand to avoid marginal generation or to match
renewables.
Deploying active V1G can be a useful strategy in this situation. The strategy entails
enhanced communication and control, supported by advanced metering and
communications infrastructure. Active V1G allows remote and co-ordinated
control of charging processes based on the needs of the local distribution network
or the wholesale market.
To activate this fully, grid codes should recognise V1G, and measures to value
co-ordinated and aggregated flexibility should be deployed. Measures such as
real-time tariffs, contracts or markets for flexibility, and opening market access to
aggregators are important to allow revenue stacking for the aggregators and the
contracted EVs. Forecasting generation and network capacity can help
aggregators anticipate and offer EV load flexibility.
Active V1G is currently practised in the Netherlands, France and Connecticut
(United States), with direct control on either the charging points or the cars
themselves. EVs in these countries or states can enroll in programmes that
participate in managing grid constraints and wholesale energy and balancing
markets.
Phase four
Phase four is where flexibility demand is high and the availability of connected
flexible EVs is also high. As the primary purpose of EV batteries is for mobility,
offering up energy to the grid comes at a premium. This means that high levels of
flexibility demand exist such that the market can remunerate this appropriately.
Such high flexibility demand can occur in power systems relying on high levels of
variable renewable energy generation, or those with limited sources of flexibility
such that EVs participating through V2G become feasible.
High availability of flexible EV load is also necessary since vehicles discharge to
the grid and need to be recharged according to the user’s targeted state-of-charge
levels. This may imply having larger batteries than the typically required range or
aggregating a large pool of connected EVs such that discharging large values of
energy still maintain a satisfactory state of charge at the individual level.
Island power systems
tend to carry these features, especially those aiming to
integrate high shares of variable renewable energy. A few V2G pilot programmes
have already been conducted in the
Azores (Portugal) and Hawaii (United States),
and future economic viability would depend on the cost of alternative flexibility
sources, such as stationary storage. Certain vehicle segments may also be better
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suited for V2G based on their charging periods and ease of co-ordination. For
example, several V2G pilot programmes are being conducted for school buses
in
the United States.
For this charging strategy, grid codes should recognise V2G. State-of-health
measurements help create algorithms that can properly remunerate the EV user
based on the accelerated degradation (or the absence thereof) of the battery for
conducting V2G services. Bidirectional protocols are also needed to activate two-
way communication, and decentralised peer-to-peer power trading can help
provide an additional avenue for V2G participation with other distributed energy
resources. Finally, reducing or eliminating two-way taxation for storage improves
the business case for V2G providers.
V2B and V2H are not included in the framework as they can be activated by the
EV users or the fleet operators according to their own individual needs for backup
and resilience.
Key framework considerations
• The phases are not a measure of progress, only a description of the conditions
that policy makers may face in their system. Certain countries may have high
levels of transport electrification coupled with sufficient network and generation
capacities or the availability of other more cost-effective flexibility sources,
such that flexibility from V2G (phase four) may not be necessary.
• The measures are cumulative, meaning that the requirements for the lower
phases will generally be needed for the higher phases. For example, the
requirements for phase two, such as the standardisation of communication
protocols, are also needed for phase four.
• The measures are not exclusive to their phases, meaning that policy makers
can deploy measures from higher phases even if they are in a lower phase.
For example, they can deploy advanced metering and communications
infrastructure (a phase three measure) even before they observe a significant
impact of EVs on their operations (still in phase one). This is possible as other
connected resources, such as distributed generation and behind-the-meter
storage, could be taking advantage of such technology deployment.
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3. Deploy measures for grid integration
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manual for policy makers
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Framework for grid integration of electric vehicles
IEA. CC BY 4.0.
Deploy active measures:
unidirectional V1G
Deploy active measures, bidirectional
charging: V2G
Hourly metering or sub-hourly
metering
Reducing or eliminating two-way
taxation for storage
Enable data exchange platforms for grid
operators, EMSPs, OEMs, CPOs and EV
users
Enable platforms for decentralised
power trading
Time-of-use or critical peak tariffs
Real-time advanced metering and
communications infrastructure
PHASE 1: No noticeable impact
No significant impact yet. Encourage
higher EV uptake through incentives
and public EVSE deployment.
Database for EV registrations and
charging points
Frameworks to incentivise demand
response
Separate metering for EVs or onboard
charging measurement devices
Contracts and markets for flexibility
Battery state-of-health considerations
for V2G cycling
EV-EVSE-grid standardisation of
communication protocols
EV-EVSE interface standardisation
and interoperability measures
Bidirectional protocols: ISO-15118-
20:2022, CHAdeMO
Market access for aggregators
Grid code definition for V1G
Self-consumption policies
Passive measures: time-of-use tariffs,
vehicle-based charging time delays
Co-ordinate charging station
deployment in areas beneficial to the
grid
Forecasting of EV availability, electricity
prices, VRE generation and grid
constraints
Data collection of travel and charging
patterns
Battery state-of-health measurements
Grid code definition for V2G
Real-time tariffs
PHASE 2: Flexible EV load
noticeable with low flexibility
demand
Distinct variability observed caused
by EV charging but demand for
flexibility is low enough that simple
flexibility measures would suffice.
PHASE 3: Flexible EV load is
significant with high flexibility
demand
Demand for flexibility is high,
matching the availability of flexible EV
load and paving the way for
aggregated smart charging.
PHASE 4: Flexible EV load is
highly available with high flexibility
demand
High flexibility demand along with
highly available flexible EV load can
provide energy back to the system in
periods of deficit.
Charging strategy
Technology
requirements
System operations
Regulation and market
design
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4. Improve planning practices
4.1 Conduct proactive grid planning
The typical process where grid operators respond to connection requests, in this
case from EVSEs, can delay the rapid uptake of EVs. In some cases, connection
requests can take from 6 months to over a year
. Policy makers can streamline the
interconnection process to help accelerate this process.
As the number of EVs increases, the grid will eventually need to be reinforced and
expanded. Reinforcing the grid to accommodate new load can take years
for
permitting and construction and can thereby slow down the electrification process.
Additional new charging points can utilise the existing network. In many cases,
however, fast-charging stations may require a new grid connection and grid
reinforcement where the existing network capacity is constrained. The connection
process from request to construction approval can be a lengthy procedure. Hence,
proactively planning the grid can help anticipate the connection requests.
Streamline interconnection processes
One way to streamline the process is to mandate time windows to respond to
connection requests. For example, in the Netherlands, network operators are
required to respond to connection requests within 18 weeks
for capacities less than
10 MVA. Standardising interconnection procedures and publishing them can help
inform the project planning and delivery of charging infrastructure.
Another tool can be to mandate the publication of hosting capacity maps.
Hosting capacity analyses help provide grid transparency and align transport
planning. The analyses are not exclusive to EV charging but can also be done for
other distributed energy resources, such as rooftop PV.
Support capacity building for distribution companies
Modelling the uptake of distributed energy resources requires planners to be more
sophisticated as penetration levels increase. Typical top-down planning
approaches, such as econometric models or Bass diffusion models
, may be simple
to execute and useful at larger scales, but they may fail to account for outliers and
exceptions in the distribution system areas. Meanwhile, bottom-up approaches,
such as activity-based or agent-based modelling, can reflect details down to EV
adoption at the household level but are computationally intensive.
California approaches this modelling challenge by mixing top-down models with
higher spatial precision as a compromise, whereas the Netherlands forecasts EV
adoption at the neighbourhood level and updates it every 2 years.
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Common challenges include a lack of capacity of the utility staff or a lack of
resources to focus on planning and modelling. These challenges have been
identified in the United States
but are common around the world.
Increasing the regulated revenue linked to improving the modelling and analytical
capabilities of the distribution companies can help address this situation. The
additional budget can allow the companies to recruit or train staff to develop the
required capabilities. It can also provide them with the resources to collaborate with
mobility planners who may already have modelling expertise.
13
Provide targets and regulatory incentives for achieving electric mobility
Government targets on EV adoption can help form the basis of planning by
distribution and transmission companies and consequently aid regulatory
decisions. In France, for example, the Mobility Orientation Law (
Loi d’orientation
des mobilités) provides distribution companies with the ability to conduct medium-
term planning on EV charging based on the government’s targets for vehicle
electrification.
Moreover, providing incentives or setting performance benchmarks tied to electric
mobility and the overall energy transition can also be an option. Distribution
companies in the United States identified that a lack of performance incentives
for
measuring support for transport electrification is one of the main barriers to
proactive planning. Providing incentives through regulatory design or setting
performance benchmarks based on the speed of connection of distributed energy
resources can help forge proactive planning.
4.2 Reflect the full value of EV charging
Power sector planning is the process by which a selected entity, usually the system
operator, outlines feasible options to meet the future long-term needs for electricity
while working towards stated policy goals for climate and energy.
Long-term plans may fail to account for new technologies and their flexible
capabilities, thereby leading to additional infrastructure costs. For example,
modelling shows that 15% EV penetration in 2030 in a representative utility area
could require transmission and distribution investments of
EUR 5 800 per EV.
These investments could be reduced to EUR 1 700 per EV if smart charging were
considered
. In Germany, the smart charging of 30 million EVs could reduce
cumulative distribution network investments between 2019 and 2050 from
EUR 80 billion to EUR 54 billion
– a 33% reduction. Hence, reflecting the full value
of EV charging can help power systems be more cost-effective.
13
Mobility planners may use several planning models with optimisation goals such as minimising infrastructure costs,
maximising the number of EVs recharged or maximising charger utilisation. More advanced models, like POLARIS in the
United States, combine activity-based modelling, which can cover EV uptake, charging location and transport mode choices.
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Revisit planning criteria for grid expansions
Traditional grid expansion planning involves forecasts of the peak load and the
subsequent build-up of lines, transformers and substations to provide the capacity
to match that peak load. Investing instead in other alternatives, such as energy
efficiency measures and demand-side flexibility programmes, to substitute for
physical capacity can sometimes be more cost-effective. Case studies
in the
United States have shown that an average load reduction of 1-85 MW through a
mixture of energy efficiency, demand response and storage can bring an average
benefit-to-cost ratio of 1.40. In
New York and California, these alternatives are
commonly used and are known as non-wire alternatives (NWAs). Including these
alternatives in grid expansion studies can help unlock the funds needed for
managed charging programmes for activating the flexibility of EVs.
Applying robust cost-benefit analyses to assess these alternatives is important.
Consideration of the wider aspects, such as the environmental costs of traditional
upgrades (e.g., new lines and transformer upgrades), can help increase
robustness. Integrating these considerations into the planning processes can help
improve the business case for NWAs. For example in California, utilities must file
Distribution Deferral Opportunity Reports
as proof that alternatives were
considered to avoid or defer upgrades or expansions.
However, policy makers must carefully balance this planning criterion with
incentivising EV uptake. Focusing heavily on cost-efficient grid investment can
reduce the incentives
for network upgrades and delay the connection of charging
infrastructure and other electrified loads.
Revisit planning criteria for system planning
Traditional system planning tends to be deterministic, where assumptions of peak
load growth are projected, and generation based on conventional technologies is
planned accordingly. This can lead to inefficient and expensive systems. For
example, newly installed generation capacity may end up being unused if EVs and
other distributed energy resources are deployed to avoid the peak load.
Large-scale electric mobility and energy transition require
innovation in power
system planning. Undertaking more sophisticated and probabilistic planning
practices can help take into account uncertainties in generation and load and
allows the participation of different technologies beyond conventional generation
technologies.
Probabilistic assessments on resource adequacy, as carried out in
the European Union, can focus on supply security characteristics, such as the
capacity value ratio (CVR).
14
They can allow more structured participation of EV
flexibility, thereby informing the planning process and reducing the total system
cost where applicable. For example, in the Netherlands,
load shifting from EVs
14
The CVR is a way of assessing the value of technologies in ensuring supply security by taking the value of their contribution
adapted to their availability. The ratio can be based on loss-of-load probabilities (LOLPs) and is similar to concepts such as
the effective load-carrying capability (ELCC) commonly used in the United States, de-rated capacity and capacity credit.
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could provide a CVR of 78.5%, meaning that a substantial part of the required
capacity during peak load hours could be satisfied by EV load shifting.
Aside from changing the planning criteria, it is also important that the
resource
adequacy mechanisms are adapted accordingly so that the expected flexibility
from EVs will actually be implemented.
Revisit regulatory design
The restructuring of incentives around revenues on capital investment is needed
to reduce bias on capital expenditure. Traditional cost-of-service regulation
remunerates grid companies based on the total costs they incur to deliver energy
to users. This could be modified to consider revenue caps or total system
expenditure (i.e., TOTEX regulation), or to consider explicit incentives for
innovation, such as supporting EV smart charging.
For example, in the United Kingdom, the
Revenue Using Incentives to Deliver
Innovation and Outputs (RIIO) regulatory framework combines the total system
expenditure approach with performance and innovation incentives, rewarding
companies that invest in innovation and meet the needs of consumers and network
users. Such measures are effective in helping distribution network operators to
proactively pilot smart-charging trials based on regulator-approved incentives.
Co-operation of transmission and distribution companies
A common difference between vertically integrated power sectors and unbundled
ones is the separation of the distribution system from transmission system
operations. The transmission system traditionally facilitates electricity delivery
from connected generators to separate distribution systems.
With the higher participation of demand flexibility and increasing amounts of
distributed energy resources, distribution systems are becoming more prominent
as they can affect operations at the transmission scale. In addition, actions in one
domain may not always align with the operational objectives of another. For
example, aggregated smart-charging participation in transmission-level frequency
regulation can affect the local distribution grid’s voltage regulation objectives.
However, this also highlights the need for co-operation to solve common
problems. For example, higher shares of variable renewable generation could
result in changes in the power flow at the transmission level due to changes in
generation output. In such cases, co-ordination with different demand areas in
distribution networks could help in balancing and maintaining system stability.
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Annex
Charging modes and levels
Charging modes are based on the manner of connection of EVs to the power grid.
Modes 3 and 4 have embedded communication and control capabilities that can
start and stop charging and modulate charging power when needed.
Charging modes based on IEC 61851-1
Mode
Description
Application
Mode 1
Direct connection to a regular
domestic socket
Typically used for electric micro-mobility
options and two- and three-wheelers.
Prohibited in the United States due to the
risks involved.
Mode 2
Direct connection to a regular
domestic socket with residual current
device protection
Typically used for two- and three-wheelers
and light-duty vehicles via a portable charger
containing residual current device protection.
Prohibited from public areas in Italy;
restricted in the United States, Canada,
Switzerland, Denmark, France and Norway.
Mode 3
Dedicated EVSE connection with
security and communication
capabilities
Can exist in a wallbox format that can be
installed in residential areas. Commonly
constructed in public AC charging.
Mode 4
Dedicated EVSE connection with AC-
DC conversion and security and
communication capabilities
Used for DC fast charging for a wide variety
of power levels.
Sources: IEC (2017), IEC 61851-1:2017 Electric Vehicle Conductive Charging System - General Requirements; IEC
(2014), IEC 61851-24:2014 Electric Vehicle Conductive Charging System - Digital Communication Between a D.C. EV
Charging Station and an Electric Vehicle for Control of D.C. Charging; Schneider Electric (2021), Electric Vehicle and EV
Charging Fundamentals.
Charging levels, on the other hand, are classified based on the power level as a
combination of the current and voltage that the connection can handle. Due to
differences in voltages and typical amperage limits among countries, the actual
charging power can vary. For example, most countries in Europe have regular
sockets rated 230 V and 16 A, which can theoretically provide 3.7 kW, whereas in
India they are rated 230 V and 15 A, resulting in only 3.3 kW.
The typical labels of “trickle”, “slow” and “fast” charging are based on the speed of
level 1, 2 and 3 charging in relation to light-duty vehicles. However, the charging
speed actually varies based on the vehicle type, such that a two-wheeler can “fast
charge” with a level 2 charger, and a bus can “slow charge” with a level 3 charger.
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Charging levels based on various power levels
Level
Description
Application
Level 1
1.9 kW AC (single-phase
120 V, 16 A)
• Common in North America due to the 120 V mains
• Technically absent in countries with 220 V mains
• Charging of two- and three-wheelers and light-duty
vehicles
Level 2
3.5-7.7 kW AC (single-
phase 220 V and 16 A, to
240V and 32 A)
11-22 kW AC (three-phase
400 V and 16 A, to 400V
and 32 A)
15 kW DC (India)
• Common in Europe, Asia (except Japan), Africa and
South America (except Colombia, Venezuela and
Ecuador) with a mains voltage of 220-240 V
• In North America, 240 V sockets may be provided,
especially for clothes dryers and stoves
• In India’s Bharat AC 001 standard, a three-phase
input with three charging points of 3.3 kW each;
lower-power DC charging also available through
Bharat DC 001
• Charging of two- and three-wheelers, light-duty
vehicles, and smaller buses and light commercial
vehicles/trucks
Level 3 50-350 kW DC
For fast charging of light-duty vehicles and slow
charging of bigger buses and trucks
Level 4
350 kW to 3.75 MW DC
For fast charging of buses and trucks
Sources: IEC (n.d), World Plugs (accessed 27 October 2022); Schneider Electric (2021), Electric Vehicle and EV Charging
Fundamentals; ENTSO-E (2021), Electric Vehicle Integration into Power Grids; CharIN (2022), Megawatt Charging System
(MCS).
Alternative charging techniques
• Inductive charging. Similar to wireless charging for cell phones, the batteries
in EVs can be charged using magnetic resonance through a transmitter pad
connected to the grid. While inductive charging is still nascent, standards
have
already been developed. The model has the potential for being integrated into
roads and parking lots, providing virtually unlimited range and enabling the use
of
smaller batteries.
• Catenary wiring. Similar to trains or tramways, vehicles with defined routes,
such as buses and trucks, can be connected directly to the grid through
catenary wiring. Urban electric trolleybuses connected by catenary wiring are
already common in certain cities. Life cycle cost assessments have shown that
sectional catenary trucks
with a 120 kWh capacity are more cost-effective
compared to battery electric trucks with an 825 kWh capacity at EUR 0.68 per
km to EUR 0.72 per km, respectively, for the same tonnage.
• Mobile EV charging. Battery piles that are mobile or piles carried by vans can
provide charging solutions for EVs while the battery piles themselves are
charged in a dedicated location. By being mobile, they can be charged where
there is grid capacity, saving on land acquisition and installation costs and
reducing the need for multiple fixed EVSE stations. This can sometimes be a
temporary solution before the installation of a fixed EVSE. Studies on the
levelised cost of electricity in China show that mobile charging is
cost-
competitive with fixed EVSE if the utilisation rates of the latter are lower than
39% and if land acquisition is not subsidised. Fixed EVSE will still be needed
though, despite the expansion of mobile EV charging. Some companies in the
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United States and the United Kingdom cater to charging provisions under land
or grid capacity constraints and rescue use cases when a vehicle is stranded.
Mobile EV charging is sensitive to battery costs, but it has the flexibility to use
lower energy density batteries or second-life batteries
, thereby improving the
utilisation of extracted battery materials.
• Automated conductive charging. Innovations in EV-EVSE charging
interfaces are still ongoing, with the aim of improving user convenience.
Innovations in automated conductive charging aim to lower infrastructure costs
and help the scalability and ubiquity of charging infrastructure.
Several
demonstrations are ongoing in Austria and offer bidirectional charging
capabilities.
Abbreviations and acronyms
AC alternating current
CPO charge point operator
CVR capacity value ratio
DC direct current
ELCC effective load-carrying capability
EMSP electric mobility service provider
EV electric vehicle
EVSE electric vehicle supply equipment
IEC International Electrotechnical Commission
IEEE Institute of Electrical and Electronics Engineers
ISO International Organization for Standardization
LOLP loss-of-load probability
NWA non-wire alternative
OCPI Open Charge Point Interface
OCPP Open Charge Point Protocol
OpenADR Open Automated Demand Response
OSCP Open Smart Charging Protocol
PPA power purchase agreement
PV photovoltaic
ToD time of day
ToU time of use
VRE variable renewable energy
Glossary
CO
2
-eq carbon dioxide equivalent
GW gigawatt
kW kilowatt
kWh kilowatt hour
TWh terawatt hour
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