VEHICLE-TO-GRID
“V2G using an AC system requires inexpensive
adaptation of the charging terminals, and also
reduces infrastructure roll-out costs”
Yasmine Assef, energy new business director, Groupe Renault
www.electrichybridvehicletechnology.com // January 2020 // 79
charging in its 2019 Future Energy Scenarios
report. This suggested that 35 million EVs
would be required by 2050 to meet the
government’s net zero carbon emissions
target. Unmanaged, these would singlehandedly
increase peak demand by up to
24GW. Controlling demand using smart
charging (V1G) could halve that peak to
12GW, while V2G would bring it down
a further 85%, to 1.8GW.
In turn, V2G could mitigate costly
infrastructure improvements. A
recent Lawrence Berkeley National
Laboratory study that examined
California’s projected electricity
requirements in 2025, showed
that V1G could off er a gridstabilising
equivalent to a US$1.5m
investment in static energy storage.
By comparison, V2G off ers equivalent
to a US$15.4bn capacity increase.
There are other benefi ts too, as Chris
Rimmer, infrastructure strategy lead at the
UK’s Centre of Excellence for Low Carbon
1. Nissan enables its
vehicles to communicate
battery state to the charge
point – and beyond
2. The technology is
being used in pilots to
examine how electric
cars could mitigate their
own impact on the grid
3. Bidirectional charging
is already supported by
the Chademo standard
4. Nissan is also testing
V2G technology at its
European R&D hub
Technologies (Cenex), explains: “By steering
people away from times when the grid is
congested, an indirect benefi t is that you’re
then moving the load towards lower carbon
generation. You could maybe halve the carbon
intensity if you took the energy at 3am rather
than 3pm. If you’re charging at night when
it’s low carbon and then you’re discharging
back to the grid when it’s high carbon, then
obviously you double the carbon benefi t over
and above smart charging.”
Tools for the job
The Chademo Association says its standard
is compatible with 41% of fast-charge capable
vehicles in Europe, but that share is likely to at
least plateau. American, European and Korean
OEMs are increasingly using the Combined
Charging System (CCS), and this doesn’t have
the required communication protocol built in.
The incoming ISO 15118 standard, designed
to enable ‘plug-and-charge’ operation similar
to a Tesla Supercharger, will enable this, but
not until the mid-2020s.
Bidirectional AC charging is also already
possible, although the architecture is diff erent.
This requires the AC/DC converter – required
to put DC power back into an AC grid – to be
integrated into the vehicle, rather than the
charging point as in a DC system. “Groupe
Renault has V2G pilot schemes underway
in seven countries using an AC system,”
says Yasmine Assef, the group’s energy
new business director. “This requires
inexpensive adaptation of the charging
terminals and also reduces infrastructure
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/www.electrichybridvehicletechnology.com
