Electric Vehicles Could Surpass
Grid or Support It
May 29, 2009 - Jeff St. John - greentechgrid.com
If a quarter of America's cars went electric,
they could store more energy than that produced
for the nation's entire electricity grid, an expert
on electric transportation says. Making them a backup
power source for the grid faces significant challenges,
Plug-in hybrid and electric vehicles could grow
to be a greater source, or sink, of power than the
entire American electricity generation system. Is
that a good thing or a bad thing?
It's a question that utilities and policy makers
have been grappling with as they prepare for what
could be millions of new electric-powered vehicles
to hit American streets. Unless those cars can be
charged at times of lowest electricity demand, they
could overwhelm the electric grid or require huge
new investments in power generation.
But Jasna Tomic, new fuels program manager for
Calstart, a nonprofit group promoting clean transportation,
sees the conundrum as a big opportunity for such
vehicles to serve as backup power for the grid,
through so-called "vehicle-to-grid," or V2G, technology.
If a quarter of the nation's car fleet was to go
plug-in hybrid or electric, the combined energy
they could store would equal about 750 gigawatts,
Tomic said Thursday at the Opportunities in Grid-Connected
Mobility conference in San Francisco. Of course,
that's a share of the market that could take decades
to reach, but if it comes about, "That basically
surpassed the size of the electric grid," she said.
And while the capital costs per kilowatt for that
vehicle storage are likely to exceed the average
rates that utilities charge for power, they're below
those that utilities pay for peak power demand times,
when they have to call on seldom-used backup sources
to meet the peak, she noted.
So when thinking of the demand that electric vehicles
will place on the grid, "There's no need to go only
one way," she said. "We really could go both ways,
and provide the power back to the grid. Think of
the vehicles not only as transportation but as resources
That's been an area of research for automakers,
utilities and smart grid companies for some time.
A consortium including the University of Delaware,
electric vehicle system maker AC Propulsion, utility
Pepco, regional transmission organization PJM and
demand response company Comverge is testing its
own V2G technology (see A V2G Test: Pool Electric
Cars for Grid Needs).
The Electric Power Research Institute is working
with General Motors Corp. and Ford Motor Co. on
projects (see Prepping for Plug-Ins to Hit the Grid).
And smart grid software developer Gridpoint, which
in September bought vehicle-to-grid software developer
V2Green, has tested V2G technology with Duke Energy
and Xcel Energy's SmartGridCity project. (see Laying
the Grid Groundwork for Plug-In Hybrids and Gridpoint
Gets $120M, Buys V2Green).
Tomic said technologies like these could lead to
new markets for electric vehicles that could help
lower their cost, which is still seen as the main
barrier to their widespread adoption.
Not that they could serve as baseload power, of
course, since they'll need that to be charged up,
But perhaps they could be linked up with utilities
looking for new sources to cover their expensive
peak power needs, she said. Several hundred thousand
vehicles could likely provide enough power to serve
utilities so-called "ancillary services" needs completely,
And "You don't need a smart grid to do ancillary
services," Tomic maintained. While utilities have
focused their V2G plans on establishing two-way
communications between utilities and homes or businesses
via smart meters, V2G efforts could use cellular
networks, radio signals or Internet connections
to handle the task, she said.
Electric and plug-in hybrids could be used to store
power from renewable energy sources like wind, which
is mostly generated at night when demand is lowest,
That's something that Danish utility Dong Energy,
IBM and a host of other partners are working on
right now in Denmark (see IBM Tests Smart Charging
But many hurdles remain between the state of electric
vehicle infrastructure today and making those vehicles
viable sources of backup power, Tomic acknowledged.
Not only do the vehicles in question need bi-directional
power electronics, wireless communications and some
form of on-board metering systems to handle the
task, she said.
They will also require a hitherto-unknown level
of cooperation between utilities and automakers,
and those two have "never had anything to do with
one another," she said.
Joel Pointon, manager of electric transportation
and clean transportation for San Diego Gas & Electric,
noted that automakers will be concerned about subjecting
car batteries to more frequent discharges and recharges
involved with being used as backup power, which
will lower their life spans.
Michael Tinskey, manager of hybrid and battery
electric vehicle applications for Ford Motor Co.,
agreed that right now Ford has no way to account
for that in its warranty system.
"We need to learn a lot more before we jump into
that arena," he said. "The utilities aren't ready,
and neither are the car companies."