Electric Cars Store Power for the Grid
V2G technology or Vehicle-to-grid, would enable electric car owners to make money while storing power for the grid. The technology was unveiled at the American Association for the Advancement of Science meeting in San Diego yesterday.
Electricity grids that are fed by increasing amounts renewable energy could operate much more efficiently if they tapped into the vast amounts of power stored in the batteries of electric and hybrid vehicles, to balance out fluctuations in supply and demand.
The first experimental V2G system has just gone live at the University of Delaware, where three electric cars are connected to the grid whenever they are not being driven.
“They are making $5-$10 a day just by being plugged in,” said Kenneth Huber, technology manager for the PJM grid , which covers the mid-Atlantic states in the US. The two-way connection not only pulls in power to recharge the battery but also sends electricity to the grid.
On September 21, 2009, Delaware’s Governor Jack A. Markell signed Senate Bill 153, making it law for electric utilities to compensate owners of electric cars for electricity sent back to the grid at the same rate they pay for electricity to charge the battery. This is the first legislation of it’s kind in the world.
V2G vehicles work like an electrical sponge, cap-able of absorbing excess energy when demand is low, and returning some to the electric grid when demand is high, said Willett Kempton, project leader at the University of Delaware .
This sort of load balancing will become increasingly important as renew-able energy sources generate more electricity.
“Vehicles we have now provide freedom and meet the needs of individuals,” said Jeff Stein, an engineering professor and V2G researcher at the University of Michigan. “Hybrid and electric vehicles can also be used in a completely different way.”
Prof Kempton says his project suggests that an investment in V2G technology could pay off quickly for an electric car owner. Once the technology is commercialised, the additional costs of fitting a V2Genabled battery and charging system would be about $1,500 – and the owner could make $3,000 a year through a load-balancing contract with the grid.
The idea of using electric vehicles to make the grid more efficient has been under serious academic and governmental study for at least several years, and projects are now getting under way in the United States and other countries to examine not just V2G technologies, but also the use of batteries to store solar electricity, a third component of the V2G equation.
In January, the U.S. solar company Suniva announced an agreement with GS Battery USA to develop solar-powered energy storage systems. GS Battery is a subsidiary of GS Yuasa Group of Japan, another country where solar-to-battery-to-grid studies are under way.
The collaboration between Suniva and GS Battery is to begin with a system using a 30-kilowatt array of Suniva’s solar modules and GSB’s battery technology at GS Battery’s headquarters in Roswell, Ga.
“Solar system owners that are able to store their energy output are also able to take advantage of many new economic opportunities,” said Yasuyuki Nakamura, President of GS Battery, in a news release. “Our state-of- the art approach allows customers to achieve better returns on investment with a more flexible and profitable solar energy supply. We are excited about the value of utilizing Suniva’s high-powered modules with our battery technology.”
V2G is economically viable because electric car owners are buying batteries anyway, so it makes sense to use them for communal energy storage. It would be more costly for electric grids to install other storage systems.
Existing vehicles cannot easily be fitted with V2G but in the next five years as many as 1m new electric cars are likely to be sold in the US.
With each car providing 10 kilowatts of power, 1m V2G cars would provide a balancing reserve amounting to several gigawatts – reducing the need for new power station construction.