The challenge: Turn electric cars into virtual power plants

NRG Energy and the University of Delaware (UD) have teamed up in a venture called eV2g to commercialize technology that lets electric-vehicle (EV) owners sell back energy stored in their car batteries to help stabilize the electricity grid.

Developed by UD professor Willett Kempton, the vehicle-to-grid technology could help make the electricity infrastructure  more resilient in the future.

“As more electric vehicles hit the road and charging stations — such as those provided by NRG’s eVgo network in Texas — continue to proliferate, EV-to-grid technology is the next logical step in the electrification of our transportation network,” said Denise Wilson, president of NRG’s Alternative Energy Services. “It’s one more way EV owners can commit to a sustainable energy future and get paid for it at the same time.”

The EV-to-grid technology would allow electric-car owners sell battery storage back into the grid while their vehicles are plugged, without creating any risk or inconvenience for daily driving needs. The NRG-UD program will start with EV fleet managers, then eventually take the technology to individual plug-in car owners.

Once vehicle owners are enrolled, eV2g allows their cars to communicate with the grid and lets grid operators take power from
connected EVs during time of peak energy use. EV owners can schedule in advance any times their vehicles need more charging than usual, as for a unusually long trip, and can specify what minimum level of charge they want to maintain at all times. eV2g collects payment from the grid operator and pays EV owners for making their vehicles available.

“The energy storage inherent in automobiles is staggering,” said David Weir, director of UD’s Office of Economic Innovation and Partnerships. “If all the automobiles in the US were electrified, it would be enough to power the entire US for half a day.”

Commercializing the EV-to-grid technology could enhance energy security, make it easier to bring renewables online and help to lower the cost of electricity, Weir added.

Electric grid operators rely on resources that can help provide or absorb short bursts of energy to keep the grid running smoothly, and parked and plugged-in EVs are ideal for helping to fill that role. Balancing the grid this way generates no additional emissions and can lead to a decrease in electricity costs over the long term by delaying or supplanting the need to build new generation facilities.