A member-owned co-op in New Hampshire has become one of the first U.S. utilities to tap into the potentially transformative power of vehicle-to-grid (V2G) technology, using the storage capacity in electric vehicles and other home batteries to even out the highs and lows of local electricity demand.
The pilot project relies on an hourly transactive energy rate that co-op members of the New Hampshire Energy Co-op (NHEC) can use to determine the best time of day to send a share of their stored electricity back to the grid, the Institute for Local Self-Reliance reports. That would be the point on the 24-hour clock when those battery and EV owners can earn the most money for the power they send back—which corresponds to the hours when electricity demand is highest, power rates are highest, and in places like Ontario, when high-emitting natural gas plants are most likely to be online.
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“Participating member-owners use the hourly energy rate to make decisions about their energy usage,” ILSR explains. “If they have a battery storage system, or even an electric car, they can send power back to the grid when it has the highest credit value. The member can then recharge their device when the cost of electricity has gone down.”
An initial calculation by Plymouth State University showed program participants saving $4,000 per year by “optimizing the value of their car,” ILSR says.
Many utilities across Canada have been considering V2G systems as a way to reduce peak demand and eliminate the need for expensive, new generating stations and transmission lines, and prevent or reduce climate pollution along the way. Within a couple of years, auto industry insiders see massive potential for V2G systems to put money in consumers’ pockets, stabilize grids, cut energy costs, and help curtail climate-warming emissions.
“By 2025, we will have 350 gigawatt-hours’ worth of energy storage at our disposal through our electric car fleet,” said Volkswagen Chief Strategist Michael Jost, cited [pdf] in an NHEC slide presentation earlier this year. “Between 2025 and 2030 this will grow to 1 terawatt-hour’s worth of storage. That’s more energy than is currently generated by all the hydroelectric power stations in the world. We can guarantee that energy will be used and stored and this will be a new area of business.”
In a podcast last April, Brian Callnan, NHEC’s vice president of power resources and access, explained “how the energy sitting in electric vehicle batteries can provide additional value to the owner and the grid,” ILSR writes.
The transactive energy rate first showed up in the co-op’s strategic planning in 2017, Callnan said, as utility planners and leaders began recognizing the “bidirectional conversation” that could take shape between utilities and their customers. “In order to more accurately compensate member-owners for the electricity they were putting back on the grid through generation or conservation, the co-op homed in on what the value of electricity was in each hour of the day,” ILSR says.
The data applies only to individual devices, not to the home’s wider energy use. But it still gives participating member-owners the hourly insights they need to make the best decisions about their electricity consumption, storage—and sales. They can still set up the transaction to leave enough power in their EV battery for routine errands or unforeseen emergencies.
With electric cars, a big advantage of the V2G approach is that it makes better use of a device that is parked and idle far more often than it’s in use. “You’re not using that vehicle all that often and you’ve got all of this potential energy stored in that battery that could be doing something if it was connected.,” Callnan told ILSR’s John Farrell.
For other jurisdictions interested in setting up their own programs, he said NHEC purposely built its demand response system using open source software. “Hey, if you guys want to do something similar to this, you don’t have to go near what we went through to pull it together,:” he said. We can share it with you.”
