Within a few years, cars may be able to power homes, participate in energy markets and help businesses lower power bills, experts say.
Electric vehicles are growing in popularity, and utilities are preparing for a future where their value goes far beyond transportation.
As more EVs hit the road, there are growing questions about how utilities will manage their charging needs. Rocky Mountain Institute (RMI) has estimated that electrifying all of the roughly 251 million light-duty vehicles on U.S roads today would increase annual electricity demand by about 25% — and that doesn’t include medium and heavy-duty applications like freight and public transit along with a host of other applications.
While the transition to a fully electric fleet could take decades to achieve, the near-term implications for grid management as more and more EVs hit the road are significant.
Along with adding demand, EVs are increasingly seen as potential grid assets: aligning their charging needs with times of higher renewables production and lower grid stress can help decarbonize transportation and operate electric systems more efficiently. Managed charging, through time-of-use rates and demand response programs, is known as vehicle-grid integration and is already the subject of utility programs around the country.
This approach to managing EV demand — largely reliant on unidirectional power flows that adjust how and when chargers are pulling energy from the grid — is sometimes referred to as level 1 integration (V1G). But there is also interest in using the energy in EV batteries to serve other loads, with what are known as vehicle-to-grid (V2G) capabilities.
While those capabilities are utilized in parts of Europe and Asia, experts say the United States is still years away from widespread use of V2G. There are a few utilities rolling out pilot programs to test the capabilities, including Duke Energy in North Carolina, but there are still safety and engineering concerns to be addressed, technical problems to solve and business cases to study.
“It can be pretty complicated to make it all work. I’ve read hundreds of technical papers on these topics and I just don’t think the value proposition of V2G is at all clear,” said Chris Nelder, a manager with RMI’s mobility practice.
That said, there is a growing consensus that millions of vehicle batteries will one day serve as energy resources beyond V1G managed charging, to power buildings and microgrids and feed energy back into the bulk power system.
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