Plugged-in electric vehicles could overload neighborhood transformers and drive up peak demand on already-stressed grids. Or, they could wield their influence in ways that brings the grid into better balance than it is today.
So say a host of companies trying to develop technology and business models around EV charging as an aggregated grid resource. By subtly shifting and tweaking when and how much electricity plug-in vehicles draw from the grid, they say, EVs could help ease congestion on distribution grid circuits, absorb excess solar and wind power, or provide sub-second response for high-priced ancillary services markets.
Figuring out the value of this still-theoretical grid resource is a tricky matter, however, given the small number of EVs on the road today, and the even smaller number of “smart” chargers being tested in pilot projects. So it's going to be hard to prove out the following business proposition: give chargers away for free, and pay off that cost through grid services revenue over their lifetimes.