Power grids need extra generating capacity to work properly. For example, about 20 percent of New York State’s generation fleet runs less than 250 hours a year. Because they don’t run much, “peaker plants” are by design the cheapest and least efficient fossil generators. When they do run they cost a lot to operate and produce more air pollution than other types of fossil generation. Wouldn’t it be great if we had a cost-effective and environmentally sustainable substitute for dirty fossil-based peakers?