In its preliminary consideration, Pacific Gas & Electric’s proposed Mokelumne Pumped Storage facility could adopt newer technologies that provide rapid response to grid fluctuations caused by integrating wind and solar power. It would be more “nimble” than the 25-year-old technology at the utility’s Helms Pumped Storage plant, said Mike Jones, PG&E director, new generation development. Decades ago, he added, planners were not anticipating the rapid movements in power intermittently provided by renewables. Existing pumped storage plants run water uphill at night, allowing downhill hydro during the day. Mokelumne could use variable speed drives to manage night pumping to respond to the grid operator’s demands. It could change power consumption at the plant by “hundreds of megawatts that might be instantaneous,” said Jones. In providing capacity or ancillary services to the grid, Jones expects that functionality could be built into the facility to react to five- and 10-minute changes when a cloud passes over solar, or wind changes course.