Hydro Waiting For Consumer Demand

By Published On: July 24, 2014

The state’s largest hydroelectric dams are holding it in—waiting for instructions to spill for peak power. Utilities anticipate a call from the California Independent System Operator to gear into peak mode to help meet grid demand when requirements are abnormally high during summer heat. Despite waiting on peaking calls, in October, Southern California Edison notes that it’s required to draw down reservoir levels. This is government oversight to avoid flooding from what’s usually considered “normal” precipitation. But, the state’s hydroelectric reservoirs are hardly in need of flood control at this time. In Edison territory, there’s one-third of the 1,050 MW in usual income into its reservoirs, according to Dean Yarbrough, director, Northern California hydroelectric division. Both Edison and Pacific Gas & Electric have been holding back their limited reservoirs during this drought. In normal years, the hydro would be available 24 hours a day for dispatch. In PG&E territory, with 3,800 MW of hydroelectricity, the utility has been waiting for peak demand to be called by the grid operator. With conservation to maximize peaking power, reservoirs behind the utility’s 17 largest dams are only down to 85 percent of normal as of mid-July, according to PG&E spokesperson Paul Moreno. Despite the drought, the grid operator forecasts manageable hydro levels. The report from May still stands, according to the grid operator. The agency has no plans to update it this summer. California Independent System Operator estimates: • 1,700 megawatts less hydroelectricity available—or 18 percent (under normal weather) to 22 percent less (under extreme hot temperatures and heat waves). • That means the total amount of hydroelectricity available this year is about 7,700 MW. “Still, we will be watching closely and will reanalyze if necessary,” noted grid operator spokesperson Steven Greenlee. “Otherwise, we will be doing another analysis early next year for the 2015 summer assessment.” According to the California Energy Commission, “With less water being available to generate hydroelectricity, natural gas and renewable energy supplies will be used to make up the difference.”

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