Looking for a way to store massive amounts of excess green energy? Water may provide the answer.
With lakes, pipes, and pumps, the Los Angeles Department of Water and Power essentially created a giant battery capable of storing enough energy to power more than 80,000 homes. The solution was necessary because the city is on a mission to cut fossil fuel use by 2045 and needed a way to harness the green energy produced during the day to offset gas and coal power used at night. A traditional battery couldn’t be built large enough to handle the task.
The process — known as pumped storage — works this way: Excess wind and solar power produced during the day at local renewable energy sites is directed to pumps that take water from Castaic Lake uphill to Pyramid Lake. When the wind and solar can no longer meet system demand, the same water makes the 7.5-mile trek back downhill where it is run through hydroelectric generators. This pumping function provides additional water for power generation beyond the supply of water available from the flow of the state aqueduct.
Each day, the cycle is repeated.
The specifications for this particular “battery” are incredible. It takes six, massive pipes to connect the lakes. The pressure of the water rushing downhill is 25 times the force of the water coming out of a typical home faucet. More than 50 employees operate the plant. The same water can be recirculated again and again.
While this solution isn’t unique, the success of this operation may be the inspiration for a massive pumped storage plant at the Hoover Dam, which was built in the 1930s and is the largest reservoir in the country when full.
Los Angeles is trying to get collaborators for a $3 billion project to put a wind- and solar-powered pump station about 20-miles downstream. Excess energy would be used to send water back up to Lake Mead to increase the power generating capacity of Hoover Dam plant, which already supplies more than a million homes in three states.
The plan is in its infancy, as an environmental study and other significant details need to be worked out before it can move forward.