Energy Storage: A Bright Horizon Ahead

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“Wind and solar powered generation is expanding, but one challenge we face is how to store that energy when the sun isn’t shining or the wind isn’t blowing.”  Those words were recently uttered by Microsoft’s co-founder, Bill Gates, during a Twitter discussion of his investment in three energy companies via his Gates Foundation supported by Breakthrough Energy Ventures (BEV) Fund.  

Gates’ statement and his creation of the BEV fund with other billionaires including Amazon founder, Jeff Bezos, and former New York Mayor, Mike Bloomberg, illustrate the crucial financial backing that energy storage technologies are attracting in order to harness fully the electric output potential of renewable energy resources like wind and solar.  These financial strides suggest the blossoming development of new energy storage technologies like those of Malta inc., which stores electricity in a molten salt and chilled liquid form, and refocuses attention on an age-old energy storage solution like pumped storage.

At a recent U.S. Senate Energy and Natural Resources Committee hearing on Energy Storage technologies, the senior Democratic member of the Committee, Sen. Joe Manchin (D-WV), noted how pumped [hydro]storage accounts for 95% of the current energy storage capacity.  Pumped storage works in two stages using an upper and lower reservoir.  When there is excess electricity, water is pumped up to the upper reservoir for storage. When electricity demand is tight, or at its peak, water from the upper reservoir is released through a hydropower turbine producing power.  Such a pumped storage facility at Raccoon Mountain in Tennessee, for example, is the largest single hydroelectric project in the Tennessee Valley Authority system.

There are currently 24 permitted and operational pumped storage facilities in the U.S. with a total capacity of 16,500 MW (1 MW powers approximately 750 homes instantaneously).  The Federal Energy Regulatory Commission (FERC) has also issued construction permits for other facilities like the Eagle Mountain Pumped Storage Project in Southern California.

Given the surge in applications flooding the FERC, pumped storage will continue to play a role in harnessing renewable energy.  Yet, pumped hydropower storage is the not the only pumped storage technology being utilized to meet electricity needs quickly during greatest demand.  In McIntosh, Alabama, resides one of two Compressed Air Energy Storage Units (CAES) in the world and the only facility in the U.S. Operated by Power South Energy Cooperative, the CAES unit pumps air into a cavern during periods of excess electricity demand. The air is stored at a compression rate of 1,100 pounds per square inch.  When electricity demand is at its greatest, the compressed air is released to produce 110 MW of power within 14 minutes.  

The CAES Unit at Power South is an innovative storage solution that dates back to 1991 when sources of renewable energy were not as prevalent as they are in today’s marketplace. Today, new energy storage technologies, particularly advancements in battery storage, are creating an environment where utility-scale renewable energy projects coupled with state-of-the-art storage are becoming increasingly competitive to power supply proposals from coal and natural gas projects.  

Xcel Energy’s Colorado Energy plan is indicative of the evolution. Ben Fowke, Xcel’s CEO, during testimony before the Senate Energy Committee, noted that his utility had selected two proposals that would couple 600 MW of grid-scale solar with 275 MW of grid scale battery storage. These two bids beat out proposals from natural gas proposals and led the Arizona Corporation commission to impose a nine-month moratorium on the approval of new large natural gas facilities in the state. Fowke was right to note in this testimony that these “…bids showed the nation that energy storage has arrived as a grid resource.” 

Energy Fairness has always advocated for fact-based conservations with policymakers and consumers about what it takes to maintain an affordable and reliable supply of energy. The facts are clear: with investments from the likes of Bill Gates, Jeff Bezos and others, new energy storage technologies will continue to evolve to a point where they will solve the age-old conundrum of how to capture energy produced from intermittent renewable resources like wind and solar. With the right investments and approaches, such energy sources can continue carving out their place as part of a broad mix of options to power America.