Much to my astonishment, Dominion Energy is taking a serious look at building a pumped-storage hydro-electric power plant in Virginia’s coalfields. I wrote about the idea back in February but it struck me as a long shot. So much for my superficial impression. It now transpires that Dominion is identifying potential sites in far Southwest Virginia and hopes to narrow the list later this year.
If Dominion decides to proceed, it will notify potentially affected landowners and set up meetings to gain public support, according to Dominion spokesman Greg Edwards. Though still in the early exploratory phase, Dominion describes the prospects as “very exciting.”
The potential impact is enormous. The pumped-storage power station would have a capacity of 1,000 megawatts, making it even bigger than Dominion’s coal- and wood-burning Virginia City Hybrid Energy Center, which cost $1.8 billion to build and generates $6 million a year in tax revenue for Wise County. “We’re talking about revenues way in excess of what Virginia City generates,” Edwards told the Coalfield Progress.
The idea behind pumped storage is to move water between reservoirs at different elevations. Dominion would let the gravity-fed water run turbines, as shown in the company-supplied graphic above, during periods of peak power demand when the cost of electricity is expensive, and then pump the water back to the upper basin when electricity is cheap. The concept is the same as Dominion’s pumped-storage dam in Bath County, the world’s largest.
Pumped storage will be increasingly attractive as eastern utilities increasingly rely upon wind and solar power, which are intermittent sources of electricity. A pumped storage facility could help even out fluctuations in electric production due to variations in wind and sunshine, or even shift power production from periods of peak solar output during the mid-day to peak demand in the late afternoon/early evening. The massive scale contemplated for the project — 1,000 megawatts, roughly equivalent to the capacity of a state-of-the-art gas-fired facility — suggests that Dominion could be considering the plant for load-shifting purposes. And that could be a game-changer.
Dominion’s Integrated Resource Plan foresees the need for a new nuclear power plant by 2030 (under the strictest CO2 regulatory regime), up to five new gas combustion turbines by 2032, and more than 5,000 megawatts of solar power by 2040. I am entering the realm of speculation here — none of this comes from Dominion — but the addition of a giant pumped-storage facility to Dominion’s generating fleet might enable the company to shift more aggressively to solar power and still maintain grid reliability. Potentially, depending upon transmission line limitations, pumped-storage could eliminate the projected need for four 240-megawatt combustion turbines. (How such a shift would impact the demand for natural gas supplied by the proposed Atlantic Coast Pipeline is a big unanswered question.)
The idea originated with coalfield legislators, not Dominion. Del. Terry Kilgore, R-Gate City, Del. Todd E. Pillion, R-Abingdon, and Sen. Ben Chafin-Lebanon, amended the state code to add pumped-storage hydroelectricity generation and storage to the list of projects which, if built in the Virginia coalfield counties, would be deemed “in the public interest.”
Learning of the proposal during the General Assembly session, Dominion quickly began exploring the idea. Early media reports emphasized the idea of using underground mines as a holding tank for the water, but Edwards told the Coalfield Progress, “We’re not wedded to underground.”
So far, Dominion’s investigations into potential sites have involved working with maps and satellite imagery. The company has looked at “literally hundreds” of possible locations. Even if Dominion finds a suitable site, however, it could take seven to ten years until a pumped-storage facility became operational.