Turning Old Coal Mines Into Massive Energy-Storage Devices for Renewable Power
A Pennsylvania entrepreneur imagines that one day, the 40-acre Shen Penn anthracite mine pit will once again deliver energy.
(TNS) — SHENANDOAH, Pa. – The Shen Penn anthracite mine pit, abandoned in the 1960s during the decline of Schuylkill County’s coal industry, is a 230-foot-deep water hole surrounded by mine waste, scrub trees, and a nearly 600-foot rock wall that imperils adventurers who creep too close to the edge of the precipice.
Adam Rousselle, a Bucks County entrepreneur, imagines that one day this 40-acre public nuisance will once again deliver energy – not by producing coal, but as a massive energy-storage device to hold renewable power generated from nearby wind farms.
Rousselle’s company, Merchant Hydro Developers LLC, last month received a preliminary federal permit to study converting the Shen Penn pit into a pumped-storage hydroelectric project. In pumped-storage systems, power is generated by releasing water from an upper reservoir when electricity is needed most. At night, when excess power is available, the units are reversed and water is pumped uphill to refill the upper reservoir.
“It’s like a giant liquid battery,” said Rousselle, 51, an executive in electric-transmission ventures who lives near Doylestown.
The Shenandoah proposal is the largest of 21 pumped-storage projects for which Merchant Hydro has filed applications with the Federal Energy Regulatory Commission. Most are in Pennsylvania, and many are situated on old strip mines or near wind farms.
One of them would be located in Bucks County, in Nockamixon Township — and not on an old mine, but on public lands owned by the Pennsylvania Game Commission.
“We’re only going to do these if they are economically viable, environmentally viable, and socially viable,” Rousselle said.
Pumped storage is not a new concept. The U.S. Department of Energy counts 42 existing pumped-storage plants, most built decades ago, that can deliver 21,600 megawatts of power, about one-fifth of the nation’s hydroelectric capacity. Exelon Generation of Kennett Square operates one site, the 1,070-MW Muddy Run Pumped Storage Facility, which opened in 1966 along the Susquehanna River in Lancaster County.
With the growth of intermittent renewable wind and solar energy, there is a growing interest from grid operators in devices that can maintain the power system’s reliability by storing energy for use when the sun is not shining and the winds are not blowing.
Though new energy-storage technology like flywheels and battery arrays have captured the public imagination, the Energy Department says pumped-storage projects still account for 97 percent of the nation’s utility-scale power-storage devices.
“Pumped storage is one of the backbones for integrating all this new generation,” said Jeff Leahey, deputy executive director of the National Hydropower Association.
Though pumped-storage facilities consume more power than they produce, they make money off the difference in the wholesale price of electricity: Power is cheap at night, when the pumps are filling the reservoir, and can be very expensive during peak hours, when the power is sold into the grid. Some new hydro turbines also can earn fees helping grid operators such as PJM Interconnection Inc. keep the grid’s voltage in balance.
But getting regulatory approval for a pumped-storage facility from a multitude of federal and state agencies is laborious, said Leahey. Investors are reluctant to back projects with long-term, uncertain horizons.
“If everything goes right, you’re looking at a five- to six-year process,” he said.
The Federal Energy Regulatory Commission has approved only two pumped-storage facilities in recent years, including the 1,300-MW Eagle Crest plant on abandoned iron mines near Joshua Tree National Park in Southern California. FERC approved that project in 2014 after a six-year review, and Eagle Crest is still lining up permits before it can break ground.
If ushering a single pumped-storage project through the regulatory process is daunting, Rousselle has his hands full with 21 of them, including one in New Jersey, one in New York and two in Maryland. FERC has granted preliminary permits to seven, which gives Rousselle exclusive rights for three years to conduct studies and to apply for a formal permit.
He offered no cost estimates, but the developers of a 400-MW facility approved in December in Montana that’s about the size of the Shenandoah project say it will cost $1 billion to build. In a 2016 report, the Energy Department said pumped-storage projects cost upward of $2,500 per kilowatt to develop, which would place the price for all of Merchant Hydro’s 21 projects north of $6 billion.
To back his venture, Rousselle will need to enlist bigger players with deep pockets. “We think there’s a lot of value in our vision of a distributed pumped hydro fleet, and we think building them in succession will reduce costs,” he said.