CASA GRANDE — Another possible use for the old Sacaton Mine is in the works.
Ramm Power Group is looking to build a renewable energy storage plant at the mine. The plant would use a pumped storage hydropower storage system. The process is fairly new to the U.S. but has been used in other countries such as Australia.
Pumped storage hydropower facilities work similar to a conventional hydropower dam, like Hoover Dam, but in reverse, because the system is designed to store energy, rather than generate a constant stream of energy.
The systems use two reservoirs, one at a higher elevation and one at a lower elevation. In order to store energy, the plant takes extra energy from the electric grid to pump water from the lower reservoir to the upper reservoir. The water is stored in the upper reservoir until there is a need for additional energy by the grid.
When there is a demand for additional energy, the water in the upper reservoir is released into the lower reservoir through a series of turbines that generate electricity, which is put back onto the grid.
The proposed Sacaton plant could store about 1,920 megawatt hours of electricity or enough to power more than 2,000 homes, according to Ramm. The average home uses about 914 kilowatt hours a month, according to the U.S. Energy Information Agency.
Two similar projects are planned in northern Arizona, both by Daybreak Power. The Navajo Energy Storage Station proposed near Page would generate 2200 megawatts of power, and another 1540 megawatts of storage is proposed near Hoover Dam.
Ramm Power Group President and Director Steve Wood said the company will protect the local groundwater by pumping out and treating existing contaminated water from the bottom of the open-pit mine and by lining both the upper and lower reservoirs to prevent water from the plant from seeping into the ground.
In order to fill the reservoirs, the company is hoping to purchase treated wastewater from the city of Casa Grande. Used irrigation water is also a possibility, Wood said.
City Public Information Officer Latonya Jordan-Smith said the city has not been formally contacted by Ramm about the possible purchase of the water, but the company may have casually inquired about the possibility.
The plant would use a closed loop system, using the same water each time to store and generate electricity, Wood said. The company would have to top off the reservoirs with additional water because of the loss of some water through evaporation. The water would also be treated at an onsite wastewater plant to make sure the water quality met the needs of the turbines.
Wood said the company does plan to hire local labor and employees to build and run the plant.
“This could be a linchpin for renewable energy in the area,” Wood said. “The potential for this facility is incredible.”