Switching From Coal To Batteries At Power Plant In Maryland

Talen Energy operates a number of fossil fuel-powered generating facilities that supply electricity to the mid-Atlantic PJM grid. One of its holdings is the H.A. Wagner plant just down the Patapsco River from Baltimore. Talen has recently shut down one unit at the Wagner facility. According to Canary Media, unexpectedly low prices from PJM’s latest capacity auction spurred a fresh wave of coal generation retirement announcements this month.

The shuttered unit was built in the 1950s and has been pumping out electricity and toxic emissions ever since. Cole Muller, who oversees Talen’s fossil fuel-powered fleet, says shutting down an existing power plant has negative consequences for the local community. “If you just retire it, you have a significant loss to both jobs and the tax base, and the communities at large.”

Instead, Talen is installing a 20 MW battery storage facility on the grounds of the shuttered site. It’s an experiment that may lead to as much as 1 gigawatt of battery storage at Talen facilities in coming years. “This is the first of hopefully many unit transitions from coal to lower-carbon sources and battery,” Muller says. “It’s really about decarbonizing — investing in the communities and continuing to provide opportunities for our people.”

Since batteries emit no carbon emissions or air pollution onsite, the switch can improve air quality for communities surrounding the plants. That environmental justice benefit is especially important in dense urban areas like Baltimore.

If the first experimental battery proves successful, the company could increase battery storage at the Wagner plant to 115 MW and install batteries with up to 300 MW of storage capacity at another facility in the future as more fossil fuel generating stations are taken offline.

Talen is working with battery developer Key Capture Energy to build the 20 MW system as a proof of concept demonstration. Its relatively small size allows for a streamlined approval process but it will act just like any other commercial power plant, bidding into PJM’s markets for capacity, ancillary services, and energy arbitrage.

Muller says there are several advantages to installing battery storage at older power plants. For instance, the sites have already been cleared to export a certain amount of power to the grid, so no expensive network upgrades are needed. “If the system can handle 100 megawatts of coal, it can handle 100 megawatts of battery output,” Muller says.

Also, most coal facilities have plenty of space available for installing batteries with plenty left over for building solar farms nearby. That means no money is needed to purchase land to make the transition to renewable energy.

Battery storage is different from a coal generating station. One the one hand, batteries can only supply electricity for a limited period of time. On the other hand, batteries can react to demand instantly whereas a coal plant can take as much as a day to ramp up. That flexibility will become more valuable as new renewable generation and old plant retirements make energy markets more volatile.

Jeff Bishop, CEO of Key Capture, says switching from coal to batteries is easier than switching from coal to gas because developers don’t need to make arrangements for a supply of unnatural gas. “Pretty quickly, you can take the existing capacity and transition it to energy storage,” he says.

“To my knowledge, this is the first battery at a coal plant anywhere,” Bishop adds. “It’s becoming more understood with the folks that own [coal] generation that the transition is happening, and they can either be part of it or they will be left behind.”