How do you store large amounts of energy? New NC project could help provide answers.

A battery storage project at a Richmond County gas-fired power plant could be supported by the U.S. Department of Energy, potentially serving as an example for long-duration storage for other utilities.

The Department of Energy’s Office of Clean Energy Demonstrations picked nine projects to fund, with each capable of storing more than 10 hours’ worth of energy. If the federal agency and the projects reach a final agreement, the Department of Energy would pay for as much as half of the projects out of a $325 million fund.

The vanadium redox flow battery system that would be built at the N.C. Electric Cooperatives’ Hamlet Generating Facility could provide power for as much as 20 hours.

A cooperatives press release said the battery system would be used to keep the grid reliable when demand for electricity is at its highest levels.

“While this selection for federal funding is a win for North Carolina’s electric cooperatives, it’s a major win for the members who rely on cooperatives to help power their lives,” Jimmy Wilkins, the cooperatives’ vice president of energy portfolios, said in the press release.

The battery system is part of the Department of Energy’s Office of Clean Energy Demonstration’s energy storage initiative, which is seeking to build batteries and other kinds of energy storage projects across the country to give businesses the confidence to embark on similar projects. There are 1,325 energy storage projects worldwide, but only 25 of them have can provide power for 10 hours or more.

“Cheaper, longer energy storage can support the expansion of renewables like solar and wind while providing stability, flexibility and optionality to the grid. It will also reduce the need for new fossil fuel capacity by firming renewables,” Juan Alvarez, the Department of Energy project manager for the energy storage initiative, said during a webinar this week.

Basically, the Department of Energy is hoping to prove that long-duration batteries and other storage systems can be built to address concerns about reliability stemming from the fact that the sun isn’t always shining and the wind isn’t always blowing. If larger amounts of power can be stored when those resources are abundant, it could cut down on the need for new “on-demand” resources like natural gas plants that burn fossil fuels and generate climate-warming emissions.

In Hamlet, the battery system would be located on the site of a so-called “peaking” gas-fired plant, which is used on the hot summer days and cold winter mornings when demand for electricity is typically highest. It will include “multiple, self-contained batteries” that will look like stacked storage containers when built, Townley Venters, a cooperatives’ spokeswoman, told The News & Observer.

If the project moves forward, the Hamlet plant’s storage would consist of vanadium redox flow batteries that could supply between 700 and 3,600 kilowatts of energy for as long as 20 hours, according to the cooperatives — roughly enough to keep the lights on in 500 to 2,400 homes.

It could be in use by 2028, according to the cooperatives.

Unlike lithium batteries that are effectively larger versions of rechargeable AA batteries, the flow batteries use vanadium dissolved into a water-based solution to generate power.

The battery system has two tanks, one that contains positive electrolytes and one that contains negative electrolytes.

When the battery is charging, those solutions are pumped through a fuel cell stack in the middle where they are separated by a thin membrane. The energy coming in allows electrons to move from the positive solution into the negative solution, charging the battery.

That process reverses when the utility or another user calls upon the battery for power, with electrons moving from the negative electrolytes over to the positive electrolytes.

The Hamlet site is one of five that are part of the Rural Energy Viability for Integrated Vital Energy project. Other sites that are part of the project are in Iowa, Maryland and South Carolina. Other partners on the project include the National Renewables Cooperative Organization and Invinity Energy Systems, which has installed its batteries in other countries.

“The project aims to deliver high benefit, low risk energy solutions to vulnerable and disadvantaged rural areas with associated workforce training,” Alvarez said.

While the Department of Energy’s announcement is an important step, it does not mean the projects are funded. Instead, they are entering award negotiations that can take up to a year and result in a cooperative agreement between the federal agency and the selected project.

A final price for the project isn’t immediately available because of the ongoing negotiations with the Department of Energy, Venters said, but the Cooperatives are also planning to seek tax credits that could support it.

The Department of Energy picked eight other projects for award negotiation, including some featuring recycled electric vehicle batteries and one in California that used a zinc bromide flow battery to provide backup power to a children’s hospital.

This story was produced with financial support from 1Earth Fund, in partnership with Journalism Funding Partners, as part of an independent journalism fellowship program. The N&O maintains full editorial control of the work.