Utility-scale FlexGen batteries at a substation in Minneapolis provide energy storage, support grid resilience, and benefit consumers. Photo courtesy of FlexGen.

Battery storage technology allows us to store energy for later use, which will ultimately be the key to expanding the reach of renewable energy and achieving our carbon emissions reduction goals. Importantly, it also plays a critical role in reducing peak demand, which in turn lowers wholesale power costs, reduces the need for future infrastructure projects, and ultimately delays or lowers the number of future rate increases.

In 2018, Cypress Creek installed 12 utility-scale solar and storage projects on BEMC’s system that can store and dispatch 6 MW of electricity; and in 2019, BEMC installed a 750 kW system at Military Ocean Terminal Sunny Point. Now, the co-op has plans for a 5 MW system adjacent to our Zion Hill substation that is slated for completion in the second half of 2022.

The Zion Hill 5 MW battery storage system will be owned by North Carolina Electric Membership Corporation (NCEMC), the trade organization that uses our collective buying power to purchase wholesale power for the 26 electric co-ops in the state. All North Carolina electric cooperatives benefit from the wholesale power cost reduction achieved through any battery storage system NCEMC installs in our network, and as the host co-op, we’ll get an additional benefit from the Zion Hill system and save even more during peak times.

"The system will consist of two long pads with two long rows of back-to-back, 8-foot-tall cabinets. Each cabinet will have its own set of batteries."

The system will consist of two long pads with two long rows of back-to-back, 8-foot-tall cabinets. Each cabinet will have its own set of batteries, as well as its own air-conditioning system and fire suppression system. The pads will be 61 feet long and 12.5 feet wide, for a total 1,525 square-foot footprint. The Bring Your Own Thermostat program, which works to reduce peak demand by adjusting participating members’ thermostats, saves about a kW per thermostat when they are called upon. For comparison, the Zion Hill battery storage system will discharge the equivalent of 5,000 thermostats, reducing the peak by that much. The 5 MW system can discharge 5 MW for a full two hours, greatly adding to our efforts to suppress wholesale power rates.

Additionally, the Zion Hill system has the capability to be configured to provide power, during an outage, to a geographic location near the system. It would operate as its own microgrid and could be used strategically, possibly providing power to Virginia Williamson Elementary school to facilitate its use as a shelter during a weather event. But it is its primary capacity, reducing peak demand and therefore lowering wholesale power costs and reducing the need for, or amount of, future rate increases, that will provide the initial, and substantial, return on investment. Hopefully, there will be opportunities to replicate this project if all goes as planned.