North Carolina regulators recently approved Duke Energy Progress LLC's plan to build a microgrid solar and battery storage facility.

Duke Energy Progress, or DEP, in October 2018 filed an application with the North Carolina Utilities Commission for a certificate of public convenience and necessity for the Hot Springs microgrid solar and battery storage facility in Madison County, N.C. The microgrid project will consist of a 2-MW (AC) solar array and about 4 MW of lithium-based battery storage.

The commission in a May 10 order granted a certificate for the construction of the solar generation and approved the Hot Springs microgrid project as a pilot program with the first progress report due no later than six months from the order. The Duke Energy Corp. subsidiary must also submit a progress report once construction is complete.

"Though it is undisputed that the Hot Springs Microgrid should improve reliability in the Hot Springs area … it is not clear that it is the most cost-effective way of doing so. However, the commission finds and concludes that there are additional system benefits from the Hot Springs Microgrid that are material," the NCUC wrote in its order.

Regulators added that these system benefits are "difficult to quantify accurately without [real-world] experience in DEP's service territory."

"DEP will gain valuable experience by operating the Hot Springs Microgrid, and this experience and data collection and analysis will be beneficial in future cost-benefit analyses of projects [that propose] to include an energy storage component," the commission wrote.

Duke Energy said the microgrid is expected to improve reliability in the remote town and defer maintenance of an existing 10-mile distribution line.

The microgrid also is part of Duke Energy's more than $1 billion Western Carolinas Modernization Project under which DEP will seek approvals for at least 15 MW of new solar generation and a minimum of 5 MW of utility-scale electricity storage. As part of this plan, DEP also will retire the 384-MW Asheville coal plant before the end of this year and replace it with the 560-MW Asheville combined-cycle gas plant.

The company plans to add about 300 MW of battery storage to its portfolio in the Carolinas over the next 15 years. (NCUC docket E-2 Sub 1185)