Duke seeks approval of solar/battery microgrid in western North Carolina

Duke Energy Progress LLC applied Nov. 10 to the North Carolina Utilities Commission for a Certificate of Public Convenience and Necessity authorizing the construction of the Mt. Sterling Microgrid Solar and Battery Storage Facility on National Park Service (NPS)-owned property in the Great Smoky Mountains on Mount Sterling in Haywood County, North Carolina.

The Mt. Sterling Microgrid would consist of an approximately 10 kW (dc) solar photovoltaic electric generation and approximately 95 kWh zinc-air battery storage.

Said the application: "This Microgrid represents an opportunity for DEP to procure, install and monitor distributed energy technologies that will allow DEP to provide a safe, cost-effective and reliable solution for serving a critical customer in lieu of performing costly upgrades to and ongoing maintenance of an existing distribution feeder, in an extremely remote and rugged mountain region in Western North Carolina.

"In view of the size of the Facility, engagement from the NPS through its environmental compliance process, the fact that implementing the Microgrid project will create a net cost savings for retail customers, and the time sensitivities of the construction phase which needs to be completed by mid-2017, DEP respectfully requests that the Commission adopt an expedited procedural schedule and consider waiving a public or evidentiary hearing if there are no intervenors or protests filed.

"The Facility will be constructed as a solar PV electric generation facility and a battery energy storage system on Mount Sterling in Haywood County, North Carolina, and will be situated on one parcel totaling approximately 5,000 square feet…. The entire Facility is located within the Great Smoky Mountains National Park, which is under the jurisdiction of the U.S. Department of the Interior. The Microgrid will ultimately operate independently from the utility grid for the purpose of maintaining electric service to an NPS-owned communication tower and eliminate ongoing operation and maintenance (‘O&M’) and upgrade costs of an existing four miles of 12.47 kV distribution feeder with the intent to de-energize and decommission a portion of the feeder following a successful deployment and validation test of the Mt. Sterling Microgrid.

"The Facility consists of PV panels affixed to ground mount 20 degree fixed-tilt ballast-mounted racking and General Electric charge controllers regulating power transfer to loads and a battery energy storage system (‘BESS’ or ‘battery’). A Fluidic Energy zinc-air BESS is connected and sized so the Facility can provide continuous service to the customer load. The nominal storage capacity for the PV will be approximately 10 KW DC. The nominal storage capacity for the battery will be approximately 95 kWh. The generation source of the Facility’s power will be 100% renewable. Additional equipment to support the Facility will include circuit breakers, combiners, surge arrestors, conductors, a disconnect switch, connection cabling and an Automatic Transfer Switch (‘ATS’). The anticipated useful life of the project is expected to be 25 years.

"The Facility will not be interconnected on the DEP-owned 12.47 kV distribution feeder. The grid feed from the DEP-owned feeder will only be used for emergency cases should the Mt. Sterling Microgrid fail during the approximately three to six month cure (test) period."

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.