Duke Energy applied for regulatory approval this week to interconnect its Mount Holly microgrid testbed for energy export.
The utility requested permission for a certificate of public convenience and necessity from the North Carolina Utilities Commission (No. E-7, SUB 1124).
The testbed is used by the 25-member Coalition of the Willing (“COW”) – so named because it constitutes vendors willing to forego corporate confidentiality and openly share their knowledge, products and expertise.
When Duke constructed the 100-kW testbed in 2015, it did not interconnect it for energy export. The facility consumed all of the power generated to meet its internal needs. So the regulatory approval was unecessary.
But now, Duke is advancing the project to the next step. By exporting the energy, Duke will be able to count the facility’s output toward meeting the state renewable energy portfolio standard.
“By connecting the Mt. Holly Microgrid to the Duke Energy grid now, it will enable the export of any excess energy for the benefit of the company’s customers,” said Jonathon Rhyne, a Duke Energy engineer III for distributed energy resources.
The site’s primary goal, however, is to “solve dynamic problems,” he said in testmony before the commission. These include how to best integrate distributed energy into the grid and push proprietary grid technologies to open themselves up to interoperability.
Designed as a platform to test the Internet of Things in a microgrid, the testbed also demonstrates a microgrid’s islanding abilities, the benefits of distributed intelligence, and grid edge capabilities.
Located on 13.45 acres in Gaston County, the microgrid testbed includes:
- A 100-kW solar array
- A 250-kWh DC battery energy storage system
- A stand-alone 10-kW DC PV solar carport for electric vehicle charging
- 500-kW automated resistive load-bank
- Instrumented and automated distribution grid equipment (i.e., reclosers, smart meters, sensors and Phasor Measurement Units)
- Wireless and wired communications devices
- Envision room with smart appliances and operations room with commercial software to monitor and control the microgrid
Duke says in the regulatory filing that it plans to continue to expand the microgrid testbed over several years. Immediate additions include a SAFT 650-kWh DC battery energy storage system, along with an ABB 650-kV battery inverter and an Enphase 5-kVa solar inverter. Duke pegs cost for the SAFT battery at $400,000.
Existing generation equipment for the microgrid testbed cost about $800,000, Duke said. This includes a Parker Hannifin/ATL battery system at $370,000 and Hanwha SolarOne panels with Parker Inverter at $320,000.
COW members include ABB, Alcatel-Lucent, AT&T, CalAmp, Cisco, Elster Solutions, General Electric, Green Energy Corp., ITOCHU, Itron, Leidos Engineering, Moxa, National Instruments, Networked Energy Services, OMNETRIC Group, Parker Hannifin, PrismTech, RTI, S&C Electric, Schneider Electric, Schweitzer Engineering Laboratories, Siemens, Sierra Wireless,
Tollgrade, and Verizon.
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