Duke Energy’s planned Hot Springs microgrid in western North Carolina moved closer to fruition earlier this week when state regulators canceled an evidentiary hearing scheduled for Feb. 25.
In canceling the expert hearing, the North Carolina Utilities Commission noted that there was public support and no opposition to the proposed solar-plus-storage project.
This was the second hearing scrapped on the project because of lack of opposition. In January, the North Carolina Utilities Commission cancelled a planned public hearing.
The evidentiary hearing had been scheduled to take up issues raised by Public Staff, the state advocate for utility customers. But those issues were settled in a confidential settlement.
“This all sounds very positive to us,” Duke spokesman Randy Wheeless said. “Hopefully, we present our revised order at the end of March, and we are off and running with first large scale microgrid project in North Carolina.”
Meanwhile, some details of the project are being worked out.
“This is first of a kind technology at this level in North Carolina. Any time you have this, there are details to be worked out,” Wheeless said. One of the issues, on the regulated side, is determining the value of battery storage, he said.
The Hot Springs microgrid facility would consist of 2 MW of ground-mounted solar photovoltaic panels, a 4-MW battery storage system, and a microgrid controller. The useful life of the facility is estimated at 25 years with anticipated replacement of the battery cells after year 10, depending on the degradation curves. The cost of the project has not been made public.
Hot Springs is a remote town of about 600 people served by a single, 10-mile, 22.86-kV feeder line that is prone to outages, especially from bad weather.
When the microgrid comes online, expected in early 2020, it would be able to provide Hot Springs with enough power to serve about 90 percent of peak load for four to six hours, if the town experiences an outage. When not acting as backup power, the microgrid would provide the grid with services such as frequency regulation and voltage support, Wheeless said.
Hot Springs microgrid first of more?
He called the project a “niche application” and an alternative to a more traditional solution.
“The microgrid concept is cheaper than trying to run another feeder to the community,” he said. “We have a lot of remote areas.”
The Hot Springs microgrid project could be the first in a line of similar projects to come, he added.
The Hot Springs project was, in fact, one of two battery projects representing a total investment of $30 million in the western Carolinas that Duke announced late last September. The other was a 9-MW lithium ion battery system at Duke’s Rock Hill substation in Asheville. Duke says that battery, which is expected online in 2019, would help support the grid by providing frequency regulation and other grid services. Because it does not include generation, the Asheville battery project did not require North Carolina Utilities Commission approval.
Since that September announcement, Duke added solar power to the Hot Springs project.
Part of Duke modernization plan
Both battery projects are part of Duke’s Western Carolinas Modernization Plan, announced last October. More broadly, Duke’s integrated resource plan calls for the utility to invest $500 million in about 300 MW of energy storage projects in the Carolinas over the next 15 years.
Under the modernization plan, Duke also plans to close its 376-MW Lake Julian coal plant in Asheville and replace it with a 560-MW combined-cycle, gas-fired plant that would also include a solar power array.
Duke has built another solar-plus-storage microgrid project in an even remoter location. The Mt. Sterling microgrid consists of 10-kW solar installation and a 95-kWh zinc-air battery deep in the Great Smoky Mountains National Park. It provides power to a communications tower in the park and eliminated the need to replace miles of aging transmission lines and allowed for the removal of four miles of distribution lines. It also allows 13 acres of wilderness to return to its natural state. Like the Hot Springs project, there was no opposition to the Mt. Sterling microgrid, so the North Carolina Utilities Commission cancelled a planned hearing.
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