Success Story: Ocracoke Microgrid
Electric Cooperatives install microgrid on Ocracoke Island
Project Purpose
NC Electric Cooperatives — an organization that supports North Carolina’s 26 nonprofit electric cooperatives — and Tideland EMC — one of those 26 rural electric cooperatives — wanted to increase the reliability of energy on Ocracoke Island. Ocracoke relies on underwater power lines connected to the mainland for electricity. On the island, overhead power lines connect homes and businesses to the grid. Just like any other location, the power can go out on the island on a blue-sky day or when a storm or high winds occur. The two energy utilities installed a microgrid, which allows the cooperatives to provide power to residents and visitors before the main grid can be reconnected.
Quick Facts
- NC Electric Cooperatives and Tideland EMC installed a microgrid and in-home energy conservation controls on Ocracoke Island in 2017.
- Ocracoke’s microgrid project features a solar array, diesel power generation and a utility-scale battery storage system. These items supply energy resources year-round to support grid resilience. The system contributes electricity during periods of high demand and can provide power when the main grid is disconnected.
- The cooperatives also installed over 230 smart thermostats and 40 water heater controls in the homes of Tideland EMC consumer-members on the island. The cooperatives can activate the thermostats and water-heater controls to reduce total load when electricity use is high (NC Electric Cooperatives, n.d.).
- The microgrid and the conservation tools improve Ocracoke Island’s resilience to power outages when the mainland grid connection fails. The project also increases the capacity of the island’s electrical distribution during peak tourism season when demand is abnormally high.
What is a microgrid?
A microgrid is a small electric system that combines local energy resources and control technologies to provide power to a defined area. Usually, a microgrid is connected to a larger system, but it can function independently when needed. The area served by a microgrid is typically much smaller than what would be served by a utility company (NC Electric Cooperatives, 2024).
Spotlight on Equity
Energy bills often strain low-income families. These residents spend a higher portion of their income on energy bills than the average household (Drehobl, Ross, & Ayala, 2020). Residents who were able to install smart thermostats and water heater controls received an annual credit that goes towards their electric bill, lessening the burden of utility costs.
| Key Info | |
|---|---|
| Location | Ocracoke Island, N.C. |
| Estimated Costs | Unavailable |
| Published | March 1, 2024 |
| Project Contact |
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| Lee Ragsdale Senior Vice President of Energy Delivery North Carolina’s Electric Cooperatives info@ncemcs.com (919) 872-0800 or (800) 662-8835 |
| Related Resources |
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- Planning and construction began in 2015. Project managers at NC Electric Cooperatives and Tideland EMC requested bids from vendors.
- The microgrid is connected to a cooperative-owned 3-megawatt diesel generator. An independent contractor installed the roof-mounted 15-kilowatt solar array. Engineers designed the array to withstand winds of up to 140 mph. Another independent contractor conducted the engineering, procurement and construction of the 1-megawatt hour battery bank, transformer and recloser systems. They installed the batteries on a 4-foot concrete base for protection against flooding.
- While the microgrid was being installed, the electric cooperatives developed the behind-the-meter demand response component. Tideland EMC marketed this component to cooperative members on the island. The program offered Ocracoke residents internet-connected thermostats and water-heater control devices at discounted prices. Program marketing highlighted the potential for energy and cost savings and the convenience of controlling thermostat settings remotely. The cooperatives gave residents with smart thermostats or water heater controls an annual credit towards their electricity bills. Tideland EMC can use the internet-connected thermostats and water heater controls when electricity is in high demand (i.e. “demand response”).
- Project managers installed communications equipment that allows for 24/7 remote monitoring and operation of the site. They also conducted several systems tests before completing the project (NC Electric Cooperatives, n.d.).
- The cooperatives considered the project operational in 2017.
NC Electric Cooperatives and Tideland EMC each have an office on the island, and the NC Electric Cooperatives plant manager oversees the microgrid’s operations. Tideland EMC and NC Electric Cooperatives conduct regular testing. A local electric and solar servicing business conducts quarterly maintenance on the microgrid.
- NC Electric Cooperatives and Tideland EMC funded the project. Total project costs are not available.
- NC Electric Cooperatives noted that communication and control technologies for microgrid projects can cost up to $500,000 (2023 estimate) depending on the size and complexity of the project.
NC Electric Cooperatives, Tideland EMC
- The cooperatives deploy the microgrid’s energy resources year-round to support grid resilience. The system contributes electricity during periods of high demand and can provide power when the main grid is disconnected.
- Hurricane Dorian in 2019 was the microgrid’s first major test. Both the main grid and microgrid were forced to shut down due to severe wind and significant floodwaters. However, once the floodwaters subsided, the microgrid’s diesel generator restored power one day before the main grid was reconnected.
- The microgrid increases the capacity of the island’s ability to meet peak electrical demand during tourism season.
A microgrid project's success depends upon committed partners with aligned goals and needs from the project.
Drehobl, A., Ross, L., & Ayala, R. (2020, September 10). Energy Burden Report. Retrieved from American Council for an Energy-Efficient Economy: https://www.aceee.org/energy-burden
NC Electric Cooperatives. (2024). Microgrid Guide: Ocracoke Island. Retrieved from https://www.ncelectriccooperatives.com/wp-content/uploads/2024/02/2024-Microgrid-Ocracoke-Factsheet.pdf
NC Electric Cooperatives. (n.d.). NCEMC Microgrid Implementation Report: Ocracoke Island Microgrid Project. Retrieved from https://www.cooperative.com/programs-services/bts/Documents/Reports/OcracokeMicrogridReport_V01.pdf