Solar Tribune

North Carolina Island Rolls Out Microgrid


Ocracoke—a popular tourist destination in the Outer Banks of North Carolina— is addressing weather-related power outages with a state-of-the-art battery-based microgrid.

According to the Ocracoke Observer,  a cooperative venture by the North Carolina Electric Membership Corporation (which owns the island’s 3-megawatt diesel generator) and Tideland Electric Membership Corporation (the local utility company) have installed a solar + storage facility at the site of their current diesel generator.  The project is in response to recent winter power outages on the island that overwhelmed the backup generator and left the island’s winter-time population of 900+ residents without power.

Heidi Jernigan Smith, Tideland spokesperson, , Bob Beadle, project manager for the NCEMC’s electric microgrid on Ocracoke, Ocracoke Observer writer David Mickey. Photo by P. Vankevich

The heart of the project is ten Tesla Powerpack units. The 3,575-pound Powerpacks are made up of 16 individual lithium-ion battery pods which are built with a cooling and heating system adapted from the Tesla Model S automobile batteries. Each unit is capable of storing up to 200 kWh of energy.

“This is a learning laboratory for Tideland,”Heidi Jernigan Smith, company spokeswoman told the Observer.  “We’re exploring the potential for a microgrid.”

Smith pointed out that by no means could the Powerpacks power the island during an outage on their own, but they could assist the generator during start up to overcome the initial demand placed on the generator which often exceeds capacity.

For example, on a freezing day in March 2015, power went off from Hatteras to Ocracoke due to “galloping lines,” or ice on the power lines that shorted the power. Tideland tried to start the island’s 3-megawatt generator, but even in the winter with mostly just residents here, the electric usage exceeded the generator’s capacity.

“The Tesla batteries could potentially help us get over that start-up load,” Smith said. “It will be interesting to learn what benefits can be derived from the various microgrid components over time.”

The Rise of Microgrids

The Ocracoke project is just one of several microgrid pilot projects in the news in recent months.

In January, Kaua’i Island Electric Cooperative announced that it will be purchasing 11% of its generation from a new solar plus storage facility, below the cost of its current fossil fuel-powered generation. This is huge news, even in spite of the fact that Kaua’i is one of the nation’s most expensive energy markets. As storage prices start to come down, “low hanging fruit” like Kaua’i will be the first to be picked by solar + storage developers. The Kaua’i project will also use the Tesla Powerpacks in their system.

Not all of the microgrid projects are in remote areas. Last year, we reported on the new Brooklyn Microgrid Project. The New York City project aims not to replace utility power, but like Ocracoke, to add “firming” to the local grid by providing peak shaving at times of heavy loads and creating a neighborhood back-up system to avoid the types of power outage problems experienced by Brooklynites during Hurricane Sandy.

Projects Like Ocracoke, Kaua’i and Brooklyn all serve as excellent test beds for what many see as the future of distributed energy generation and a major paradigm shift in how utility companies do business. While Tesla is leading the way in high-profile microgrid projects, competitors like German battery giant Sonnen are entering the microgrid market. Microinverter pioneer Enphase and even iconic auto manufacturer Mercedes are getting into the game.

“Tideland is pleased to serve as host for NCEMC’s first microgrid project and the opportunity it affords our employees to learn about next generation energy technologies,” said Paul Spruill, Tideland’s chief executive officer and general manager. “We are also appreciative of our sister co-ops across the state for funding this project, which will all stand to gain from our collective knowledgebase as the energy industry evolves.”


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