A year after a construction crew accidentally cut power to the Outer Banks, Ocracoke is taking advantage of cheaper solar panels and batteries to make its own energy right on the tiny island. Thousands of people had to evacuate the areas south of the Bonner Bridge at the height of tourist season last summer because of the power outage.
The reasons for doing this are multiple. There's a concern with resilience. The ability for the power system to absorb a shock. A storm. -Tim Johnson
“It was quiet,” said Longtime Ocracoke resident David Mickey. “All the tourists had to leave and it devastated local business.”
Even though tourists were under a mandatory evacuation, Mickey and the other 600 people who call Ocracoke home year-round were able to stay. They received power from a 3 megawatt diesel engine on the center of the island.
“It’s essentially the type of engine you’d find on a ship or locomotive,” said Jim Musilek, with North Carolina Electric Membership Corporation.
The generator has served as the heart of the island’s microgrid since it was installed in 1990. The term microgrid is a broad industry term that refers to any source of energy produced outside a centralized power plant.
Ocracoke’s decades-old microgrid underwent a modernization a couple years ago. Tideland EMC, which is Ocracoke’s local power co-op, added rooftop solar panels and two large Tesla batteries to the building that houses the generator after prices for both dropped dramatically.
“That really was a push. Because the batteries are the major component of the microgrid in addition to the generator,” Musilek said.
The batteries can store up to half a megawatt of excess energy. Tideland can draw on that stored power to meet peak demand during summer months, when thousands of people visit the island and energy use triples from roughly 2 megawatts to 7 megawatts.
It can also use that stored energy when power to the island is cut. Mickey received two hours of electricity every six hours during last summer’s outage.
“It’s enough to keep the food in your fridge from going bad,” he said. “And that’s a big deal.”
But even with the batteries and solar panels, Ocracoke’s microgrid is still just for backup. The generator is expensive to run and dependent on fuel imported from the mainland.
Photovoltaic energy production offers a sustainable alternative to the diesel engine. But the island has been struggling to increase solar capacity, according to Heidi Smith of Tideland.
Rooftop panels need to withstand hurricane winds of 140 miles per hour and land for ground mounts is limited.
“And if you could find land it’s probably going to be in a conservation easement or it’s going to be considered developable lands,” Smith said.
But not all islands share Ocracoke’s limitations. Tesla recently powered an entire island in American Samoa using only solar panels and batteries.
Access to cheaper batteries and solar panels is prompting places like New York and Chicago to build microgrids that can power an entire community.
“The reasons for doing this are multiple,” said Tim Johnson, a professor with Duke University’s Nicholas School of the Environment. “There’s a concern with resilience. The ability for the power system to absorb a shock. A storm.”
Hurricane Maria and Superstorm Sandy showed the vulnerability of electric grids centered around a single power plant.
Puerto Rico is experimenting with solar-centered microgrids after Hurricane Maria left parts of the island without power for months last summer.
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Power systems are slowly trending towards a more decentralized system because there are also concerns a centralized power grid can be hacked, according to Johnson.
And places like California are slowly decentralizing as they shift towards cleaner, more renewable energy. Stone Edge winery in Sonoma, California, is an example of a self-sufficient microgrid powered by renewable energy.
“They have microturbine, they have photovoltaic cells and they have many different battery technologies,” Johnson said. “They can generate hydrogen on site for power and for transportation uses.”
Not only is Stone Edge creating its own energy, its microgrid system allowed it to stay open during last summer’s massive wildfire. And scientists predict extreme weather, like wildfires and coastal storms, will only get worse in the future.
North Carolina Emergency Management is currently looking at ways to make the Outer Banks’ power grid more resilient in the face of this weather. It’s unclear what that power system will look like.
“But microgrids are certainly a piece of the puzzle,” according to Keith Acree of Emergency Management.
