When an Old Law Gets in the Way of a New Microgrid

By Elisa Wood, Microgrids Now

No one would dispute that electric regulation is complex, at times so byzantine it gets tied into knots of unintended consequences.

Such is the case for a group of small islands off the coast of Maine suffering from expensive power reliability issues. They would like to fix the problem with a microgrid, but are stymied by a law passed a quarter of a century ago, before microgrids became a serious alternative.

The Cranberry Isles, south of Bar Harbor, Maine, rely on power cabled underwater from the mainland. Its winter population is under 200, but it can swell two to three times in the summer.

When power outages occur there, it’s a big deal, and that can happen pretty easily. A car hits a pole, a tree falls on a line, or a coastal storm churns up on the islands that increasingly flood because of sea level rise.

“And it’s not just that we lose power, but if we lose power for more than 20 minutes to an hour, we lose the diversity that’s built into our system. And this is particularly important to understand, especially in the summer, when there are a lot of refrigerators powered up on the island,” said Alden Hathaway, an energy consultant and president of the Cranberry Isles Community Solar Association. “They come back on at the same time because they haven’t been cooling their important load.”

That sudden inrush of current trips the newly restored line, and the power goes out again. The mainland utility, Versant Power, must then send a bucket truck out to the islands, disengage the line, and re-engage it bit by bit.

It’s expensive for the utility and irksome for the islanders.

So a group of islanders is investigating a grid-connected, solar plus storage microgrid to keep the power flowing when the grid goes down.

It may sound like the islanders’ problem is solved. But no. Here's why...

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