Granite Geek: A Solar 'Microgrid' On Star Island May Be A Model For The Mainland

Apr 7, 2015

For years some ships have brought tourists and conference goers to Star Island. Others have brought diesel fuel to run the island's generators. But a new solar farm is generating most of the island's energy.
Credit Sara Plourde / NHPR

Life on New Hampshire’s Isles of Shoals isn’t always the same as it is for those of us on the mainland. But a solar energy project there may point the way toward the future of energy all over the region.

Here to explain is David Brooks, who writes the weekly Granite Geek science column for the Nashua Telegraph and GraniteGeek.org. He wrote about the Star Island installation in his most recent column.

 

The Star Island installation is the largest off-grid solar farm in New England. How big are we talking?

It's 130 kilowatts, about 420 panels, and covers about a half acre of the island - the island is 44 acres, I believe. Importantly, it's connected to a 600 kilowatt battery system, which replaced a couple of diesel generators so that they can draw electricity when the sun isn't shining, as it has an annoying habit of doing.

They say in the wintertime, when obviously there's just the caretaker there, and even in the spring and fall, when it's just caretaker and staff, it should be able to provide all their electricity. In the summertime, when the tourists descend and they have their conferences and whatnot, it should provide about 60 percent of the island's electricity.

There were quite a few reasons behind this change. One was simply that they're not hooked up to the grid.

Exactly - they're six miles, I think, off the shore, and no one's run a cable out to them. So they've always had their own generator on the island that's powered by diesel. They're wonderful machines, they do a fabulous job at producing electricity but they tend to be noise and suck up a lot of fuel. That's a problem when you're on an island and you need to get your diesel. They had their diesel brought in from Portland, Maine - a couple shipments a year, it's totally difficult. So there were definite benefits to switching to solar.

My first thought was, what about wind power? I mean, there you are out on the ocean. But it sounds like that wasn't necessary the most optimal choice.

That is surprisingly often the case with wind. Wind is a fabulous resource in the right places, but the right places are fewer and further between than laymen like you and I think. It's not enough that it's really breezy occasionally. It's got to be breezy enough for enough of the time, and that really wasn't the case, particularly in the summertime

Along with the new sources of energy, there's also an effort to have the people on the island conserve energy. They're using less.

This is a common theme. One of the big power sucks on the island is creating fresh water. They use a reverse osmosis system that basically pushes seawater through a filter so that the salt stays on one side and the water goes on the other side. Pretty standard method, but it uses a lot of electricity. They couldn't really do away with that, but they were able to do away with some other things, reduce their usage - they even talked about the dishwasher. You wash a lot of dishes when you have hundreds of guests coming in the summertime. So they use new systems that use less power, use less water - which is a good thing - and therefore also send waste water to their waste water treatment system, which is another issue on islands.

How feasible is it that we might see this same approach in areas that are currently on the grid?

Microgrid is the term du jour for this. It's becoming feasible enough for both cost and technology reasons to establish microgrids, which is [to] cut yourself off from the grid because you have enough batteries to use your own electricity you've generated on site. Colleges or large company sites or jails - big institutions that are self-contained - can really start realistically thinking about whether it would be better for them to be separate from the grid.

It's still a small thing, but New York state, for one, has got seven, I think, research sites around the state where they're looking at establishing microgrids, usually in places where the grid has some issues. Instead of spending lots of money and building more wires and more pylons - and we know how much people like that - instead of doing that, maybe you can establish a microgrid for part of the usage, and then you won't need to upgrade your grid. That's part of what's being looked at and it's potentially a real game changer.

One of the potential selling points for projects: the people on Star Island say it a lot quieter now. Makes it easier to listen to science conversations on the radio.

Which is exactly what everybody wants to do.