Before we delve into details of creating a clean-energy microgrid on scenic Appledore Island, a question: Would you rather hear about battery chemistry, recharge rates and load-balancing, or would you rather hear about bird poop on solar panels?
Yeah, that’s what I thought.
“We initially put some effort into cleaning the panels, but honestly we just kind of let it go and hope for rain,” said Ross Hanson, head engineer of the Shoals Marine Laboratory.
Come on – there has been a teaching and research facility on Appledore Island for half a century! You’re telling me this cutting-edge lab doesn’t have a high-tech response to gulls’ goopy white mix of feces and urine?
“Last year we looked at a special coating on the panels that was supposed to help clear it, a nano-coating. But honestly, we don’t think it made a huge difference,” Hanson said.
Case in point: My phone conversation last week with Hanson and Jennifer Seavey, executive director of the Shoals Marine Laboratory, was repeatedly interrupted by a gull that had landed outside their window and wanted to make sure we received our daily ration of ear-piercing avian screams.
In between bird cries, we discussed the evolving microgrid on Appledore Island which, like its larger neighbor Star Island and other members of the Isles of Shoals, does not have a power connection to the mainland.
Islands have long depended on generators burning fossil fuel, usually diesel, for their electricity. That works pretty well, but it’s expensive and stinky. The arrival of cheap solar power and ever-cheaper batteries pushes many of them to dump the diesel, for environmental and budgetary reasons. By doing so, they create a new kind of power grid.
The Shoals Marine Lab, the famous research institute run by UNH and Cornell University on Appledore, started switching to solar power back in 2007 as part of an overall sustainability push. This year they’ve ramped it up, expanding solar power to 62.5 kilowatts with the goal of powering the whole multi-building facility, including the power-hungry seawater pump that is vital to the marine lab.
“We used to burn over 10,000 gallons a summer. The last two summers that’s been about 1,500 gallons,” Hanson said. “We’re on track to probably cut that in half with this new system.”
The full system turned on last month and is still in the process of being tweaked.
The big obstacle, of course, is providing electricity when the sun isn’t around without using the generator. On Appledore, that means using electricity stored up during the day in batteries, with help from a small wind turbine. The turbine is more useful in winter, when much more wind blows off the coast of New Hampshire, so it takes lots of batteries to make it through to dawn without having to fire up the 27-kilowatt generator.
“We made it through the night a few times since June,” Seavey said. I could almost hear her rubbing her hands in glee.
The project has long been supported by the power utility Unitil, even though the islands aren’t utility customers because they’re not connected to the mainland grid.
It started with former Unitil CEO Mike Dalton, who is a fan of the Isles of Shoals and of the marine lab. The company has funded engineering interns at the lab for some time and increased the commitment this year, including funding a communications intern.
Alec O’Meara, Unitil spokesman, said there’s a payback for the utility in supporting this microgrid project.
“They have reached a point where they are, through solar arrays and battery storage, all these things we talk about on the mainland, closer to what a modern grid will look like for us,” O’Meara said. “It’s useful seeing these ideas, mostly still on the theoretical side, being implemented … seeing how all these technologies integrate with each other.”
“If you’ve ever tried to build something, you know there’s that value of seeing things work and seeing the types of things you have to deal with on a regular basis,” he said.
Yes, including bird poop.
“They’re seeing how much is this impacting efficiency; how regularly do we want to clean it to make sure we’re getting maximum output. If you have an array on your roof, how often are you going to be cleaning your roof? That’s interesting,” O’Meara said.
Of course, more technical issues are being worked out, too.
“We’re looking at how often, how much to draw down the batteries, thinking about their lifespan,” Seavey said. Tweaking the island’s usage and system configuration so that batteries don’t go through the draw-down-and-recharge cycle more than once a day is an important part of what’s being learned; for example, on a sunny day a reverse-osmosis system could be used to create extra fresh water, which is a limited resource on the island, reducing the need of power for pumping when the sun’s not around.
“We hope to have it dialed in before we leave this summer,” Hanson said. “We want to do some cool stuff down the road, but you have to do just one change at a time, so you see how the system reacts or doesn’t react, and go on from there. If you change too many things at once, it’s hard to know what happened.”