On the Isle of Eigg, the arrival of the ferry always elicits a flurry of activity. Islanders crowd the pier to greet friends and family or collect letters and parcels from the mainland, some 10 miles away.

At the cozy tearoom by the jetty, kettles boil water for hot drinks and bacon sizzles on the grill.

In the old days, dealing with the sudden rush of customers required careful calculation. A limited power supply produced by the tearoom's diesel generator meant the oven couldn't be switched on at the same time as the dishwasher. The small freezer was switched off at night.

But on Feb. 1, all of Eigg, a spectacularly scenic island off the west coast of Scotland, switched on its own continuous, clean, and renewable energy supply.

Before, electric service was spotty. Residents mostly relied on noisy, expensive diesel generators or mini-hydroelectric generators. Now, the islanders, who number just over 80, enjoy luxuries of modern living that mainlanders take for granted.

"I can use the deep fry and the dishwasher at the same time – it's great!" says Stuart Fergusson, who works at the tearoom. "Before, when the power used to go, I'd have to rush up the hill to the fuse box and jiggle about with it with a half-cooked grilled sandwich on the [grill]. Things are so much better now – we might even buy another freezer!"

The island makes its electricity through a combination of solar panels, wind turbines, and a hydroelectric generator, all scattered strategically across the island and linked in a single grid. Storage batteries provide a backup. Two diesel generators stand ready to provide emergency power.

Each household is allocated a ration of electricity not to exceed a draw of 5 kilowatts (kW) at any time (the equivalent of turning on 50 100-watt light bulbs all at once). Even at the full ration, that's only about one-half to two-thirds the amount used by a household in Britain, though islanders can supplement that with a diesel generator or heat from a wood stove. If the islanders use too much electricity and trip up the system, they will have to pay £20 ($40) to be switched on again. Businesses are allowed a draw of 10 kW. All these conditions were agreed to by the residents.

Kathleen Miller is a young mother of two who is descended from a long line of islanders. She lives in a white cottage on the opposite end of the island from the pier, with breathtaking views of the beach below and the neighboring island of Muck. Author J.R.R. Tolkien is rumored to have stayed there.

Ms. Miller remembers the old days.

"We used to switch off the generator at night, so there was no light once you went to bed. You had to use candles or gas lamps," she says. "But now I can read in bed and put the light on when I get up. And I'll finally be able to use that toaster I got as a wedding present years ago."

The electrification of Eigg began in 2006, after members of the Island of Eigg Heritage Trust, a locally owned and managed body that runs the island's affairs, commissioned feasibility studies on the best way of connecting islanders to one main power grid.

At more than $8 million, the option of tapping the mainland's power grid through an underwater cable was far too expensive.

"We didn't want to have our electricity coming from nuclear power on the mainland anyway," says Maggie Fyffe, secretary of the trust and fundraiser for the project.

The islanders decided on a combination of solar, wind, and hydropower. They raised $3.2 million from a number of sources, including the European Union's regional development fund, Britain's national lottery, the Scottish government, and local and regional government programs. A newly created company, Eigg Electric, a subsidiary of the trust, appointed a project manager and partnered with an electrical company from the mainland.

"It was a very exciting project, as integrating all three renewables had never been done before," says Eigg Electric co-director John Booth, a retired industrial relations consultant from England who moved to the island in 2000 with his wife to renovate an old house.

When the idea for the project took hold, he poured himself into it as a full-time volunteer. No one knew if the grid would really work, he says. "We did our homework, and when we came up against something we didn't know, we went back to the physics books."

The project could not have developed had a defining event not taken place on Eigg just over a decade ago. For centuries, the entire island had been owned by a series of single landowners, meaning the residents were renters who could never own land. In 1996, the exasperated islanders teamed up to buy the island for themselves. Donations flooded in from across Britain and from as far away as Detroit.

In June 1997, the islanders took ownership of Eigg. In the following years, they built a new jetty; renovated the village hall, school, shop, and tearoom; and, in the most expensive project to date, created the new electrical grid.

"Before the buyout we were just surviving. Now we can look ahead and build a solid future," says Camille Dressler, the island historian, who was drawn to Eigg as an anthropology student and never left. "The electri­city is part of this dream which has come true. It's very liberating."

Critics of the new scheme – none of them islanders – say it was too expensive and a waste of taxpayers' money. On the ferry, one visitor pointed out that for the price of the grid per head, every inhabitant could have been given a small yacht.

But for Booth, the benefits of Eigg's green power outweigh the cost. Renewable energy doesn't risk becoming much more expensive, unlike the diesel fuel used to power the old generators. Islanders also say their pricing system is fairer.

"On the mainland, everyone can use as much electricity as they want. But market forces dictate what the price will be, and the people who can pay, will. That penalizes the poor," Booth says. "Our system has a much more social aspect to it. Everybody is allocated the same amount of electricity, so everybody pays the same. That way everyone benefits.

"Not only is our system sustainable, but people actually have to think about how much power they can use."