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Tides, waves and whisky
By New Scientist  |  Published October 18, 2011
Ten underwater turbines will generate electricity from the tidal stream flowing off Islay

The island of Islay is fast becoming a poster child for clean living by harnessing the power of the sea -- and even its world-famous distilleries are going green

On the remote island of Islay, off the west coast of Scotland, locals can raise a glass of whisky with a clear conscience. Not only is the island fast becoming a poster child for clean living by harnessing the power of the sea that surrounds it, but its world-famous distilleries are also going green.

Islay is the southernmost of the Hebrides islands. Its location on the edge of the Atlantic Ocean means its 3500 inhabitants are subjected to blistering winter gales, powerful tides and tempestuous seas. Yet it is this very remoteness that local communities are now embracing, as they transform their home into a pocket of low-carbon energy generation and a test bed for cutting-edge technology.

Its efforts are largely the work of the Islay Energy Trust, a community-owned organisation formed in a bid to maximise the island's energy resources. The trust hopes to build on the success of the Limpet, the world’s first wave-power device to be connected to the grid. Installed by Inverness-based Voith Hydro Wavegen in 2000, the 150-kilowatt Limpet is fixed to the shore and generates energy as incoming and outgoing waves push and pull a column of air through a turbine.

Islay's pioneering wave-power machine

Tidal giants

The Limpet is set to be dwarfed by the world's first array of tidal-power generators, due to be installed in 2013 in the Sound of Islay, a narrow strait between the island and its neighbouring island of Jura. This tidal farm will consist of ten 1-megawatt turbines developed by Norwegian firm Hammerfest Strøm.

The suite of 30-metre-high turbines will resemble a wind farm sitting on the seabed. The turbines generate electricity as their blades are moved by hefty tidal currents that flow through the strait at up to 3 metres per second. The blades can change their pitch through a wide range of angles so they can harvest energy no matter which way the tide is running.

The farm will cost about £50 million so the electricity generated will be relatively expensive. The pay-off is that it gives the project's developer, ScottishPower Renewables, the chance to trial the system before beginning work on a 95-megawatt tidal array at the Ness of Duncansby off Scotland's wild north coast.

For Islay, the tidal turbines offer the chance to produce more electricity than its inhabitants consume. "Islay only uses about 6 megawatts, so when the array is generating 10 megawatts, six will come to Islay and four will go back to the mainland," says Andrew Macdonald of the Islay Energy Trust. During slack tides, which last a few hours each day, Islay will continue to import energy from the mainland.

Distilled genius

Big companies like Scottish Power are not the only ones investing in Islay's green initiative. The whisky industry is getting in on the act, with two of Islay's eight distilleries using their waste as forms of clean energy.

Bowmore Distillery, for example, is using waste heat generated during distillation to both pre-heat water needed for its production process and to heat a local swimming pool.

Bruichladdich Distillery is planning to use its watery post-distillation waste, known as pot ale, to produce the electricity and heat needed to power the plant. Microbes will convert organic material in the pot ale into methane and carbon dioxide. This biogas will be burned to produce electricity and heat, which can be recycled into the plant.

Islay is blessed with generous renewable energy resources, but it's also the mindset of the locals, who are subjected to frequent power cuts from the mainland and so have decided to take their energy needs into their own hands. "They understand the fragility of the system, and how important energy is," MacDonald says.

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