Tidal power from Pentland firth 'could provide half of Scotland's electricity'

http://www.guardian.co.uk/environment/2013/jul/10/tidal-power-penland-firth-scotland-electricity


The world’s best site for tidal power, the Pentland firth, could provide half of Scotland’s electricity, a study has shown. Photograph: Albaimages / Alamy/Alamy

The world's best site for tidal power, the Pentland firth, could provide half of Scotland's electricity, according to the first robust estimate of its potential. The tidal streams, which surge through the firth at five metres per second, could bring large amounts of renewable energy in reach within a decade if enough government support is available, said the Oxford University engineer behind the new study.

From Anglesey to the Severn estuary to Portland Bill, the UK has the greatest potential for generating predictable, clean energy from tidal channels. Turbines are already operating at Strangford Loch in Northern Ireland and prototypes are being tested in the Menai Straits off Anglesey.

But the Pentland firth is the greatest resource. "It is almost certainly the best site for tidal stream power in the world," said Thomas Adcock, at Oxford University, who led the new work published in the journal Proceedings of the Royal Society A. The water flow is rapid there because the tide shifting from the Atlantic into the North Sea is forced through a narrow eight-mile channel.

The engineers developed new models to find the technical and economic "sweet spot" between the extremes of bringing water in the firth to a standstill and having a free flow. They calculated that underwater turbines strung across the entire width of the firth could generate a maximum 1.9GW of energy, averaged across the fortnightly tidal cycle. That is equivalent to 16.5 terawatt hours of electricity a year, almost half Scotland's entire annual electricity consumption in 2011. As Scotland already produces 14.6Twh a year of renewable energy, a fully exploited Pentland would bring Scotland close to meeting its aim of 100% renewable electricity by 2020.