Monday, June 01, 2009

"Potentially astonishing" discovery

The world's offshore wind resource may even be greater than originally thought. More focused and precise measurements of the winds off the Scottish coast raise a couple of points worth noting. First, the winds in some locations much stronger than those found off the coast of England. However, scientists have also discovered that wind speeds can vary significantly within the same offshore wind regime. This second revelation suggests that the need to install anemometers at the specific sites being considered for windfarms is more important than ever. (GW)

Blown away by the North Sea

Offshore wind farms in Scottish waters ‘could produce 40% more power than English equivalents’

By Steven Vass
Sunday Herald
May 25, 2009

SCOTTISH NORTH Sea zones earmarked for offshore wind farms have the potential to produce 40% more electricity than their English equivalents, new research has found.

The study by Edinburgh-based Atmos Consulting and the US space agency Nasa, which follows up on related findings published in the Sunday Herald last month, also indicates for the first time substantial variations in the electricity-generating potential of different areas of the same offshore zone.

Given existing fears of the economic viability of offshore wind, this means that the exact location of a wind farm within a zone could make the difference between success and failure.

Although the discovery is still very tentative, one expert described it as "potentially astonishing".

The study uses Nasa satellite data covering the Moray Firth and Firth of Forth zones in Scotland and the Hornsea (Yorkshire) and Norfolk zones in England, all of which are up for tender by the Crown Estate in the so-called "round three" awards later this year.

Although Atmos would not release the wind speeds it had recorded within each zone, it said that Moray, Forth and Norfolk had been found to respectively produce 42%, 25% and 10% more power each year than Hornsea.

The conclusions will further underline the importance of Scottish territorial waters to the offshore wind industry. Given that Norfolk is further south than Hornsea, it also challenges the long-held assumption that wind speeds are greater further north.

Jenny Hogan, senior wind energy officer at Scottish Renewables, said: "This study helps us to see more clearly the picture of the rich wind resource that Scotland boasts. We already knew Scotland had a quarter of Europe's wind resource, but this work shows just how competitive these individual Scottish North Sea sites are.

"There is a huge prize to be won by Scotland in generating clean green energy to help combat climate change, reduce our dependence on imported fuels and create jobs - this positive new data should build even more investor confidence that the prize is in our reach."

Atmos associate director John Sturman said he believed the findings would be seen as the most useful to date because previous North Sea measurements have been taken from oil rigs and ships and not from the actual zones.

The Nasa data covers a period of more than 20 years, far longer than any previous study. Sturman said this was likely to help potential developers make much more confident calculations about the power output of their sites. He also stressed, however, that scientists regard 50 years as the minimum period to establish a compelling trend and that the Atmos data had to be read with that in mind.

John Aldersey-Williams of Aberdeen-based renewables specialist Redfield Consulting welcomed the findings.

He said: "I am not at all surprised that it's windier in the Moray Firth than in Norfolk, but I am a bit surprised that Norfolk is windier than Hornsea."

Of the variation within one of the individual zones, which Atmos found to be as much as 14%, Aldersey-Williams said this would be "astonishing" if it turned out to be a general trend.

"If you are in the middle of the sea, it is hard to know why one area 100km to the east or west or south would be systemically windier. I would struggle to say what the consistent influencing factor would be, unless the shoreline was still an influence, which of course it could be," he said.

Sturman said the Atmos research had been checked thoroughly by electricity giant E.ON, which is buying data, and that the 14% variation was a consistent 20-year trend.

"It's a much larger figure than people are expecting at the moment. It can mean the difference between making a wind farm economic or not," he said.

The round-three Crown Estate awards cover development zones that are many kilometres away from shore, with the four analysed by Atmos all being about 60km out. There have been several different award phases for sites closer to the shore, which in Scotland saw 10 proposals get Crown Estate permission in February in areas as diverse as the Moray Firth, Tay Estuary and Kintyre.

Scottish and Southern Energy subsidiary Airtricity was the big winner, with four awards, while ScottishPower, RWE, E.ON, Mainstream Renewable Power and Sea Energy were also among the successful bidders.

The Atmos research is the result of a non-exclusive contract it has signed with Nasa to get access to detailed satellite data of UK territorial waters dating back to 1987. The Nasa satellites measure UK wind speed using a device called a scatterometer, which analyses reflections on the water surface through radio signals. Atmos then correlated this with data from meteorological masts that have been offshore for the past two to three years.

The findings published in the Sunday Herald last month suggested that the UK offshore wind industry is becoming up to £400 million more valuable every year thanks to the fact that summer wind speeds have been rising substantially over the past 20 years.


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