John Muir Trust Study Reports Wind Farms at 22% Efficiency

Front page article on today’s Sunday Times (UK) reports (behind a paywall so no link):

“One of Scotland’s leading conservation bodies has called on ministers to ditch their ‘obsession’ with wind power amid evidence that turbines produce about a quarter less energy than developers claim. The John Muir Trust (JMT) said a study of 47 wind farms in Scotland and England over a 13-month period revealed that they ran at 22% capacity. The wind farm industry has claimed that during the course of a year a turbine operates at 30% efficiency.”

The paper reports Helen McDade, head of policy at JMT says

“Wind farms are costing huge amounts of money, much of it from consumers’ bills, yet it isn’t delivering what the industry claims. The economics of this is a scandal and needs to be urgently reviewed.”

JMT’s results are in line with my initial analysis and is consistent with that experienced in Denmark over the last 25 years. While I have what I think is good wind power generation data from National Grid, I don’t yet have much authoritative information about what wind farms are reported in the National Grid data to enable a good assessment of the “efficiency” or load factor.

I’ve looked the JMT website, and I don’t see any reference to any report. I’ve sent them an email asking for more information.

More posted here as I get insights from them or elsewhere.

I’ll close with an interesting quote attributed in this article to Niall Stuart, chief executive of Scottish Renewables, which said that the winter of 2009/2010 was one of the calmest on record and that it was “no surprise” that output figures for the year were below average. Further they report he said:

“It’s well understood that there are variations with and between years, but no form of electricity works at 100% capacity 100% of the time”

We do not expect 100% efficiency (thermodynamically impossible!), and Mr. Stuart suggesting this as a reasonable thing “not to expect” is a red herring probably meant to help justify continued support in future investments in “high-yield” wind energy generation and usurp the figures reported by JMT. But there is a big difference between design load factors of 30-45% [I’ve heard some wind farm developer’s expect the high-end of this range as that’s what they say has been achieved in Scotland … as yet an unconfirmed “sighting”, though] and getting 22% as reported by the JMT. The first step, seems to me, that we need to get our expectations closer to reality, e.g. get the numbers and system designs right, to help make prudent investments where warranted.

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Update 2 Jan 2011: “Andy” reports at Bishop Hill web site that this JMT report came in out September 2010 (!) and that JMT has always been against wind. A mystery, then, why the Sunday Times doesn’t say either of these things (date of the report or the position of JMT) and why it would be put on the front page of the Sunday Times today. I can’t take exception to the blatant message–that wind farm efficiencies appear to be well under that claimed. That concerns me as we don’t need more “toxic investments”. What else is going on is unknown to me.

Update 3 Jan 2011: The referenced article appeared in the Scottish edition of the Sunday Times. It reportedly was not published in other editions.

Update 5 Jan 2011: I have received email from Helen McDate at JMT. She indicates that they do not have a report yet on this topic which they can send me. She also reports

“I can tell you the data quoted is based on analysis over 14 months from November 2009 to December 2010 and that we hope to have a report looking at 26 months data to December 2010 in due course. I note from an indirect link from your website that there was the suggestion that this is old news. On the contrary, the data runs to December 2010.”