Facts take the wind out of turbine lobby

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Significant flaws undermine the defence of wind ­turbines made by Joss Blamire, policy director of Scottish Renewables (Letters, 8 May).

First, recent research suggests net reductions in carbon dioxide (CO2) emissions, for turbines on peatlands (most of them in Scotland) have been over­estimated.

In addition, calculations of CO2 savings are normally made under the most favourable assumptions, namely current or legacy generation. When compared with the new generation of combined-cycle gas turbines, savings are significantly lower.

Thirdly, it is not clear compensation for the intermittency of wind is adequately included in calculations for savings, particularly if wind becomes an increasing proportion of total generation.

Fourthly, recent research into mature UK and 
Danish wind turbines 
suggests a dramatic decline in efficiency long before the expected ­20-year lifetime claimed by Mr Blamire.

But the most serious flaw in Mr Blamire’s argument is the assumption that questionable reductions in CO2 associated with wind generation will significantly tackle “climate change, the greatest threat to our natural environment”.

Such confident overstatement of the threat, coupled with unsubstantiated faith in wind as a solution to that perceived threat, lacks the credibility necessary to underpin public policy on energy.

(Cllr) Cameron Rose

City Chambers

Edinburgh

Joss Blamire of Scottish ­Renewables justifies the use of wind farms on the basis that they are partly responsible for displacing 8.3 million tonnes of carbon dioxide, which he claims amounts to 15 per cent of Scotland’s total carbon emissions.

Interestingly, he fails to quote the actual figure for wind farms, which, of course, will be substantially lower after taking into account other renewable sources, such as hydro power.

More significantly, his figures fail to take into account Scotland’s real carbon footprint, which has to include the sale of North Sea oil, which could release up to 10 billion tonnes of CO2 over the next 40 years.

The fact is that our wild landscape is being systematically destroyed by ­thousands of wind turbines without achieving any ­material impact on Scotland’s poor record of contributing to higher levels of CO2 in the ­atmosphere.

Alan Black

Camus Avenue

Edinburgh

I AM interested in Joss Blamire’s interpretation on the carbon life-cycle of wind farms and think he would agree that the savings are utterly dependent on how much electricity a wind farm actually usefully produces.

We do not have any meaningful way of storing electricity in this country – I think pumped storage would last around a day, therefore electricity has to be produced minute by minute.

A wind farm has a theoretical capacity based on the wind blowing at the right speed all the time and the grid being able to use that electricity at the moment it is produced.

This is installed capacity. This is an impossible figure so what actually happens is called the capacity factor – a percentage of what could have been produced in perfect conditions.

Stuart Young produced a rigorous assessment in 2011, and, from this, official figures showed that over a 15-month period the average capacity of a group of dozens of wind farms was 22 per cent.

Until then it was assumed to be much higher. For example, on the Blacklaw wind farm website it uses the capacity factor of 30 per cent.

From April 2009 to March 2010 the actual capacity factor of that Lanarkshire wind farm was 19.9 per cent. I see that last year the capacity factor for Blacklaw wind farm was 15.42 per cent.

Surprisingly, developers have applied for an extension at Blacklaw and as, the council has objected, it has gone to a public inquiry.

Professor Gordon Hughes has produced a report that says capacity factors diminish over time, estimating a loss of about a half in 12 years.

I wonder what capacity factor was used for the reports quoted. What a shame scientists and mathematicians are scarce in political circles as even a layman can see this does not add up.

Celia Hobbs

Peebles Road

Penicuik

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