Wind critique falls flatus

August 19, 2010

Martin Cohen cites wind power in Denmark as an example of how well-meaning government initiatives can do more environmental harm than good ("Profits of doom", 29 July). However, his analysis is questionable.

He claims that wind power generates just 4 per cent of Denmark's electricity: in fact, the figure is about 20 per cent. He further asserts that almost all of it is wasted: perhaps he regards electricity exports as waste. The Danish grid is well connected to its Nordic neighbours and Germany, and it makes perfect sense to export excess wind-generated electricity, balanced over time by imported hydroelectricity from Norway and Sweden.

Cohen claims that wind power must be matched by an equal capacity of back-up generation. This is misleading: conventional "firm" generation would be needed in any case. Wind energy replaces the use of fossil fuels, reducing our dependence on diminishing (and ever-more-expensive) resources.

Danish wind power development has been underwritten by its electricity consumers. In effect, they subsidise their neighbours' electricity, and to that extent the country's investment (as distinct from the resulting energy) has been "wasted". It is therefore pertinent to examine the UK's Renewables Obligation, designed to incentivise a 20 per cent renewable contribution to Britain's electricity by 2020. The article claims that the requisite turbines would occupy an area greater than Wales.

In reality, 12,000 2MW wind turbines (assuming a capacity factor of one-third typical of UK sites) would generate on average the 8,000MW corresponding to 20 per cent of British demand. Spacing the turbines seven rotor diameters apart would yield a footprint just over the size of Pembrokeshire. This is still a massive requirement, but remains credible.

Clumsy subsidies can result in sub-optimal solutions. Cohen's welcome article draws attention to some worrying examples - but Danish wind power should not be included.

Brendan Fox, Queen's University Belfast.

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