A blot, or a gift...

In UK, there is much hot air being generated by talk on wind energy. Are wind turbines a blot on the landscape, or a gift to the planet? Are they really clean?

For instance, does the energy used to construct a wind turbine outweigh the energy produced during its lifetime in operation? Some say so. Others think not. An evidence review published in the journal Renewable Energy in 2010, which included data from 119 turbines across 50 sites going back 30 years, concluded that the average windfarm produces 20-25 times more energy during its operational life than was used to construct and install its turbines. It also found that the average "energy payback" of a turbine was 3-6 months.

A life-cycle analysis published in 2011 by Vestas, a Danish turbines manufacturer, of a 100MW onshore windfarm consisting of 33 3MW turbines concluded, unsurprisingly, that the siting of the turbines is crucial in maximising the energy return ratio. "Doubling the distance to the grid from 50 km to 100 km typically increases impacts per kWh by 3-5%," it concluded. "If the wind plant operates in low-wind conditions then the [negative] impacts per kWh electricity produced increases by 23% compared to medium wind conditions." But it stressed that the energy used to transport and install the turbines was "very insignificant".

There is the question of new jobs! (Don't ask about old ones lost.) According to the wind trade association RenewableUK, offshore wind could spark £3bn of investment in the UK supply chain by 2022, supporting more than 45,000 long-term jobs.

As to tech innovation, wind energy is constantly improvising. From onshore to offshore to floating turbines, the efficiency keeps rising and costs dropping.

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