Paying the difference

Various windfarm projects have been in the news recently, with the usual statistics of 'x' MW capacity to supply enough electricity for 'y' thousands of homes. The 'greens' love them; the sceptics emphasise the low utilisation factors. But nowhere is it possible to assess whether they will actually, overall, reduce CO₂ levels.

A recent article implied a total cost of £6bn for the 630MW London Array, but other websites state £2-3bn, which seems to be the going rate for off-shore windfarms of £1m per 100kW of actual average generation.

Obviously, the complexity of all the human activities required to produce a windfarm, or anything else, is enormous and it would be impossible to break down CO₂ emissions for all the millions of activities. But there must be a relationship of CO₂ emitted versus overall cost. What is it?

There is an abundance of information, from bodies such as the Carbon Trust, on CO₂ emissions for various forms of energy and fuels. But nowhere are CO₂ emissions related to the cost (not price) of anything, be it a car, making a house carbon neutral, or the cost of the final 1GW London Array.

So, how can we determine if the 1.9 million tons of CO₂ emissions displaced annually is worth it? What are the CO₂ emissions to produce the London Array?

To be able to roughly equate the capital-intensive costs of any energy development, such as wind, combined heat and power, and solar, with CO₂ emissions, would allow transparency as to whether any scheme will be effective in reducing atmospheric CO₂ in the long term, or at least give the CO₂ payback period.

There is a reason to be concerned — wind energy is free but windfarm electricity costs 10p/kWh compared with 4p/kWh for efficient power stations, and we have to pay for the difference.

PH Field, St Albans