Ben Southwood: Cold facts blow an ill wind for renewables

IT is widely known that wind farms are inefficient compared to what they could theoretically produce.

Officially, they run at about a quarter 
of their “nameplate” (i.e. potential) capacity. But we have only now discovered just how intermittent and variable wind farms’ electricity output is – a fact which should make us very sceptical about the intention to make it such a large part of the UK’s carbon reduction plans.

This is important – the UK, says the National Grid, is facing its tightest energy crunch in eight years this winter and may be forced to resort to emergency measures to keep the lights on in the event of worse-than-normal weather.

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According to a new paper from Dr Capell Aris, and released by the Adam Smith Institute and the Scientific Alliance this week, far from providing a steady and regular quarter of its total potential, wind farms produce negligible amounts for hours at a time.

In the UK, output is below 20 per cent of nameplate for 20 weeks, and under 10 per cent for nine weeks.

The most common efficiency is just eight per cent, and much of the periods of negligible output come during the cold winter months when energy is in highest demand.

What’s more, inter-connection 
cannot solve the problem because the entire fleet is often producing next to nothing – not just particular local sections.

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Dr Aris found this by looking at nine metre highly reliable half-hourly wind readings from 22 RAF and civilian sites over the UK. and 21 sites over Ireland and continental Northern Europe.

The results mean that only around five per cent efficiency can really be considered “guaranteed” and if the UK did move toward a 10GW wind fleet by 2020 it would need around 9.5GW of extra fossil capacity – equivalent to about two and a half Drax power stations — on top of the wind just to make sure the lights don’t go out.

Because we don’t have much capacity for storing energy, and in any case doing so is costly and difficult, we cannot simply build an even bigger wind fleet and store the extra energy produced when the wind is blowing.

Running “load following power plants” that make up for the deficit when 
wind is not providing power is possible, but these plants are more expensive to run, and would be yet more expensive if dealing not with relatively predictable daily and seasonal movements in demand, but relatively unpredictable wind speeds.

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According to the best estimates, there are good reasons to reduce carbon emissions.

The most authoritative review estimates that though warming will 
raise living standards on net until 
about 2080, thereafter the impact 
may start to become increasingly negative.

But wind farms are an expensive 
way to do so. Even working on roughly constant efficiency, and including an estimate of the carbon costs, 
the Government reckons it costs about £90-100 per MWH of energy from onshore wind, versus about £70 per MWH for nuclear and £80-85 for natural gas.

And this ignores the possibility that there is any cost to people from having to regularly see and live near structures they dislike.

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A 2013 paper from Professor Stephen Gibbons at the London School of Economics found that houses within 
two kilometres of visible wind farms lost up to 15 per cent of their value.

In other words, households were willing to spend about £600 per year 
in order to avoid living close to 
turbines.

The fact it seems pretty windy in Britain, combined with the fact that we need to reduce our carbon emissions, might lead us to believe that wind is the natural solution.

However, wind cannot provide a cheap, reliable supply of energy, and many people consider wind farms a blight on landscapes.

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It may not even substantially reduce emissions due to the need to “back up” wind supply with fossil fuel capacity almost the same size.

Therefore it seems that a smarter strategy would be aiming toward relatively low carbon natural gas and carbon-free nuclear power to provide the UK’s energy needs over coming decades.

Ben Southwood is head of policy at the Adam Smith Institute.