Dr Eamonn Butler: Wind power - the more you have, the bigger the problems

Dr Eamonn Butler is Director of the Adam Smith Institute. Follow Eamonn on Twitter.

“Curse this wind,” said Spike Milligan on The Goon Show. “I should never have eaten those balloons.”

Today it is the wind farmers who are cursing the wind. It just won’t blow consistently enough to make their kit run efficiently. Which is why there is so much talk about building more and bigger turbines – generating even louder curses from the people who live within sight of them.

With wind farms now well established in the UK, practical experience is now taking over from the original – and apparently optimistic – theory. Many people, at the start, presumed that turbines would produce no CO₂ at all, except that used in their manufacture. That was always naive, but estimates of the actual life-cycle CO₂ emissions from wind turbines vary massively, from 5 to 100 grams equivalent per kilowatt-hour of electricity produced.

It’s our accursed weather again. When wind speeds vary inconsistently, there are wide variations in power output at different times and in different places. So if power companies are to keep the lights on, they need other, backup generation systems – mostly, fossil-fuel generators. Exactly how much backup they need will depend not just on the wind variability but on the nature of the grid itself – things like the distance between the hills where the turbines are located and the city you need to get the power to. But let’s face it, the CO₂ produced from that backup is an inevitable part of the wind-turbine deal.

So how much of a reduction in CO₂ emissions can turbines actually produce? A report released this week by the Adam Smith Institute reckons it is about 18% – absolute tops. We could never have more than a fifth of our electricity produce by wind precisely because of the need for backup alternatives, and even wind produces some CO₂ emissions.

You might, of course, be able to push wind generation beyond a fifth of the total by developing energy storage facilities. These would fill up when the wind was blowing strongly and consistently enough to generate more power than customers were demanding, and would empty again when wind speeds were too low to meet demand (or indeed, when wind speeds were too strong or too variable for the turbines to be used safely and efficiently).

But that is expensive. And working against you are the higher operating costs and the lower reliability of the grid as a result of the variability of that accursed British wind. There will be times when the storage facilities are full and the wind is still breezing nicely; but others when they are empty and it resolutely refuses to blow. And don’t forget the environmental impact of the new storage, backup generators, grid improvements and the rest.

It’s a trade-off: the more wind power you have, the bigger these obstacles become. The report concludes that the practicable upper limit for wind generation is about a tenth of our total needs, reducing CO₂ emissions by about 45g CO₂ equivalent per kilowatt-hour, that is, about 9% of total emissions.

In reality, the power companies are even less optimistic about wind energy. E.ON, for example, bases its strategy on an ultimate wind contribution of under 4%, saving about 18g of CO₂ equivalent per kilowatt-hour, or just 3.6% of total emissions. That’s not exactly going to save the planet, is it?

You can read the full report here.