BUTLER EAMONNDr 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

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.