BRENT Knoll villagers and councillors were celebrating today (Tuesday) after learning the appeal bid to build a wind farm in near the Knoll has been turned down.
Renewable energy company Ecotricity lodged the appeal after Sedgemoor District Council originally rejected plans to construct five wind turbines at land at Inner Farm in Edithmead.
Good. Apart from anything else, there really is no such thing as a "renewable energy company" in the commercial sense: these bastard things are built with massive government subsidies. Which means, of course, that we poor fucking taxpayers are compelled to stump up at least twice; first through the direct subsidies and, second, through higher energy prices. And how!
Burning Our Money has been looking at the figures for wind power and, really, they aren't good. Well, that's something of an understatement: they are abysmal. I would say that they just don't add up but unfortunately they do: they add up to tens of billions of pounds.
Denmark is the world leader in terms of the proportion of wind power in overall electricity generation capacity, and the country is often presented as the energy model for us. But a fascinating paper [PDF] by Hugh Sharman in Civil Engineering walks us through exactly why it wouldn't work here (HTP A Reader).
Of course the easiest way for the paper to summarise why wind power wouldn't work here would be to point out that it is because wind power doesn't work in Denmark or, indeed, anywhere else. But I digress.
To start with, wind power is a highly unpredictable source of energy. Denmark has installed wind capacity of 2,374 Mw (end-2003), but Sharman produces the following chart to show how actual generation varies wildly below that theoretical maximum, reflecting weather conditions:
Of course, this level of variability would be utterly unsustainable anyway: look at those lows. If half the country put their kettles on at the same time, all of the lights would go out.
Now, we non-specialists need to remember a simple but key point about electricity: it can't be stored. Yes, there are various techniques like using off-peak power to pump water uphill—or to compress air—which can then be used to drive generators later. But in reality, they are expensive and limited in application (the existing UK reservoir storage system at Dinorwig can cover 5% of generating capacity for five hours). They can't deal with the large and largely unpredictable peaks and troughs of wind power.
Given that electricity can't be stored on a large scale, demand and supply need to be balanced dynamically by grid controllers. That means being able to call on additional generating capacity as demand fluctuates through the day and through the seasons.
Which makes the variability of wind power a major headache. Sharman has the following chart showing how, far from helping, the variability of wind generation actually compounds the problem of demand variability:
No wonder grid managers are not keen. Indeed, according to this briefing paper, "grid management authorities faced with the need to be able to dispatch power at short notice treat wind-generated power not as an available source of supply which can be called upon when needed but as an unpredictable drop in demand."
We've pretty much proven the unfeasibility of wind at this point, but let's close in to the bitter end, shall we?
What's more, because of this extreme variability, on average, wind turbine generators operate far below their theoretical capacity. Denmark's operate at 80% below theoretical maximum capacity. Or to put it the other way round, their "load factor" is just 20%.
That of course, increases costs. According to Sharman, each 1,000 Mw of installed capacity costs on average £1bn (50% onshore and 50% offshore). But if it's only operating at a 20% load factor, to get a real 1,000 Mw you must multiply that by 5, equals £5bn. On Sharman's calculations that would mean the government's renewables target involves spending over £40bn on wind generators.
But there's more.
More than £40 billion (apart from the fact that you can pretty much guarantee that, if the government is anywhere near the project, that figure will be nearer £80 billion)? Oh, yes...
Even if we spend £40bn and install 41,000 Mw of wind generation capacity, because the power would still be variable and unpredictable, we'd need some back up.
In that respect, Denmark is in a much better position than us. They are linked into the much larger grids of Sweden, Norway, and Germany, so they can draw back up supplies when the wind drops (or blows too hard for generation—oh yes, there's that problem as well).
And since Denmark is relatively small, they can draw this back up from their larger neighbours without too much of a problem. Moreover, the process is greatly assisted by the fact that both Norway and Sweden have a lot of hydro electricity, which turns out to be a lot easier to ramp up and down than other potential back-ups.
None of this is available to us. We can import a little bit from France, but not on Denmark's scale.
In reality, to make wind power workable, we'd need to maintain/install massive back up here in the form of conventional power stations.
How much? The normal industry rule of thumb is that wind power needs 90% back up capacity. 90%!
So, have you got that? To provide the electricity that we need, we would have to build £40 billion worth of turbines and then we would have to build conventional powerstations to underwrite 90% of the power that those turbines are supposed to generate!
Does anyone think that wind power is still a good idea? Apart from the fuckwits in the government, of course.