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Sunday, 18 September 2011

The most expensive electricity in the world - UPDATED

It's tricky to determine what's the most expensive form of electricity generation and you can probably come up with different figures depending on whether you include capital and decommissioning costs, not to mention the thorny and not always transparent issue of subsidies. However, if you want to use a very simple measure of income generated divided by electricity generated then the most expensive electricity in the world is wind, which can come in at a cost which is literally infinite, which is what my calculator says £1.2 million for producing absolutely nothing works out to be.
A wind farm has been paid £1.2 million not to produce electricity for eight-and-a-half hours.
The amount is ten times greater than the wind farm's owners would have received had they actually generated any electricity.
The disclosure exposes the bizarre workings of Britain's electricity supply, prompting calls last night for an official investigation into the payments system.
Well, if governments are prepared to pay farms not to grow things then it's not that much of a leap to pay wind farms not to produce electricity, but this seems to be all to do with grid management.

The National Grid asked the company, Fred Olsen Renewables, to shut down its Crystal Rig II wind farm last Saturday for a little over eight hours amid fears the electricity network would become overloaded.
The problem was caused by high winds buffeting the country in the wake of Hurricane Katia.
Crystal Rig received by far the largest single payment because the National Grid runs an auction, inviting energy companies to say how much they want in compensation for switching off.
Crystal Rig's owners asked for £999 per megawatt hour of energy they would have produced had they been switched on. Incredibly, the figure Crystal Rig had bid was accepted by the National Grid.
Had the turbines remained on, Crystal Rig's owners would have received the going rate of about £100 per megawatt hour instead. Half of that is in the form of a generous consumer subsidy.
Needless to say there's a certain amount of political jumping up and down about it.
Tim Yeo, chairman of the Energy and Climate Change Select Committee, called for an urgent inquiry into the prices paid to the wind farms.
"The very principle of paying wind farm owners for not producing is one that is offensive to consumers," said Mr Yeo, "It looks like a new version of the Common Agricultural Policy where people are paid not to produce things.
"It looks on the face of it like an extraordinary overpayment by National Grid, for which an urgent explanation is required."
I'm no expert, but the principle is not hard to understand. In fact much less hard to understand than how Tim Yeo got to be chairman of a select committee with energy in its remit without having come across it already. For his benefit the problem, as I understand it, is that the amount of electricity generated must be matched constantly and fairly precisely to the amount that's actually needed. If too little is generated then obviously lights don't come on, or at least not as brightly, but if too much electricity is generated you have to store the surplus or things can go bang. And storing electricity isn't easy. It can't sit in the wires like water can remain in pipes until it's needed and you can no more have a reservoir of it than you can carry a bucket of electricity around your house. The nearest thing to a bucket of electricity is a battery, but of course batteries are DC and electricity grids are AC, and there's no such thing as an AC battery. That leaves you with two options: either you convert it into DC so you can store it in batteries, or you use it to do some kind of work, such as pumping water uphill or turning flywheels or compressing air, that can be used to generate electricity again later.

Unfortunately neither option is as simple as it sounds. Batteries tend to be very big and heavy for the amount of power they can provide. You only need to look at electric cars to get a sense of this. The petrol version of the Smart car has a 33 litre tank, which means carrying about 28 kilos of fuel for a range of about 800km (according to Smart's Australian brochure). I haven't found out what the battery weighs in the electric version but according to this review the car is 140 kilos heavier than the petrol version, and since the electric motor ought to be smaller and lighter than the petrol engine you'd expect the battery to be all of that 140 kilos and probably a lot more. Let's be conservative and call it 150-160 kilos, which would mean it weighs five times as much as a full fuel tank. Oh, and that's only enough electricity to get you 135km, which would mean that to get the same kind of range as that 28 kilos of fuel provides you'd need a battery six times as big and weighing the best part of a tonne (ignoring the fact that you couldn't then fit it in the car and that the poor little thing probably wouldn't move if you could). How big would the battery installations needed for the grid to cope with the output of a large number of generators, say enough to provide the third of the UK's power that Gordon the Clown suggested, going on and off more or less randomly? I don't know exactly but my back of the envelope calculations worked it out to be 'fucking enormous'.

Check if you don't believe me.

Things aren't much better when it comes to using surplus power to do work that can be converted back into electricity later. Flywheels would need to be big and plenty of 'em, which is basically the same problem as batteries except that you've also got the obvious concerns with any large mass spinning at high speed. Compressed air doesn't weigh so much but it also takes up a lot of room, and a reservoir full of water on top of a hill or behind a dam isn't exactly small either. In both cases you also have problems with where to put it, what to do about leaks and what might happen in the event of catastrophic failure. And that's before we even get into the inevitable losses as energy is converted from electricity to kinetic or potential energy and back again.

Of course, balancing generation and demand absolutely precisely is asking a lot, so sure, you can spin a few flywheels or pump some water up a hill when you've generated slightly too much or generate power from them when a few more kettles go on than you'd bargained for. But the bottom line is that while all of these things can be - and are - used to help balance electricity grids it's not usually practical to use them as the energy equivalent of a gasometer, and while there are lots of reservoirs with hydroelectric plants some are there to address a water problem as well and probably wouldn't have been worth constructing for electricity alone if the only water source is water pumped up by surplus electricity. All this means that surplus electricity creates a big headache since the capacity of the grid to do something with it is inherently limited.

And into this comes marching wind (and also solar) power, which rather than producing electricity on demand produces when it feels like it. This isn't a huge technical problem when you want it to produce and it isn't - you just have to have the same capacity in backup generation ready to go as soon as the wind drops or the clouds roll in. Simples, as the saying goes, but also expensives because that usually means using a non-renewable resource to keep generators in 'spinning reserve' - spinning and consuming fuel (and, if you're a warble gloamist, emitting CO2) without generating electricity. On it's own that seems like a good argument not to have wind where you don't really need it.* But as we've seen there's also a problem with when it feels like producing electricity and you don't want it to, and lacking any means to store huge amounts of electricity it's a harder problem to solve. In fact once the grid has compressed as much air, pumped as much water and spun as many flywheels as it can there's really only one thing left to do to prevent overload damage and the cost of repairs and pissed off customer, and that's to start paying generating companies to keep the generators switched off. It's not always going to be a wind farm but when it is, as The Teletubbygraph article points out, its often won't be cheap because unlike non-renewables there's no fuel saving to offset their loss of revenue.

None of which should be news to Tim Yeo. Christ, people have been bagging wind generation for years because of the difficulties its essentially random nature creates for balancing the grid. I know the hope is that if you've got enough of it then mostly it'll even itself out, and over a large enough area this sounds reasonable. Is the UK a large enough area? We don't know because nobody's tried yet. What we do know is that Denmark, which is admittedly quite a lot smaller, was a fair way ahead of most when it came to installing wind generation capacity - it hit about 20% of their generating capacity several years ago and already it was giving them grid management problems, occasionally forcing them either to buy electricity from their neighbours when there wasn't enough wind to generate enough power for themselves or, when it was too windy, to sell surplus electricity to them, often at a loss. Denmark and its neighbouring countries have quite a few connections between them, making this more a financial problem than a technical one. Until recently Britain had one 2000 megawatt connection to France and 500MW between Scotland and Northern Ireland (and I imagine NI and the Irish Republic can trade power with each other), and this year added a 1000MW connection to the Netherlands. With these plus the limited amount of storage, spare generators in spinning reserve, emergency diesel generators and other means the fluctuations wind power brings to the grid can be managed and production and demand balanced, though now and again, as the article shows, it's still necessary to pay someone to turn things off.
RenewableUK, the industry trade body, said wind farms were not the only sources of energy to be occasionally paid to be shut down.
A spokesman said: "Wind turbines are generating a great deal of clean, green energy – the problem is that the National Grid simply doesn't have the capacity to take it all in.
"This shows that we urgently need the National Grid to be upgraded to cope with the extra electricity that the wind industry is generating with increasing efficiency."
Hear that? The grid needs upgrades to cope, and remember that that's with wind power capacity of about 6 gigawatts normally producing about 1.5GW. The UK's peak demand is nearly 60GW and capacity is about 70GW (not all of which is available at any given time since due to maintenance and failures), and so if the UK were to fulfil the Brownian fantasy of a third of its power needs met by wind you'd be looking at something like 20 gigawatts produced by installations with a combined capacity of 80GW - about 15% more than all of Britain's current generators combined. Can you imagine what kind of upgrades would be necessary? Even if a lot of the wind fluctuations do balance each other out most of the time there will inevitably be an occasion when the wind blows nearly right nearly everywhere, meaning the grid will need to be updated such that at short notice it can either use, store or sell abroad an amount of power close to (maybe even exceeding) the country's peak demand, rapidly cut an equivalent amount of power produced by other generators, or any combination of the two.

Of course if you can see the wind coming in time, and to be fair to the Met Office they probably would be able to give enough notice of the kind of weather that's going to be favourable for turbines across the whole country, then you can simply pay all the wind farms to put the brakes on their turbines and not produce any electricity at all. At the rate of £999 per megawatt hour that the operators of the 138 MW Crystal Rig II wind farm got for switching off the bill for a countrywide shutdown would come to nearly one hundred and seventy million pounds for the same period of time. And since finding storage or a use either in the UK or its neighbours or even combined for that much electricity at short notice seems unlikely (Eire and Holland have only 10.5 million people between them and could each use only a fraction, while France generates much of its base load from nuclear power which can't be turned off in a hurry) they'd probably get it.

I was going to end it there but while typing that last paragraph a thought occurred to me. People who know more about these things might well laugh and shoot me down in flames, but what if the relationship between generators and the national grid changed so that smoothing out supply wasn't the grid's problem anymore? What if the situation was more like the grid maintaining the ability to balance, say, ±10GW and it being the responsibility of the generators both to supply the grid's need on demand and to maintain that supply? So if you have a gigawatt capacity wind farm and the grid needed you to supply, say, 500 megawatts for an hour, then 750 for two hours and then 250 for three hours it would be your responsibility to supply precisely that and not a lightbulb's worth more or less. How you do it is your problem, and if it means you need to operate your wind farm in combination with a large fossil fuel power station and some kind of storage facility like a reservoir or a battery the size of Blackburn then so be it.

Sorry, did you just say that would make wind energy ludicrously uneconomic unless the government flings taxpayers' money at you by the trainload? Isn't that what its critics have been saying for years?

UPDATE - This afternoon I've noticed that The Telegraph have a comment piece on why wind power is a bad idea and why wind power that gives a million quid to a foreign company for doing 8 hours of bugger all is a particularly bad idea. The electricity storage problem is brought up, and in the comments I saw this.
There is also hydrogen storage, thermal storage using the same system as solar-thermal plants and pumped hydroelectric storage. The last two are proven technologies; we built pumped storage in the 1970s in Wales.
I've already touched on the problems with pumped storage above such as cost, space and the need for the landscape to be suitable, but I neglected to mention hydrogen.

You certainly could use surplus electricity to electrolyse water and make hydrogen, but as with other storage solutions there are problems. There is almost no hydrogen infrastructure, of course, though that's something that could be tackled Gordon Brown style - throw enough money at it and it'll go away (the difference being that that approach would probably work). But hydrogen being such a small molecule is a real bugger to store without leaks and can even diffuse through metal, which has the nasty side effect of weakening it and making pipes and containers brittle over time. On top of that while hydrogen has a high energy density by mass it's got a low energy density by volume - about a third that of natural gas - and volume is the important factor when it comes to storage. Imagine gasometers three times the size of the ones you see around Britain today, except that you'd need them to be near where you'd use the hydrogen to produce electricity rather than scattered about. That'd mean huge tank farms which might be even more tempting for someone to fly a plane at than an office building. Remember the bang that fuel depot on Hemel Hempstead made when it went up? Probably bigger. You could save compress it of course, but that's means more expense. On the plus side if it could be used in fuel cells you could produce electricity controllably and on demand, and efficiency isn't all that great with 50-80kWh being used up per kilo of hydrogen produced, which in turn holds about 40kWh, about half of which you'd lose in a fuel cell. At the upper end this makes it as efficient as or a bit better than pumped storage (at the lower end you probably wouldn't bother), so if you used materials that aren't prone to becoming brittle and built enough hydrogen tanks and pipes and electrolysing plants and fuel cells or whatever you're using to get electricity back from hydrogen then it just becomes a matter of building enough to cope with the surplus generation of 80GW worth of turbines all spinning at once plus whatever else was pumping juice into the grid at the time. Oh, and not minding all those tanks standing around mostly empty the rest of the time.

Thermal storage is a new one on me and I'd want to do some reading before I say anything. On what I've looked at so far it seems like it'd involve gasometer sized structures, each of which is capable of storage in the gigawatt hour range. No idea of what costs, efficiency, difficulties and so on are like but again it'd just be a case of building enough to cope with inevitable but infrequent occasions when vast surpluses of electricity are produced and not minding them doing little or nothing otherwise. Possibly a combination of storage methods and increased ability to trade to neighbours would work but it seems likely to mean a lot of expense and infrastructure, possibly with a large footprint and almost certainly with a lot of CO2 emissions associated with production to upset the warmistas, and all because of an over reliance on a means of generation that's difficult to control and forces you to install four times as much capacity as you expect the bloody thing to actually deliver on average.

* Obviously there are places where it's not practical or economic for there to be a connection to the grid, and then solar arrays, wind turbines and battery installations make perfect sense. I could give you examples of possible applications in remote areas such as outback Australia, but you could go down to any marina see a bunch of yachts with small turbines and/or solar panels stuck to them in lieu of a huge drum with the world's longest extension lead trailing up the motorway and into the garage.
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