5000 Wind Turbines or One Single LFTR? PDF Print E-mail
Written by Karl J. Hansen, klimabedrag.dk   
Tuesday, 21 September 2010 19:49

landscape-wt-lftr-cutWind turbines could have, and may in the future, be the right way to produce electricity, if not for a series of problems that need to be solved. The main problems are: footprint, CO2 release, power-on-demand, price, logistics, resources, environment and birds, to name a few.

I used to be very enthusiastic 25 years ago, when I was one of the pioneer developers of wind turbines. Back then it was the independence of fossil fuels, that spawn the revival of using the wind to power the industry and our homes. The customers were encouraged to invest in the turbines through stately subsidies and relative favorable rates per sold KWh to the grid. Largely the existing grid was strong enough to deal with the few and small 75KW turbines.

This positive view has since remained firmly anchored in most peoples' mind. However, large wind turbines and lots of them causes challenges of all sorts to pileup. It is possible that some of these problems can be sorted out by further development and additional techniques, like electricity buffers, much less use of concrete, etc.; but at least one factor is inescapable: the footprint.

landscape-wt-lftr

On the picture above you can see a graphical illustration of the footprint problem. If you are very generous, you could hope to achieve a CF (Capacity Factor) of 20% in very windy areas or maybe even 25% out at sea. On the picture we assume a CF of 20% and an effective production of 1GW (1,000,000KW), in which case we need 5,000 wind turbines. The same 1GW could also be produced by a 1GW LFTR (Liquid-Fluoride Thorium Reactor) seen far right in the picture.

In Denmark we would theoretically need more than 30,000 wind turbines with a rated effect of 1MW (1,000KW) each, if we were to supply the whole country with electricity from wind turbines. Assuming the use 50 hectare each, all 30,000 turbines will occupy 1,500,000 hectare or 15,000 sq Km. Denmark consists of 42,434 sq Km land, thus 36% of the land would have to be covered with wind turbines. Okay, you can save some land by moving some of the turbines to sea for an added cost.

It should be clear that such a large scale deployment of wind turbines will meet resistance in the population; but even if the land was transformed to this extend with the peoples' acceptance, it would not be enough to deliver permanent electricity supply and would electrically not work. Wind turbines mostly use asynchronous generators, which in practical terms limit the rated capacity to 80% of max production on the grid. With a CF of 20% and Denmark's need for 6GW power, the actual limit will be 960MW or 4,800 turbines in a system with no connection to other countries.

When I stated that 30,000 turbines would not be sufficient to give us electricity all the time, it was based on another problem, the fluctuation of the wind. By doubling the wind speed you theoretically increase the power eight fold, which makes it ever so difficult to have turbines produce anything near rated output at even moderate wind speeds and below 4 m/sec you should not expect any output at all.

The changing wind speeds disqualifies wind turbines to provide base load and power-on-demand is out of the question too. Peak load could be satisfied as likely as finding a needle in a haystack. Therefore you need almost the same immediate capacity available as standby in form of traditional power plants, like coal, natural gas, nuclear, LFTR or hydro. Using hydro as standby power is fine, this is fast and you don't waste any water while the wind turbines have wind passing their wings; but it is somewhat questionable what benefits, if any, you have from doubling the clean hydro with the not so clean wind turbines. In the case of Denmark, either coal fired power plants or export to Sweden, Norway and Finland are the main options.

wind-flux
Above an example how wind energy has to be compensated from minute to minute around the clock.

If we take a country like United Kingdom, much of the prospects for wind turbines is even worse. In UK there are no heavy duty links to other countries, to which they can sell excess wind power, thus all wind turbines have to be backed up by primary coal and to a lesser extend nuclear. In either case, the coal and nuclear plants have to work more less full power during the day, without actually delivering electricity at times of fresh to strong wind. Even if the operators dare to lower the fuel input on the coal plants during windy periods, they are likely to need to ram up the boilers when the wind decreases. This ram up is said to produce more CO2, compared to just letting the plant run full backup capacity. The nuclear power plants does not produce any CO2, they would probably be the best standby option of the two; but UK has way to few.

The result of the many wind turbines in Denmark, is very high electricity rates. This is not surprising, but now the rates will increase in south west Sweden due to the Danish wind turbines. This is because the Danes have managed to sell excess wind electricity at outrageous high prices to the Swedish operators and who is to pay other than the Swedish consumers. Sweden used to be among the cheapest and cleanest in Europe with most of their electricity produced by hydro and nuclear.

There are many other severe problems with wind turbines; but this will be too much to cover in this little article. The key point is the gigantic footprint, which is now mounting a large resistance in Denmark and even in Sweden where there is much more land available. Not only are the many wind turbines an eyesore, they are killing our birds, bats and in many cases our sleep. Could we make more effective wind turbines, so the footprint could be significantly smaller? - No! There is only so much energy in the wind, leaving very little room for improvement. In comparison Denmark could provide all their electricity need with 6 nuclear or LFTR stations or classic reactors, rather than tenth of thousands of wind turbines. With the wind turbines, we also need the nuclear or LFTR stations.

You may argue that we can continue selling excess wind energy in Denmark to the neighbor countries. That option has it's limits, both physically and economically, and Denmark could be near that limit already. The question is, to what extend neighboring countries can "manage" Denmark's excess electricity at the current state. This will get even worse when Sweden increases their own wind power supply. In times of average high wind speeds, in particular at night time or in Week-Ends, the whole grid could collapse due to overproduction and result in major blackout.

You sometimes hear the argument that the wind is always blowing somewhere in the country. This is true at times; but just as often absolutely untrue. Not seldom is the whole country, Denmark, without even the lightest wind for extended periods. Sometimes, more seldom, you have near storm in most of the country. You have cold winter days where the whole of northern Europe is very, very calm. In these situations we need much more electricity than usual and a brownout or a blackout would cost many people their life, when left to survive -20C in their houses.

More and more homes become dependent on uninterrupted electricity, both for comfort and for running heat exchangers, circulation pumps, regulation systems, water pumps, stoves, etc.. It is possible to avoid interruption in the electricity supply with many installed wind turbines, but the cost is tremendous high, totally unnecessary and a waste of resources. We need engineers to plan our electricity supply and not misguided politicians. Denmark, of all countries, should be the first to know this, after all we have had capacities like Niels Bohr to lead the way towards a genuinely sustainable solution.

Wind turbine production cannot go on for much longer due to limited known quantities of the rare earth mineral, neodymium, used for neodymium iron boron magnets in wind turbines. They have largely mined what was available in USA and Japan, so today only China can provide and they will need more and more for their own production of various electronics containing permanent magnets. For each modern wind turbine something like 600Kg neodymium is used. Although computer hard disks used to account for the largest consumption of neodymium, wind turbines are now taking a leading role. On top of that, as the hybrid car gets more popular, the definitive end of neodymium is coming nearer and there is no known substitute for neodymium. Considering how needless and environmentally unfriendly the wind turbines are, it is a disgrace we waste our very limited resources of neodymium on them.

For a more in debth analyses and implications of large scale deployment of wind turbines see Jon Boone's article.
Last Updated on Tuesday, 21 September 2010 22:28
 

Add comment

To be able to vote, have easier access to write comments, etc., go to Login and login or register yourself.
You are given the option to login via FaceBook.
For at kunne stemme o.a., gå til Login og login eller registrer dig selv.
Du gives mulighed for at logge ind via FaceBook.


Security code
Refresh