The government is attempting to build a 25 gigawatt wind farm by 2020. But researchers have found wind variability to be a big problem:
One of the most frequent criticisms levelled at wind power is variability. That is, when the wind drops (or blows too hard) the windmills stop spinning and you get no power. To begin with, Oswald simulates the output rises and falls that might result from a lot of windfarms distributed around the UK by using Met Office archived data from different points up and down the land. Many wind advocates have argued that with enough windfarms, widely enough distributed, you would get more reliable power output as some windmills would always have wind.
Oswald's analysis says this isn't true, with calm conditions across pretty much all the UK being fairly regular events.
Analysis from 1996 to 2005 shows similar results: large, rapid, and frequent changes of power output being common occurrences ... any national power system has to manage under the worst case conditions likely to occur ... These are not extreme cases, whose frequency is so low as to render the events negligible. Rather, these are representative ...
If the government succeeds in building its mighty 25 gigawatts of wind base by 2020, according to Oswald's Met Office data-based model its output will dip to pretty much nothing fairly routinely.
In fact, they've found 3 day events with no wind at all to be fairly common, and occasionally 5 day events with 10 day becalming, while rare, certainly something which happens.
It's hard to power a grid when your generating mechanism is sitting idle. So that means that you have to have a backup.
That backup is gas turbine technology.
In his view, all this means that - certainly in a 2020 timeframe - the only feasible backup for the planned 25-gig wind base will be good old gas turbines. These would have to be built even if pumped storage existed, to deal with long-duration calms; and the expense of a triplefold wind, gas and pumped storage solution would be ridiculous. At present, gas turbine installations provide much of the grid's ability to deal with demand changes through the day.
The trouble is, according to Oswald, that human demand variance is predictable and smooth compared to wind output variance. Coping with the sudden ups and downs of wind is going to mean a lot more gas turbines - ones which will be thrashed especially hard as wind output surges up and down, and which will be fired up for less of the time.
So the result will be a hybrid system that is probably not the most efficient and certainly a producer of CO2.
Even though the hardware will be cheap and tough, it will break often under such treatment; meaning increased maintenance costs and a need for even more backup plants to cover busted backup plants. Thus, the scheme overall will be more expensive than the current gas sector. And since people won't want to thrash expensive, efficient combined-cycle kit like this, less fuel-efficient gear will be used - emitting more carbon than people now assume.
And that brings us to the bottom-line of present "windfarm" technology:
In essence, wind plans aren't actually wind plans, according to Oswald. They're gas plans with windfarms used to reduce the amount of gas actually burned in the plants. But he thinks the assumptions now made on costs and emissions reductions to be anticipated are unduly optimistic.
And, of course, such estimates always are.
Obviously wind has some future in the "alternative" or "renewable" energy field. But it certainly isn't a panacea and it has some rather large technological hurdles to overcome before it is a large contributor to the energy demands around the world.
There was the infamous 2005 Boxing Day event in Germany where a sudden becalming shutdown that country’s wind production overnight. They would need the equivalent of 4 to 6 nuclear reactors on hot standby to make up the difference. Fortunately, the nuclear-heavy French grid had some excess available. The report by the utility E.On has disappeared from the web.
Then there was the California heat wave of 2006 where the state’s wind capacity was operating at only 6%. What a waste, just when we needed it. Here’s a link to an analysis by a DoE engineer:
The characterization of a major wind contruction program as really a gas turbine or nuke or coal contruction program is so true. Wind turbines are only valuable as a way to save fuel for real power generation investments.
Here in Kansas, I have had some experience with two pilot wind turbines out at St. Mary’s. Under @7mph of wind, the turbines shut down. Over @60mph, the turbines shut down. Gusting wind in Kansas is pretty common, so far, the turbines have been down more then they have been up.
The author attacks a strawman: Nobody claims that 100% wind electricity is possible. Most scientific studies on grid-integration of wind energy come to the conclusion that it is possible to produce about 20% of the electricty with wind turbines without the need of extra back-up. By increasing the capacity of international connections, this percentage can be increased even further.