Wind Power: What is going on?

UK Electricity Generation charted in 30 minute periods throughout May 1st 2011. Wind is the brown segment above the 'Grey and Blue' nuclear segments. Click to enlarge. For numbers see the table at the end of the article.

I have been trying to work out exactly what contribution wind generation is making to the UK’s electricity requirements. I was moved to do this by having read three stories seeking to discredit ‘wind’ as a serious contributor to our electricity requirements.

Now all these stories are interesting stories in themselves, and I sympathise with all the authors. They are all expressing frustration at the current malaise in which the UK  lacks (IMHO) a credible energy policy. The first advocates a nuclear solution, the second draws attention to the amenity value of high wind sites,and the third is part of a call for transparency in the energy market – including the availability of exactly the data I have been unable to find! But when I come across them in short succession I wonder if they might be part of a campaign to discredit Wind Energy? Reading these stories makes me want to look at the data and see what is actually going on.

How much electricity does wind power actually generate? As I write at 12:02 a.m. on May 2nd 2011 I can tell you that currently Wind is generating 1.340GW (5.2%) of 25.779 GW of total demand and that over the last 24 hours wind power has generated 41.618 GWh (an average of 1.73 GW) which was 6.1% of today’s total demand for electricity 682.077 GWh (Average 28.4 GW). I can get this information from this BM Reports web site (viewable only with Internet Explorer on a PC). Now this data refers to a rather mild but windy low-demand Sunday and so I think this rather flatters wind generation. You can read total demand for the last 7 days here. The BM Reports web site contains lots of fascinating data but I can find no way to aggregate it to cover several days, let alone years!

Another way to get data is to rely on answers to parliamentary questions. One answered in April 2011 (see table below) reports that in 2010 wind generated 10,021 GWh, around 2.6% of the electricity used in the UK. Dividing by the number of hours in a year (8760) yields an average power of 1.14 GW. The British Wind Energy Association inform me that currently there are 3184 Turbines in the UK with a maximum capacity of 5.267 GW. In 2010 around 1.1 GW of capacity was added, so if we divide this by 2 we can estimate that in 2010 the maximum capacity was was approximately 5.267 – 1.1/2  ≈ 4.7 GW, which implies that wind power in 2010 generated at around 24%of capacity.

2009 2010 (provisional)
Onshore wind generation (GWh) 7,564 6,979
Offshore wind generation (GWh) 1,740 3,042
All wind generation (GWh) 9,304 10,021
Total electricity generation (GWh) 375,665 381,247
Onshore wind share of total generation 2.0% 1.8%
Offshore wind share of total generation 0.5% 0.8%
All wind share of total generation 2.5% 2.6%

And so we conclude… the current combined effect of every wind turbine in the UK, when added together, is sufficient to supply ≈ 1/40th of the UK’s electricity requirements – rather more than 1 large nuclear, coal or gas fired power station. Plans call for this capacity to be increased to 30 GW maximum generating capacity by 2020. On average this will contribute ≈ 7.5 GW to our supply – roughly equivalent to today’s nuclear generating capacity. There will be occasions when wind generates 30 GW of power and other generators will have to switch off or the wind power will be wasted, and also  occasions when essentially none of this wind energy is available and it must be replaced by coal-fired or gas-fired generation.

As I read what I have just written, I feel some sympathy with the critics. Wind power definitely works – but as its contribution grows we will find that the entire electricity infrastructure will need to re-shape itself to accommodate the fluctuations of wind power. And I find myself unable to answer a simple question

  • Do I feel happy about this?
Electricity Generation by source for 1st May 2011

Electricity Generation by source for 1st May 2011


4 Responses to “Wind Power: What is going on?”

  1. Martyn Says:

    Yes you should. We have been storing power using pumped water for decades. Now we need to store more. And it is being done- 20GW stored in flywheels eventually :

  2. protonsforbreakfast Says:

    ‘Greenbang’ is a good name for a web site describing a 20 GW flywheel :-).

    The report you link to actually identifies a host of technologies for storage, but most are on the scale 1 to 10 MW for 1 second to a few minutes. These are useful, but don’t really address the intermittency characteristic of wind. Only two technologies are identified for serious demand managements – 1 to 10 GW for 1 to 10 hours. These are pumped storage – we could easily do more – and compressed air storage, which has not been demonstrated at the required scale.

    My unease over wind is … hard to put my finger on. I think it is that there are actually quite a few wind turbines around at the moment. And ALL of what we see from Scotland to Cornwall just replaces roughly 1 – 2 conventional power stations. This doesn’t ‘seem’ like very much. If we have 6 times this quantity of Wind turbines things may feel… crowded?

    Basically I am grateful to anyone who does anything that even marginally ‘greens’ our electricity supply. But National Grid projections for 2020 predict increased demand, and I think we need to do something bolder than building wind turbines.

  3. Stephanie Says:

    UK Electricity Generation’s graph would tell a clearer story if the “constant baseload” nuclear generation was shown along the bottom of the graph!

  4. Wind Power Generated | Wind And Solar Says:

    […] much electricity does Wind power actually generate. As I write at 12:02 a.m. on May 2nd 2011 I can tell you that currently […]

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