Wind versus Nuclear: The real story in pictures

Graph showing the electricity generated by nuclear and wind power (in gigawatts) every 5 minutes for the months of September and October 2014. The grey area shows the period when wind power exceeded nuclear power.

Graph showing the electricity generated by nuclear and wind power (in gigawatts) every 5 minutes for the months of September and October 2014. The grey area shows the period when wind power exceeded nuclear power. (Click Graph to enlarge)

For a few days in October 2014,  wind energy consistently generated more electricity in the UK than nuclear power. Wow!

You may have become aware of this through several news outlets. The event was reported on the BBC, but curiously the Daily Mail seems not to have noticed .

Alternatively, you may like me, have been watching live on Gridwatch – a web site that finally makes the data on electricity generation easily accessible.

I was curious about the context of this achievement and so I downloaded the historically archived data on electricity generation derived from coal, gas, nuclear and wind generation in the UK for the last three years. (Download Page)

And graphing the data tells a powerful story of the potential of wind generation – but also of the engineering challenges involved in integrating wind power into a controllable generating system.

The challenges arise from the fluctuations in wind power which are very significant. The first challenge is in the (un)predictability of the fluctuations, and the second challenge is coping with them – whether or not they have been predicted. Both these challenges will grow more difficult as the fraction of wind energy used by the grid increases over the next decade.

As an example, consider in detail an event earlier in October shown in the graph at the top of the page

Graph showing the electricity generated by nuclear and wind power (in gigawatts) every 5 minutes for the months of September and October 2014. The grey area shows the period when wind power exceeded nuclear power.

Detail from the graph at the top of the page showing how earlier in October, wind power went from an impressive 6 GW to less than 1 GW in a period of around 18 hours . (Click Graph to enlarge)

The grid operators have a wind forecast running 6 to 24 hours ahead and would have planned for this. The forecasts are typically accurate to about 5% and so at the high end that amounts to a margin of error of 0.3 GW – which is within the reserves that the grid can cope with routinely.

However the fluctuations in wind power are becoming larger as the amount of wind power increases. The graph below shows the monthly averages of electricity produced by Wind and Nuclear since May 2011. Also shown in pink and light blue are the data (more than 300,000 of them!) taken every 5 minutes.

Monthly averages of electricity produced by Wind and Nuclear since May 2011. Also shown in grey are the data (more than 300,000 of them!) taken every 5 minutes. It is clear that the fluctuations in wind power are large - and getting ever larger. (Click Graph to enlarge)

Monthly averages of electricity produced by Wind and Nuclear since May 2011. Also shown in pink and light blue are the data (more than 300,000 of them!) taken every 5 minutes. It is clear that the fluctuations in wind power are large – and getting ever larger. (Click Graph to enlarge)

Incorporating wind energy is a real engineering challenge which costs real money to solve. Nonetheless, as explained in this excellent  Royal Academy of Engineering report, we expect capacity to double to ~20 GW by 2020, and to at least double again by 2030. So these problems do need to be solved

Because wind-generated electricity supply does not respond to electricity demand, as the contribution of wind energy grows we will reach two significant thresholds.

  • When demand is high, unanticipated reductions in wind-generated supply could exceed the margins within which the grid operates.
  • When demand is low, unanticipated increases in wind-generated supply could exceed the base supply from nuclear power which cannot be easily switched off

These challenges will require both economic and engineering adaptations. At the moment, because the marginal cost of wind power is so low, we basically use all the wind power that is available.

However, it is possible to ‘trim’ wind turbines so that they do not produce their maximum output. In a future system with 40 GW of wind generating capacity, we might value predictability  and controllability over sheer capacity. Then as the wind falls, the turbines could adjust to try to keep output constant.

These challenges lie ahead and are difficult but entirely solvable. And their solution will be essential if we really want to phase out fossil fuels by 2100.

But for the moment wind is providing on average about 2 GW of electrical power, which is around 6% of UK average demand. This is a real achievement and as a country we should be proud of it.

Perhaps someone should tell the Daily Mail.

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7 Responses to “Wind versus Nuclear: The real story in pictures”

  1. Bernard Naylor Says:

    The growth in the contribution made by wind power to UK energy needs is impressive, although it falls well behind what has already been achieved in (say) Denmark and Germany. So it appears we still have some way to go before deriving maximum benefit from wind with current technologies and their exploitation.

    I am a little surprised by the strong concentration on wind power, to the relative neglect of other options. The solar pv panels on my roof were installed over 4 years ago. Each year they have produced electrical power amounting to more than half of all our annual domestic consumption. And any power produced surplus to our immediate requirements is exported to the grid, and can offset the burning of fossil fuels. In daylight hours, solar is, to some degree, complementary to wind because winds tend to be stronger when the sky is overcast. Ours is not a particularly big installation – about 2.4 kW.. With installation costs falling substantially, I think there ought to be more of a drive to equip available roofs with solar pv panels, and also to install larger arrays of panels on land of low agricultural value. Solar panels are less obtrusive than wind turbines and grid pylons; in ground based arrays,they are much like large hothouses or polytunnels.

    One thing that surprises me is that so little emphasis is being put on tidal power, the potential of which will presumably alter little so long as the moon is in the sky! I think the technological thinking on tidal power has gone well beyond major barrages such as Morecambe Bay or the Severn Estuary. Surely a bit more investment in research will bring forward practical technologies based on submerged turbines? With our enormous coastline, we ought to be at the forefront in exploiting this potential.

    In a previous contribution on water supply, I pointed out that, in Bermuda, each building is built in such a way as to harvest its own supply from the rain falling on its roof. Maybe we should be looking at the potential for every building complex to make a serious contribution to meeting its own energy needs through renewable technologies?

    • protonsforbreakfast Says:

      I agree and I agree doubly about tidal power. I think the absence of this kind of thing reflects the way this ‘market’ operates: dysfunctionally. But I am confident we will get there eventually.

      You are just in time to comment on the planning for the Swansea Bay Tidal Lagoon.

      http://www.tidallagoonswanseabay.com/

      All the best

      Michael

  2. telescoper Says:

    Reblogged this on In the Dark and commented:
    Here’s an interesting analysis of the statistics of wind power versus nuclear power in the UK over the past couple of months. There’s obviously room for more growth in renewable energy generation, but I still think we’ll need to increase nuclear capacity to provide a counter to the intermittent variability of wind power if we are to reduce our dependency on fossil fuels, which still produce most of the UK’s energy…

  3. Michael Merrifield Says:

    Isn’t the real engineering challenge here to come up with an efficient large-scale way to store generated energy (pumped storage? cracking water?) to level the wind contribution out that way rather than by throwing away the peaks of generation to level things out?

    • protonsforbreakfast Says:

      Michael,

      Good point. The energy storage issue is a separate but connected issue. The only technology I know of that definitely works is pumped water storage and although not easy, we have the potential to do much more of this that we actually do.

      The point I was making is that there is also one more available tunable parameter that I (at least) wasn’t previously aware of.

      Clearly storage, both locally at the point of generation and as grid-scale balancing facility is essential if the penetration of renewables is ever going to proceed to 50% or higher.

      All the best

      Michael

  4. Bill Says:

    Perhaps nuclear power isn’t so bad after all, since said “renewables” are no more than environmentally cynical hypocrite solutions.
    http://en.wikipedia.org/wiki/Environmental_impact_of_wind_power#Ecology
    http://en.wikipedia.org/wiki/Solar_power#Environmental_impacts
    http://en.wikipedia.org/wiki/Biomass#Environmental_impact

  5. Klaas Says:

    Storage of electricity is expensive and difficult – batteries are not cheap. However, parallel to the growth of wind-generated electricity is the growth in electric vehicle numbers. Electric cars have batteries that can store large amounts of electricity, and spend a large part of the day sitting idle, connected up to charging points. There are some studies ongoing to see if there are ways in which this large capacity of batteries in cars can be used to deal with peaks and lows in electricity production, using “smart” charging points. These vehicle-to-grid (V2G) schemes have been tested successfully in Denmark. While not a complete solution of course, this gives some indication that there are certainly ways to connect variable production with variable usage markets.

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