Spain’s grid operator shows how CO2 changes as wind and solar vary.

One of the common responses to the article that Mark Lynas and I wrote for the Guardian earlier this week was to question our assumption that a lower fossil fuel share of total generation would result in lower emissions. It seemed obvious to us that if we showed that higher wind generation reduced the number of gas-fired power stations operating it would cut CO2 emissions. This certainty was not shared by some readers.

Other national electricity grids provide real time data on CO2 emissions that may help settle the issue. Non-UK data will enable enthusiasts – for want of a better word – to track estimated greenhouse gas emissions and watch how they change as the balance of suppliers on the grid adjusts to higher and lower wind.

I’m a particular fan of the Spanish graphics.

Follow the yellow line with your mouse and the site will provide the CO2 and generation at each time period. The wonderful pie chart on the right adjusts to reflect the changing balance of supply. If you want to check that wind cuts emissions without doing any boring spreadsheets, look through some of the days this week when the wind was blowing and compare them to when it was not. The data for previous days can be shown by adjusting the date in the bottom left hand box. The tabs on the bottom right allow you to look at the CO2 emissions or power output.

Really, really lovely visualisation of data.

  1. Luke Collie’s avatar

    Unfortunately, this data from Spain, and the similar graphics for France, don’t show quite what you need. Click the ‘Help’ button and you will find

    ……the CO2 emissions associated with different sources of generation are presented. Such emissions have been calculated by associating to each technology the emission factor contained in the Spanish Renewable Energy Plan 2005-2010, in line with the Decision of the European Commission 2007/589/CE…….

    In other words, they are assuming an average CO2 factor for each technology and multiplying the power supplied by the factor to get the CO2 at each time, just as you did for gas in your own article. This still leaves unanswered the question of how much worse the CO2 factor for gas gets when the plants have to run at varying partial loads to cope with changes in the wind.

    On today’s (28th September) data, the wind has been very steady and most of the variability has been in demand, with most of the stress for this taken by the international connectors, so I expect that the wind contribution has indeed saved very nearly all of the emissions from the plants that would otherwise have had to run to supply the demand, but the available data does not *prove* this.

    Yes I am an ‘enthusiast’ aka an energy geek, yes, I am being very picky here, but the myth of wind not saving CO2 is very persistent. It’s been shot down many times, but you need the 6′ stake and the holy water, or it will just get back up again. You need the real time gas demand.

  2. Chris Goodall’s avatar

    Dear Luke,

    Thank you very much for this extremely helpful comment. Point taken – we need real gas usage data, moment by moment, to prove the point to the wind sceptics. I just thought the data looked so beautiful…..


  3. Martin Normanton’s avatar

    Lovely graph and pie chart, though not easy to relate the CO2 to wind, as variations in demand are the dominant factor. Interesting to see how hydro sometimes goes to zero at low demand times.

    It seems obvious to me that variations in required spinning reserve will affect CO2 saved by wind, so the CO2 saving could for example be 90% or 95% of the expected saving. If you have enough high head hydro and pumped storage then you wont neeed any spinning reserve, but we in the UK are not that lucky.
    The data that we need are actual CO2 per KWh for a number of comparable days in terms of demand where the days have differing wind conditions.
    So the climate change deniers have got hold of something (that there may be a spinning reserve cost – maybe 5 to 10%- to cope with intermittent power sources) and twisted it to claim that the factor is 100%. Maybe next they will claim that it is 200% and WTs actually increase emissions! There is no telling what clueless people will come up with. Note that wind comes in for special attention, could this be anyuthing to do with perceptions that WTs despoil the landscape while solar and tidal are aesthetically OK?


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