Creative accounting with wind energy

As seen in last post, it is deceitful to use the metric of “household equivalents” when talking about an intermittent energy source injected in a continuous working grid. It is one thing that journalists do this, but producers of wind power should know better, right? Then think again. The very first post on this blog, back in february 2013, was about such a claim made by a wind energy producer, C-power. They went even furter than this in their environmental impact page in which they paint an incredibly rosy picture of wind energy. It all starts with the “it is good for our (grand)children” meme:

“With our 325,2 MW offshore wind farm, we contribute to delivering a cleaner and safer environment to our children and grandchildren”, says CEO Jaak Rutten.

Throughout the years I have learned this to be a red flag. They continue:

Compared to the environmental impact of traditional energy sources, the environmental impact of wind power is very positive. Wind power consumes no fuel, and emits no air pollution. Wind power does not generate any toxic waste nor does it constitute a major safety risk.
The energy consumed to manufacture and transport the materials used to build a wind power plant is equal to the new energy produced by the plant within a few months.

C-Power will, with its expected yearly production of 1 TWh, avoid every year 415,000 tonnes CO2, which represents:

  • the annual CO2 absorption of a forested area of 65.000 ha
  • 1/3 of the forest area within the Flemish Region

The story they paint is so skewed that I don’t really know where to start here.

That windmills do no directly consume fuel and do not directly emit air pollution is true, but that is not the case for other stages of the life of the turbines. For example, the production of rare earth metals (used in the magnets of windmills) causes severe pollution in China. Another example is the production of steel and concrete that is not exactly low in CO2 emissions.

I don’t know whether it is true that the energy of manufacturing and transporting the materials is only worth a few months of operation. It seems really low to me. Probably only the manufacture and transport of the materials were accounted for?

Energy and emissions, although related, are not the same thing. If those materials were made in developing countries, that would lead to more emissions than when they are produces here. Those countries don’t exactly care about emissions and use for example coal because it is a cheap way to produce energy.

But the most incredible statement was that they expect to avoid 415,000 tonnes of CO2 every year. That seems very unrealistic. I understand where that 1 TWh comes from. I already calculated that in the first post: if we take the capacity of their wind farm (325.2 MW) and multiply that by equivalent full load hours of the turbines (3,300 hours/year), then we get 1,073,160 MWh which is a tad more than 1 TWh. As calculated in that first post, 3,300 hours per year equals to 38% of the time. Which is plausible for a new offshore turbine, but not for its complete life cycle. There is the wear and tear of turbines in a salty, corrosive environment, which mean more times with no production because of maintenance as the turbines get older.

If they get 1 TWh per year then they assume an average of the Belgian energy sources of 415 g CO2 per kWh. For a country with about half of the electricity production coming from nuclear (low emissions), somewhat more than a one fourth for gas (around 400 g/kWh) and about five percent coal (with high emissions) that seems a bit high. Or probably calculated in a time there was less nuclear and more coal?

Whatever the case, as far as I can see they seem to assume that the turbines keep on producing as new during the complete life cycle and that every kWh electricity produced by wind replaces one kWh electricity produced by conventional sources… They also don’t take into account the efficiency losses in the grid (because of the balancing of intermittent electricity production) or non-dispatchable electricity. Belgium, having an old energy infrastructure and hardly any pumped storage available, these losses could well be substantial.

That is typical alternative energy reporting: just count the blessings and forget about the rest. Image that companies would adopt this kind of accounting. Just state only the potential gains and ignore the real losses. That way it is always possible to declare a profit, even if one is completely bankrupt…

4 thoughts on “Creative accounting with wind energy

  1. poitsplace

    The worst part is that turbines powered by fossil fuels must be kept turning and when they are forced to ramp up or down energy output rapidly their energy consumption is far higher than normal. Unfortunately, this is often accomplished with coal plants, which are not as well suited to such tasks. And after you take that and other things into account, it actually starts to become questionable if ANY new energy is being created at all.

    One analysis I saw of actual daily carbon use by power plants compared between high wind and low wind days…found that effectively only 1/3 of the wind turbines’ energy output was ever being used in a way that offset carbon. That number would be higher if the best/newest gas fired turbines were used, but efficiency would still be well below that claimed.

    Just to illustrate how monumentally bad the choice to use renewables is at meeting our needs…I looked around at costs and found that the cheapest way to back up the wind energy without fossil fuels was to just build even more wind turbines to deal with a 60% loss in efficiency that you would get, convert excess energy into hydrogen…and then burn it in conventional gas turbines when output was too low. So you basically end up with real-world output of less than 1/10 of nameplate capacity.


    1. trustyetverify Post author

      I have seen quite some numbers of CO2 savings and they are ranging from every kWh saves CO2 to almost no CO2 savings. It probably depends on what assumptions were made or what is counted in (or not). It is a pity that the numbers (fossil) fuel use are not available. That would give clarity. Whatever the case, the higher the share of wind energy, the more the intermittent nature will effect the grid and the more need to balance the output. This means somehow store the energy to use it later when energy production is low. But this increase the price even more.


  2. manicbeancounter

    You have some very valid points here, that completely invalidate the argument for wind turbines. But I have another that is even stronger case that complement your points.
    The theory is that GLOBAL greenhouse gas emissions (which are rising) are causing GLOBAL greenhouse gas levels to rise, which in turn are causing GLOBAL warming. This is alleged to have nasty GLOBAL consequences. 415,000 tonnes of CO2 is a vast amount, but only equivalent to 0.0008% of global GHG emissions of about 52GtCO2e. Add together all the actual savings, along with any policy proposals that are around and still emissions will continue rising for decades to come. This is even if the EU, with 500 million population, meeting its emissions target, along with USA, Japan and some other countries.


    1. trustyetverify Post author

      You are right. Even if this 415,000 tonnes of CO2 is actually saved, in the grand scheme of things this means nothing and levels will keep on rising for decades to come.



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