I think no one's forgotten the last time WWF played accounting tricks:
WWF does not consider nuclear power to be a viable policy option. The indicators “emissions per capita”, “emissions per GDP” and “CO2 per kWh electricity” for all countries have therefore been adjusted as if the generation of electricity from nuclear power had produced 350 gCO2/kWh (emission factor for natural gas). Without the adjustment, the original indicators for France would have been much lower, e.g. 86 gCO2/kWh. A country using nuclear energy is therefore rated as a country using gas, the most efficient fossil fuel.
Now, in their latest highly polished-looking 159 page study, Brian Wang finds the following "model assumptions" hidden in the appendices:
Let's see how these figures compare to reality. They give a "high" limit of 80% for nuclear power capacity factors. Yet, oddly, that's less than the global average - 81.3%:
(Average over all nuclear power plants, 2006-2008)
And in fact many countries average 90%+ nuclear capacity factors - including the little one called the 'United States'. Apparently this reality is unrealistic to the WWF models.
Even more magical is the wind power. Readers will be surprised to here that wind farm capacity factors are "40-60%". That's news to the AWEA, which advertises a completely disjoint range of 25-40%. And that's the wind industry.
Let's calculate some real numbers. Referring to 2008 numbers from
Here we have both national generation figures and nameplate capacities for several countries. There's a slight methodological issue: the nameplate capacities change over the year, as wind farms are installed. So my solution is to use both end-of-2007 and end-of-2008 capacities, to get a lower and upper bound for capacity factor.
|Country||2007 wind capacity||2008 wind capacity||2008 wind generation||average capacity factor|
|Germany||22.2 GW||23.9 GW||40.4 TWh||19-21%|
|Spain||15.1 GW||16.8 GW||31 TWh||21-23%|
|France||2.4 GW||3.4 GW||5.6 TWh||19-27% (24% given)|
|Sweden||0.8 GW||1.0 GW||2 TWh||22-29%|
|World||120.8 GW||260 TWh/year (est.)||24.5%|
The 'world' TWh/year figure is GWEC's estimate for the 120.8 GW of wind capacity:
The 120.8 GW of global wind capacity installed by the end of 2008 will produce 260 TWh of electricity and save 158 million tons of CO2 every year.
There are no US or China generation figures, but they would be difficult to use anyways because of the very fast rate of wind growth (large uncertainty in capacity means large uncertainty in capacity factor).
In short, WWF's "low" figure for capacity factor is twice as high as real-world capacity factors. And their "high" figure is, to the best of my knowledge, impossible. In fact I've never seen any number higher than about 43%, for offshore wind in the North Sea:
Anyway I think it's clear their numbers are very far from reality, and the direction of the manipulations (understate nuclear, overstate wind) pretty much reflect WWF's ideological bias.