The Financial Times has picked up on David Mackay's 2050 energy calculator, noting some of the oddities in the assumptions used - assumptions that I think it's fair to say many people assume were made with Guardian headlines in mind.
Strikingly, the renewables option is the cheapest of these with the nuclear the most expensive. As a result, in contrast to the Telegraph, the Guardian takes a different line: it’s headline is “Low-carbon energy ‘no dearer than doing nothing‘”. (Although, curiously, it’s online version mirrors the Tel with “UK switch to low-carbon energy will cost £5,000 per person per year“).
But matters are still not perfectly straightforward. The key question for DECC is why the “higher renewables” scenario is combined with “more energy efficiency” when the other options are not to the same degree?
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Why is there a presumption that if we move towards wind/solar power then people will use more insulation? It does not necessarily follow. Presumably if you combined the extra energy efficiency to nuclear or fossil fuels they may no longer come out as the most expensive options.
Mackay himself has commented on the article, which can be read here.