The three would-be climate and energy ministers Ed Miliband (New Labour), Simon Hughes (Lib Dem) and Greg Clark (Conservative) recently participated in a pre-election debate organised by The Guardian. In response to the question:

"Academic research has shown that for the UK to meet the emissions reductions targets implied by the 2008 Climate Change Act would require an effort the equivalent of 30 new nuclear power plants by 2015, just to get part way to the target. Clearly this is not going to happen."

Miliband simply said that he disputed the figures, but he didn't provide any details. It came as no surprise that Hughes and Clark failed to take him to task on this, no doubt because their respective parties have also signed up to the UK's CO₂ emissions reductions targets without having a clue about how they can be achieved.
 
The Guardian has set up an online UK 'carbon calculator' so that assumptions can be played around with in order to achieve the 2020 target. Roger Pielke Jr, author of the 2009 study: 'The British Climate Change Act: A Critical Evaluation and Proposed Alternative Approach' (Environmental Research Letters, Vol. 4, No. 2), posted the following comments on his blog:

"Using the calculator, you can get to the 2020 target by eliminating all 20 coal-fired power plants and an additional 30 natural gas power plants. To balance energy supply and demand these would have to be replaced by carbon-free generation. So, when I say that the level of effort is equivalent to 30 1GW nuclear power plants to get only part way to the short-term target, you can easily see that number is correct using the online calculator (how very cool). Spreading that level of effort around many sectors of the economy does not make the magnitude of the task any smaller and arguably makes it more complex. On this issue, Ed Miliband is simply wrong. His opponents in the debate, however, did not seem any better on the substance. Whoever inherits or retains the job of energy minister is eventually going to have to deal with the failure of the Climate Change Act. Denying the figures will only work for so long."

ABD Environment spokesman Paul Biggs said,

"Miliband and his shadows are exposed as clueless against an objective, well published climate policy expert. Speaking at the recent Birmingham City Council Transport Summit, Climate Change Committee member Professor Julia King admitted that some sectors would be unable to meet the UK's climate targets, so transport would have to make a bigger contribution in order to compensate. More evidence, if we needed it, that the three main parties are embarking on 'emission impossible' and drivers can therefore continue expect a disproportionate bashing over CO₂ after the election."