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Government modelling on gas and carbon targets still missing

  • 08 Oct 2012, 13:35
  • Christian Hunt

What are the government's plans for gas power in the UK? The Department of Energy and Climate Change (DECC) have endorsed 20GW of new gas plant and ambitious carbon targets for 2030. But there's no explanation yet of how the two are compatible.

The Committee on Climate Change (CCC) says the UK power sector needs to be "virtually decarbonised" by 2030. For every kilowatt hour of electricity generated in the UK, no more than 50 grammes of carbon dioxide should be emitted on average, it says. At the moment, according to the CCC, the average figure is nearly ten times higher, at 486 grammes of carbon dioxide per kilowatt hour. (p.24)

Generating electricity using gas produces an average of 405 grammes of carbon dioxide per kilowatt hour - so using too much gas is incompatible with the CCC's recommended 2030 decarbonisation target. Ultimately this could mean the UK misses its binding 2050 emissions target contained in the climate change act.

But how much is too much? DECC doesn't see a problem - in a speech to a gas industry conference today, energy and climate secretary Ed Davey lays out the government's big picture vision for gas power. He says:

"... in electricity generation ... I see unabated gas playing a very significant role throughout the 2020s, and, increasingly as back-up or with carbon capture and storage, through the 2030s and 2040s."

The UK will build a significant amount of new gas plant, he suggests - 20 gigawatts of new gas capacity by 2030 - between 10 and 20 new power stations. But this will not be at the expense of cutting carbon overall:

"... a substantial investment in gas generation and gas import infrastructure here in the UK is completely consistent with Britain's plans to cut carbon emissions, set out in our Carbon Plan."

DECC's carbon plan does not include a 2030 decarbonisation target for the power sector. More informally, Davey has endorsed a 2030 carbon target range of 50-100 grammes of carbon dioxide per kilowatt hour, but this isn't yet government policy.

The CCC have recently said:

"Extensive use of unabated gas-fired capacity (i.e. without carbon capture and storage technology (CCS)) in 2030 and beyond would be incompatible with meeting legislated carbon budgets..."

The CCC have created a scenario for 2030 in which power sector emissions are below 50 grammes per kilowatt hour. There is a small role for unabated gas, generating 8% of electricity, compared to 40% from renewables, and 40% from nuclear. (p.10) Currently, the UK gets about 30% of its electricity from gas.

We have pointed out there isn't yet a clear answer from government to the question of how the UK can build new gas capacity over the next few years and still meet a 2030 decarbonisation target. That doesn't mean it's not possible, just that the government haven't yet detailed how.

Any answer will need to take the form of detailed modelling, which answers three key questions. How much will new gas plant be used, how much can carbon capture and storage reduce emissions, and what will the 2030 carbon target be?

DECC says that it has done modelling in this area, which presumably answers these questions. But it is not published, and DECC previously told us it has no plans to do so. Today, DECC says that considering how to square gas power with carbon targets is part of the work underpinning the department's forthcoming gas generation strategy - due to be published this autumn.

To us, that sounds like another way of saying that the calculations supporting Davey's current assertion that 20GW of new gas plant is compatible with the government's carbon targets are unlikely to be published.

And that means that DECC's description of the role gas can play in the UK - "...a very significant role throughout the 2020s, and, increasingly as back-up or with carbon capture and storage..." - has still not been detailed or clarified.

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Updated 10th October - we had originally said the carbon intensity of the UK power system was around 600 grammes of carbon dioxide per kilowatt hour, based on the figures at Real Time Carbon. The CCC make a lower estimate - 486 grammes - and we have updated the blog to use the CCC's numbers.

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