Forget wind turbines and nuclear power stations – the world could cut greenhouse gas emissions just using carbon capture and storage (CCS) technology. At least that's what Myles Allen, a prominent climate scientist, suggests. But how realistic is the prospect of cutting emissions using CCS? We ask the experts.
Writing in today's Guardian and last week's Mail on Sunday, Professor Myles Allen, head of climate dynamics at Oxford University, proposes that governments introduce a new regulation requiring companies that extract or import fossil fuels to sequester and store a fraction of the carbon dioxide they emit. Allen writes:
"the only thing that really matters for long-term climate is that we deploy the technology – carbon capture and sequestration (CCS) – to bury carbon dioxide at the same rate we dig up fossil carbon before we release too much."
This would be far simpler than introducing a complex bundle of legislation aimed at shifting the country away from fossil fuels and toward renewables, he argues.
CCS – in the political doldrums
At the moment, the prospect of a large scale roll-out of CCS seems fairly distant. According to consultants Poyry, the UK has the best prospects for the technology in Europe, with "clear policies and programme" to demonstrate the technology.
That's not saying much, however – the government's first competition to fund projects collapsed in 2011, and it is currently reviewing the feasibility of two short-listed projects having re-launched the competition last year – with a final decision due in 2015.
Allen's proposal would mean a significant shift in government policy – with a fairly radical top-down approach to cutting carbon emissions. But, that question aside, how effective could a CCS-only approach be in practice – and how close is it to being at least a technical possibility?
It seems to be generally agreed that CCS is viable. The three parts of the process – capture, transport and storage – have all been demonstrated in different countries, but they haven't been put together on a commercial scale. This makes it a lot harder to predict whether Allen's plan would work.
One important limitation is finding a place to store the carbon dioxide. The UK has the advantage here because it can store the carbon dioxide under the sea – in depleted oil and gas fields or alternatively saline aquifers, where the carbon dioxide would be partially dissolved in salt water.
Perhaps predictably, CCS trade body the Carbon Capture and Association (CCSa) is quite bullish about this prospect. A spokesperson tells Carbon Brief:
"Current estimates show we have space to store about 300 years of the UK's emissions in our saline aquifers".
That sounds impressive. But there are two possible problems. First, the use of saline aquifers hasn't been tested yet. Dustin Benton senior policy adviser at green thinktank Green Alliance, which published a report on CCS rollout last year, tells Carbon Brief:
"Theoretically they [saline aquifers] could work but practically we don't know how much CO2 they could store…We don't know because we haven't done it".
Second, not everyone has access to a significant undersea carbon storage resource. Smaller, land-locked countries may struggle to find anywhere to store its carbon dioxide without prompting significant local opposition. CCSa recognises this, telling Carbon Brief:
"[Governments] shouldn’t force it [CCS] on countries that don't have the storage space to do it."
A CCS catch-22
CCS presents some tantalising questions about energy policy – like whether the UK could make money by selling off its undersea resource to other countries as a carbon dioxide store. How much would full scale CCS cost?
Unfortunately, while CCS remains untested on a commercial scale, it's hard to get the answers to those questions. And that means that forcing companies to install CCS might not be a good idea at this stage. Professor Jim Watson tells Carbon Brief:
"my concern … is that it is simply too early to mandate CCS … until we know whether CCS works at full scale, and how much this really costs, mandating could be counter-productive."
Watson explains that introducing regulations to make companies use CCS before the technology has been tested properly could mean they stop investing in fossil fuels full stop.
Alternatively, they might end up making bad decisions – investing in CCS when it's too expensive or exhibits poor technical performance. He points out that the latter option risks undermining public and government support in the technology, which could set things back even further.
It seems risky to implement Allen's proposal without having tested CCS out properly first, something he doesn't quite address in his articles. But his idea could add to political pressure to get CCS going – and that could be good news for greenhouse gas emissions.