Talking Energy: carbon capture and storage

Carbon capture and storage (CCS) - also known as 'clean coal' - could soon allow for a new generation of coal-fired power stations. By Andrew Charlesworth.

Andrew CharlesworthPublished: 5:38PM GMT 27 Nov 2009

Hot topic: fully operational carbon capture and storage (CCS) is still several years away, but when it finally arrives this "clean coal" technology will change the face of energy generation
The UK is facing transformation of its energy generating system. The closure of end-of-life nuclear and coal power stations is coinciding with ambitious commitments to reduce carbon emissions and the demise of North Sea gas.
Whatever we replace our current generating capacity with has to provide affordable, reliable and lowcarbon power – an energy trilemma.

This fifth article in a series of 10 looks at where carbon capture and storage fits into the trilemma debate. Coal used to be the mainstay of UK electricity generation. But falling gas prices over the last three decades have seen us play it down.
Now, aware of the need to balance our options, we are reconsidering our use of coal. “Given the importance of supply diversity to our security, it would be foolish to abandon coal,” wrote ex-energy minister and MP for Croydon North Malcolm Wicks in his report Energy Security: A national challenge in a changing world. “UK coal production could be retained at current levels of around 20 million tons per year through to at least 2025.”
Unfortunately, coal emits more than double the CO2 as gas per kilowatt of energy produced when burned. Step forward carbon capture and storage (CCS) – sometimes called “clean coal” – which promises to remove a large proportion of emissions from burning coal.
“Promise” is the choice word. Current research by the Carbon Sequestration Leadership Forum suggests there are 273 CCS projects under way worldwide, 64 of which are of commercial scale. Of those, seven are operational end-to-end, but none as yet generate electricity.
“Carbon capture has been used in petrochemical and chemical processes for many years,” says Andy Read, clean coal business development manager at E.ON. “We are confident we can build CCS at a commercial scale. We know the technology needs to improve and are confident it will.”
In October, energy secretary Ed Miliband reaffirmed the Government’s commitment, stating that no new coal station can be permitted without at least a quarter of it having CCS capability.
The government is currently running a £1bn competition to fund a CCS plant. There are currently two entrants in the competition; E.ON and Scottish Power.
Of course, this money has to come from somewhere, and the new Energy Bill has clauses in it for a levy on energy bills to fund up to four CCS projects, in line with the Government’s Low Carbon Transition Plan and the recommendations of the Climate Change Committee.
The four CCS plants would play a role in achieving the goal of a 50 per cent cut in emissions from the power sector by 2020, the Committee’s report said. It is also thought that the European Commission will fund a 900-megawatt plant with CCS fitted at Hatfield in Yorkshire.
Fully operational CCS as it is envisaged by the power companies is still several years away and developing it to a reliable technology will be expensive.
So, we can’t rely on CCS alone to fulfil all three criteria of the trilemma – reliability, affordability and low-carbon. Nevertheless it is another part of the mixed portfolio of sources that the UK needs in order to meet its future energy requirements.
Carbon Capture and Storage (CCS): why it matters
CCS (carbon capture and storage) covers a range of techniques for removing most of the CO2 emissions from coal-fired power stations.
The two main techniques, pre- and postcombustion have their pros and cons, their cheerleaders and critics.
Neither is suitable for retrofitting to the UK’s old coal-fired power stations, so whichever is used we would need to build new plants. Both require captured CO2 to be stored as liquid in underground chambers, such as depleted gas fields, so they require pipelines from power station to storage site.
The techniques involved are all in current use: post-combustion CO2 is used in fizzy drinks; pre-combustion gasification is used in the production of ammonia; and CO2 is injected into gas and oil fields to drive out the last reserves.
But no one has yet combined these in an end-to-end process at the scale required for clusters of power stations. Oxyfuel technology, an alternative carbon capture technique, is under trial in Germany.
CCS is vital to the struggle against global climate change, because the emerging economies of India and China are almost wholly dependent on coal for electricity generation.
Speaking at the Carbon Sequestration Leadership Forum in London in October, US energy secretary Steven Chu predicted it was highly unlikely that the US, China and India would stop burning coal.
The International Energy Agency estimates 100 CCS plants will be needed by 2020, up to 850 plants by 2030 and 3,400 plants by 2050.
CCS technology developed in the west will probably be deployed in countries like China and India as part of a deal to help them industrialise without skyrocketing emissions.
Indeed, work began on China’s first clean coal plant, in the northern city of Tianjin, in June. The $1bn project is funded by a group of investors, one of which is US coal giant Peabody Energy.