CCUS: An unlikely saviour?

- Advertisement -

For a country like the UK, which has committed to generating net-zero CO2 emissions by 2050, it appears that developing the technology of carbon capture and storage (CCS) will be “a necessity not an option,” to quote the IMechE’s Jenifer Baxter. Many others agree, and the UK has just announced a major funding commitment for the approach. But is it enough? Envirotec reports

dracx-powerplant-yorkshire
An aerial view of Drax power plant in Yorkshire, where £5 million in government funding was awarded in June to assist with scaling up a bioenergy and CCS project

CCS refers to a variety of methods that promise to allow most of the CO2 emissions from power plants and industrial facilities to be captured – rather than simply released into the atmosphere – and stored. Even better than storage is the idea of recycling it – converting it into useful products or materials, an emerging capability included within the increasingly popular acronym of CCUS (or carbon capture, usage and storage).

Approaches

Broadly, carbon capture is divided into three separate categories of method: Post-combustion CCS refers to methods for removing CO2 from the flue gas of an industrial facility or power station, perhaps using a process like passing the gas through an absorber column; pre-combustion CCS refers to processes for removing CO2 from fuel before it is combusted, and applies to methods such as coal gasification, whereby the CO of the resultant syngas is reacted with water to produce CO2, which is then stored; and the third method is ‘oxyfuel’, whereby coal, for example, is burned in an environment with a very high concentration of pure oxygen, giving rise to an exhaust gas that is almost pure CO2, and this can be condensed and stored. This third method has traditionally been more energy intensive.

In typical installations in the oil and gas industry, the CO2 is liquified and transported – possibly up to several hundred miles – and buried, either in underground geological formations, or disused oil fields, or in saline aquifers deep underground.

One of the first ever plants was set up in 1996 at the Sleipner West oil field in Norway, which still collects about 1 million tonnes of CO2 per year – about 11 million tonnes have been collected so far, according to the website of the British Geological Survey, which studies the facility. In this case the CO2 is removed from the natural gas produced at Sleipner – a prerequisite of getting it to saleable quality anyway – which is then injected down a 3km-deep well and stored in a porous rock formation.

Cost conundrum

In the UK there have been various attempts by energy and petrochemicals firms to build CCS projects since the mid-2000s, but these seem to have largely stalled for funding reasons, following the closure of two government funding programmes in 2007 and 2012, which were shelved for cost reasons.

Indeed, concerns at the price tag of the method have also come from environmental campaigners, that it might soak up subsidies that would better be spent on techniques with a more proven track record. Also, there are concerns that CCS might undermine efforts to move away from fossil fuels.

But there seems a growing consensus that, for countries looking to meet ambitious emissions targets like ‘net zero emissions by 2050’, carbon capture will be indispensable. The UK government appears to be backing this view and in late June awarded £26 million of funding to nine projects deemed “essential” if the UK hopes to reach its net-zero target.

Around £4.2 million of this fund was awarded to what it is hoped will be the UK’s largest CCUS project to date: a facility located at Tata Steel Europe’s soda ash and sodium bicarbonate manufacturing plant in Cheshire.  It will seemingly capture around 40k tonnes of CO2 per year from the flue gases of the company’s CHP plant – reducing the firm’s carbon emissions by 11%. The gas will then be liquified and purified, for use in the manufacture of sodium bicarbonate – used in products like glass, baking soda, and Pot Noodles. The project is estimated to cost £16.7 million in total, and is expected to be operational by 2021.

The project appears to be a major step change in the UK’s ambition for CCUS, able to trap about 100 times the CO2 of an existing plant being run at Drax in Yorkshire. TSE’s Martin Ashcroft described the project as “a great example of business and government working together to rise to the challenge of decarbonising industrial production.”

The government’s £26 million fund is being awarded in two separate streams: the Carbon Capture, Usage and Demonstration scheme, which aims to encourage industrial sites in the UK to capture CO2; and the Call for CCUS Innovation programme, which will fund projects for developing novel technology and processes that reduce the cost of CCUS.

Tata’s proposed facility qualifies under the first scheme, as do a couple of projects awarded to Drax in Yorkshire. Drax has received £500k towards a fuel cell carbon capture study, which has the potential to produce power at the same time as capturing CO2. The group is also receiving £5 million jointly with C-Capture, a firm developing solvent systems for carbon capture, to go towards an £11.1 million project that seeks to scale up C-Capture’s technology for deployment at the bioenergy and CCS project at Drax power station, which began capturing CO2 at the plant this year.

Projects awarded funding under the second stream – ‘Call for CCUS Innovation’ – include a project that aims to integrate CCUS with hydrogen fuel production. Led by Progressive Energy, the Hynet project aims to help decarbonise the Northwest of England’s industrial cluster. In its first phase it will try to develop the infrastructure to allow CO2 emissions to be captured from industrial sites and stored in depleted gas fields in Liverpool Bay.

A long way to go

Such projects sound promising, but is it enough? The International Energy Authority (IEA) estimates that around 6 billion tonnes of CO2 have to be stored by 2050, but there is currently very little deployment at large scale – projects that capture at least 1 million tonnes of CO2 per year. The CCC, for one, has said that CCUS technology must progress with “far greater urgency”, as the FT reported on 1 July.

The Tata announcement appears to be consistent with the UK government’s CCUS action plan, produced late last year, which set out an intention for the UK’s first large scale CCUS facility to be up and running by the mid-2020s.

The CBI issued a statement on 28 June, recommending that the government build new nuclear power stations and scale up carbon capture technology and infrastructure if it is serious about reaching the target of net-zero GHG emissions by 2050. Support from the business world seems a vital ingredient.