Carbon capture and storage – fantastic or realistic?

David Few | 05 Oct 2015 | Comments

Carbon capture and storage (CCS) has for long seemed quite fantastical. The idea of catching and setting aside carbon emissions may at first appear like pie in the sky, but getting CCS right and diverting CO2 away from the atmosphere could have a major impact on reducing global carbon emissions.

What is CCS? Put simply, it involves separating carbon dioxide from the flue gas of fossil fuel power stations – thus rendering the electricity “near carbon free”, then compressing the CO2 to a liquid for transport to permanent underground storage usually in depleted hydrocarbon reservoirs or saline aquifers (water permeable rocks that are saturated with salt water).

The UK has binding targets to reduce greenhouse gas emissions (GHG) by 80% of 1990 levels by 2050, and the Government’s four stranded decarbonisation strategy includes CCS along with renewables, nuclear and energy efficiency. The cost of decarbonising the energy system without CCS is big – £40 billion ($61 billion) per year according to the Energy Technologies Institute. These are some of the reasons why the UK government has put aside £1 billion to seed fund one or two CCS projects as an opportunity to prove that the technology can be deployed commercially.

Undoubtedly, as with all developing technologies, CCS will present some challenges, not least of which is driving the costs to levels comparable to other low carbon technologies, nonetheless, it offers a practical proposition and could play an essential role in the efforts to reduce carbon emissions. Arguments against CCS tend to focus on the fact that to date it has been expensive and more broadly any use of fossil fuels, even with carbon capture, is inherently bad for the environment and should be discontinued.

The sequestration technology itself is estimated to be about 33% of the cost of CCS projects and whilst the process for extracting and storing carbon emissions is broadly a case of reversing the process of natural gas extraction, it’s not quite that simple. There are lots of crossovers with the oil and gas industry in terms of supply chain and skills base – as well as the potential reuse of facilities and infrastructure – but injection instead of extraction technology is needed and the composition of the CO2 is different to the hydrocarbons that will have been extracted; a similar viscosity to gas with a density closer to a liquid.

Existing plants worldwide already capture 25 million tonnes of CO2 per year, but it’s not yet being done in a way so that it pays for itself commercially just for electricity generation. Where it is viable is through enhanced oil recovery schemes and around ten projects in the USA are currently doing this. In Canada, Australia, China and Norway various projects are underway and at different stages of development. Regulations in Norway tax CO2 and this has encouraged carbon sequestration schemes.

In the UK, the government is looking to give up to £1 billion to a project or projects which could play a major role in the integration of CCS into the UK energy system.

It’s generally accepted that fossil fuels will have to play a role in the global energy mix for the foreseeable future whilst we transition to using more low-carbon and renewable forms of energy. In the meantime, capturing and storing CO2 from coal and gas fired power stations will provide a way of lowering emissions in the short to medium term.

Whilst the technology for doing it is well-established, the pressing need now is to demonstrate full and large scale integration into the energy sector and show that CCS can be commercially viable. This is important as commercial viability builds confidence within the investment community and will enable government support to be reduced to prices comparable to other low carbon forms of technology by 2020.

Atkins has been at the heart of this process acting as technical advisor to the UK Department of Energy and Climate Change for 2 years bringing together an incredibly diverse range of skills from across the company advising on specifications, contracts and negotiations. Whether a large scale worldwide roll out of the technology will happen as soon as was predicted remains to be seen. Ultimately the process in the UK is about pioneering and establishing a viable new industry that is commercially sustainable for use without extensive government support.