By Professor Ben Anthony and Dr Peter Clough, Cranfield University.
Carbon Capture Storage (CCS) have become the dirtiest words in the energy sustainability debate. The costs have appeared too great, the rewards too temporary. In the past two years alone, six major UK projects have been shelved.
However none of the criticism or lack of will on funding have changed the fact that we need more CCS facilities – and sooner rather than later. That’s why CCS continues to be high on the agenda of a nation like Norway, with a major state programme of research and technology development, CLIMIT , which is running its latest international summit on 26-27 February 2019.
It’s a fantasy that the UK, as well as many other nations, can avoid carbon emissions in the near term. While decommissioning coal-fired power stations has made an instant impact on CO2 figures, other future emissions reductions will be much more difficult to achieve without CCS. As the cheapest and most reliable option, many countries are still looking to expand their fossil fuel power generation, but this cannot continue in an unabated manner.
So what are the options? To decarbonise the UK’s grid using renewables alone, it’s estimated we’d need to build and install renewable power generators at three to four times the electricity demand to balance the variable weather. To provide consistency of power supply through our highly inconsistent weather would demand vast battery (energy) storage capability, likely to be lithium ion batteries, for which there isn’t enough lithium on the planet.
Thankfully, new technologies are increasingly making CCS look commercially viable.
As one example, the decades of drilling under the North Sea mean there are vast resources of space for CO2 storage, enough to last 100 years – potentially also for the UK to take CO2 from other parts of Europe. What matters now is a focus on approaches that can be deployed and brought to market in short periods of time, within 10 years, to start changing the hard emissions figures. Smart blue-sky thinking is of no value if it’s going to take 20-30 years for results to be delivered.
‘Amine scrubbing’ – a process to separate CO2 from flue gas – has now been developed and validated at the commercial-scale for the treatment of flue gas from coal fired power stations. Three projects in particular represent significant milestones: the 100 MWe SaskPower Project at Saskatchewan and the 240 MWe Petra Nova facility in Houston, Texas, both of which are able to capture 90% of the CO2 produced. The third large-scale (pre-combustion capture) demonstration project is the Japanese Tomakomai CCS demonstration project which sequesters 100,000 tonnes of CO2 per year.
There are a number of other CCS technologies which are being explored including calcium looping (which is less toxic than amine scrubbing, and by-products of the process have the potential to be used as part of cement production, but requires high initial set-up investment and a constant flow of limestone is needed to maintain levels of effectiveness); chemical looping combustion (which is the most energy efficient option, able to capture almost 100% of carbon via the process; it’s also currently the most expensive operation because plant needs to be made from materials able to withstand constant abrasion from metal particles); and oxy-fuel combustion (a more concentrated CO2 is produced for easier storage, but again with high initial costs and questions over pollutants in the exhaust gas). Each technology has its associated problems in terms of cost and efficiency – but there still remains no major technological barriers to their implementation.
Making use of the UK’s largest chemical looping test facility, Cranfield is involved with projects that are demonstrating what else is possible. This includes working with the LEILAC pilot plant facility hosted by Heidelberg Cement in Belgium which is situated immediately nextdoor to the cement plant. LEILAC is a ‘calciner’, it takes some of the raw meal from the cement plant and calcines it – producing a pure stream of CO2 suitable for CCS – before being made into cement.
We need more proof and momentum to reach the tipping point as quickly as possible for CCS. This may well be through the implementation of the Liverpool-Manchester Hydrogen Cluster by Cadent or the H21 Leeds Citygate initiative to convert 100% of the city’s natural gas grid to hydrogen by 2021. The combined H21 North of England plan from Cadent and Northern Gas Networks alongside the Norwegian state energy provider Equinor, makes the case for a 12.15 GW natural-gas-based hydrogen production facility across the North of England, capable of decarbonising 14% of the UK’s heat by 2034 by converting 3.7 million homes and businesses in the major towns and cities of the region to using hydrogen. CCS will be an essential part of the model, storing 20 Mt each year by 2035 – making it the world’s largest CCS project. In addition H21 leaders believe it can be achieved at an estimated cost of less than £6 per tonne.
CCS is critical for the interim period before we solve the issues of energy storage and reach a renewables only phase, and is the most cost-effective way the world will be able to meet COP21 commitments and avoid the hazardous – if not catastrophic – CO2 levels in the environment of 450 ppm and above.
Faced with their own carbon targets, more industries are coming round to the idea of investing into CCS, meaning less reliance on government funding. What’s needed now is realism from governments. CCS isn’t a perfect solution – there needs to be substantial financial investment, and there will be ongoing costs, but no-one’s pretending it’s for the long-term. The most useful role for governments would be twofold: culturally, in demonstrating a commitment to the principle of CCS as both an ‘accepted’ technology and critical stop-gap for reducing carbon emissions; and secondly in providing a framework for industry to work with and contribute to, as the UK does for electricity – a kind of National Grid for CCS.