Carbon Capture and Storage in the UK
Some of the most widely-advocated strategies to tackle climate change, such as switching to renewable energy and enhancing one’s energy efficiency, are increasingly appearing to be inadequate. According to the UNEP’s recent Emissions Gap Report, the atmospheric concentration of greenhouse gases reached a record high in 2011. The disappointment spelt by such reports has only reinforced the need to promote additional mitigation tools that could help sequester the current carbon dioxide pool in the atmosphere.
Carbon capture and storage (CCS) is one such mitigation tool which has lately been a subject of heated discussion both amongst the international scientific community and within the global climate change brigade. CCS technology involves the capture of millions of tonnes of carbon dioxide, which might potentially amount to 90% of what is generated from the use of fossil fuels in power plants and other industrial units across the world1 . Due to the pressure exerted by the mounting demand for energy, fossil fuels appear likely to be a necessary evil, and its consumption figures are expected to rise up until 20352. Given such a scenario, CCS technology may arrive as a panacea of sorts, since it offers an opportunity to limit the emissions that result from the increased consumption of fossil fuels.
The CCS process primarily consists of 3 components: capturing carbon dioxide, transporting it, and finally storing it underground. The technology used to capture the gas involves separating it (in pure, highly-concentrated form) from the other gases generated after combustion of fossil fuel. This carbon dioxide is then transported to and stored in a suitable site from which it cannot escape into the atmosphere. The options for CO2 sequestration include saline formations and oil wells which use captured CO2 in enhanced oil recovery3. At present, there are three main technology options for carbon capture from fossil fuel combustion:
- Post-combustion capture
- Pre-combustion capture, and
- Oxy-fuel combustion
Post-combustion capture is most technologically proven and widely tested method of carbon capture. It uses chemical or physical solvent to isolate and capture CO2 after combustion of fossil fuels. Flue gas, a by-product of fossil fuels combustion, is passed through a liquid which causes a chemical reaction and separates the CO₂ ready for transportation and storage. This process of separating CO₂ from the flue gas is called scrubbing. Post-combustion capture technology is most suitable for pulverized coal, supercritical and ultra super critical power plants. It can also be retrofitted to existing fossil fuel power stations.
In Pre-combustion capture technology CO₂ is separated or removed prior to the burning of fossil fuels. This method converts fossil fuels into a gas made up of CO₂ and Hydrogen (H₂). These gases are then separated through scrubbing, just like in the post-combustion capture process. Hydrogen thus obtained can be used to fuel the power plant and the CO₂ is captured, ready for transportation and storage. This method is mostly applicable in IGCC (integrated gas combustion cycle) power plants, chemical and fertilizer industries.
In oxy-fuel combustion method fossil fuels are combusted in presence pure oxygen, instead of air, to eliminate the nitrogen (N2) contained in combustion air. The flue gas thus produced only contains CO₂ and steam, which are then separated by a cooling process. Though this method can reduce carbon emission to almost nil, it is a highly energy intensive process. This technology of oxy-fuel combustion can be applied to both, new and existing fossil fuel power stations.
According to the International Energy Agency (IEA), global emissions should peak by 2020 at the latest and then be more than halved by 2050 relative to 1990 levels if the increase in global temperature is to be capped at 2ºC. One-fifth of this required emissions reductions would arise from CCS, otherwise emissions reduction cost would increase by more than 70% annually. The IEA projects that in order to meet this 2050 goal, 100 CCS projects would need to be established by 2020, with the number to rise to over 3000 before 2050. Another benefit which may result from the deployment of CCS is the creation of a big job market. The entire supply chain involved in CCS can create a wide palette of jobs for local communities. The UK government estimates that the market resulting from the adoption of CCS processes could create a market worth £6.5 billion per year by 2030, and provide some 100,000 jobs4.
However, there exist major barriers against the adoption of this technology - exorbitantly high capital investment and high operational costs. It is hence imperative that governments lend a helping hand, in the form of a favorable policy environment, if CCS technology is to see widespread deployment.
To promote CCS, the UK government has established a policy which mandates that all new coal-fired power stations must be CCS-enabled for at least a proportion of their capacity. Furthermore, all new thermal power plants (coal, gas, biomass, oil) with capacities of over 300MW must be designed to be “Carbon Capture Ready” (CCR) in order to receive a planning permit. On top of this, UK law has moved to incorporate the ‘EU CCS Directive’, which provides a legal framework for the safe geological storage of carbon dioxide. The UK government is presently also contemplating the introduction of an Emissions Performance Standard (EPS) to regulate the carbon dioxide emitted by power plants per unit of electricity output. If implemented, this EPS would help to further promote CCS and its technology applications in the power sector5.
More importantly, the UK has one of the most comprehensive governmental intervention programmes aimed at delivering cost-competitive CCS infrastructure in the 2020s. The five integral components of the programme are:
- A CCS Commercialisation Programme, with £1 billion in capital funding to support commercial-scale CCS. Its major objective is to enable private electricity producers to adopt CCS technology (by investing in CCS equipped fossil-fuel power stations) in the 2020s without requiring capital subsidies from the government. This would allow them to produce power at prices that are competitive with other low-carbon generation technologies. The government announced in October 2012 that it was assessing and negotiating four of the eight full bids it received to undertake work on carbon capture, transport and storage. It will soon decide which projects to support further in 20136.
- A £125m, 4-year R&D and innovation programme to bring into the market the best ideas for increasing the cost-effectiveness of CCS-related processes, and the establishment of a new UK CCS Research Centre.
- Development of a market for low-carbon electricity. This market is expected to be created through the Electricity Market Reform (EMR), and will include ‘Feed-in Tariff Contracts for Difference’ which apply to low-carbon electricity, so as to take care of CCS-equipped fossil fuel power stations.
- Intervention to address key barriers to the deployment of CCS, which will include measures to improve the CCS’ supply chain and its transport and storage networks, to enable its industrial application, and to guarantee a regulatory framework for CCS.
- International engagement for the exchange of knowledge on CCS technology.
Although experts worldwide are working extensively on CCS and its technology, progress has been slow. Presently only eight large-scale integrated CCS projects are in operation in the world. Most of these projects involve the extraction of carbon dioxide from gas processing and fertilizer plants, which is then injected into older oil wells to push out the otherwise-inaccessible crude oil. This technique is known as enhanced oil recovery (EOR)7.
Four of these eight operational projects are located in the USA; of the remainder, two are in Norway, while one project is functional in North Africa and Canada each. The Sleipner plant located in Norway’s North Sea has been operational since 1996, and injects into the seabed over 1 million tonnes of CO2 annually. The Snøvit plant in northern Norway, operational since 2008, has a capture and storage capacity of 700,000 tonnes of CO2 per year8.
Although the current number of CCS projects is small, the imminent future is expected to bring significant increases in the level of activity in the CCS domain. The technology received nods from the climate change brigade represented at the UN Climate Conference at Durban in 2011, as it was granted acceptance under the Clean Development Mechanism.