Carbon capture and storage / ‘Clean’ fossil fuels
Carbon capture and storage (CCS) is a major departure from other climate mitigation strategies as, rather than stopping a damaging activity or replacing fossil fuel use, it allows current activities to continue but captures the carbon emissions and buries them under the ground. CCS is a major plank of the European Union’s strategy of moving towards ‘sustainable fossil fuels’.161 The CCS approach fails to recognise the wider systemic problem of overconsumption or deal with the other impacts of that overconsumption.
CCS is also closely associated with enhanced oil recovery (EOR), where the carbon dioxide pumped into ageing oil wells makes more oil available, which in turn produces more emissions when burned. Companies’ duty to pursue profit above other concerns means CCS would be used with EOR wherever possible unless this is actively prevented.
For some environmentalists, CCS is a lesser evil than either nuclear power or devastating climate change. But could it work in time, and what are its side effects?
How the technology works
CCS is a system for capturing, transporting and storing carbon dioxide from large emitters. Most of the work is currently going into applying this technology to power stations but it could theoretically be used to capture the emissions from other large single-site emitters such as cement, iron or steel works and oil and gas refineries.162
There are three main methods for capturing carbon dioxide from a power station being put forward:163
Pre-combustion capture involves gasifying the fuel to separate it into hydrogen and carbon dioxide. The hydrogen is lighter so the two gases are easily separated and the carbon dioxide stream is relatively pure. The hydrogen is then burnt to power a generator and produce electricity.
Post-combustion capture chemically ‘scrubs’ the carbon dioxide from the mixture of gases produced during the combustion process. This has the advantage that it can be retrofitted to existing plant.
Oxyfuel combustion involves burning the fuel in oxygen rather than air, meaning that the exhaust gas consists primarily of water vapour and carbon dioxide. When the water vapour is condensed out, the remaining carbon dioxide gas can be captured.
Each of these options requires a large amount of extra energy – 10-40% more depending on the technique used.164 This energy is used to compress the carbon dioxide for transportation and in the capture process – either to gasify the fuel, to ‘scrub’ the flue gas of carbon dioxide, or to extract oxygen from the air.
The most effective means of transporting the captured carbon dioxide is via pipelines, similar to the gas pipeline infrastructure that already exists. Tankers could also be used but would be more expensive and less efficient.165
There are three main options for storage of captured carbon dioxide:166
Geological storage in depleted oil and gas fields, saline aquifers (geological formations containing
undrinkable water with high salt contents), or unmineable coal beds.
Ocean storage either by dissolving the carbon dioxide in ocean water or pumping it deep down to the
ocean floor. Below a certain depth and pressure in the deep ocean, carbon dioxide liquefies and
becomes denser than water so in theory should form a stable lake on the ocean floor.
Mineral sequestration in which the carbon dioxide reacts with quicklime (calcium oxide), to form limestone
(calcium carbonate). The IPCC has estimated that a power plant equipped with CCS using mineral storage
would need 60-180% more energy than a power plant without CCS.167
Carbon Capture & Storage Current Position
Status of the technology
Aspects of this technology already exist to various levels of maturity as carbon dioxide is already used by the oil industry to enable exploitation of oil reserves that would otherwise stay in the ground. This technique is known as Enhanced Oil Recovery (EOR). Carbon dioxide pumped into ageing oil fields dissolves the oil, making it flow more easily so that it can be pumped. Norwegian oil company Statoil has been pumping carbon dioxide into the Sleipner field in the North Sea since 1996,168 this is simply for storage not for EOR. This carbon dioxide has been removed from gas deposits that have too high a carbon dioxide content to be allowed onto the market.169
At the capture stage, both pre and post combustion technologies are used in some commercial projects. Pre-combustion capture is used in fertiliser manufacturing.170 Post combustion capture is used in the natural gas processing industry.171Applying this technology to power plants would require further development and demonstration projects.
Oxyfuel combustion is at the demonstration phase.172 Pipeline transport of carbon dioxide is an existing technology (in the USA, over 2,500 km of pipelines transport more than 40 Mt/carbon dioxide per year).173 Of the storage options, the geology of oil and gas fields well understood because of the experience of the oil industry, however more research is needed to confirm whether these structures are suitable to store carbon dioxide for thousands of years.174 Less is known about storage in saline aquifers.175
Another proposed use is to store carbon dioxide in coal seams to enable the extraction of methane; this technology is also at a demonstration phase.176 Ocean storage and mineral carbonation are both at a research phase.177 Systems for injecting carbon dioxide and monitoring storage need further development, including adaptation from existing applications used by the oil industry.178 There is no method yet for determining how much can be stored and how to tell if things are going wrong.179
The IPCC suggests that from well selected storage sites, storage rates are likely to exceed 99% over 100 years.180 Leakage is possible from sites in two ways, either large scale leaks during transportation or injection,181 or gradual seepage over time from abandoned oil wells or damage to the geological structure as a result of earlier oil and gas exploration.182 Potential sites would have to be well surveyed to minimise the possibility of seepage.
Although the technologies needed for various aspects of a CCS system exist to varying degrees of development, there are no examples of a fully integrated CCS system in existence.183
Support for the technology
Many governments are currently supporting the development of carbon capture and storage, including demonstration projects in the USA, UK, Norway, EU, Australia and China.
Developing a fully integrated CCS system would require numerous demonstration projects adapting various systems for capture with different designs of power plant and testing out options for storage. These programmes would need to be run for a number of years in order for the technology to be properly demonstrated. The UK government anticipates that this would take at least 15 years.184 The EU estimates that CCS could be commercially available in 2020185 and that 12 demonstration plants of 300MW would be required costing at least ?5bn (?4bn).186
The UK has announced a competition for a demonstration project to apply post-combustion CCS to either a new or old power plant.187 The USA’s main demonstration programme, FutureGen, will not be operating until 2015.188 The UK government’s scenario envisages emissions reductions from CCS not starting until 2020, and increasing from a very low base of initially saving 300,000 tonnes of carbon per year.189 For comparison, the UK’s largest coal plant, Drax, alone produces over 20 million tonnes of carbon dioxide each year.190
Companies likely to bid for UK CCS demonstration competition:
Powerfuels, E.On, Scottish Power, Scottish and Southern Energy, Centrica, Progressive Energy,
Conoco Philips, RWE
Members of Futuregen:
American Electric Power, Anglo American, BHP Billiton, China Huaneng Group, CONSOL Energy, E.ON,
Foundation Coal, Luminant, Peabody Energy, PPL Energy Services, Rio Tinto Energy America, Southern
Company Services, Inc, Xstrata Coal
Carbon Capture & Storage Issues
Delaying action on climate change
CCS is only useful as a solution to climate change if it can be used now and scaled up. A study by MIT suggests CCS will not be operating on a commercial scale until 2030. Shell says it will not be in widespread use until 2050. But even taking the optimistic projections of various governments, if CCS will not be available on a large scale until at least 2020 it cannot contribute to peaking global greenhouse gas emissions by 2015 or to managing the energy descent in time to avoid devastating climate change. Because waiting for its introduction is being used as an excuse to keep burning coal, CCS will not so much smooth the transition to a low carbon economy as delay it.
The optimistic timescales already look like they are beginning to slip. Despite statements from senior executives saying, ‘developing commercially viable CCS should be a priority for companies and governments all over the world’, Shell, along with its partner Statoil, ditched a CCS demonstration project in Norway which would have enabled EOR from their Draugen and Heidrun oil fields due to lack of profitability.
The US government’s FutureGen project, a joint initiative between the government and the coal industry, is also floundering. Having originally planned a single demonstration plant and completed a tendering process to determine the location, the Department of Energy announced in January 2008, just six weeks after the location of the project was announced, that the project is being restructured and the money will instead be shared between a number of projects.191 This has put the date the demonstration plants are supposed to begin operating back from 2013192 to 2015.
For all the spin, governments and companies have not been prepared to put their money where their mouth is on CCS, waiting for the carbon market to kick in and make the projects economically viable. The projected dates of 2016 and 2020 may well be overoptimistic. When will real emissions reduction action begin? Other technologies are available now.
The potential to reduce carbon emissions is over-hyped
The IPCC estimates that by 2050 20-40% of global fossil fuel emissions would be technically suitable for capture including 30-60% of emissions from electricity production and 30-40% of emissions from industry.193 Actual emissions captured would inevitably be less than this, and there would be additional emissions resulting from the processes of CCS which can itself consume up to 40% of the energy produced by a power station depending on the method used.194 In addition, energy used to extract and transport coal takes up to quarter of the energy coal produces at the power station. These emissions cannot be captured. The most comprehensive assessment, made by Peter Viebhan of the German Aerospace Centre suggests that CCS can reduce greenhouse gas emissions from coal power stations by little more than two thirds.195 This is less than the deep cuts which scientists are saying need to be made.
Justifying the expansion of coal
Choosing CCS means choosing coal. While CCS could theoretically be used for capturing emissions from a range of large point sources of carbon dioxide, most of the interest is in capture from coal power stations. Coal is a much more abundant resource than oil and gas (reserves exist to last up to 147 years at current rates of production according to the World Coal Institute196), coal reserves are widely geographically spread, and coal is cheap. CCS is expensive, so to become competitive the fuel needs to be cheap.
CCS is already being used as an excuse for the expansion of coal. For 20 years, no new coal power stations have been built in the UK.197 With many of the UK’s coal power stations coming to the end of their life and expected to close by 2015,198 the coal industry is using the possibility of future CCS technology to push the government into granting permission for a new generation of coal plants. German energy company E.ON is planning two new 800 MW coal power stations at the site of its current plant at Kingsnorth in Kent.199 The plant will emit more than 8 million tons of carbon dioxide a year.200 Nationally there are another six coal power stations in the pipeline.201 It is assumed that new plants will be built ‘capture ready’, so that CCS technology could potentially be added if it becomes commercially viable.
In practice, this means little more than designating space for a future carbon capture plant at the site. It is unclear whether the government will require all plants to be capture ready in any case.202 Emails between the Department for Business Enterprise and Regulatory Reform (BERR) and Kingsnorth’s owner, E.On, have revealed that E.On vetoed BERR’s suggestion of including CCS in the conditions for the plant.203 Since then, E.On have announced that Kingsnorth will be entered into the government’s competition for funding for a CCS demonstration plant.204 If they do not win will they cancel their plans?
The new Kingsnorth plants are expected to open in 2013. In the best case scenario, where the new plants would be adapted for carbon capture straight away when the technology becomes available and economically competitive (the technology may be available and tested as a complete system by 2020, but it could take a decade for the system to be applied to all existing plant)205 there will be a significant overlap where the new plants are emitting huge quantities of carbon dioxide with no CCS in place. Building new coal plants in Kent is also problematic. Kingsnorth power station is a long way from potential storage sites in the North Sea oil fields. If coal and CCS are to be used then it makes more sense to concentrate plants further north than to build pipeline infrastructure across the country. The government has acknowledged this, saying, ‘we will need to recognise that for some projects the scope for CCS (eg because of geographical location or other technical limitations) may be limited’.206 In addition, retrofitting existing plants is much less economical than building new plants with carbon capture once the technology is ready. The EU estimates the cost of retrofitting ‘capture ready’ plants to be ?600,000 – 700,000 (?475,000-554,000) per megawatt of capacity.207 So building new coal plants under the excuse of future CCS increases medium term emissions and the eventual cost of emissions reductions.
Expanding coal use means more mining. In 2007, work began at the new Ffos-y-Fran open cast mine in Merthyr Tydfil, Wales, one of the largest in Europe.208 The mine covers 400 hectares209 with the edge of the site only 36 metres from people’s homes210 and is dubbed a ‘land reclamation scheme’ by the mining company, Miller Argent.211 It will excavate 11 million tonnes of coal212 resulting in 30 million tonnes of carbon dioxide emissions.213 Ten new coal mines were approved by the Labour government in 2006.214 The UK government’s commitment to ‘securing the long term future of the coal industry’,215 seems to outrank reducing emissions.
Sustainability impacts of coal
CCS means burning more coal than is used in a conventional coal plant, so bar the impact of the carbon dioxide which is captured, all the other unsustainable impacts of coal are multiplied. Coal is the dirtiest of all fuels, from its mining to disposal of waste products. It releases toxic pollutants into the air, water and land, and destroys habitats. The coal industry claims that with ‘clean coal’ technology these impacts are reduced, but even with the most cutting edge technology harmful emissions from coal plants are not eliminated, and in most cases they remain higher than for other forms of electricity generation. These technologies are expensive and with the expense of CCS already added to the cost of electricity generation it is highly unlikely that they would ever be universally applied.
Sustainability impacts of carbon storage
The main impact of geological storage of carbon dioxide is from leakage. Large scale leaks would have a global impact on the climate. Can anyone be sure that significant leaks would not happen because of human error or technical faults? The effect of seepage of carbon dioxide on ecosystems is little understood. In places where carbon dioxide leaks naturally from the earth ecosystems are adapted to it. There is a danger of significant ecosystem disruption if carbon dioxide seeps into an ecosystem that is not adapted to it. Carbon dioxide dissolved in water creates a mild acid, and seepage could pollute drinking water sources or contribute to ocean acidification. There is a concern that companies wanting to minimise the cost of transportation of the carbon dioxide will use less than perfect sites that are closer to the sources of emissions. If this technology is used, any leaks would have to be found and remedied, yet the technology to ensure this does not exist. There are significant legal questions around who will be responsible for long term storage – similar questions around responsibility for nuclear waste have proven intractable.
With ocean storage of carbon dioxide there is a distinct likelihood that this technology would contribute to the acidification of the oceans caused by climate change, which is already a grave concern. There is also little chance of effectively monitoring ocean storage. This approach is extremely risky and should not be pursued.
Pumping fossil fuels that would otherwise stay in the ground
The close association between CCS and enhanced recovery of oil, or methane from coal beds, is one key incentive motivating CCS’ backers. Oil and gas reserves which are already accessible contain sufficient carbon to cause devastating climate change if burned. Accessing more fossil fuels does not make sense as part of a system for emissions reductions.
In 2005, BP sought government support for a CCS demonstration plant at Peterhead in Scotland. The project, a ?500 million pre-combustion capture natural gas plant, would have been used for enhanced oil recovery (EOR) at BP’s Miller oil field.216 However, government support was not received and the project was cancelled. If it had gone ahead, BP claimed that 26 million tonnes of carbon dioxide would have been sequestered.217 The carbon dioxide would have been used to pump an extra 40 million barrels of oil. Based on the emissions from an average barrel of oil, these 40 million barrels would have produced 12.68 million tonnes of carbon dioxide.218 If captured carbon dioxide is used for EOR then it is by no means ‘carbon free’ energy as companies like BP claim.
Its proponents claim that CCS offers a route to gradually wean ourselves off fossil fuels while rapidly cutting carbon emissions. However, this thinking prolongs business-as-usual, preserving the dominance of the fossil fuel industries and diverting attention and investment from more sustainable methods of emissions reduction.
For CCS to be part of a sustainable solution, it would have to be used as a strictly interim measure, not longer than the lifespan of a power station, to enable gradual transition from high emission fossil fuel use, building up of renewables capacity and changes to lifestyles and economies to use less energy. It would not be used to enhance recovery of fossil fuels, to perpetuate the dominance of the fossil fuel industries, to justify the expansion of the coal industry while CCS technology is not available, or to divert funding away from renewables. Since this scenario is a long way from reality, and is unlikely to emerge in time to be useful, CCS will not be an effective solution to climate change.
Effectiveness at reducing greenhouse gas emissions: 3/10 – unlikely to be available in time, and emissions reductions are offset by the effect of enhanced oil recovery
Living up to the hype (science to spin ratio): 1:7
Democratic ownership and control: 1/10 – perpetuates dominance by big energy corporations
Social justice: 3/10 – no new side effects, but perpetuates injustices of the coal industry
Sustainability: 3/10 – absolute sustainability limited by coal reserves, also mining has negative impacts on ecosystems
Scalability: 4/10 – only applicable to very large emissions sources.