Carbon Capture and storage. Stuart Haszeldine Vivian Scott INSTANT EXPERT. 00 Month 2010 NewScientist 1

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1 Carbon Capture and storage Stuart Haszeldine Vivian Scott INSTANT EXPERT 00 Month 2010 NewScientist 1

2 Halfway to disaster How much is too much? Nobody knows for sure, but sophisticated climate models suggest that if average global temperatures rise by more than 2 C then the consequences are likely to be dramatic, from more natural disasters to a higher number of agriculture Alfredo D Amato/Panos Jim Richardson/ngs/getty failures. The concentration of in the atmosphere needed to force a 2 C rise can be calculated: around 450 parts per million. A simpler way to consider this threshold is to calculate the total mass of carbon that we would need to burn and emit as to force a 2 C rise. That turns out to be 1 trillion tonnes of carbon (or 3.6 trillion tonnes of ). This is useful, because it means we can estimate how much of this total fossil carbon budget we have already used. By looking to projected rates of fossil fuel combustion, we can also calculate how much time is left until the remainder of the budget is used up. The results are shocking. The world is already around halfway through its budget of carbon emissions. To satisfy growing energy demand, the trillionth tonne of carbon is likely to be burned within the next 20 to 30 years. Most of the world s electricity comes from burning fossil fuels Reducing emissions For the near future, we will continue to rely on coal, oil and gas for more than 80 per cent of our energy needs. It will take time to develop programmes of energy efficiency and renewable power generation. So unless we are willing to gamble on the future ecology of the continents and oceans, then there is no better way to rapidly reduce carbon emissions over the next 30 to 60 years than by capturing and storing. Carbon capture and storage (CCS) is no panacea, but it could provide a major contribution to emissions reduction. The International Energy Agency calculated the cost-effectiveness of the various methods for reducing emissions, and concluded that CCS should provide one-fifth of the reductions required by 2050 (see right). Achieving the same cuts without CCS will cost massively more. For this reason, CCS is an integral part of the low-carbon ambitions of rich industrialised nations, such as the members of the European Union, the US, Canada, Norway and Australia. It is also recognised as an important technology by rapidly industrialising nations like China, South Africa and Brazil. For CCS to deliver, it will need to be installed on all new and existing power plants burning fossil fuels as well as on industrial sources of. CCS requires extremely large and complex equipment. Large-scale industrial development of CCS has to start now, in 2011, to make the required impact on emissions a challenge unprecedented in scale and cost. ii NewScientist

3 The case for carbon capture Burning fossil fuels provides most of the world s electrical energy. It also produces large amounts of carbon dioxide. Carbon capture and storage (CCS) offers one of the most direct and rapid ways of reducing emissions right now. It involves capturing from the exhaust gases of large emitters, such as power plants, natural gas production platforms and industry. The gas is then transported by pipe or ship and injected into porous rock to be stored deep underground for millennia. Using CCS to capture and store emissions will be crucial to preventing atmospheric concentrations reaching a level that will drastically change global climate and the acidity of the oceans. The impact of carbon dioxide The volume of released by humans has overwhelmed the Earth s natural By 2050 an estimated 57 gigatonnes/year of will be emitted, unless reduction measures are taken. According to the International Energy Agency, the most cost-effective approach has carbon capture providing 20% of the necessary cuts TOTAL YEARLY CARBON EMISSIONS CARBON CAPTURE 8Gt NUCLEAR 3Gt 2Gt POWER GENERATION EFFICIENCY FUEL & EFFICIENCY SAVINGS 16Gt RENEWABLES 7Gt FUEL SWITCHING 7Gt carbon cycle. Concentrations of in the atmosphere and upper layers of the ocean have risen significantly since industrialisation. The effects are twofold. First, the atmosphere retains more heat, leading to global warming and regional climate change. The most recent predictions from climate scientists make a 2 C warming look inevitable by 2100, and a 5 C warming quite possible. The other effect is less well known but very potent: ocean acidification. When dissolves in water, it forms carbonic acid. Ocean acidity has been stable for the past 20 million years, but climate scientists predict that by 2100 our seas will be four times as acidic as they are now. The effects on marine ecosystems and the species that depend on them, including humans, could be catastrophic. NECESSARY CUTS: 43Gt Coal remains the largest source of the world s electrical energy today NewScientist iii

4 three routes to carbon capture Post-combustion captures from the exhaust gas. It uses chemicals called amines that selectively react with when exhaust gas is bubbled through. Heating this solvent releases the concentrated, allowing the solvent to be reused. Amine-based capture is now used in natural gas processing and at pilot carbon capture plants. It can be retrofitted to existing power plants. Pre-combustion strips the out of the fuel before it is burned, via a series of interlinked chemical reactions. The fossil fuel is converted to syngas (carbon monoxide and hydrogen), which is then reacted with water vapour (a shift reaction ) to form an easily separated mixture of hydrogen and. The hydrogen is then burned. Many proposed CCS projects plan to use this method. Oxyfuel combustion burns fuel in almost pure oxygen instead of air. This means that the exhaust gas is made up mostly of and water, which are easily separated. However, producing pure oxygen is an expensive and energy-intensive process. A handful of pilot test facilities currently operate. Air Exhaust gas Exhaust gas Air Air Fossil fuels Fossil fuels Fossil fuels N 2 Power & heat COMBUSTION PROCESS SYNGAS PRODUCTION Water H 2 +CO Power & heat AIR SEPARATION O 2 Combustion process Exhaust gas SEPARATION SHIFT REACTION & SEPARATION H 2 Power & heat Combustion process STORAGE STORAGE STORAGE iv NewScientist 2 April 2011

5 Capturing carbon dioxide Carbon dioxide forms around 10 per cent of a typical coal power station s exhaust gas, so before burial it must be separated from other gases. Burying all the exhaust would be infeasible, not least due to the huge volumes involved. However, separating is currently the most expensive part of carbon capture and storage (CCS), so extensive research is under way to increase efficiency. Ultimately, the most efficient solution could rest in an entirely different style of fuel combustion smaller, better, cheaper Momatiuk - Eastcott/Corbis Present day capture methods (left) use up a lot of energy, so a lot of effort is going into developing more efficient alternatives. At present, chemicals called post-combustion amines are used to capture by reacting with it. They are likely to be replaced in the near future by advanced amines, which require less heat to release the they capture. They will also be more resistant to degradation by other chemicals in the flue gas, so will last longer. Upgrading won t require any expensive major restructuring either. In the medium term, physical adsorbents of may be introduced. These materials stick to rather than reacting with it, so less energy is needed to release the and reuse the adsorbent. Initially, these physical adsorbents are likely to be liquids, but switching to solid materials known as molecular sieves could greatly reduce the physical size and operating costs of equipment. Another technology under development uses crystalline compounds called metal organic frameworks, which have a vast internal surface area relative to their weight. Pressure changes can force these materials to selectively soak up or release as required. The equipment would be minimal in terms of size and energy consumption compared with current methods. Alternatively, an existing type of filter called a selectively porous membrane could capture from exhaust gases. These films are already established in other industries, for separating from hydrogen. However, to work with exhaust gas the whole membrane needs to be increased in size, adapted to hotter operating temperatures, and attain higher purity of separation. Algae are widely considered for use in separation. Exhaust gas could be pumped through tanks of algae, which would photosynthesise the. This would produce biomass that could then be reused as liquid or solid fuel. However, very large surface areas would be necessary to absorb enough sunlight and a lot of nutrient input would also be needed. Ultimately, the most efficient solution could rest in an entirely different style of fuel combustion a process known as chemical looping. Instead of using air to supply the oxygen necessary to burn fuel, the oxygen carrier would be a solid metal oxide. This reacts with the fossil fuel to form easily separated hydrogen and ; the hydrogen is used as a fuel, while the is captured. This requires energy input, but regenerating the metal oxide by exposing it to air releases energy so the two processes almost cancel each other out. Overall, the energy needed to capture this way could be as low as 2 per cent of the total energy generated, a fraction of the 25 per cent penalty of current systems. Power stations will need large-scale equipment to apply current carbon capture methods NewScientist v

6 Helping hand required To accelerate deployment, governments are subsidising early carbon capture projects. For example, the UK government has committed up to 1 billion for the UK s first large-scale project. Member governments of the European Union have also introduced several supporting policies. As part of the European Economic Recovery Plan, 1 billion has been split between six CCS demonstration projects to help pay for their design. The EU also operates the world s first emissions trading scheme, where producers purchase the right to emit from a fixed total of emissions. From 2013, almost all commercial power plants in Europe will have to purchase an emissions permit for each tonne of they release. By 2020, the permit price could rise to around 40 per tonne, which would be high enough to encourage industry investment in CCS. Around 4 billion from the sale of EU emission permits is also being used to support the first generation of large-scale CCS validation projects. Through these measures, the EU hopes to encourage industry to invest in up to 12 large-scale CCS demonstration projects during These projects will use different capture and storage processes, to explore the technical feasibility of each approach. Each project will also require considerable investment from the operating company, or the national government of the host country. These contributions are proving difficult to extract, and the speed at which demonstration plants are being built remains too slow and uncertain. Still, if these demonstrations succeed, the EU will lead the world in the design, deployment and financing of CCS. Nations outside the EU are also subsidising CCS development. In the US, Canada and Australia, governments have awarded grants to support CCS projects, as well as guaranteeing loans and tax breaks. In the future, large carbon trading markets may be introduced to encourage investment. Alternatively, if the demonstration plants prove that CCS is technologically and economically viable, governments might simply make CCS mandatory for fossil power plants and intensive industry. The country where carbon capture is perhaps most advanced is Norway. In 1991 the country introduced a high tax on emissions, which has resulted in the application of CCS to two large offshore natural gas extraction and processing facilities: Sleipner, operational since 1996; and Snohvit, operational since To date, these projects have safely stored a combined total of over 12 million tonnes of, deep beneath the bed of the Norwegian Sea. CARBON CAPTURE TODAY Operational large scale (greater than 0.7Mt stored per year) Projects in development with large funding Operational full chain (capture and storage) pilot projects Challenges of storage Kjetil Alsvik/statoil After capture, is stored kilometres beneath Earth s surface. Microscopic pores in reservoir rock, such as sandstone, can be filled with dissolved or liquid. Above this reservoir, layers of impermeable rock, such as shale and clays, prevent the migrating to the surface. As a guide, a storage site is expected to operate with less than 1 per cent loss to the surface over the next 10,000 years. Most countries have potential storage capacity for many decades-worth of. Europe has vast storage potential offshore beneath the North and Baltic seas. The rocks beneath the UK seabed account for 35 per cent of all European Union storage capacity. Though capacity is not a problem, finding storage sites is not easy, due to the general public s concern about safety. Very few communities have agreed to host an onshore storage site, because there are few obvious incentives to do so, and they are nervous about the impact of leaks. However, a number of injections have already been safely carried out around the world. For now, it may be easier to develop a few, much larger sites offshore. Combining stringent storage site selection with detailed monitoring during and after injection allows tracking of the under the surface. The most difficult part is to construct licensing and liability legislation that is both sufficiently rigorous to protect the public and state, and yet attractive enough for commercial investment. vi NewScientist

7 Transport and storage Transporting and then storing carbon dioxide below ground are the final stages of carbon capture and storage (CCS). The safe and secure burial of is the most difficult part of the process and prompts the greatest public concern. Yet scientists and engineers are confident that safe transport and storage is possible. Natural has been securely trapped underground for many tens of millions of years, for example, under large swathes of Italy, central France, south-east Germany and the south-western US. And the expertise and technology required for transporting, injecting and monitoring the gas can be directly derived from the oil and gas industries. Norway s Sleipner natural gas extraction facility (left) was one the world s first plants to adopt CCS The oil industry already pipes large volumes of hydrocarbons around the world (right) Kjetil Alsvik/STAToil / harald sund/getty Tankers continually criss-cross the North Sea carrying carbon dioxide for fizzy drinks and dry cleaning Piped in Very few large sources of are lucky enough to sit above a suitable storage site, so the gas needs to be transported. If carbon capture and storage (CCS) reaches full scale this will be a huge undertaking with a daily movement of fluids comparable to the volumes of all oil and gas transported today. This rules out using trucks or rail; pipelines and shipping are the only option. Piping is an established technology in the US, hundreds of kilometres of pipes carry to oilfields, where it is pumped underground to enhance oil recovery. These pipelines have been operating for 30 years with an excellent safety record. In Europe, onshore power plants and factories will, where possible, be connected to local storage destinations, but if storage is not accessible or acceptable then long-distance pipelines to the coast will be needed. Building such a pipe is not cheap up to 1 million per kilometre but the cost would be recovered by charging the producer a small fee for every tonne of transported. Pipelines or ships can carry to offshore storage sites. Commercially, undersea pipes are generally cheaper if used for at least 30 years. Yet shipping wins out if the plan is to transport less than 5 million tonnes of per year, or if the distance from a single source on the coast to the offshore injection site is greater than around 500 kilometres. Like the pipelines, shipping has a good safety record. Today, tankers continually criss-cross the North Sea carrying. These ships supply the gas for everything from fizzy drinks and coffee decaffeination to dry-cleaning. NewScientist vii

8 Stuart Haszeldine Stuart Haszeldine is a professor of carbon capture and storage at the University of Edinburgh, UK. His research has improved our understanding of the origins of coal, North Sea oil and gas, and the deep storage of radioactive waste. He leads Scottish CCS, the UK s largest academic research group for CCS and has played an important UK role in developing CCS research and policy. Vivian Scott Vivian Scott, also at the University of Edinburgh, works on CCS as a climate mitigation technology, engaging with the policy development required for enabling the first generation of large-scale CCS projects in Europe. Next INSTANT EXPERT Caleb Scharf astrobiology 7 May An unprecedented challenge Carbon capture and storage (CCS) is now in a critical period of development and initial deployment that will determine if the capital and operational costs are viable. The legal frameworks, financial support and demonstration plant designs are nearing completion in several countries around the world. So far, only a handful of large complete CCS operations exist or are under construction. By 2015, at least 20 commercial-size demonstration plants will have to be built and start operating to prove that CCS is a viable proposition. The greatest challenges do not lie in developing improved carbon capture methods, or in safely and securely storing the underground. The two critical problems are primarily political. Firstly, the financing of large individual projects is difficult in a market economy in which is still not priced at its true environmental cost. Secondly, we urgently need to develop a balanced legal framework to cover the storage sites, which both protect the public interest and enable CCS to be commercially viable. Industry must be able to transport, inject and store, and then close and withdraw from filled storage sites without fear of overly onerous long-term liability. For CCS to deliver the emissions reductions required, thousands of projects will be needed. This requires heroic rates of construction and large financial expenditure. To make this happen outside the world s richest countries, we may need a piecemeal global agreement on emissions reductions and carbon markets, or to impose carbon tariffs on goods imported from developing countries which have produced significant emissions in their manufacture. The unabated combustion of the known commercial resources of oil, gas and coal will easily surpass the environmental limits calculated for a secure climate and a healthy ocean. Mitigating climate change demands massive and rapid technological advancement and application. To develop CCS regionally and globally, continued personal, political and corporate courage and much more urgency will all be required. recommended READING and links Carbon Dioxide Capture and Storage Intergovernmental Panel on Climate Change special report Carbon Capture and Storage: How Green Can Black Be? by Stuart Haszeldine, Science, DOI: / science Scottish Carbon Capture and Storage Zero Emissions Platform The European Network of Excellence on the Geological Storage of Cover image: Gene Wong/EPA/Corbis viii NewScientist