To the layman, carbon capture sounds simple and eminently sensible: collect carbon dioxide (CO2) emissions from burning hydrocarbons and return them securely to the depths of the earth. The use of carbon capture and storage (CCS) on an industrial scale is also essential to any hope of meeting global climate change targets.
|The first phase of the 650 MW GreenGen IGCC project near Tianjin is expected online in 2011, generating 250 MW Source: GreenGen|
The International Energy Agency’s (IEA) roadmap projects thousands of CCS projects in use by 2050. This will require capital investment of nearly $100 billion in CO2 capture, transport and storage equipment by 2020, increasing fivefold by 2050. If this is realized, huge business opportunities will follow for companies with expertise in designing, developing and manufacturing the technology.
But the clock is ticking. While the component pieces of the technology exist, the application of the technique is in its infancy. Full-scale deployment has yet to be achieved on a fossil fuel power plant anywhere in the world.
Demonstration projects call on public funding
Right now, development work is essential. Large demonstration projects are necessary to build-up experience. As industry currently lacks the appetite for investment, incentives and policies are needed to find a way forward and to divert private investment into a frontier technology.
The European Union (EU) has been funding research into CCS since the 1990s. Along with its ETS (Emissions Trading Scheme), the EU envisages CCS playing a key role in cutting carbon emissions. In March 2007, European governments agreed that 12 CCS demonstration plants of at least 250 MW capacity should receive part-funding to become operational by 2015.
The EU has two funding packages to part-fund CCS projects: the New Entrant Reserve (NER) mechanism and the European Economic Recovery Plan (EERP). The NER funding will come from auctioning permits under the EU ETS and should be matched by equivalent funding from the Member States. But the subsidies will not cover the costs of the projects and substantial investment from developers will also be required. The results of the first NER competition are due to be announced later this year.
European governments, notably the UK government, have been eyeing the prospects. Charles Hendry, a UK energy minister, told a conference in February 2011 that CCS could create up to 100 000 jobs in the UK alone, with annual export opportunities worth up to à‚£6.5 billion ($10.6 billion) by 2030, quoting figures from AEA, a climate change consultancy.
But the slow pace of development means there is no certainty that the technology will originate in Europe. Earlier this year the Pew Environment Group put China at the top of its clean energy investment rankings for 2010. Investment in China reached $54 billion, with Germany in second place ($41 billion) and the US in third ($34 billion).
How rapidly can China embrace CCS?
China is responsible for half the world’s coal consumption and for colossal CO2 emissions. But it has steadily improved the efficiency of its coal power fleet over the past two decades and is now exploring CCS technology, both with and without international funds.
COACH ” the Co-operation Action within CCS China-EU project ” aims to prepare the ground for implementing large-scale generation facilities in China, with options for coal based electric power generation, as well as production of hydrogen and synthetic fuels. The project receives funding from the European Commission under the Sixth Framework Programme.
|The CCS unit at Longannet in Scotland Source: ScottishPower|
The joint UK-China Near Zero Emissions Coal (NZEC) initiative was signed in 2005 as part of the EU-China Partnership on Climate Change. NZEC aims to demonstrate advanced, near zero emissions coal technology through CCS in China and the EU by 2020. NZEC is funded by the UK’s Department of Energy and Climate Change, and is being taken forward in partnership with China’s Ministry of Science and Technology (MOST). Project partners in both the UK and China include academic institutions, as well as industrial companies.
The EU GeoCapacity project, co-financed by the European Commission, has pioneered storage capacity estimation and GIS mapping in China through a comprehensive study of the Hebei Province, near Beijing, and in the Bohai Bay sedimentary basin.
Dr. John Topper, managing director of the IEA Clean Coal Centre, believes work under way in China could position it to become a world leader in CCS technology. “We are seeing a deliberate move, quietly encouraged by the authorities, to get into a position where China owns its own intellectual property,” he said. “A significant number of Chinese universities and institutions are running research programmes related to CCS. At the same time some of the leading companies are starting to build pilot plants at real-scale and planning demonstration units of their own.” Yet considerable interest at a grass roots level is currently not matched by policy commitment, says Dr. Topper.
An opposing view comes from a UK-China collaborative research project by the Sussex Energy Group, which brings together the University of Sussex in the UK and the Laboratory of Low Carbon Energy of Tsinghua University in China. Its conclusions on low-carbon technology transfer to China published earlier this year states: “The possibility that China might take the lead here seems unrealistic. In this power-hungry country, most utilities are put off by the 25 per cent loss in thermal efficiency required to power the carbon capture equipment.”
But Dr. Topper believes the People’s Republic is positioning itself to be ready when the commercial market for CCS technology opens up. He draws an analogy with supercritical boilers, where the Chinese developed the technology and began manufacturing on a grand scale within the last few years.
“What I perceive is that Chinese are preparing for a day when they commit seriously to CCS and will then have capability to build equipment quickly and cheaply, and will be able to export the technology,” he said.
Three techniques for carbon capture
Carbon dioxide can be separated from gasified coal to produce hydrogen and CO2 either before combustion in ‘pre-combustion capture’ or scrubbed from flue gases in ‘post-combustion capture’. A third approach is to burn the coal in an oxygen environment.
Component technologies exist for all three approaches. But in each case the techniques have yet to be applied on an industrial scale to coal, so development work via demonstration and pilot projects is needed. The three techniques are being developed in China and the EU and also further afield, notably in the USA and Australia.
Post-combustion capture, where the CO2 is removed after combustion of the fossil fuel, is significant because it could be retrospectively applied to existing coal fired power plants. The technology is well understood and is currently used in other industrial applications, but not on the same scale required for commercial power stations.
Pre-combustion comes from an integrated gasification combined-cycle (IGCC) technology that turns coal into synthesis gas (syngas). Impurities are then removed from the coal gas before it is combusted. Some of the pollutants can be converted into re-usable by-products. This results in lower emissions of sulphur dioxide, particulates and mercury. Excess heat from the combustion and generation is then passed to a steam cycle, similarly to a combined-cycle gas turbine. This offers higher efficiency than conventional pulverized coal. The technology for pre-combustion is widely applied in producing fertilizer, chemicals and gaseous fuel ” both hydrogen and methane. In comparison with conventional post-combustion carbon capture, it offers various advantages and disadvantages.
The CO2 is removed after combustion of fossil fuels but before the flue gas is expanded to atmospheric pressure. This scheme can be applied to new fossil fuel burning power plants, or fitted to existing plants where repowering is an option.
In oxyfuel combustion, the fuel is burned in oxygen instead of air. To limit the flame temperatures to appropriate levels, cooled flue gas is recirculated and injected into the combustion chamber. The flue gas consists mainly of CO2 and water vapour.
The result is an almost pure CO2 stream that can be transported to the sequestration site and stored. The technique is considered promising, although the initial air separation step is energy-intensive.
The World Coal Association says that the cost of CCS should decline from an initial $80″$120 per tonne of CO2 stored to $40″$60 per tonne as experience is gained. Technological advances should bring about significant opportunities to lower the costs, notably for CO2 capture, which is generally the most expensive part of a project.
Transportation and storage
The final stage of the CCS chain is to transport and store the CO2 in deep underground locations where it will remain locked away. Transporting is most efficient when the CO2 is pressurized to become liquid. It can then be conveyed by tanker or pipeline to its final store. A depth of 800 metres or more ensures a high enough pressure to keep it in a liquid state. An impermeable layer ” such as mud or clay ” is required to act as a cap to prevent the CO2 escaping upwards.
|A Huaneng Group facility in Beijing to capture 3000 CO2 tonnes/year|
Three storage options are being assessed for suitability: coal seams, depleted saline aquifers and depleted oil and gas fields. Current estimates are that 40 years of global CO2 emissions could be stored in the world’s known oil and gas fields. Saline aquifers could offer 100 times this capacity.
An alternative approach to storage is to use the captured CO2 to enhance production of hydrocarbons such as oil, gas or coal bed methane. This option depends on the proximity of production facilities.
Nations differ greatly in their endowment of oil and gas fields or saline aquifers. The UK’s access to depleted gas and oil fields in the North Sea gives it some of the best storage sites in Europe. But India and Japan, for example, lack oil or gas fields and might need to export CO2 to find underground storage sites.
Public acceptance of overland transport and underground storage is proving controversial in Europe ” notably in Germany ” and regulatory frameworks have yet to be developed.
China moves ahead as EU stalls
Chinese CCS projects ” which cover all three competing CCS technologies ” are currently outpacing those in Europe, as demonstrated on p.26. While the EU’s Member States are making progress on small-scale demonstration projects, large demonstration plants are yet to come onstream in Europe.
In the EU, a number of CCS plants are in operation, but the much-heralded big projects have been held up by a lack of finance and by issues around permitting and regulation regimes.
A Huaneng Group unit in Shanghai to capture 120 000 tonnes of CO2 /year
In 2009, a consortium of companies including Doosan Babcock, Scottish and Southern Energy, ScottishPower, EDF, Vattenfall and E.ON opened a 40 MW oxyfuel test facility in Renfrew, Scotland. ScottishPower also has a small post-combustion CCS demonstration plant at its Longannet power station in Fife which it hopes to expand if it can win funding.
Vattenfall opened a 30 MW oxyfuel demonstration plant in Brandenburg, East Germany, in 2008. The original aim was to bury the carbon dioxide 3 km underground in a depleted gas field, but this was prevented by the lack of relevant legislation.
In another project at Brandenburg, Vattenfall planned to capture CO2 from its Schwarze Pumpe coal station and store it under the town of Beeskow. But the local council vetoed Vattenfall’s plans to conduct geological research and criticized the German federal government for allowing Vattenfall to proceed with its plans before a law on CCS exists. Opposition to CCS is seen as consistent with opposing open cast mines and power plants, and reflects a general mistrust of big infrastructure projects in the energy sector.
The EU has been talking up CCS for some years and has a competition under way for part-funding demonstration projects. But industry experts question whether the funding is too little and too late. While Chinese developers are funding projects, European utilities are dragging their heels in a market where both investment and demand for power have slumped since the economic downturn. Funds allocated under the EERP are insufficient to build any projects and adding equivalent funding from Member States may still not establish enough subsidy.
The two key issues delaying European CCS development are finance and regulation. But a planned economy can determine both centrally, so China could accelerate its CCS programme if its government decides to do so.
The EU has ambitions to be a leader in developing CCS technology and talks a good game. But plants will not be built without concerted action. Unless enough momentum is established to create jobs and manufacturing in Europe, European CCS plants over the next decades risk carrying the label ‘Made in China’.
Chinese CCS projects
China currently has projects under way that cover all three competing CCS technologies. Proposed facilities featuring CCS include:
Lianyungang IGCC with CCS Project
Capture Type: Pre-combustion and post-combustion
Transport Type: 100 km pipeline
Storage Type: Deep saline formations
Developer: Lianyungang Clean Energy Innovation Industrial Park
This project aims to construct 1200 MW IGCC and 1300 MW ultra-supercritical pulverized coal (PC) fired power plants. Heat integration is being pursued between the IGCC, ultra-supercritical PC and solar heat collector to further improve the efficiency of the system. Up to 1 million tonnes of CO2 would be recovered each year from the syngas and the ultra-supercritical PC flue gas. Captured CO2 would be transported by pipeline to Binhai, near Yancheng in the province of Jiangsu, for injection into saline formations or enhanced oil recovery.
The pre-feasibility study has been completed and the feasibility study is expected to be completed by June 2011. The plant is anticipated to be operational by 2015, subject to government approvals. The Lianyungang Clean Energy Innovation Industrial Park has the objective of promoting industrial development based on clean energy to reduce the emissions of CO2 and other greenhouse gases to the atmosphere.
Dongguan Taiyangzhou IGCC with CCS Project
Capture Type: Pre-combustion
Transport Type: 100 km pipeline
Storage Type: Depleted oil and gas reservoirs
Developer: Dongguan Taiyangzhou Power Corporation, Xinxing Group, Nanjing Harbin Turbine Company Limited
Dongguan Taiyangzhou Power Corporation is in the early phases of planning construction of a 750 MW (net) IGCC plant with CCS. The plant will be a new build IGCC power plant using coal as a feedstock and is expected to capture up to one million tonnes per annum of carbon. The CO2 would be transported in a pipeline and stored in near-depleted offshore oil and gas reservoirs about 100 km from the power plant. The plant would be operational for 20 years. Future moves to ramp-up the level of CO2 capture depend on the cost and availability of storage sites.
GreenGen IGCC Project
Capture Type: Pre-combustion
Transport Type: Pipeline
Storage Type: Beneficial reuse (enhanced oil recovery)
Location: Binhai New Area, Tianjin
Proponent: Hua Neng (Tian Jin) IGCC Company Limited
The GreenGen plan is that by 2011 a 250 MW IGCC power plant and a 30 000 tonne/year CO2 capture pilot facility will be operating. A 400 MW demonstration IGCC power plant with CO2 capture plant and near zero emission is planned by 2020.
More than 80 per cent of the CO2 would be separated and transported. Enhanced oil recovery is being considered as an option for CO2 reuse.
The project is part of the Tianjin Lingang Industrial Zone Circular Economy Plan. GreenGen plans to research, develop and demonstrate a coal based energy system with hydrogen production through the use of coal gasification and electricity generation for widespread uptake of low emissions technology in China. Peabody Energy is the only foreign investor in the $1 billion project, with a 6 per cent stake.
Shenhua CTL Phase 2
Capture Type: Pre-combustion
Transport Type: 30″100 km unspecified transport
Storage Type: Deep Saline formations
Location: Ordos, Inner Mongolia, China
Developer: Shenhua Group
Operation at pilot scale will see around 100 000 tonnes per annum of CO2 captured at the plant. By 2020 and when operating at full-scale, around 1 million tonnes per annum of CO2 will be captured at the proposed coal to liquids plant. The project received funding in the first phase of the US Department of Energy’s American Recovery and Reinvestment Act funding.
Potential storage sites are currently being investigated for the second phase of the project.à‚
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