Select Committee on Science and Technology Written Evidence


Memorandum from the Royal Academy of Engineering


  The Royal Academy of Engineering is pleased to submit evidence to the House of Commons Select Committee on Science and Technology Inquiry into Carbon Capture and Storage Technologies. This response has been prepared following consultation with a number of Fellows with expertise in this area.

  The Committee will be aware of the Department of Trade and Industry's recent Consultation "A Carbon Abatement Technologies Strategy for Fossil Fuel Power Generation" of August 2004.  The Academy responded to that consultation and our response to the DTI is annexed to this report.

  The contributing Fellows are of the opinion that fossil fuels will form a major component of energy supply until at least 2050 and there is considerable evidence to support this statement. Thus it is suggested that if the Government's target of a 60% reduction in CO2 by 2050 is to be realised, then carbon abatement technologies will be required. Carbon Abatement Technology (CAT) using carbon sequestration is a means of undergoing a smooth transition from a fossil based economy to a more advanced energy supply. A number of large developing countries use fossil fuels, particularly coal, on a very large scale and will continue to do so for a long time and this would be an excellent technology to export. A significant electrification of the developing world will take place in the next few years and the UK could have a pivotal role in assisting the developing world to progress towards lowering CO2 emissions.

  In addition to being used for electricity generation, fossil fuels provide a route to hydrogen via gasification. Gasification has the dual advantage that it can produce a clean fuel gas for combustion in gas turbines via an Integrated Gasification Combined Cycle (IGCC) producing electricity and heat. Secondly gasification can produce, by alteration of the process conditions and in conjunction with carbon sequestration, hydrogen. Such a plant is planned to generate "carbon free" electricity from hydrogen by BP, ConocoPhillips, Shell and Scottish and Southern Energy. In this example, natural gas is used as the feedstock for a gasifier, electricity being generated by a combined cycle gas turbine (CCGT) and the carbon dioxide used for enhanced oil recovery (EOR) in the Miller oil field.

  Detailed responses to the Select Committee's questions are set out on the following pages.


  There is a strong case for a trial to be undertaken using a suitable power plant. The technology exists for CO2 removal from flue gases and this can be undertaken immediately in a number of ways at the present time using developed technology and either natural gas or coal as primary fuel. The efficiency penalty of currently available carbon capture technology is too high to be considered for a simple bolt-on addition to an existing power station. Some other efficiency improvement technology would be desirable to win back some of the losses associated with amine regeneration as part of the CO2 capture process, but even then the economics of retrofitting a power plant that may be at or beyond its design lifetime or emissions control capability would need close scrutiny.

  The oil and gas industry in the North Sea has also allowed the UK to develop geological, engineering, logistics and PR skills that would be useful in CO2 sequestration issues. Future development of CATs should trade on these skills, rather than trying to replicate those that may exist in other countries, to ensure that an optional position is reached in respect of both meeting the UK's national requirements effectively and without excessive cost, whilst exploiting overseas export potential. Involvement with pilot or commercial scale demonstrations of relevant technologies must form part of the future strategy. This should be complementary to continuation of R&D into underpinning sciences, for which the UK is rightly respected, in a vertically integrated partnership between industry and academia.

  There are several options for the continued use of fossil fuels, mainly coal, for power generation together with carbon capture. The choice will depend on local circumstances and the decisions of the power companies. One route would be the capture of CO2 from existing, possibly upgraded power plant. In this respect, retrofitting a post combustion carbon capture technology onto a CCGT power station could represent one least costly, least risky and quickest option. It would enable scale up of currently applied carbon capture technology to be tested against all of the operational requirements previously mentioned whilst potentially reducing the requirement for government/host site funding because of the potential value of the CO2 being produced either for enhanced oil recovery (EOR) or as carbon credits. Short term application to a coal fired plant is much less attractive because of the additional costs and significant reduction in efficiency from an already lower base figure. However, continual involvement in the development and demonstration of higher efficiency, ultra supercritical conventional coal combustion technology might enable the combination with carbon capture to be considered within a 15 year time frame. Other options being studied for coal include gasification cycles and advanced combustion cycles involving combustion in oxygen or oxygen/carbon dioxide mixtures which facilitates the separation process. These options may prove to have advantages over conventional methods in the context of the development and demonstration of CATs. Thus it is important that these developments should be carried out with eventual application to both coal and natural gas fuelled plant and hydrogen production in mind.

  The technology will continue to develop after the basic feasibility has been demonstrated. Particular lines of development include oxygen separation technology, improvements in CO2/H2 separation, gas turbine advances, and studies of the behaviour of CO2 in oil and gas reservoirs and coal seams. These studies need to be supported in UK laboratories alongside the development and demonstration activities that may involve international co-operation.

2.1  Projected Timescales for producing market ready scalable technologies

  Much of the technology required is available and has been tested in this and other countries. Certain types of plant could be constructed using existing technology in approximately five to 15 years. There is a considerable amount of R&D required to improve the solvent systems that are currently available to address the efficiencies/cost issue. It is also worth noting that the largest commercial demonstration of carbon capture is still a fraction of that required for a 500 MW based power station, so there may well be scale-up problems.

  In the case of the BP, ConocoPhillips, Shell and Scottish and Southern Energy project the announced time scale is that it would commence in 2009.  This uses existing technology for a natural gas reformer plant to create hydrogen and sequester the carbon-related gases, conversion of a CCGT unit to hydrogen-firing and to adapt the Miller oil field topsides facilities and export line. The Miller oil field is 240 km offshore and it would then facilitate delivery and injection of the CO2 for enhanced oil recovery and long term storage.

2.2  Cost

  The costs arise from the separation process, which entails a considerable loss in efficiency, transportation and well-head operations. The overall loss in efficiency is about 30% but this estimate is subject to debate, and should be the area in which much of the R&D effort should be directed.

  The Royal Academy of Engineering Report (The Costs of Generating Electricity, March 2004) gives the following figures for electricity generation, and for generation with flue gas CO2 removal by sequestration respectively.

Table 1


Basic Cost (p/kWh)
Cost with Carbon
Sequestration (p/kWh)

Coal Fired Pulverised Fuel
Coal Fired Integrated Gasification
Combined Cycle
Gas Fired Combined Cycle Gas Turbine

  On this basis the total cost is comparable with that for renewable energy. The embedded fuel costs play a significant role in fossil fuel electricity generation and the sensitivity to a 20% change in fuel price has been examined in the Academy's report. This suggests that the upward pressure of costs on natural gas is greater than that for coal.

  The typical cost of sequestration is about 1-2.5 p/kWh, whilst the cost for EOR is about 0.5 to 1 p/kWh, but the latter process is limited to a small number of suitable fields.

  However the UK Offshore Operators Association (UKOOA) have indicated that in the case of offshore sequestration the cost of the well-head operations may be higher than previously estimated.

2.3  Geophysical feasibility

  Evidence suggests that the technology is feasible since the techniques are already available and employed using carbon dioxide for enhanced oil recovery. It is estimated that the total capacity for CO2 in aquifers in the North Sea is 13 times the estimated output of the UK to 2050.  Although natural gas has been stored in some of these aquifers for many thousands of years without leakage care has to be used in selecting appropriate reservoirs with regard to rock cracking and the loss of the stored CO2 by seepage. Whilst the behaviour can be modelled it is impossible to predict the situation in the long term, say 100 years and it will therefore be necessary to install appropriate monitors.

2.4  Other Constraints

  The Government will need to develop and enact enabling and enduring policies to allow electricity from these projects to compete with those using traditional fossil fuels. At present Decarbonised Fuels (ie hydrogen etc.) are not competitive with the fossil fuels from which they are derived and would need enabling government policy valuing carbon at a level similar to Renewable Obligation Certificates (ROC) available to renewable energy sources.

  In the immediate future a major hurdle is the legality of the disposal of CO2 offshore where enhanced oil recovery is not appropriate. This is a well-known issue but has to be resolved quickly before any considerable activities could take place.

  Another matter relates to the planning of a complex activity involving a number of multi-national companies.

  A further issue relates to the long term ownership of the reservoirs which will have to monitored and maintained for a considerable period.


  The emphasis must be on reducing the efficiency losses currently associated with CATs so that fossil energy is conserved and on the safety, legal and public acceptability issues that are currently shrouded in uncertainty.

  The UK industry retains: niche capability in supercritical boiler technology; biomass co-firing; modelling; project management; advanced control systems; and materials. These capacities have been developed or maintained by the involvement of industry in major international projects.

  Likewise the oil and gas industry in the North Sea has also allowed the UK to develop geological, engineering, logistics and PR skills that would be useful in CO2 sequestration issues. These technologies should be encouraged and involvement with pilot or commercial scale demonstrations of relevant technologies should form part of the future strategy.

  If a hydrogen-based economy is to be developed, particularly for transportation, there is little doubt that a CAT programme will make a significant contribution towards this aim. However there are other possible alternatives such as the development of synthetic fuels based on captured carbon dioxide and hydrogen.

  Pre-combustion carbon capture combined with integrated gasifier combined cycle gas turbine (IGCC) technology is likely to emerge as the eventual natural gas or coal fuelled option that may be sustainable in a carbon constrained world. This is recognised by the US Department of Energy FutureGen programme and the European equivalent (Hypogen), both of which have made significant advances towards a hydrogen economy. However, the technology is at least 15 years away in respect of commercial viability and so interim technologies will be required to help fulfil the growth in demand in the developing world and the replacement plant that will be required in more mature markets. Two possible options, both of which could be produced in a carbon capture ready arrangement, are IGCC and (ultra) supercritical pulverised fuel technologies. Both provide a significant incremental increase in efficiency and hence reduction in CO2.

September 2005

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