Role of carbon capture in CO2 management
Gasification of low-value refinery residuals could be used to raise utilities and hydrogen, allowing the relatively easy capture of half the plant’s CO2 emissions
Tony Creek, Foster Wheeler Energy Ltd
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The European Union has targeted reduction of CO2 emissions between 2008 and 2012 by an average of 8% below those prevailing in 1990, thereby meeting its commitments under the Kyoto Protocol. The EU proposed the development of an emissions trading scheme (ETS), and the EU Emissions Trading Directive was finally agreed in July 2003, following discussions between the European Commission, the European Parliament and the European Council. The Directive is likely to come into force before this article goes to press.
Currently, fossil fuels (coal, oil and natural gas) supply over 85% of the world’s commercial energy, account for 65% of the world’s electricity generation and 97% of the energy for transportation. Global energy use is expected to grow to 75% by 2020 and most of the demand will be met with abundant, affordable fossil fuels. Fossil fuel power generation currently accounts for one third of global annual CO2 emissions.
The Foster Wheeler model of the life cycle of carbon-based resources, from extraction through manipulation and final use and disposal is shown in Figure 1.
Emission profiles have also been generated for typical LNG (to power) and typical oil (to transport fuels) on a basis of 1MW of energy delivered (Table 1).
Predictably, approximately 90% of the emission from the energy chain comes from combustion of the final product (regassed LNG in a combined cycle power plant and combustion of gasoline/diesel etc in a combustion engine). It is interesting to note, however, that the energy trains for LNG and refining are similar, with approximately 90% of the energy reaching the final market.
Legislation and fiscal pressure can be expected to target the end product user and this is already taking place. For example, in many countries diesel fuel is subject to a lower rate of taxation compared to gasoline, because diesel generates less CO2 per kilometre travelled. This is contributing to a significant shift in product demand towards diesel. In Europe, for example, the diesel supply/demand deficit is expected to grow from the current 10 million tonnes/year to around 45 million tonnes/year by 2010.
The vehicle manufacturers have a voluntary agreement with the European Commission to reduce average CO2 emissions from new cars by 25% to 140 gm/Km by 2008. Although, a relatively small contributor to CO2 emissions in the oil sector overall, the refinery can be expected to come under pressure to reduce emissions. Legislators appear to group the refining activity with the power generation sector and other stationary sources.
Complementary CO2 strategies
Fundamental changes to the world energy system cannot take place rapidly. A sustained energy research and development (R&D) effort that includes a broad portfolio of technologies will be required to achieve the massive reductions in emissions needed to stabilise greenhouse gas (GHG) concentrations.
In order to achieve meaningful CO2 reductions a portfolio of carbon management strategies will have to be implemented, including:
- Improvements in energy efficiency
- Reduction in carbon intensity of fuels
- Carbon capture and sequestration
- Terrestrial sequestration.
Terrestrial carbon sequest- ration is an important part of global carbon management. The goal of terrestrial carbon sequestration and management is to increase levels of CO2 stored in terrestrial ecosystems. The International Energy Agency (IEA) and other interested parties cover this subject in more detail.
Nuclear power will continue to be an important part of the energy mix and could be expanded if environmental and nuclear concerns can be resolved. However, fossil fuels will continue to dominate and therefore advancements in research development and demonstration of zero emissions technologies for fossil fuels are critical.
The EU ETS will require each member state to impose binding caps on emissions of CO2 from facilities with energy activities (refineries, power plants etc). The basis for determining liabilities of individual facilities is to be through national allocation plans, which will set emission caps and allowance allocations in each member state. The Commission will develop allocation criteria.
Facilities will be able to trade EU CO2 allowances within the EU to help meet their binding caps. Failure to meet the emission caps will result in penalties of †40 and †100 for 2005 and 2008 respectively for each tonne of CO2 by which the cap is exceeded. Traders are already brokering speculative deals between companies around the world where CO2 allowances/credits are changing hands for up to †5 a tonne. The EU agreement is likely to stimulate greater levels of trading possibly by businesses seeking to buy early rights to EU carbon allowances at potentially lower prices to hedge their prospective carbon liabilities under the pending EU ETS.
In February 2002, US President George W Bush announced the Global Climate Change Initiative (GCCI). Its goal was to reduce significantly the greenhouse gas intensity of the US economy over the succeeding 10 years, while sustaining economic growth needed to finance investment in new, clean energy technologies.
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