[February 2006]  A very economic route for reducing the UK’s CO2 emissions? by Mike Knowles

The Government’s Carbon Abatement Technologies Strategy (CATs) report was published in June 2005. The report states “CATs cover a range of generic options for reducing the CO2 emissions from fossil fuel combustion. These include: higher efficiency conversion processes e.g Supercritical and IGCC coal-fired power plant; fuel switching including carbon neutral biomass; carbon capture and storage in depleted oil/gas fields and saline aquifers etc.,”

£40M is initially being allocated for a number of technologies. This will be split between: 

• Finding ways to increase the amount of biomass additive in conventional
• power stations. 
• Promoting increased efficiency. 
• Removing carbon from fossil fuels – i.e. post-combustion (using an amine plant on the stack) or Oxy-firing with supercritical or pre-combustion (taking carbon out of the fuel before burning it) either by reforming natural gas to produce hydrogen for combustion in a CCGT and IGCC with CO2 removal.

However only £25 Million is allocated to removing carbon from fossil fuels. With its potential for economic return this is very modest compared with the £500 million grants and Renewables Obligation costs of £1000M per annum by 2010 for the UK renewables programme.

The report asks the question “Does UK business have the capabilities to commercialize CATs?” and “What are the opportunities and constraints affecting the development of CATs in the UK?” These are questions many members in the Power Industries Division can help to answer and do. In the last 4 years Power Industries Board & EESG members have worked very hard to contribute thoroughly researched technological responses to Government like the PIU Review on Energy; the Energy White Paper and more recently the House of Commons Environmental Audit Committee’s Inquiry into “Nuclear, Renewables and Climate Change - Keeping the Lights On”- October 2005.

In the last response, the IMechE stated that in the medium term, existing coal fired power stations are life-limited by a number of factors:

1. The age of existing plants. 
2. The Large Combustion Plant Directive, reducing coal-fired plant capacity and/or limiting operating hours. However 15 GW of coal fired plant are or will be fitted with FGD/LoNOx and therefore available beyond 2015. 
3. The EU Emissions Trading Scheme, raising costs and limiting emissions and therefore generation. 
4. The likelihood of even tighter emissions controls in the future (e.g. Mercury, which is becoming an important issue in the USA).

It is likely that 1 & 2 will mean that 15GW of existing coal-fired plant recently fitted with FGD will be available up to 2025-2030, if sufficient upgrading and maintenance of them is done. In the short-term, retrofitting efficiency improvements (more MW per tonne of CO2 emitted), biomass co-firing and gas-turbine feedwater heating all give substantial reductions in CO2 emissions – and in combination could match typical levels for many gas-fired power plants - see Fig 1 – page 3 (1)

Drax Power has turned down bids of £2.5 billion, which indicates the confidence level for coal-fired plant, this in spite of the UK’s emissions cap and trading of CO2 at around £20/t.

Other major reductions in carbon emissions can be achieved via new IGCC and Supercritical/Advanced Supercritical plants achieving up to 55% efficiency (THERMIE AD 700 - 350 bar/7500C), or a 29% reduction on existing CO2 emission levels.

Longer-term, as regulations and infrastructure permit, carbon dioxide capture and storage
(CCS) is possible, including use of the carbon dioxide for enhanced oil recovery (EOR) from
depleting North Sea oil fields, such as BP’s Miller Field proposal. (1)

This will be to the potential benefit of UK’s workforce and technology base but what is the
likely cost per tonne of CO2 saved for these technologies?

Carbon abatement costs set alongside renewable energy are given in the UK Advanced Power Generation Technology Forum’s (2) report, 2004 “A vision for clean fossil power generation” –an associate programme of UK Foresight Programme that covered USC Thermie 700; Advanced Supercritical ; Low NOx & Gas and coal reburn Low NOx systems etc., especially for export markets such as China. Figures quoted for carbon abatement for 2020/25 (£/tCO2) range from:

Back to top