The reduction of CO2 emissions

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					                                                                                Clean Power Today!
                           The reduction of CO2 emissions

POSITION PAPER                                       Date: 18/09/06

Growing levels of CO2 and other Greenhouse Gases are increasingly contributing to global warming and
to fundamental shifts in the Earth's climate. It is now generally accepted that a more stringent post-Kyoto
reduction in CO2 emissions will be required to limit world temperature rise to 2 to 3°C over the coming

Existing power generation accounts for a third of these Greenhouses Gases. Worldwide demand for
electricity is expected to grow by 3% a year over the next ten years, even more so in developing economies
such as China and India, increasing needs for energy production.This implies a need for substantial
reduction in CO2 emissions from power generation, compared to a "business as usual" scenario.

Whilst a shift to non-CO2 energy sources (hydro, nuclear, renewables..) will play a more significant role
going forward, such technologies are unlikely to displace fossil fuels as a primary source of energy.
Irrespective of price issues, coal in particular is abundantly available, with over 160 years of reserves,
nearly three times that of natural gas.

The challenge today for ALSTOM's customers is to limit CO2 and other emissions while maintaining plant
economics, guaranteeing an ultimately affordable energy price to consumers.

ALSTOM - in its unique role as plant integrator and the only service provider designing and manufacturing
the different components of the power plant, from GT to ST, boilers and environmental control systems - is
leading the way in the race to curtail emissions, both of traditional pollutants and CO2.

The main issue today is the CO2 emitted by existing plants and ALSTOM's first focus is therefore on what can
be done to produce cleaner power in today's fossil plants, using advanced but proven technologies. ALSTOM
has extensive experience as leader in the retrofit market and ALSTOM technology is present in 25% of the
world installed base.

Efficiency is the first target. Improved efficiency means a low rate of fuel used per MW of electricity. A 10%
efficiency gain is equivalent to 20% less CO2 emitted. Innovations in boiler technology will enable ALSTOM's
new supercritical and ultra-supercritical coal-fired plants to achieve around 50% efficiency, against close to
45% already achieved today and an average of 30-35% in the installed base.

In addition to improving the efficiency of its PC plants, ALSTOM also offers other mitigation solutions such as
fuel switching, including bio-mass co-firing, and has R&D programmes to develop larger, more flexible GTs.
PT/PE Sector – Communications - September 2006                                                        1/3
The reduction of CO2 emissions - content owners : Ph. Paelinck - Ch. Soothill
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Whilst improved efficiency and fuel switching are existing options, they will not of themselves resolve the
problem of CO2 pollution. ALSTOM strongly believes that CO2 capture and storage is a must and as such,
our company is at the forefront of developments to produce reliable, cost-effective solutions for CO2 capture
in zero emission plants.

There are three main CO2 capture technologies: post combustion processes, oxyfiring and pre-combustion

Post-combustion capture

ALSTOM is actively involved in developing post-combustion capture, which has the advantage of being the
most readily available technology today and the most easily adaptable to the huge installed base of coal and
gas units.

In this technology, the CO2 is selectively removed from the flue gas of the power plant through a capture
unit. The most widely developed post-combustion capture solvent is amine, which has been used since the
1970's for CO2 capture in other industries. The main challenge of amine capture is its cost: this is due to the
important heat requirement in the stripping phase to separate the amine solvent and CO2, leading to a 25%
drop in plant output.

ALSTOM is an active participant in the European CASTOR programme that aims to improve amine capture
systems and for which a new state-of-the art amine capture pilot plant was recently launched at Esbjerg
Power Station in Denmark.

ALSTOM is also pursuing a very promising new post-combustion process involving chilled ammonia. This
technology has lower energy requirements, causing only a 10% drop in net plant output, which could
significantly reduce the cost of CO2 capture.


The overall principle of oxy-firing technology is to burn solid fuel with pure oxygen rather than air. The
combustion is controlled with a recyle stream of CO2. The flue gas obtained from oxy-combustion
combustion is mainly composed of water and CO2, the latter being easily captured at the back-end by water
separation. Oxy-firing applies to new units but may suit some retrofits as well.

The main challenge of oxy-firing technology lies in the cost of producing oxygen on a large scale through Air
Separation Units, a major reason for the 20-25% drop in net plant output compared to an air-fired plant.
This issue is currently being addressed by major gas specialists, who are working on improving ASU
technology and exploring new oxygen-production techniques.

ALSTOM is playing a key role in developing oxy-firing PC and CFB techniques and has been selected to set
up the first steam power plant using oxygen combustion of brown coal for the power producer, Vattenfall.

Based on its CFB know-how, ALSTOM is also investigating breakthrough technologies such as chemical
looping. This unique system replaces the traditional boiler with a two stage chemical conversion process,
using an oxygen "carrier" to transfer oxygen to the fuel. The exhaust gas is similar to oxy-firing, enabling easy
CO2 capture. Preliminary tests at the 10kW Chalmers unit (under the EU ENCAP programme) and on-going
research on the Chemical Looping process development unit of ALSTOM in Windsor (CT) are very promising.

PT/PE Sector – Communications - September 2006                                                          2/3
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The principle of IGCC (Integrated Gasification Combined Cycle) is to transform a carbon-rich fuel such as
coal or petroleum residues, through a chemical reaction, into fuels like syngas (a mixture of CO and H2),
which can then burned in a combined cycle plant.

IGCC technology is mainly destined for new plant construction, since repowering of PC or NGCC into an
IGCC plant is complex.

IGCC environmental performance is broadly similar what a new PC plant offers today: emissions post clean-
up of traditional pollutants are comparable to best available USC plants. Emissions of CO2 are also similar
because these plants have comparable efficiency levels.

Pre-combustion CO2 capture is the technology adapted to IGCC plants. In pre-combustion capture, carbon
is separated right after the gasification phase, before the syngas is burnt in the gas turbine. This involves a
shift reaction from a CO/H2 blend to pure hydrogen, followed by CO2 absorption by a physical solvent.

The pre-combustion capture process is in itself cheaper than available post-combustion systems and already
validated in other industries, even if never implemented in IGCC plants.The challenge lies not so much in the
capture itself, but in the fact that syngas - after CO2 removal - essentially contains only hydrogen. Burning a
hydrogen-rich syngas raises significant issues for gas turbines and is a technological hurdle which has yet to
be fully overcome.

In addition to longer-term CO2 challenges, IGCC faces two major issues: its reliability (availability is currently
several percentage points below that of USC plants) and its cost (currently around 30% more expensive than
USC technology and still around 10% more expensive with future CO2 capture).

ALSTOM is participating in IGCC developments for the future and has put in place in-house programmes to
develop its GT fuel flexibility for syngas and H2 combustion. We already participate in the gasification
market as a supplier of components, including synthesis gas cooling equipment and low calorific value fuel
gas turbines. When the time comes where IGCC is a reality, ALSTOM’s Plant integrator capability will be a
differentiator to provide CO2 capture ready combined cycles

PT/PE Sector – Communications - September 2006                                                           3/3
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