Cleaner coal power


Developing components for the next generation of coal-fired power stations is the aim of the COMTES700 (‘Component test facility for a 700°C power plant’) project. The technologies developed by the project will result in much more efficient power stations than those in use today. As a result, greenhouse gas emissions from coal-fired power stations could be reduced by up to a third.

In this way, the project is making an important contribution to the EU’s efforts to reduce its greenhouse gas emissions and meet its international climate change targets, as agreed under the Kyoto Protocol.

A test facility developed by the project has been in operation in Gelsenkirchen in Germany since 2005, and the project results are already arousing the interest of the power industry, both in Europe and elsewhere. One of the project partners has already announced its intentions to take the concept further and construct a demonstration power plant.

The six project partners who are carrying out the research come from Germany and Denmark and include power plant operators and energy suppliers. The project is steered by the COMTES700 Partners Consortium, which is made up of a further 11 major European power generators from 6 EU Member States.


Coal – a crucial component of our energy mix

Like other sources of energy based on fossil fuels, coal-fired electricity generation is causing greenhouse gas emissions that must be reduced to avoid climate change.

Nevertheless, studies by the International Energy Agency and the EU’s ‘World Energy, Technology and climate policy Outlook 2030’ (WETO) report suggest that fossil fuels such as coal will have an important role to play in meeting our energy needs for some decades to come, because energy demand is predicted to rise over the next few decades.

In addition to this, many existing power stations are nearing the end of their lives and will soon need replacing. Together, these facts mean that new coal-fired power stations will soon need to be built.

The challenge is to find ways of making these plants as clean and efficient as possible, and this is where the COMTES700 project comes in. The aim of the project is to design, develop and operate a component test facility which will demonstrate how new, advanced materials and components perform in the next generation of coalfired power stations.

Turning up the heat

The project partners aim to improve the efficiency of coal-fired power plants by ramping up the temperature and pressure of the steam that drives the turbines. Currently, the best commercially operating plants in Europe, which have an efficiency of 43 % to 45 %, run at temperatures of up to 600°C and pressure of up to 280 bar. In the power station of the future, the temperature will rise to over 700°C and the pressure will reach 350 bar.

As a result, the efficiency of the plant could exceed 50 %. In contrast, the average efficiency of plants in the EU is just 36 %. In other words, the new plants would reduce CO2 (carbon dioxide) emissions by a third, while also saving precious fuel. More efficient power plants are also urgently needed in Asia; according to the WETO report, energy demand is predicted to rise sharply there between now and 2030, and much of this need will be met by coal.

The project’s test facility is scheduled to operate for 20 000 hours during the project. This gives the project team ample opportunity to identify major problems, gather information on the technical requirements of the technology, determine the specifications for the components and work out the optimum operating conditions.

One of the biggest challenges facing the COMTES700 team was to produce components which could withstand the heat and pressure of the new system. This entailed using nickel-based alloys, which are much harder than the steel used in conventional power stations. Furthermore, the hardness of the materials means that it takes five to six times longer to manufacture the components.

Getting the best out of carbon capture technologies

By improving the energy efficiency of the coal-fired power plant, the COMTES700 concepts opens up the prospect of using carbon capture and storage technologies, thereby reducing greenhouse gas emissions still further.

When carbon capture technologies are added to a power plant process, it affects the plant’s efficiency. Therefore, from a strategic point of view, it is better to attach carbon capture technologies to more efficient plants.

By taking coal-fired power stations over the 50 % efficiency threshold, COMTES700 is contributing to the feasibility of the use of carbon capture and storage technologies.

Today Europe, tomorrow the world!

The COMTES700 project has taken the 700°C technology a big step forward by developing components that can withstand the intense heat and pressure in the next generation of power plants.

Within Europe, the COMTES700 project partners are working on a prototype power plant based on the 700°C technology and integrating the components developed by the project. This is being built in the German coastal town of Wilhelmshaven, where supplies of coal can be easily delivered by ship and where cooling water is readily available. Building work is scheduled to start in 2010, and the plant should become operational in 2014, with a capacity of 500 megawatts.

The project’s results have also aroused the interest of the power industry elsewhere in the world, notably in Japan and the USA, further underlining Europe’s status as a leader in this important field.