Pre-Engineering Study "NRW Power Plant 700 °C”

Project Number 297

The pre-engineering study project for a high-efficiency power plant with a live steam temperature of 700 °C (Power Plant 700) represents the first stage for the construction of a low-emission power plant, which is to be erected once its technical and economic feasibility has been confirmed.

The project has been conceived as a cross-border transnational project. To date, ten European energy utilities have joined together with the aim of developing this sustainable European concept for generating power on the basis of fossil fuels. These are:

  • DONG Energy Generation A/S, Denmark,
  • E.ON Energie AG, Germany,
  • Electrabel N. V., Belgium,
  • Electricité de France, France,
  • EnBW Kraftwerke AG, Germany,
  • EVN AG, Austria,
  • RWE Power AG, Germany,
  • STEAG GmbH, Germany,
  • Vattenfall A/S Nordic Generation, Denmark,
  • Vattenfall Europe Mining & Generation AG & Co. KG, Germany.

In the context of the study, the European energy utilities involved will determine viable technical and economic decision-making principles for power plants with a live steam condition of 700 °C.

The project is thus directly linked to the COMTES700 test facility realized with financial aid from the European Commission (Research Fund for Coal and Steel, Contract-No. RFC-CP-04003). COMTES700 is the world’s first test facility for the production of live steam at a temperature of 700 °C. The test facility has been operating successfully in Scholven/Gelsenkirchen (Germany) since July 2005.

Background

To determine in good time whether the 700 °C technology offers an economical option for power plants to be built in the future, it is necessary to examine in detail the technical and economic possibilities for realizing this high-efficiency power plant technology in the pre-engineering study that forms the basis for this project.

The technological further development of fossil-fired power plants, with a marked increase in efficiency levels to around 50 %, is at the forefront of this initiative. In the phase of power plant renewal in the medium term, i. e. in the years from around 2015 to 2020, it could thus be ensured if the project is concluded successfully that the European CO2 reduction targets can be achieved by means of efficient, economically viable power plant solutions. A reduction in specific CO2 emissions per MWh generated of around 25 % compared to power plants currently in operation (mean efficiency 38 %) is associated with 700 °C technology. The proportional reduction in the fuel mass flow used can also partly offset rising fuel prices. The competitiveness of the European energy industry and also of the capital goods industry that is to be supplied with electricity and process heat can thus be stabilized.

In the long term, i. e. in the new construction period after 2020, the realization and safe operation of a power plant using 700 °C technology represents together with other technologies like Oxyfuel and IGCC an essential prerequisite for flushing CO2 economically out of the flue gases and transferring it to suitable deposits. Currently existing fossil-fired power plants, with a mean efficiency level of around 38 %, are entirely unsuitable for operation incorporating CO2 flue gas scrubbing if considered from the point of view of handling fossil primary energy carriers responsibly. The reduction in efficiency level of around 12 percentage points caused by CO2 flue gas scrubbing would result in the fuel mass flow supplied to the power plant having to be increased by approx. 46 % to generate the same power. As well as increasing the consumption of fossil fuels, flue gas scrubbing would mean that substantially more CO2 would have to be separated and stored.

Structure and Organisation of the Project

European power plant operators and plant manufacturers will produce the pre-engineering study jointly. VGB in conjunction with its European project partners will specify the technical and economic determinants. To this end, the integration of the PP700 joint project into the European EMAX project is envisaged. The EMAX power plant initiative aims to foster coal as a more reliable, economic and environmentally friendly process of power generation in the European Union.

The conventional plant engineering and the overall power plant concept are planned in this case primarily by specialist departments of the power plant operators. The innovative features such as steam generators, steam turbines and other critical plant components subject to high temperature are to be handled by specialist companies that have the relevant know-how in the field of high-temperature engineering. The relevant European plant manufacturers and component suppliers are being integrated into the project as subcontractors for this purpose. An in-depth exchange of information between all parties involved is guaranteed by the creation of various specialist groups, to which the EMAX partners can delegate their experts as required.

This procedure is intended to ensure that the power generators, as potential investors in 700 °C power plants, are provided with sufficient information by the manufacturers, in particular about the innovative components that carry high risks, to be able to make further decisions on the construction of a 700 °C installation.

The study is being executed in three project stages:

  1. Planning of a 700 °C demonstration plant fired by hard coal
     (output approx. 500 MW).
  2. Transfer of technical and economic findings to a commercial 700 °C hard coal facility
    (output approx. 1,000 MW).
  3. Transfer of technical and economic findings to a commercial 700 °C brown coal facility
    (output approx. 1,000 MW).

In the first project stage, the basic feasibility of a demonstration plant with a live steam condition of 700 °C is to be examined. To limit the financial risk for a subsequent investor or group of investors, the size of the facility should be roughly 500 MW. Cost savings that normally result for larger facilities of this kind due to degression of the specific plant costs (euros/kW) are to be dispensed for reasons of the risk for the demonstration plant concept. It is expected that the electricity producing costs of this facility will lie above the market value.

In the second project stage, it is to be examined whether the 700 °C technology can also be realized for a commercially operated hard coal plant. The results of these studies are of great importance for the first project stage too (construction of a demonstration plant). If a large plant to be operated under commercial conditions cannot be realized, then the construction of a smaller demonstration facility does not make any sense either. The reverse procedure, consisting of pre-engineering for a large facility and subsequent “downscaling” to a smaller plant, was deliberately rejected, as this method would mean that no detailed findings regarding the demonstration plant size would be available at the end of 2007. Due to the detailed studies that would then still be required for a 500 MW demonstration plant, no realization of the demonstration plant in the course of the 7th Framework Programme for Research of the European Union would be able to be implemented in time.

In the third project stage, it is to be examined whether the 700 °C technology can also be realized for a commercially operated brown coal plant. It is of particular significance here whether the lower combustion temperatures in steam generators fired by brown coal and the lower temperature gradients between flue gas and bundle heating surfaces associated with this result in dimensions for the steam generator that are still economical.

The project is funded by the German federal state North Rhine-Westphalia in the scope of the State Initiative Future Energies NRW (Landesinitiative Zukunftsenergien NRW) from the programme Efficient Use of Energies and Use of Unexhaustible Energy Sources (Rationelle Energieverwendung und Nutzung unerschöpflicher Energiequellen). The European Union is co-financing the project from the European Regional Development Fund.