GREENHOUSE GAS EMISSIONS FROM POWER STATIONS

Introduction [Back to contents page]
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This report, the first in a series of public summaries of work undertaken by the IEA Greenhouse Gas R&D Programme, presents the results of studies on four power generation options. The options were selected to cover the spectrum of methods of fossil fuel power generation, CO2 capture and CO2 disposal. They have also been evaluated as to whether they are a presently available technology, likely to be available in the near future, or long term prospect but requiring considerable development. Standard criteria were set for the power generation schemes to enable a fair comparison of the results. The options were compared for their power costs (in US$), energy efficiency, emission of greenhouse gases, and ease of capture and disposal of CO2 from the flue gas.

The four power generation schemes are outlined below:

  • Pulverised fuel and flue gas desulphurisation (PF+FGD) represents the most commonly available technology and provides a base case against which other power generation technologies can be compared. An internationally traded coal, is burnt in a modern pulverised fuel power station equipped with FGD facilities. The plant is a high temperature, subcritical steam unit, but supercritical operation is considered in outline. The study was carried out by the Coal Research Establishment of British Coal Corporation (BCC).
  • Natural gas fired combined cycle (GTCC) also represents available technology. A North Sea gas is fired in a modern gas turbine and a steam turbine is incorporated into the cycle. The input fuel is predominantly methane which, together with the high excess air levels, necessary to control the turbine temperature, results in a low concentration of CO2 in the exhaust gas. This study was carried out by the Norwegian Institute of Technology (SINTEF).
  • Integrated Gasification Combined Cycle (IGCC) is representative of emerging technology likely to be appropriate. An oxygen blown gasifier of the entrained flow type with a wet feed of slurried coal was chosen as being the most established variant of this technology. The study was carried out by the Netherlands Energy Research Foundation (ECN).
  • Power generation by combustion of the standard coal in an atmosphere of oxygen and recycled CO2, was studied as a long term option. Schemes of this type have the advantage of concentrating the CO2 released in the exhaust gas making it easier to collect. This study was performed by the Centre for Energy Research in Northern Ireland.

The following sections will consider the emission of greenhouse gases from the selected power generation schemes. There is a detailed description of each of the case studies. In the discussion the results are compared, other technologies not covered in-depth are mentioned, as is the role of energy efficiency, the importance of the concentration of CO2 in the flue gas and the impact of reducing other emissions as well as CO2.

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