Due to the growing concern for global warming, the EU25 have implemented the European Union Greenhouse Gas Emission Trading Scheme (EU ETS). In the first trading period (2005-2007), part of the targeted GHG emission reductions presumably will have to result from a switch from coal fired electricity generation to gas fired electricity generation. It is possible to calculate the allowance cost necessary to switch a certain coal fired plant with a certain gas fired plant in the merit order. The allowance cost obtained is a so called switching point. When comparing historic European Union Allowance (EUA) prices (2005) with the corresponding historic switching points, the EUA prices were found high enough to cause a certain switch in the summer season. This finding leads to the use of switching points in establishing allowance cost profiles for several scenarios. A variable gas price profile is used in the simulation tool E-Simulate to simulate electricity generation and related GHG emissions in an eight zonal model representing Western Europe. Several GHG allowance cost profile scenarios are examined. For each scenario, electricity generation in the considered countries is clarified. The focus however lies on the GHG emission reduction potentials. These potentials are addressed for each scenario. (c) 2006 Elsevier Ltd. All rights reserved.