Simulations with the power market model EMPS and the energy system model EFOM have been made to assess the effects of large-scale wind production on the CO2 abatement in the Nordic countries. We are mostly focusing on the year 2010, comparing the results with Substantial wind power amounts to a base case scenario. The results for the EMPS simulations with 16-46 TWh/a wind production in Nordic countries (4-12% of electricity consumption), show that wind power replaces mostly coal-fired power generation. As a result of all fuels replaced by wind production a CO2 reduction is achieved, of 700-620g CO2/kWh. The results for the simulations of Finnish energy system show similarly that new wind power capacity replaces mainly coal-fired generation. In another scenario it has been assumed that the use of coal-fired generation is prohibited in order to meet the Finnish Kyoto target. In this case new wind power capacity would replace mainly natural gas combined-cycle capacity in separate electricity production and the average CO2 reduction would be about 300 g CO2/kWh. This case reflects the situation in the future, when there is possibly no more coal to be replaced. (C) 2003 Elsevier Ltd. All rights reserved.