The object of the thesis was to evaluate the environmental competitiveness of electricity and heat production methods in regional energy system planning. Electricity and heat production methods were compared based on their greenhouse gas emissions. The method used was life cycle assessment. The modelled methods for electricity and heat production were mainly based on renewable energy. The life cycle model was used to compare solar and wind electricity based scenario to scenario with combined heat and power (CHP) production from forest biomass. Also the net energy of the solar, wind and CHP production was evaluated.

This research concludes that the optimum energy system is often a combination of different electricity and heat production methods. Low emission level in some specific category is irrelevant if the energy supply system is not reliable. It is also important to notice that availability of renewable energy sources is extremely dependent on the location. Due to this when planning regional energy system it is important to take into account the regional characteristic.