Estonia is the only country in Europe with significant environmentally intensive oil shale-based energy production. However, the legal obligations of the EU will make substantial changes over the coming years to current electricity production technology. Increasing the use of alternative energy carriers for responding to future requirements has also been in focus. In this study, three different future electricity supply scenarios for Estonia in 2020 are considered and compared to the situation in 2002. They are based on domestic oil shale, imported natural gas, and imported nuclear power. According to the aims of the national energy policy, renewable energy sources were raised to 10% in all scenarios. Using the LCA methodology, the least damaging impact on the environment occurs in the 'nuclear scenario', with nuclear energy as the main energy source. The best scenario, however, depends on the weight or acceptance of accidental releases or other impacts not defined in this context. The 'Oil shale scenario' would be a slightly more damaging alternative than the 'Natural gas scenario' even if new technical solutions will remarkably improve the environmental performance of oil shale electricity production. Land use and waste disposal are crucial issues, particularly for oil shale and nuclear electricity production. However, the depletion of oil shale is not as critical an issue as the depletion of natural gas and uranium. According to the significance analysis of impact categories, climate change is the most significant impact on the environment in the scenarios. Future decisions on the development of the Estonian energy sector are most likely to be based on technological, economical and political aspects. Political aspects are likely to be the most significant. However, this type of study can give additional value to the discussion due to the increasing role of sustainability in energy issues. (c) 2007 Elsevier Ltd. All rights reserved.