Fundamental documents of the European Commission - Green Papers on EU strategy for energy supply and related legislational acts as Directives, Regulations and Decisions of the European Parliament and of the Council present options available with view to stemming the increasing dependency for energy supplies whilst continuing to pursue the environmental goals. A series measures have been taken to meet with four key challenges: managing demand, diversifying European sources, enhancing the effectiveness of the internal energy market and controlling external supply. On January 23, 2008 European Commission published the so-called environmental package, i.e. complex of drafts of legal regulations by which the political commitment of member countries of the spring summit of European Council in March 2007 should become binding standard. In EU climate change and energy package EC has put forward a fully integrated policy package covering both climate and energy policies: "An Energy Policy for Europe" and "Limiting Global Climate Change to 2oC: The way ahecd for the EU and the World for 2020 and beyond". The published package includes also the draft of revision of the Directive on greenhouse gases emissions allovance trading, draft of the Directive on usage of renevable energy sources and draft of the Directive of capture and storage of CO2 (CCS technology). In view of the present share of renewable sources in the energy consuption in Poland realization of legal obligations will mean the necessity of significant and very costly increase of production of electricity from RES. More serious is problem of carbon sequestration: CCS technologies are at the beginning and are non used in the commercial operations so for. Paper present some assessment of costs related to fulfilling EU regulations and connected threads for the Polish power sector.