Electricity generation is the largest source of greenhouse gas emissions in many countries. Most emissions trading systems (ETS) therefore address emissions from electricity generation. The design of an ETS and the structure and regulation of the electricity sector have a large impact on the environmental effectiveness and the quality of the carbon price signal. This report analyses the interaction of carbon and electricity markets in Poland and Germany. In a largely liberalised market, especially the capacity mix, the age of the fleet and the design of complementary policies determine the impact of the ETS on abatement in the power sector, which is therefore different in both countries. This case study is part of the project “Influence of market structures and market regulation on the carbon market” that aims to identify the impact of market structures and regulations on carbon markets and to investigate the interdependencies between carbon and energy markets in Europe, California, China, South Korea, and Mexico.