This special issue of "Climate Policy" journal examines the impacts on the competitiveness and the commercial incentives available from the CO2 allowance allocations under the EU Emissions Trading Scheme, and discusses appropriate allocation methodologies, and whether - and if so at what stage - the ETS itself may need to be amended. The study is multidisciplinary, combining economic, legal and policy analysis, with specific studies of impacts on electricity, cement and other industrial sectors and allocation issues. It brings together the results of research conducted over the past two years from various research centres and consultancies in Europe, and in particular work commissioned by the Carbon Trust and Climate Strategies Network. Through these, it presents the most comprehensive and detailed set of analyses of allocation and competitiveness yet conducted.