The Institute for Prospective Technological Studies (IPTS) of the European Commission's Joint Research Centre has published a study on "Technological change and energy policy in different national contexts", which addresses issues relating to the use of CHP (combined heat and power, cogeneration) in the UK and Germany. The study, prepared in 1996, aims to study the recent rise in the use of cogeneration in the United Kingdom and Germany, and draw comparisons and conclusions for Europe as a whole. Cogeneration, although not a new technique, has been revived in many European countries in recent years, as it fulfils the need for more sustainable and decentralized energy technologies. Existing theoretical and conceptual approaches to the study of technological change have been used to structure and compare material gathered from both countries. The changing patterns and mechanisms are analysed, before an evolutionary interpretation of the determinants of technological change is proposed. Finally, the study draws conclusions with regard to existing initiatives in energy policy, both at national and European level.