Based on 25 years of involvement in a number of important and representative political decision-making processes in Denmark and other countries, this paper presents the unified learning of some of the institutional barriers one will meet when radical technological changes such as the replacement of fossil fuel with renewable energy are to be implemented, and how to overcome such barriers. On the one hand, the cases reveal the lack of ability of organisations and institutions linked to existing technologies to produce and promote proposals and alternatives based on radical changes in technology. On the other hand, the stabilisation of the Danish primary energy supply over more than three decades shows that the ability to act as a society has been possible despite conflicts with representatives of the old technologies. In Denmark, the description of concrete technological alternatives and alternative energy plans has played an important role. (C) 2010 Elsevier Ltd. All rights reserved.