Due to the liberalisation of the energy markets the market position of cogeneration systems is becoming more difficult. Necessary is a new legislative regulation for the promotion of cogeneration in competetive markets. In this context the definition of quality requirements is necessary to make sure that only - in ecological point of view - good cogeneration systems will be promoted. Moreover such criterions could help to stand up against the reservations concerning the suitability of an increasing use of cogeneration for climate protection.