Abstract The IIASA research project on Environmentally Compatible Energy Strategies includes the assessment of options and measures for mitigating global CO 2 emissions. The basis of this assessment is the comparative inventory of technological and economic measures including efficiency improvement, conservation, enhanced use of low-carbon fuels, carbon free sources of energy and measures for removing carbon from fuels, flue gases and also from the atmosphere such as afforestation, and finally also measures for enhancement of carbon sinks. To include all potential options, the comparison is based on energy end-use accounting for the fully interlinked energy conversion chain up to energy resources. The analysis is supported by a fully interactive data bank system, CO2DB, that is capable of evaluating full energy chains with respect to their economic, technical and environmental parameters. The paper reports energy requirements, cost and CO 2 emissions for different energy chains providing industrial drives, cooling and air transport services. At additional cost, emissions can be reduced drastically on all these end-use categories.