he greenhouse gas mitigation technology inventory developed at the International Institute for Applied Systems Analysis over the last five years, CO2DB, its software capabilities and the present coverage of technologies are discussed. For some clusters of the more than 1400 technologies represented in the database, the frequencies of investment estimates are analyzed. The special capability of CO2DB to evaluate full energy conversion chains, from primary extraction to final utilization of energy, is applied in a comparison of various options to reduce the CO2 emissions related to a specific application of electricity. This evaluation proves useful in the numerical comparison of the cost of reducing CO2 emissions by various technological options
