Energy Technology Classification System

Our interactive explorer enables navigation of the revised 2025 edition of the International Energy Agency’s (IEA) energy technology classification system. The classification system is a structured framework that categorises energy technologies within nine main areas.

Updated in co-operation with governments to reflect technological developments since its last revision in 2011, the classification now covers a full range of energy technologies, from those that improve the efficiency of end-uses, to those that improve or change the nature of energy supplies. As of 2025, it covers technologies relating to the extraction and processing of critical minerals for energy technologies and the electrification of industrial processes. The logic relating to the allocation of cross-cutting technologies, including batteries, hydrogen, and CO2 capture, has also been clarified. Further details about the classification system and the recent changes can be found in the PDF version of this classification.

Originally developed by IEA members to guide their collective sharing of public energy research, development and demonstration (RD&D) spending, the classification now has broader application. It is applied by the IEA to provide consistency across outputs including the ETP Clean Energy Technology Guide and The State of Energy Innovation. The IEA welcomes the wide use of this classification system to provide a common basis for analysis and dialogue internationally.