In Madrid, the Unit of Electric Power Systems, representing the CIEMAT, hosts the event related to the COP25, in particular with the role of the Energy Services Companies (ESCOs) in the national contributions to stop the climate change, entitled : “Energy Service Companies in Nationally Determined Contributions – the energy efficiency accelerator for climate change”. Organized by United Nations Environment Programme (UNEP) and the global ESCO Network, the event has involved different institutions such as Sustainable Energy for All (SEforALL), United Nations Environment Programme, Conoler, Honeywell, Norvento Enerxía y International Partnership for Energy Efficienccy Cooperation, IPEEC. The CIEMAT has been represented by the Director of Energy Department, Mercedes Ballesteros, and Marcos Lafoz has participate in one of the round tables related to the barriers affecting energy efficiency and solutions to overcome them.