UN-Energy, the United Nations’ mechanism for inter-agency collaboration in the field of energy, was established in 2004 to help ensure coherence in the United Nations system’s multidisciplinary response to the World Summit on Sustainable Development (WSSD), and to support countries in their transition to sustainable energy. The core fields of access to energy, renewable energy and energy efficiency - UN-Energy’s clusters - have garnered major attention and experienced rapid growth in investments and policy-related focus with an ever-growing number and variety of players involved.

UN-Energy aims to promote system-wide collaboration in the area of energy with a coherent and consistent approach, as there is no single entity in the United Nations system that has primary responsibility for energy. Its role is to increase the sharing of information, encourage and facilitate joint programming and develop action-oriented approaches to co-ordination. It was also initiated to develop increased collective engagement between the United Nations and other key external stakeholders. UN-Energy brings together members on the basis of their shared responsibility, deep commitment, and stake in achieving sustainable development.

UN-Energy's work is organized around three thematic clusters, each led by two United Nations organizations:

• Energy access: led by UN DESA and UNDP, in partnership with the World Bank
• Renewable energy: led by FAO and UNEP, with support of UNESCO
• Energy efficiency:  led by UNIDO and the IAEA