About this report
In support of its presidency of the G20 in 2017, the German government requested the International Energy Agency and the International Renewable Energy Agency to explore how an energy transition to address climate change might look. In this follow-up study, the IEA takes stock of progress towards a low-carbon energy sector and provides further insights into the fundamentally important role of energy efficiency to achieve a clean energy transition. This report reviews recent progress with regards to the clean energy transition and the role of energy efficiency, and explores two clean energy transition scenarios to assess the contribution required from energy efficiency to achieve the goals of the Paris Agreement and the energy-related objectives that the international community has set with the United Nations 2030 Agenda for Sustainable Development. It also assesses sector-by-sector the economic case for energy efficiency investment and the payback period over the lifetime of individual technologies, and develops insights as to what policy makers can do to overcome economic and non-economic barriers to accelerate energy efficiency investment, ranging from high-level strategic approaches to detailed concrete end-use sector policies.