Cutting the energy use of buildings: How deep can the planet go?

While it is a well-accepted fact in the energy efficiency expert community that reducing energy use in the building sector is one of the most effective and cost-effective ways for climate change mitigation, the magnitude of the real opportunities has rarely been quantified in a rigorous manner. Reliable figures on the real contribution of the building sector to climate change mitigation and meeting other global societal goals are crucial in the arena of a broad portfolio of different alternatives, strongly competing for their market shares. The Centre for Climate Change and Sustainable Energy Policy (3CSEP) at the Central European University has been assessing and synthesizing various global research initiatives in this field for over a decade, including leading efforts for the IPCC’s 4th and 5th Assessment Reports, the Global Energy Assessment, and now for the newly established Global Building Performance Network. In a rigorous, detailed modelling exercise based on a novel and comprehensive methodology, new mitigation scenarios on global and regional building energy use and related CO2 emissions have been constructed, rooted in the latest building science and using best practice experiences. The results of this modelling work attest that buildings can play a crucial role: despite growing population, welfare and increased energy service levels in buildings, global final energy use for heating, cooling and water heating in 2050 can be reduced by one-third as compared to 2005 levels. In contrast, the research highlighted that present policy trends are still very far from reaching such ambitions: about 80 % of cost-effective energy savings will be locked-in for decades, where only a fraction of this potential can ever be harvested and at much greater costs. The paper clearly demonstrates the urgency of ambitious policy efforts, actions in the developing world, urban areas and specific building types.