The greenhouse gas mitigation potential of different economic sectors in three world regions are estimated using a bottom-up approach. These estimates provide updates of the numbers reported in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4). This study is part of a larger project aimed at comparing greenhouse gas mitigation potentials from bottom-up and top-down approaches. The sectors included in the analysis are energy supply, transport, industry and the residential and service sector. The mitigation potentials range from 11 to 15GtCO2eq. This is 26-38% of the baseline in 2030 and 47-68% relative to the year 2000. Potential savings are estimated for different cost levels. The total potential at negative costs is estimated at 5-8% relative to the baseline, with the largest share in the residential and service sector and the highest reduction percentage for the transport and industry sectors. These (negative) costs include investment, operation and maintenance and fuel costs and revenues at moderate discount rates of 3-10%. At costs below 100US$/tCO2, the largest potential reductions in absolute terms are estimated in the energy supply sector, while the transport sector has the lowest reduction potential.@en

Reducing heat demand of buildings, due to legal and technological advances in the EU, shifts the ratio of operational vs. embodied energy towards an increasing share of the latter. This leads to a shifting focus on building materials (embodied) energy use. In this study the relationship between heat demand and embodied energy use was investigated, using Dutch residential buildings as a case study. The analysis was performed using the 3SCEP HEB (Center for Climate Change and Sustainable Energy Policy High Efficiency Buildings) model and a constructed Embodied Energy Database Management System (EEDMS), containing embodied energy use of materials most common in Dutch residential construction. The resulting embodied energy use in Dutch dwelling archetypes varies from 52 to 106 MJ/(m²·a), annualised over building lifetimes and 3.0 to 6.4 GJ/m2 in total. These values are for the building construction and exclude recurrent embodied energy and technical installations. For operational energy use the range is 124 to 682 MJ/(m2·a). A total energy use reduction of 36% can be reached in 2050 through 46% reduction in operational energy use and 35% increase in embodied energy use, compared to 2015. This research confirms that the relative importance of embodied energy use is increasing: the embodied energy use in standard homes is about 10–12% of the total energy use, while it is 36–46% in energy efficient homes. Particularly in light of the goal to reach a maximum global temperature increase of well below 2 °C by 2100, it is important to include embodied energy use in future policy objectives.@en