Electricity savings and greenhouse gas emission reductions from global phase-down of hydrofluorocarbons

Abstract. Hydrofluorocarbons (HFCs) are widely used as cooling agents in refrigeration and air conditioning, as solvents in industrial processes, as fire extinguishing agents, for foam blowing and as aerosol propellants. They have been the primary substitutes for ozone-depleting substances regulated under the Montreal Protocol (MP). However, HFCs are potent greenhouse gases (GHGs) and as such subject to global phase-down under the Kigali Amendment (KA) to the MP. In this study, we develop a range of long-term scenarios for HFC emissions under varying degrees of stringency in climate policy and assess co-benefits in the form of electricity savings and associated reductions in GHG and air pollutant emissions. Due to technical opportunities to improve energy efficiency in cooling technologies during the phase-down of HFCs, there exist potentials for significant electricity savings under a well-managed phase-down of HFCs. Our results show that annual pre-KA baseline emissions of HFCs are expected to increase from almost 0.5 to about 4.3 Gt CO2eq between 2005 and 2050 and reach between 6.2 and 6.8 Gt CO2eq in 2100. The growth is driven by a strong increase in demand for refrigeration and air conditioning services, which in turn is driven by an expected increase in per capita wealth in developing countries and a warmer future climate. We estimate that full compliance with KA means cumulative global HFC emissions that are 87 % lower than in the pre-KA baseline between 2018 and 2100. Also, the opportunity to simultaneously improve energy efficiency in stationary cooling technologies during such a transition could bring about additional climate benefits of about the same magnitude as that attributed to the phase-down of HFCs. If technical energy efficiency improvements are fully implemented, the resulting electricity savings could exceed a fifth of future global electricity consumption. Together with an HFC phase-down, this means preventing between 390 and 640 Gt CO2 equivalent of GHG emissions between 2018 and 2100, thereby making a significant contribution towards keeping the global temperature rise below 2 °C. Reduced electricity consumption also means lower air pollution emissions in the power sector, estimated at about 10 % for SO2, 16 % for NOx and 9 % for PM2.5 emissions, compared with a pre-KA baseline.