Infrastructural inertia in energy-emissions scenarios

International efforts to avoid dangerous climate change require large and rapid reductions of fossil fuel CO₂ emissions worldwide, 42% of which were produced by the primary power sector in 2015. However, the rate of emission decreases from the power sector may be constrained by the lifetime and economic operating cycles of existing infrastructure. Using projections of electricity from fossil sources in several hundred energy-emissions scenarios based on the Shared Socioeconomic Pathways, we evaluate the implicit lifetime and utilization rates of power infrastructure and compare these with emissions and mitigation rates under different operational assumptions. We find that the average lifetimes of coal-and gas-fired power plants in scenarios with 1.9 and 2.6 W/m² of radiative forcing are in both cases <10 years, which is several decades less than such plants have operated historically. Allowing required plants to instead operate with historical capacity factors and lifetimes would result in roughly 200 Gt of additional CO₂ emissions this century, which may be incompatible with mean warming <2°C unless compensated by commensurate (and in most cases additional) negative emissions. Ambitious climate mitigation scenarios thus entail drastic and perhaps unappreciated changes in the operating and/or retirement schedules of power infrastructure.