When are fossil fuels displaced? An exploratory inquiry into the role of nuclear electricity production in the displacement of fossil fuels.

We explore how renewable electricity production influences nuclear energy and fossil fuel use in the electricity sector for 109 nations from 1960-2015 and how such patterns change over time. We find that although a one-unit increase in the number of kWh produced from renewable sources does not appear to displace an equivalent number of kWh from fossil fuels, such an increase is associated with an equivalent reduction in the number of kWh drawn from nuclear sources between 1960 and 2015. However, further analyses indicate that there has been a trend toward displacement of fossil fuel sources by renewables, as well as an attenuation of the displacement of nuclear sources by renewables, since the late 1990s in nations with the capacity for nuclear electricity production. These findings suggest that decarbonize the existing electricity grid, especially outside of the 31 nations capable of producing electricity from nuclear energy sources.