RE100 is a global renewable energy initiative in which influential companies voluntarily commit to securing 100 percent of their electricity from renewable energy sources. In order to reach this goal of RE100, firms must procure sufficient renewable energy. This study examines the future environment of RE100 implementation by Korean firms and reveals a gap between RE100 and the objective of electricity grids with net zero carbon. In projecting RE100 implementation in 2036, we find that about 45.6 terawatt-hours (TWh) of surplus energy is generated in the renewable energy supply for the year. We can further break down the resulting amount into 65.8 TWh of surplus and 20.2 TWh of deficiency. Looking at it in the aggregate, Korean firms can achieve RE100 even while maintaining a significant distance in real time from net zero electricity grids. In addition, the scenario analysis shows that the gap between RE100 and net zero becomes less cost effective as use of renewable energy expands. The results of this study suggest the need for
a clean energy certification system to help reduce the gap between RE100 and net zero.

[Key Words] RE100, Renewable energy, Electricity demand, GHG emissions