The role of renewables in the Japanese power sector: implications from the EMF35 JMIP

Abstract

The Japanese power system has unique characteristics with regard to variable renewable energies (VREs), such as higher costs, lower potentials, and less flexibility with the grid connection compared to other major greenhouse-gas-emitting countries. We analyzed the role of renewable energies (REs) in the future Japanese power sector using the results from the model intercomparison project Energy Modeling Forum (EMF) 35 Japan Model Intercomparison Project (JMIP) using varying emission reduction targets and key technological conditions across scenarios. We considered the uncertainties for future capital costs of solar photovoltaics, wind turbines, and batteries in addition to the availability of nuclear and carbon dioxide capture and storage. The results show that REs supply more than 40% of electricity in most of the technology sensitivity scenarios (median 51.0%) when assuming an 80% emission reduction in 2050. The results (excluding scenarios that assume the continuous growth of nuclear power and/or the abundant availability of domestic biomass and carbon-free hydrogen) show that the median VRE shares reach 52.2% in 2050 in the 80% emission reduction scenario. On the contrary, the availability of newly constructed nuclear power, affordable biomass, and carbon-free hydrogen can reduce dependence on VREs to less than 20%. The policy costs were much more sensitive to the capital costs and resource potential of VREs than the battery cost uncertainties. Specifically, while the doubled capital costs of VRE resulted in a 13.0% (inter-model median) increase in the policy cost, the halved capital costs of VREs reduced 8.7% (inter-model median) of the total policy cost. These results imply that lowering the capital costs of VREs would be effective in achieving a long-term emission reduction target considering the current high Japanese VRE costs.

Demand-side decarbonization and electrification: EMF 35 JMIP study

“…In AIM/Hub, the electrification rate decreases from the 26by30 + 80by50_Def scenario in the HiVREcost (− 4.3%pt) and the NoNuc (− 2.2%pt) scenarios by increasing liquids consumption, while the electrification rate increases from the 26by30 + 80by50_Def scenario in the LoVREcost (+ 4.5%pt) and the HiVREpot (2.1%pt) scenarios by decreasing liquids consumption. In DNE21, only the NoNuc scenario shows a slight decrease in the electrification rate (− 0.2%pt) from 26by30 + 80by50_Def because DNE21 has a high share of nuclear power generation due to no quantity constraint (see Shiraki et al 2021) in 26by30 + 80by50_ Def. IEEJ and TIMES-Japan models show a competitive nature between VRE and hydrogen.…”