100% renewable electricity in Japan

TL;DR

This study demonstrates that Japan has abundant renewable resources and can achieve 100% renewable electricity by 2050 at costs comparable to current market prices, using a detailed 40-year energy model.

Contribution

It presents the first comprehensive 40-year hourly energy balance model for Japan's electricity system, showing feasibility and cost estimates for 100% renewable energy transition.

Findings

Japan has 14 times more renewable resources than needed.

Levelized cost of renewable electricity is competitive with current market prices.

A feasible, cost-effective pathway to 100% renewable electricity in Japan is demonstrated.

Abstract

Japan has committed to carbon neutrality by 2050. Emissions from the electricity sector amount to 42% of the total. Solar photovoltaics (PV) and wind comprise three quarters of global net capacity additions because of low and falling prices. This provides an opportunity for Japan to make large reductions in emissions while also reducing its dependence on energy imports. This study shows that Japan has 14 times more solar and offshore wind resources than needed to supply 100% renewable electricity. A 40 year hourly energy balance model is presented of Japan's electricity system using historical data. Pumped hydro energy storage, high voltage interconnection and dispatchable capacity (hydro, biomass and hydrogen energy) are included to balance variable generation and demand. Differential evolution is used to find the least-cost solution under various constraints. The levelized cost of electricity is found to be USD 86 per MWh for a PV-dominated system, and USD 110 per MWh for a wind-dominated system. These costs can be compared with the average system prices on the spot market in Japan of USD 102 per MWh. In summary, Japan can be self-sufficient for electricity supply at competitive costs.