Renewable Energy Institute’s 2040 Scenario Published in Energy PolicyFull Access to the Paper Available Until 14 July

in Japanese

A paper by Renewable Energy Institute presenting a scenario in which 90% of Japan’s electricity is supplied by renewable energy by 2040 has been published in the international academic journal Energy Policy*.

An Energy Scenario for Japan Towards 2040: Focused on Efficiency Improvements and Renewable Energy
DOI: 10.1016/j.enpol.2026.115398

The paper presents a scenario in which renewable energy accounts for 90% of Japan’s electricity supply by 2040, based on two key pillars: comprehensive improvements in energy efficiency and large-scale expansion of renewable energy.

It also provides a comparative analysis with the Japanese government’s Strategic Energy Plan, examining differences in assumptions and power generation mix, as well as the respective roles that renewable energy and energy efficiency can play in Japan’s energy transition.

Full access to the paper is available until 14 July 2026.

View Paper (until 14 July 2026)

Highlights

• ​Japan can achieve stable and affordable electricity supply in FY2040 with around 90% renewable electricity, even without nuclear and coal power, while the Seventh Strategic Energy Plan (SEP) relies on CCS and hydrogen or ammonia co-firing, leading to higher costs and lower energy self-sufficiency.
• Low-cost operation at high renewable shares requires adequate system flexibility and a balanced renewable mix, rather than over-reliance on solar PV.
• Battery storage is effective for integrating solar PV, while interregional interconnections are essential for wind power integration.
• Large-scale renewable deployment enables domestic hydrogen production equivalent to about 20% of Japan's planned FY2040 demand.
• Electrification, efficiency improvements, and high share of renewables in electricity generation using existing technologies can reduce energy-related CO₂ emissions by over 80% by FY2040.