Research Paper

Future Energy Landscape - Global Energy Agenda - Ensuring Adequate Generation Capacity During Prolonged Periods of Low Variable Renewable Energy Output - Addressing Dunkelflaute and Utilizing Existing Thermal Power Plants as Strategic Reserves -

Author	Kenichi Onishi
Summary	In recent years, Japan has seen increasing deployment of variable renewable energy (VRE) sources, particularly solar photovoltaic (PV) and wind power. Because electricity generation from ...
Outline	As the deployment of variable renewable energy (VRE), particularly solar PV and wind power, expands, addressing prolonged periods of low generation output, known as Dunkelflaute, is becoming increasingly important. Although long-duration energy storage (LDES) and LNG-fired power plants are promising options, they may face limitations when prolonged generation shortfalls coincide with fuel supply constraints. Therefore, utilizing existing coal-fired and other thermal power plants capable of stockpiling fuel as strategic reserves is an important option. Japan should consider strengthening the requirements of its Reserve Power Source System, including startup capability within several days and sufficient fuel inventories to sustain generation over extended periods.
Keyword	sakiyomi, Dunkelflaute, Variable Renewable Energy (VRE), Strategic Reserve, Reserve Power Source System, Long-Duration Energy Storage (LDES), Coal-Fired Power Plants
Media	ＨＰ (11/5/2026)
URL	https://eneken.ieej.or.jp/en/sakiyomi_energy_issues.html
Report PDF	https://eneken.ieej.or.jp/data/13640.pdf