Japan cut natural‑gas‑fired power output sharply in May, turning to coal plants to keep the grid humming as LNG shipments faltered. The shift followed a sudden tightening of supplies after several tanker movements were delayed near the Strait of Hormuz, a chokepoint for Middle‑East oil and gas exports. Operators reported a noticeable drop in gas‑burn generation. Cost penalties rose for generators.

Utilities compensated the shortfall by ramping up output at older coal‑fired stations, which emit more CO₂ but can be brought online quickly. The move raises concerns for Japan’s climate commitments, yet the immediate priority remains supply security. Energy traders noted tighter spot LNG pricing, while coal demand in the country edged higher, nudging regional fuel markets. Domestic coal imports rose modestly.

The episode underscores how geopolitical friction around the Hormuz corridor can reshape national energy mixes in real time. With Japan‑run power grids relying more on carbon‑intensive coal, emissions footprints will climb until gas supplies normalize. Policymakers now face pressure to diversify import routes and bolster storage to avoid repeat swings in fuel strategy. The episode also highlights storage gaps.