Japan’s environment ministry has warned that a planned liquefied natural gas (LNG)-fired power plant in Okinawa could damage nearby coral reef ecosystems and increase carbon emissions unless tied to the phase-out of older fossil fuel facilities, in an unusually detailed intervention that highlights growing tensions around the country’s energy transition.
The ministry said last week that it had submitted its opinion to the Ministry of Economy, Trade and Industry (METI) regarding Okinawa Electric Power Company’s plan to build a new 130-megawatt (MW) gas turbine combined cycle (GTCC) unit at the Makiminato thermal power plant in Urasoe City on Okinawa’s main island.
The proposed facility, scheduled to begin operations in fiscal 2032, would replace ageing heavy oil-fired units that have operated for more than 40 years and support Okinawa’s isolated power grid.
But the environment ministry warned the project’s location near coral communities and seagrass beds could pose risks to marine ecosystems if warmer discharge water raises sea temperatures, potentially causing coral bleaching and damage to marine vegetation.
The ministry called for detailed environmental assessments based on expert advice, as well as “careful and sufficient” consultation with local residents.
It also warned that unless the project is linked to the retirement or suspension of inefficient existing thermal power units, the new LNG plant could become an “additional” source of carbon emissions.
The ministry said Okinawa Electric should ensure that total company-wide greenhouse gas emissions fall below current levels once the new plant begins operating in 2032, including through the shutdown of older fossil fuel facilities.
The unusually detailed guidance also urged the utility to establish clearer emissions reduction targets covering its own power generation operations, saying the company had not sufficiently specified such goals despite broader commitments to achieve net-zero emissions by 2050 and reduce emissions linked to electricity sales by 30 per cent by fiscal 2030 from 2005 levels.
The ministry further called on the company to prioritise renewable energy and high-efficiency plants, reduce minimum fossil fuel output through more flexible operations, and accelerate deployment of decarbonisation technologies including ammonia co-firing, hydrogen fuels and carbon capture, utilisation and storage (CCUS).
It said Okinawa Electric should consider “all options”, including curtailment or eventual shutdown of the facility, if it cannot demonstrate a pathway consistent with Japan’s climate goals for 2035, 2040 and 2050 and the Paris Agreement’s 1.5°C target.
While Japan’s environment ministry routinely submits opinions during environmental review procedures, the guidance in this case was unusually detailed and interventionist, extending beyond standard mitigation measures to include possible future curtailment or shutdown of the plant if it cannot align with Japan’s climate targets.
The project reflects broader challenges facing Japan as it seeks to balance decarbonisation with energy security.
Japan has promoted LNG, hydrogen and ammonia technologies as transitional energy sources while maintaining stable electricity supplies after the Fukushima nuclear disaster increased the country’s dependence on imported fossil fuels.
Okinawa Electric first announced the project in November 2025. The new GTCC unit would use LNG supplied from the existing Yoshinoura thermal power plant in Nakagusuku village through gas pipelines.
The plant would use a latest-generation gas turbine supplied by IHI Corporation and is designed to allow future conversion to cleaner fuels such as ammonia.
METI is expected to issue formal feedback to Okinawa Electric after considering the environment ministry’s recommendations, before the utility decides whether to proceed to the next stage of environmental impact assessments under Japanese law.
