erex Co., Ltd.

Completed Joint Test with Vietnam’s Vinacomin Power Holdings
Biomass Co-Firing Test at Coal-Fired Power Plants to Realize a De-Carbonized Society;
Achieved a Co-Firing Ratio of 30% at the 2nd Unit (Cao Ngan Power Plant Unit 2)

As announced on December 24, 2025, erex Co., Ltd. (Head Office: Chuo-Ward, Tokyo; Representative Director and President: Hitoshi Honna; hereinafter referred to as “the Company”), in collaboration with Vinacomin Power Holdings (Head Office: Hanoi, Vietnam; General Director & CEO: Bùi Minh Tân; hereinafter referred to as “Vinacomin Power”), conducted a biomass co-firing test at the coal-fired Cao Ngan Power Plant (57.5MW x 2 units) owned by Vinacomin Power (hereinafter referred to as “the Co-Firing Test”).

Initially, the co-firing ratio in the Co-Firing Test was planned to be up to 20%, but the Company is pleased to announce that a co-firing ratio of 30% was achieved in the test conducted on January 5, 2026, and the Co-Firing Test was completed on January 13.

By increasing the co-firing ratio to 30%, CO2 emissions will be reduced by 30% compared to coal-fired (coal only) combustion, and more effective use of Vietnam’s domestic biomass resources will be made possible.

１．Background of the Co-Firing Test (Re-Iterated)
Vietnam’s electricity demand is growing at an annual rate of approximately 10%, and the country relies on coal-fired power plants for approximately half of its power supply. Vietnam has also declared its goal of becoming carbon neutral by 2050, and its 8th National Power Development Plan calls for the country to start co-firing biomass and other fuels at coal-fired power plants that have been in operation for 20 years or more. Co-firing these fuels contributes to reducing CO2 emissions and improving energy self-sufficiency, and biomass fuels in particular can be procured domestically.

The Co-Firing Test was conducted based on the MOU on biomass co-firing with coal-fired power signed in September 2022 and the addendum to the MOU (signed on June 17, 2025), both signed with Vinacomin Power, a subsidiary of Vietnam’s state-owned Vietnam Coal Mining Group (Vinacomin)

From September to November 2025, the Company conducted Vietnam’s first biomass co-firing test at the Na Duong Power Plant, where biomass co-firing with wood chips at a co-firing ratio of up to 20% was implemented. The co-firing test at the Na Duong Power Plant provided the Company with insights into efficient biomass fuel transportation and other things.

２．Overview of the Co-Firing Test at the Cao Ngan Power Plant
The Co-Firing Test was conducted for one of the two 57.5MW units, and involved co-firing of up to 30% biomass. Wood pellets were used as fuel.

The main factors that enabled the increase in the co-firing ratio this time include the fact that the boiler is a CFB (Circulating Fluidized Bed) type, which does not require fuel pulverizing, and that wood pellets, used as fuel for co-firing, have a low moisture content and are almost free of harmful components that affect exhaust gas properties, making it possible to maintain combustion conditions and efficiency equivalent to those achieved when firing coal alone.

The Subject Power Plant	Cao Ngan Power Plant (coal-fired) of Vinacomin Power, Vietnam
Output	57.5MW x 2 Units (Test was conducted on one of the two units)
Co-Firing Ratio	Gradually implemented from 5% to 30%
Co-Firing Fuel	Wood Pellets

The Co-Firing Test was selected as subsidy recipient for the FY2025 Resource-Rich Country De-Carbonization and Energy Conversion Technology Support Program by the Agency for Natural Resources and Energy, Ministry of Economy, Trade and Industry on March 11, 2025, and the subsidy was approved on April 15, 2025. The Co-Firing Test uses this subsidy.

４．Future Developments
The Company aims to start biomass co-firing business (co-firing ratio of 20-30%) at coal-fired power plants in Vietnam from FY2026. Furthermore, through these activities, the Company will contribute to Vietnam’s goal of achieving carbon neutrality by 2050 and improving its energy self-sufficiency rate.

■The Company’s Overseas Business
The Company is promoting business developments toward de-carbonization, such as the construction of biomass power plants in Vietnam and Cambodia. The Company believes that this will not only contribute to the de-carbonization of both countries, but also to improving energy self-sufficiency rate and creating jobs.

【Major Initiatives of the Company’s Overseas Business】

2025	March	Vietnam: Tuyen Quang Pellet Factory started productions
	April	Vietnam: Hau Giang Biomass Power Plant started operations
	September	Vietnam: Vinacomin Power’s Na Duong Power Plant started biomass co-firing test
	November	Vietnam: Vinacomin Power’s Na Duong Power Plant completed biomass co-firing test (5-20% co-firing ratio) Vietnam: EPC contract for Yen Bai Biomass Power Plant was signed
	December	Vietnam: EPC contract for Tuyen Quang Biomass Power Plant was signed Vietnam: Vinacomin Power’s Cao Ngan Power Plant started biomass co-firing test
2026	January	Vietnam: Vinacomin Power’s Cao Ngan Power Plant completed biomass co-firing test (5-30% co-firing ratio)
2026	June	Cambodia: Construction of hydroelectric power plant will be completed
FY2027		Cambodia: Biomass and solar power plants will start operations Vietnam: Yen Bai Biomass Power Plant will start operations Vietnam: Tuyen Quang Biomass Power Plant will start operations

■ Contact
erex Co., Ltd. / IR&PR Department
TEL：+81-3-3243-1167
E-mail：ir.info@erex.co.jp

Note:
This document is an English translation of the original Japanese language document and has been prepared solely for reference purposes. No warranties or assurances are given regarding the accuracy or completeness of this English translation. In the event of any discrepancy between this English translation and the original Japanese language document, the original Japanese language document shall prevail in all respects.