Energy Development Corp. (EDC) is planning to retire and repurpose its Upper Mahiao geothermal plant in Leyte, which has hit the end of its economic and technical life after nearly 30 years. It will be retired in phases from 2026 to 2029.
Commissioned in 1996, the 129-megawatt (MW) geothermal power plant is now deemed technically incapable of generating electricity. EDC Vice President Ryan Velasco explained that major geothermal plant components typically last 15-20 years, making the Upper Mahiao power plant long overdue for major upgrades.
Velasco also said that EDC will be conducting feasibility studies for the potential repurposing and redevelopment of the power plant. The company has previously submitted a letter of intent to the Department Of Energy (DOE) for decommissioning Upper Mahiao.
Maintaining Core Geothermal Supply
The retirement of the geothermal plant, however, will be done in phases so that it will not impact the power supply. Upper Mahiao is part of the Leyte geothermal complex, which is the country’s flagship geothermal resource.
EDC still has a large active capacity in the area with the 232.61-MW Malitbog, the 198.14-MW Mahanagdong, and the 123-MW Tongonan power plants, so the basin remains a core geothermal asset.
Shutting down Upper Mahiao will initially involve two of the four units for phase one, which will be completed in 2026. The remaining units will be decommissioned by 2029.
Providing Clean Power To The Grid
EDC, a subsidiary of First Gen Corp., continues to lead the Philippine geothermal sector with over 1,200 MW across more than 13 plants – the largest such portfolio in the country.
The proposed repurposing of Upper Mahiao fits into the company’s long-term goals of solidifying the country’s geothermal resource, as it plans to drill 19 new geothermal wells before its 50th anniversary in 2026. This initiative is expected to provide an additional 141-MW of clean power to the grid.
The company is also moving beyond local markets, advancing geothermal projects in Indonesia and scouting additional growth prospects overseas.
Sources:
https://www.philstar.com/business/2025/10/22/2481512/edc-plans-repurpose-retiring-geothermal-plant
https://business.inquirer.net/456917/edc-s-tongonan-facility-symbol-of-resilience-and-sustainability
https://www.philstar.com/business/2025/05/27/2445982/edc-drilling-19-new-geothermal-wells