EDC readies P100 billion geothermal upgrade in Leyte

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January 12, 2026 | 12:00am

MANILA, Philippines — Energy Development Corp. (EDC) of the Lopez family is ramping up its geothermal push with plans to invest up to P100.88 billion to expand its capacity in Leyte.

EDC has filed for a key environmental clearance to implement upgrades at its Tongonan Geothermal Project (TGP), which includes the 136.5-megawatt Upper Mahiao, the 180-MW Mahanagdong, the 232.5-MW Malitbog and other optimization units.

The upgrades aim to increase TGP’s generation capacity to 967.22 MW from the current 637.21 MW, the company said in a document submitted to the Department of Environment and Natural Resources.

One of the proposed modifications is the construction of the 450-MW New Upper Mahiao Power Plant (NUMPP) to replace the existing facility, which is approaching 30 years of operation.

With a potential 75-MW expansion, the new facility will be built near the existing Upper Mahiao plant and will use modern turbines to harness available steam more efficiently, EDC said.

Construction of the NUMPP is expected from 2026 to 2028, with phased commercial operations scheduled to begin next year.

“The old Upper Mahiao plant will remain operational until the new facility is commissioned, after which decommissioning will proceed,” the country’s largest geothermal player noted.

The Upper Mahiao plant, commissioned in 1996, has been slated for phased decommissioning after reaching the end of its economic lifespan.

Furthermore, EDC plans to upgrade the three existing units of the Mahanagdong plant to improve efficiency, maintain reliability and reduce emission intensity.

Its proposal also includes expanding and reconfiguring existing wells and pads to sustain steam supply at TGP.

In geothermal operations, there are two main types of wells: production and reinjection. Production wells bring steam and water from the geothermal reservoir to the surface, while reinjection wells return the used geothermal fluid back into the reservoir.

A pad, meanwhile, is a prepared area of the land where a geothermal well is drilled.

For this proposed project, EDC intends to open and construct around 27 new well pads and drill about 172 wells.

At Alto Peak, the company also aims to start exploration drilling by 2027. Activities include pad preparation, drilling and well testing, with potential integration into existing systems if results prove favorable.

Beyond geothermal power, EDC is targeting the construction of a 20-MW battery energy storage system adjacent to its 10-MW Tongonan BESS.

Expected to be operational by 2029, the new BESS facility is designed to support various applications, including frequency regulation and integration with renewable energy sources.