The Philippines is sitting on a massive hydropower opportunity, but industry experts warn that unlocking it will require billions of dollars and navigating some of the country’s toughest engineering and accessibility challenges.

Philhydro Association president Gertrude Roque said the country’s hydropower potential is estimated at 650 gigawatts (GW), but much of it remains out of reach because developers cannot access the sites. 

“The estimate is 650 gigawatts of potential because we’re an archipelago. Of course, we’re surrounded by water. But not all sites are accessible. It’s really difficult to do road openings, as we call it, right, those in the mountains. So very costly, difficult, risky,” she said in an interview.

The scale of investment needed is equally formidable. “Actually, it’s around $5 million per megawatt (MW). $5 million to $6 million per MW,” Roque said — making hydropower among the most capital-intensive renewable energy projects in the country.

Mutiple technology preferred

Roque said the Philippines cannot rely on a single technology if it hopes to meet growing electricity demand and stabilize the grid. “Each hydro technology has different classifications, run-of-river (RoR), dam-type and pumped storage. So I cannot choose. A combination of those will be best,” she explained.

RoR plants depend entirely on river flow, while dams store water for flood prevention and irrigation. Pumped storage, she said, acts as a controllable buffer, supporting intermittent renewable energy and helping stabilize the grid. 

Despite its enormous potential, hydropower remains the country’s most underdeveloped renewable energy resource. Its future now hinges on whether investors and policymakers are willing to take on the cost, the terrain and the risk.

Government data show that as of the end of August, the Philippines’ grid-connected installed capacity reached 31,849 MW, with only 954 MW — roughly 3 percent — supplied by RoR hydropower plants.