Potential renewable energy site identified in southern Philippine Sea; new faults found off Palawan- UP marine scientists

The southern portion of the Philippine Sea was found to be a potential prime location for marine renewable energy operations, according to the expedition findings led by the University of the Philippines Marine Science Institute (UPMSI). It also found new faults off eastern Palawan that were previously unmapped.

“The strong surface-to-deep temperature contrast observed in the southern Philippine Sea meets the thermal requirements for OTEC (Ocean Thermal Energy Conversion),” Dr. Charina Lyn Amedo-Repollo, lead of the Physical Observation Laboratory, said in a statement.

She noted that this indicates the area has high potential for continuous baseload renewable energy, and added that it could also support applications for desalination and seawater cooling.

The southern Philippine Sea was found to be ideal, as the critical 20-degree Celsius temperature difference between surface and deep water is already observed at a depth of only 200 meters, Ms. Repollo said.

This is shallower than what is observed in many other tropical regions and other parts of the world, where the same temperature difference is found at depths of up to 1,000 meters or deeper.

The 20-degree Celsius temperature difference is ideal for efficiently operating OTEC, a renewable energy source that harnesses the temperature gap between warm surface waters and colder deep waters.

The findings said the unique condition of the southern Philippine Sea is due to its open-ocean environment exposed to solar heating and influenced by large-scale ocean circulation.

The expedition was led by UPMSI and joined by scientists from the University of California, Santa Cruz and Mindanao State University–Naawan last December.

The team surveyed submarine volcanoes, active faults, internal waves, and areas for potential renewable energy in the Sulu Sea, Celebes Sea, and southern Philippine Sea.

Meanwhile, the researchers also found previously unmapped faults off eastern Palawan. One lies along the continental slope and shows about 10 meters of displacement, while another extends about 20 kilometers along the projected extension of the Ulugan Bay Fault, cutting through sediment layers.

The findings align with earlier mapping by French and German scientists and may explain the magnitude-5.1 earthquake that struck Palawan on June 11, 2024, which the state seismologist linked to a known fault in the area.

Dr. Fernando P. Siringan, who led the Philippine team, said the structures could also be tied to volcanic features in the Sulu Sea and stressed the need to reassess Palawan’s geology, especially it is being considered as a potential nuclear power plant site. — Edg Adrian A. Eva