A new current of clean energy

Exploring Japan’s breakthrough in ‘osmotic’ power and how it can benefit the Philippines’ renewable energy mix

- By JOYCE REYES-AGUILA

In the Japanese coastal city of Fukuoka, the natural mix of saltwater and freshwater is being harnessed to produce renewable energy.

The country has unveiled its first so-called “osmotic” power facility, which, according to Renewable Energy Institute’s website, can generate around 880,000 kilowatt-hours of electricity annually. It is only the second facility of its kind in the world, following a similar one in Denmark that was introduced in 2023.

In “Japan’s First Osmotic Power Plant: What It Means for Clean Energy,” the organization explains that salinity gradient power generation “positions seawater and freshwater on opposite sides of a specially designed membrane, with the seawater kept under mild pressure. As freshwater moves across into the saltier side, the volume of pressurized liquid grows, creating energy that can be captured.” The resulting pressure builds up, drives water through a turbine, which a generator converts into usable electricity.

The Fukuoka District Waterworks Agency’s plant can also function as a desalination facility that supplies drinking water to the city and nearby areas. The Institute cited findings by Dr. Ali Altaee of the University of Sydney, noting that the Asian osmotic plant’s output could supply an average of 220 households and continue operating despite weather changes or the absence of daylight.