Ateneo scientists identify 3 Visayas straits as top sites for tidal power

MANILA, Philippines—Harnessing just a fraction of the Philippines’ tidal energy resource could theoretically generate enough electricity to match the country’s current power consumption, according to Ateneo de Manila University researchers who identified three Visayas straits as among the most promising sites for future tidal power projects.

In a study assessing tidal energy potential in the Visayas, Ateneo researchers Justin Kyle O. Ricafort and King Harold A. Recto identified the San Bernardino Strait, San Juanico Strait and Cebu Strait as viable locations for tidal-stream energy systems because of their water current conditions, proximity to population centers and access to electrical grids.

The findings come as the Philippines continues to seek new sources of renewable energy while reducing its dependence on imported fossil fuels.

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“According to independent studies, the Philippines’ coastal waters have a total theoretical potential power of as much as 170 gigawatts, compared to the country’s current installed capacity of 32 gigawatts,” Ricafort said in a statement.

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“Although not all of the ocean’s power is practically recoverable, harnessing even just 18% to 20% of the archipelago’s total tidal energy is theoretically sufficient to cover the Philippines’ current power consumption,” he added.

The Philippines, an archipelago with more than 266,000 square kilometers of coastal area, has long relied on coal, natural gas and other imported fuels to meet growing electricity demand. The researchers said the country’s surrounding seas represent an underutilized energy resource that could help strengthen energy security while supporting climate goals.

Their study, “Assessing Tidal Energy Potential in the Visayas: Viability of the San Bernardino, San Juanico, and Cebu Straits,” examined geographic, energy demand and infrastructure factors that could affect the deployment of tidal energy systems.

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Unlike solar and wind energy, tidal power is driven by the predictable movement of ocean tides. The researchers noted that this predictability makes tidal energy a potentially stable source of renewable electricity.

READ: Green groups insist on shift to renewables

The study focused on tidal-stream systems, which use underwater turbines to capture the kinetic energy of moving currents and convert it into electricity. These systems function similarly to wind turbines but operate beneath the sea surface.

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Why these three straits stood out

The researchers evaluated potential sites based on water current speeds, proximity to electrical grids and population centers, and maritime activity.

Among the locations examined, the San Bernardino Strait emerged as a strong candidate because of its high tidal energy potential and relatively low maritime traffic. Earlier studies cited in the paper estimated the strait’s tidal energy potential at around 2.2 gigawatts.

The strait is also home to an ongoing renewable energy project near Capul Island in Northern Samar, where a 1-megawatt tidal-stream energy system is being installed to replace diesel-powered generators serving the island community.

The project uses the HydroWing, a bidirectional tidal turbine system developed by a Dutch company that generates electricity from tidal currents.

READ: Northern Samar to host Southeast Asia’s first tidal energy plant

According to the researchers, the Capul project could serve as a model for future marine renewable energy developments elsewhere in the country.

The San Juanico Strait was identified as another promising location because of its proximity to Samar and Leyte, areas that still lag behind other Visayas islands in electricity consumption and electrification.

The study noted that Leyte and Samar recorded a combined peak power demand of 344 megawatts in 2023, significantly lower than demand in Cebu, Panay and Negros.

The researchers said future tidal energy projects in the area could help improve access to electricity while reducing transmission losses because of their proximity to local consumers.

The Cebu Strait was also found to have strong potential because of its location near one of the country’s largest urban and economic centers. Cebu’s dense electrical grid and substantial energy demand make it attractive for large-scale deployment.

However, the researchers pointed out that the area’s heavy maritime traffic could complicate the installation and maintenance of tidal energy infrastructure.

As the study noted, “One key issue is the high volume of maritime traffic, largely due to the area’s proximity to a major metropolitan hub and the port of Cebu. As shown in marine traffic data, much of the vessel movement in the Visayas passes through this strait, making it less suitable for tidal infrastructure deployment.”

Cost remains a challenge

Despite its promise, tidal energy remains more expensive than more established renewable technologies.

The study cited previous analyses showing that electricity from tidal-stream systems could cost between P25.82 and P64.47 per kilowatt-hour, compared with around P2 to P5 per kilowatt-hour for wind and solar power.

The researchers acknowledged that tidal energy remains a relatively new technology but argued that it offers advantages that are difficult to replicate with other renewable sources.

“Tidal energy is highly predictable, stable, and environmentally friendly, offering a reliable alternative to conventional energy sources like coal and natural gas, which are often subject to price volatility and environmental concerns,” the study noted.

They also emphasized the broader opportunity presented by the country’s geography, writing that “with the country’s extensive coastline and rising energy demands, tidal energy presents a largely underutilized yet promising resource that can address both local and global energy challenges.”

The researchers noted that the technology’s higher cost can partly be attributed to its limited deployment and relative novelty. As more systems are installed and the industry matures, they said costs could gradually decline.

The study also framed tidal energy as a way to address the country’s energy trilemma, balancing sustainability, energy security and energy equity. While large-scale deployment would require substantial investment, the researchers said marine energy could eventually help deliver reliable electricity to underserved coastal communities while reducing exposure to fuel price volatility.

Building a foundation

The researchers said further site-specific studies are needed, particularly on water currents, environmental impacts, marine protected areas and long-term system performance.

Even so, they concluded that the San Bernardino, San Juanico and Cebu straits offer a strong foundation for future tidal energy development in the Philippines.

“This study has identified the San Bernardino, San Juanico, and Cebu straits as promising candidates for tidal-stream systems based on key site characteristics and early feasibility indicators,” the Ateneo scientists said.

“It establishes a foundation for integrating small-scale tidal systems in Philippine coastal waters, with the HydroWing installation in Capul Island serving as a real-world reference for potential implementation,” they added.

While the researchers said additional site-specific data and technical validation are needed before wider deployment, they said their findings demonstrate the practical potential of tidal energy as a less intrusive alternative to land-based renewable energy systems such as solar and wind.

The study was first presented at the IEEE Region 10 Conference (TENCON) in October 2025.

As the country looks for new sources of clean and reliable electricity, the researchers said tidal energy could be among the options in Philippine waters.

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