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Ateneo de Manila University researchers have identified three major waterways in the Visayas as promising locations for tidal energy projects, highlighting the potential of the Philippines’ vast coastal resources to support future electricity generation and strengthen long-term energy security.
In a study assessing tidal energy potential in the Visayas, researchers Justin Kyle O. Ricafort and King Harold A. Recto found that the San Bernardino Strait, San Juanico Strait and Cebu Strait possess characteristics that could support tidal-stream energy systems. The findings come as the Philippines seeks to expand renewable energy sources while reducing dependence on imported fossil fuels.
According to Ricafort, independent studies estimate that Philippine coastal waters hold a theoretical tidal energy potential of as much as 170 gigawatts, far exceeding the country’s current installed power generation capacity of about 32 gigawatts.
“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 said.
Untapped Resource Beneath Philippine Waters
While solar, wind, hydropower, and geothermal projects dominate discussions on renewable energy, tidal power remains largely unexplored in the Philippines and across Southeast Asia. No commercial tidal power facility is currently operating in the region despite years of studies and project announcements.
The Ateneo researchers argue that the Philippines may be uniquely positioned to develop the technology because of its geography. With more than 7,600 islands separated by narrow channels and straits, the country naturally funnels large volumes of seawater through confined waterways, creating strong currents that can potentially be converted into electricity.
The study focused on tidal-stream technology, which uses underwater turbines to capture the kinetic energy of moving water. Similar to wind turbines, these systems generate electricity through rotating blades, but they operate beneath the ocean surface.
Because water is significantly denser than air, tidal turbines can produce substantial amounts of energy even at relatively modest current speeds. Researchers said the challenge lies in identifying locations where water movement is strong, predictable, and economically viable.
Unlike solar and wind resources that can fluctuate because of weather conditions, tidal energy is driven by the predictable movement of ocean tides, allowing power generation patterns to be forecast years in advance.
“Tidal energy’s predictability distinguishes it from other renewable technologies,” the study noted, pointing to its potential role in creating a more stable renewable energy mix.
Three Strategic Straits
Among the sites examined, the San Bernardino Strait emerged as one of the strongest candidates because of its high tidal energy potential and relatively low maritime traffic.
Located between Southern Luzon and Northern Samar, the strait connects the Philippine Sea and the Samar Sea and experiences powerful tidal currents generated by the movement of large volumes of water between the Pacific Ocean and inland waters. Previous studies cited in the research estimated the area’s tidal energy potential at around 2.2 gigawatts.
The strait is also home to an ongoing renewable energy initiative near Capul Island in Northern Samar, where a one-megawatt tidal-stream system is being installed to replace diesel-powered generators serving the island community.
The project utilizes HydroWing, a bidirectional tidal turbine system developed by a Dutch company that generates electricity from tidal currents. Researchers said the Capul installation could serve as a practical reference point for future marine renewable energy developments elsewhere in the country.
The San Juanico Strait, which separates Samar and Leyte, was also identified as a promising location because of its proximity to communities that continue to face electrification and energy access challenges.
The study noted that Leyte and Samar recorded a combined peak power demand of 344 megawatts in 2023, considerably lower than demand levels in Cebu, Panay and Negros.
Researchers said tidal projects in the area could help improve local power supply while reducing transmission losses by generating electricity closer to consumers.
Meanwhile, the Cebu Strait offers advantages linked to its location near one of the country’s largest urban and economic centers. Cebu’s dense transmission infrastructure and substantial electricity demand make it an attractive candidate for future large-scale deployment.
However, researchers cautioned that the strait’s heavy maritime traffic could complicate the installation and operation of tidal energy facilities, given its role as one of the busiest shipping corridors in Central Visayas.
Opportunities and Challenges
Despite its promise, tidal energy remains one of the least developed renewable energy technologies globally. Commercial projects are concentrated in only a handful of countries, including South Korea, the United Kingdom, France, and Canada.
The technology continues to face significant barriers, including high capital costs, challenging underwater operating conditions, and environmental considerations involving marine ecosystems, fisheries, and navigation.
The study cited previous analyses estimating electricity costs from tidal-stream systems at between ₱25.82 and ₱64.47 per kilowatt-hour, significantly higher than the roughly ₱2 to ₱5 per kilowatt-hour often associated with solar and wind power.
Researchers attributed much of the cost gap to the technology’s limited deployment and early stage of development. They said costs could decline as more projects are built and the industry matures.
The study also framed tidal energy as a potential contributor to addressing the country’s energy trilemma of sustainability, energy security and energy equity.
“Tidal energy is highly predictable, stable, and environmentally friendly, offering a reliable alternative to conventional energy sources like coal and natural gas,” the researchers said.
While further site-specific assessments on currents, environmental impacts, marine protected areas and long-term performance are still needed, the researchers concluded that the San Bernardino, San Juanico and Cebu straits provide a strong foundation for future tidal energy development.
As the country continues to search for new sources of clean and reliable electricity, the study suggests that some of the country’s most promising renewable energy resources may be flowing through its coastal waterways.
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