The following is an opinion column by Marvin Tort, originally published by BusinessWorld. The views expressed are the author's own.

Growing up in the 1970s, Marvin Tort used to watch an animated TV show called Sealab 2020, a US-produced series set in an underwater research base on a seamount. The setting was, of course, the year 2020. The show's producers imagined that humans would already be living underwater roughly 50 years on, in a station home to 250 people dedicated to exploring the seas and protecting marine life. Back then, the thought of living underwater was as mesmerizing as living in space — and science fiction, as turns out, tends to be a good predictor of things to come.

It is on that note that Tort, a former managing editor of BusinessWorld and a former chairman of the Philippine Press Council, argues for looking to the seas for Philippine energy security. The country's power mix already includes coal, natural gas, geothermal, hydro, solar, and wind. But for an archipelagic nation, he contends, the most obvious energy frontier all along may have been the water moving around it.

This, he writes, is no longer science fiction, and it is more than an environmental slogan. Marine renewable energy should be treated as a strategic national priority because it directly addresses three chronic problems: expensive electricity, dependence on imported fuel, and unreliable power supply in island and coastal communities.

In his view, it all starts with ensuring security and control over the country's oceans and seas — particularly the West Philippine Sea and parts of the Sulu and Celebes seas, the Philippine Sea in the east, and the waters around the Batanes Islands. Only with full control and security, he argues, can an effective national ocean energy strategy be developed.

That strategy should be built around three technologies: tidal stream energy, ocean thermal energy conversion (OTEC), and osmotic power. Research indicates that when properly located, these technologies can offer firm, predictable, or near-baseload power. They can complement solar and wind without requiring the same scale of battery dependence and, unlike coal, oil, or gas, they do not require imported fuel whose price can be dictated by global shocks, shipping disruptions, foreign wars, or exchange-rate movements.

For a country made up of thousands of islands, Tort writes, the conclusion should be obvious: rather than merely being a consumer of imported energy technologies, the Philippines should become a regional laboratory, investor, and eventual leader in ocean energy. The research is available. What is missing is national policy and the political will to push ahead.

Tidal stream: the most accessible starting point

Among the three technologies, tidal stream power may be the most accessible starting point. It uses underwater turbines to capture the movement of tidal currents, especially in straits where water naturally accelerates between islands. Because tides are governed by gravitational cycles that can be predicted years in advance, tidal power is one of the more reliable renewable sources available.

Ateneo researchers have already drawn attention to the tidal potential of Philippine straits such as San Bernardino Strait, San Juanico Strait, and Cebu Strait. Near Capul Island in Northern Samar, a one-megawatt tidal-stream system using HydroWing technology is being installed to replace diesel generation, the usual fallback in off-grid island communities. How that system performs against diesel in a real off-grid setting will offer one of the first domestic reference points for the other straits researchers have flagged.

OTEC and a potential Philippine advantage

Likewise significant is OTEC, which uses the temperature difference between warm surface water and cold deep water to generate electricity. In most locations, achieving the required temperature difference means sinking pipes to 800 or 1,000 meters, which makes projects expensive and technically demanding. Intake depth is a key driver of that cost and complexity, which is why the difference between 200 meters and 1,000 meters is the kind of variable that can decide whether a project moves forward at all.

But recent work by the University of the Philippines Marine Science Institute points to a potential Philippine advantage. UP researchers reported that in the southern Philippine Sea, the critical temperature difference of about 20° Celsius may be found at around 200 meters depth. If validated through further site-specific studies, that finding could sharply improve the feasibility of Philippine OTEC compared with locations that require far deeper intake systems.

OTEC also has benefits beyond electricity. Cold deep seawater can support desalination, aquaculture, and district cooling. A future OTEC project could function as a coastal development platform that provides power, fresh water, cooling, and high-value aquaculture in one integrated system — particularly for island provinces dealing with water stress and food-security needs.

Osmotic power: from theory to demonstration

Another technology, osmotic power, is less familiar but still deserves attention. It uses the energy released when freshwater and saltwater meet across a membrane. The Philippines, with its river systems flowing into bays and gulfs, has natural candidate sites.

A Philippine study on pressure-retarded osmosis found encouraging economic indicators, including a seven-year discounted payback period and an internal rate of return above 12% under certain assumptions. A UP thesis also examined an osmotic power plant design for the Agno River-Lingayen Gulf Delta System.

Japan opened one of the first commercial-scale osmotic power plants in Fukuoka in 2025. The facility is modest in scale, expected to generate about 880,000 kilowatt-hours annually, but its importance is not scale — it is demonstration. Osmotic power is no longer merely theoretical. For any Philippine candidate site, Fukuoka now serves as a working reference rather than a concept on paper.

A portfolio of pilots

Tort argues the Philippines needs a portfolio of pilots: one tidal pilot in a strong strait, one OTEC pilot in the southern Philippine Sea, and one osmotic pilot at a river-sea interface such as the Agno-Lingayen. Each should have clear performance metrics, defined timelines, and honest evaluation criteria. This, he says, is where the Maharlika Investment Corp. should enter.

The risks are real, he acknowledges. The marine environment is harsh, capital costs for ocean energy are high, and typhoons, saltwater corrosion, subsea maintenance, and grid connection are genuine technical challenges. But feasibility cannot be determined by hesitation.

Maharlika is a sovereign development fund whose mandate includes long-term, infrastructure-heavy, strategically domestic investments. Renewable energy and off-grid island solutions fit that mandate; ocean energy fits it even more precisely. The fund could help push a national ocean energy strategy from concept to demonstration, seeding the pilots that private capital will not fund alone.

Tort also proposes that the government designate three national demonstration zones — one each for tidal stream energy, OTEC, and osmotic power — and build the regulatory framework around them before deployment rather than after. In practical terms, the near-term markers are identifiable: whether the southern Philippine Sea temperature finding survives site validation, whether the Capul tidal system comes online and holds up in an off-grid setting, and whether demonstration zones and Maharlika participation move from proposal to commitment.

A 2023 report on marine renewable energy in the Philippines, prepared by Filipino energy scholars and institutions, made the basic point that the country has indigenous marine resources that can contribute to energy security and the low-carbon transition. The report also recognized that marine energy technologies require government support to become bankable: pilot funding, tariff support, regulatory clarity, and institutional urgency are the levers. Everything starts with recognizing the potential and building a strategy around it.

The broader energy mix

Solar and wind alone cannot solve the country's baseload and island-grid problems. Natural gas is a limited resource, coal is mostly imported, and nuclear remains politically and institutionally complicated. The answer to the country's energy future will not come from the sea alone, Tort writes — but for an archipelago, it would be strange not to ask the sea to do more.

The tides, the thermal gradients, and the rivers meeting the sea are already there. The Philippines does not have to invent the sea; it is surrounded by vast bodies of water. The country only has to finally include the seas in its energy imagination — "and a Philippine Sealab by 2030."

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Marvin Tort is a former managing editor of BusinessWorld and a former chairman of the Philippine Press Council. He can be reached at matort@yahoo.com.