Today we typically associate marine energy production with massive floating platforms capable of withstanding extreme conditions, building-sized turbines, and projects worth hundreds of millions of euros reserved for large corporations and public bodies. But a decade ago, a 15-year-old American student showed that one could also look in the opposite direction: making the technology smaller, simpler, and dramatically cheaper.
Her name is Hannah Herbst, and her invention was called “BEACON” (Bringing Electricity Access to Countries through Ocean Energy): a small hydrokinetic generator built from a PVC pipe, a 3D-printed propeller, and components that barely cost $12 (about €10 at the time). It couldn’t power a city, but it could light LEDs or provide energy for small desalination systems.
But as the years went by, that school project makes more and more sense, because the race to harness the power of the sea is increasingly shifting toward exactly that terrain: small, autonomous devices capable of delivering energy in places where laying a conventional grid is unfeasible.
The Power of a Water Current Can Be Greater Than It Appears
The BEACON operation rests on a fairly simple idea: harnessing the kinetic energy of moving water without the need to build dams or alter the surrounding environment. The secret lies in the ocean itself: saltwater is about 800 times denser than air, meaning that even currents that seem gentle hide a tremendous amount of energy.
In Hannah Herbst’s prototype, as she explained in her presentation, a small 3D-printed propeller spun with the flow of water and transmitted that motion to a generator capable of producing electricity. It’s the same principle used by today’s large offshore turbines, just scaled down to a tiny size and designed to offer an affordable solution in places where a major energy infrastructure is unviable.
Nevertheless, the hardest part of scaling such a thing would be keeping it running for months or years at sea, since seawater accelerates the corrosion of metal components and marine biofouling causes algae, barnacles, and other organisms to adhere to surfaces, potentially clogging the propellers and reducing performance.
That is why current commercial systems rely on composite materials, special coatings, and corrosion-resistant alloys that boost durability, though they also multiply the price exponentially.
The Industry Isn’t Looking Only for Ocean Giants Anymore: It Wants Small Generators Too
While big offshore energy projects continue to advance, part of current research is heading toward smaller, modular systems capable of powering coastal communities, ports, scientific sensors, or small islands that still rely on diesel generators. A philosophy typical of the so-called “blue economy,” aiming to harness ocean resources more sustainably.
In this sense, initiatives like the Decarbonization Hub, British Columbia Ocean Energy, and companies such as Minesto or CorPower Ocean are developing technologies adaptable to different needs and scales. One of their major advantages is the predictability of tides and ocean currents, whose cycles can be calculated with far greater precision than other renewables that rely on weather conditions.
But beyond generating electricity, these small systems can also power reverse osmosis desalination plants and provide drinking water in coastal areas far from large infrastructures, precisely one of the goals Hannah Herbst had in mind when she designed “BEACON”.
That tiny generator built from a PVC pipe and a 3D-printed propeller made her the winner of the 2015 Discovery Education 3M Young Scientist Challenge, and a year later took her to present her work at the White House Science Fair organized by the Obama administration. Today, her career remains closely tied to innovation and technology, appearing on the Forbes 30 Under 30 list. She is also an entrepreneur in the field of medical technology.
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