FOR years, marine energy has been dominated by massive tidal barrages and underwater turbines anchored to the seabed. Now, a different technology is attracting attention by generating electricity from machines that fly beneath the ocean's surface.
Known as energy kites, these underwater systems are emerging as one of the most innovative approaches to harnessing tidal power. And with new financing support in Europe and expansion plans in Asia announced this year, the technology is moving beyond experimental trials and closer to commercial deployment.
At the center of the effort is Swedish marine energy developer Minesto, which has spent more than a decade refining its "Dragon" energy kite technology.
Unlike conventional tidal turbines that remain fixed in place, Minesto's system resembles a small underwater aircraft tethered to the seabed. As tidal currents flow through the water, the kite flies in a controlled figure-eight pattern, carrying a turbine beneath its wing-like structure.
The movement allows the turbine to travel several times faster than the surrounding current, dramatically increasing the amount of energy that can be extracted from the water.
The principle is similar to that of a traditional kite flying through the air. A kite can move much faster than the wind itself, generating greater forces than a stationary object. Underwater energy kites use the same concept, but with the much denser medium of seawater.
This enables electricity generation in locations where tidal currents may be too slow for conventional seabed-mounted turbines. The potential advantage is significant. Most tidal energy projects require strong currents concentrated in narrow channels or coastal passages. Such locations are relatively limited worldwide. Energy kites could potentially operate in a broader range of sites, opening up previously inaccessible marine resources for renewable power generation.
The technology has already been tested in Wales and the Faroe Islands, where Minesto has been working to demonstrate the commercial viability of underwater kite systems.
This year marked a major step forward. In January, the company announced that it had been selected by the European Investment Bank (EIB) for Project Development Assistance to support the development of a proposed 10-megawatt Dragon Farm within European Union waters.
The project would become the first commercial-scale array of tidal energy kites in the European Union and is intended to serve as a blueprint for future deployments. Through the EIB program, Minesto will receive investment advisory support aimed at strengthening the project's business case and helping secure approximately €25 million in capital for development.
For the marine energy sector, the announcement represents more than a financing milestone. It signals growing confidence that underwater kite technology may be ready to move from demonstration projects to utility-scale renewable energy installations.
The company is also looking beyond Europe. Minesto recently received grant funding from the Swedish Energy Agency through its Global Innovation Accelerator program to accelerate market development activities in Taiwan. The initiative is intended to support partnerships, project identification and commercial opportunities in one of Asia's most promising renewable energy markets.
Taiwan has invested heavily in offshore wind development and is seeking additional sources of clean energy as it works to strengthen energy security and reduce carbon emissions. The island's coastal geography and tidal resources make it a potentially attractive market for marine energy technologies. The expansion effort reflects growing interest in deploying energy kites in regions where conventional tidal infrastructure may be difficult or expensive to install.
Despite the recent momentum, significant challenges remain. Marine energy developers must contend with corrosion, biofouling, harsh weather conditions and complex maintenance requirements. Any technology operating beneath the ocean surface faces engineering demands that exceed those encountered by most land-based renewable energy systems. Questions also remain regarding long-term operating costs, scalability and performance over decades of commercial use.
Yet supporters argue that energy kites offer a compelling advantage at a time when power systems are increasingly dependent on intermittent renewable sources. Unlike solar and wind energy, tidal currents are governed by the predictable gravitational interaction of the Earth, moon and sun. As a result, tidal energy production can be forecast years in advance, providing grid operators with a level of certainty rarely found in renewable generation.
If energy-kite technology succeeds in making lower-speed tidal resources economically viable, it could significantly expand the amount of predictable renewable energy available worldwide.