Underwater Kites: Could Ocean Tides Become the Next Clean Energy Source?

The search for reliable clean energy is moving beyond solar panels and wind turbines toward one of Earth’s most powerful natural systems: the ocean. Underwater kites, also known as tidal kites or tethered undersea kites, are an emerging technology designed to capture energy from moving seawater. Instead of relying on a large stationary turbine, a kite-like device is tethered to the seabed and steered through tidal currents.

The concept is attracting attention because tides are highly predictable, unlike sunshine and wind. Demonstration projects have shown that the technology can work, but major questions remain about cost, durability, environmental effects and commercial scale. Could tidal energy become a significant part of tomorrow’s clean-energy mix?

What Are Underwater Kites?

An underwater kite is essentially a hydrodynamic wing with a turbine, control system and tether. It is anchored to the seabed while moving through the water along a controlled path.The concept is comparable to the way a kite moves through air, except the “wind” is replaced by a tidal current. Because water is much denser than air, even relatively moderate underwater currents contain substantial kinetic energy.

Minesto, a Swedish marine-energy company, describes its Deep Green technology as a system that uses a kite-like principle to generate electricity from tidal streams and ocean currents. The basic objective is simple: make the turbine experience a faster relative flow of water than it would receive while remaining stationary.

How Does a Tidal Kite Generate Electricity?

A conventional tidal stream turbine is generally positioned so that moving water passes through its blades. An underwater kite takes a different approach.The tether holds the device in position while onboard controls guide it through the water. The kite can travel along a repeated trajectory, creating a higher relative flow across its turbine.

The turbine then converts the kinetic energy of moving water into rotational mechanical energy. A generator converts that mechanical energy into electricity, which can be transmitted through underwater cables.

In simplified terms, the energy pathway is:

Tidal current → Kite movement → Turbine rotation → Generator → Electricity grid

Research into tethered undersea kite systems has examined how geometry, structural design and code optimized to increase power output while maintaining stable operation. 

Why Are Tides Attractive for Renewable Energy?

One of the biggest advantages of tidal energy is predictability.Solar power depends on daylight and weather. Wind power varies with atmospheric conditions. Tides, however, are driven primarily by the gravitational interactions of the Earth, Moon and Sun and therefore follow highly predictable cycles.

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This does not mean tidal power produces electricity continuously at a constant level. Tidal currents change over time and depend heavily on local geography. Nevertheless, the timing of those changes can be forecast much more accurately than many weather-dependent renewable resources.That predictability could make ocean energy useful as part of a diversified renewable-energy system. It could potentially complement solar and wind rather than compete with them.

Underwater Kites vs Conventional Tidal Turbines

Traditional tidal turbines can resemble underwater versions of wind turbines. They rely on the turbine rotor.Underwater kites attempt to increase the effective water speed experienced by the turbine by moving through the current.This difference can potentially allow kite systems to operate in locations where conventional turbines may not be economically attractive.The Open Energy Information database describes Deep Green as an underwater kite designed for lower-speed currents, with the technology developed around controlled underwater movement. However, “lower-speed current” should not be interpreted as meaning that the device can operate economically in every weak current. Real performance depends on the particular design, water speed, depth, trajectory, turbine efficiency and operating conditions.

Where Is This Technology Being Tested?

Underwater-kite technology has moved beyond computer simulations into real marine demonstrations. Minesto has developed its Deep Green technology and tested different generations of devices. A project at Holyhead Deep in Wales was designed to demonstrate a 0.5 MW device and support further commercialization work.

The Faroe Islands have also become an important location for tidal-kite development. Minesto has deployed Dragon-series devices there, including the larger Dragon 12 system. Available project information records grid-connected tidal-kite deployments in the islands.These projects are important because ocean-annot be fully validated in laboratories alone. Devices must withstand saltwater, strong currents, marine growth, corrosion, storms and continuous mechanical loading.

The Potential of Tidal Stream Energy

The global potential of tidal stream energy is significant because oceans cover most of the planet and many coastal regions experience strong currents.But resource potential is not the same as commercially available electricity.

A tidal-energy site must have suitable water velocity, depth, seabed conditions, grid access and regulatory approval. Installation and maintenance also become much more complicated. A 2025 review of the economic development of tidal-stream turbine arrays highlighted the importance of scaling up from small demonstration projects to larger arrays while reducing costs through engineering improvements and greater industry experience. The future of underwater kites will depend not simply on whether they can generate electricity, but whether they can generate it reliably and economically at scale.

Major Benefits of Underwater Kites

1. Predictable Renewable Power

The predictability of tidal cycles is one of the strongest arguments for tidal renewable energy.Power-system operators can forecast tidal conditions well in advance, helping them understand when tidal generation is likely to increase or decrease.

2. No Fuel Required

Like other renewable-energy technologies, tidal kites do not require continuous fuel combustion.Their energy source is naturally moving seawater.

3. Small Physical Footprint

Because water is dense, underwater turbines can potentially be much smaller than wind turbines producing comparable power.The kite concept may also reduce the amount of massive seabed infrastructure required in some designs.

4. Minimal Visual Impact

Motes underwater, meaning there is little or no visual impact from tall towers or large surface structures.

5. Potential for Remote Coastal Communities

Island communities and remote coastal regions often face expensive electricity-generation challenges.Tidal power could potentially provide a locally available source of renewable electricity where suitable marine conditions exist. The European Commission’s CORDIS platform has previously highlighted underwater-kite technology as a potential source of renewable energy for small islands. 

What Are the Challenges?

Despite its promise, underwater kite energy is not yet a mature global energy solution.

High Costs

Marine construction, underwater cables, specialized vessels and offshore maintenance can be expensive.Reducing the cost per megawatt-hour is one of the most important challenges for tidal-energy developers.

Harsh Ocean Conditions

Saltwater is highly corrosive. Waves, currents and storms place substantial mechanical stress on equipment.A commercial device may need to operate for many years while remaining safe and reliable.

Maintenance

Repairing an underwater device is significantly more difficult than repairing equipment on land.Engineers need systems that can be safely recovered, inspected and redeployed without excessive downtime.

Marine Ecosystem Questions

Any technology placed in the ocean must be assessed for its effect on marine ecosystems.

Researchers need to understand possible interactions with fish and other organisms, as well as underwater noise and changes in local flow patterns.This does not automatically mean tidal kites are environmentally harmful. It means environmental monitoring must accompany commercial deployment.

Limited Suitable Locations

A tidal kite cannot simply be placed anywhere in the ocean.Commercial viability depends on the combination of current speed, water depth, seabed characteristics, grid connection and other local factors.

Could Underwater Kites Beat Solar and Wind?

Probably not-and that may not be the right question.The future energy system is unlikely to depend on a single renewable technology.

Solar power is highly scalable and increasingly inexpensive in many markets. Wind power can produce large quantities of electricity, particularly offshore. Hydropower provides established storage and generation in suitable regions.

The Role of Technology and Artificial Intelligence

Advanced control systems could become increasingly important for underwater-kite technology.A kite operating in moving water has to continuously adjust its trajectory. Sensors can monitor position, current conditions, mechanical loads and other operating parameters. Artificial intelligence and advanced control algorithms could eventually help optimize trajectories and identify maintenance requirements.

However, AI does not eliminate the fundamental engineering challenges. Materials, underwater cables, turbines, anchoring systems and marine environmental assessments will remain essential.

What Could the Future Look Like?

If engineering costs decline and reliability improves, underwater kites could become part of commercial marine renewable energy arrays.Instead of one device operating alone, multiple underwater kites could potentially work together in carefully selected tidal-energy zones.Such arrays would require sophisticated planning to prevent devices from interfering with one another and to optimize the use of available water flow.

The Faroe Islands provide an interesting real-world case study because tidal-energy developers have been working with local energy infrastructure to explore larger-scale applications. Current information describes plans and development ambitions, but these should not be confused with a fully mature global commercial market. The industry therefore remains in an important transition period: moving from promising prototypes and demonstrations toward reliable commercial systems.

A Broader Perspective on Responsible Development

​Beyond the engineering feat, this technological leap raises a fundamental question: What should human progress ultimately serve? In the spiritual teachings associated with Sant Rampal Ji Maharaj, human knowledge is meant to foster harmony, social welfare, and environmental purity. While science addresses the mechanics of power generation and spirituality addresses human consciousness, they intersect at the principle of responsible development.

Clean-energy innovations like underwater kites are truly meaningful only when they minimize ecological harm without creating new burdens for marine ecosystems or future generations. From this broader perspective, underwater kites are more than just a clever mechanism-they illustrate how human intellect can align with natural ocean cycles to meet society’s energy needs respectfully and sustainably.

FAQs on Underwater Kites

1. What are underwater kites?

Underwater kites are tethered marine-energy devices that move through tidal or ocean currents along controlled paths. They use the movement of water to drive turbines and generate electricity.

2. How do underwater kites generate electricity?

A kite-like structure is tethered to the seabed and moves through flowing water. A turbine attached to the device converts the kinetic energy of the moving water into mechanical energy, which a generator converts into electricity.

3. Are underwater kites better than conventional tidal turbines?

Not necessarily. Underwater kites use a different operating principle and may have advantages in certain lower-current locations, but their costs, reliability and environmental performance must be evaluated against conventional tidal technologies.

4. Is tidal energy reliable?

Tidal energy is highly predictable because tides follow regular astronomical cycles. However, electricity production still varies according to the timing and strength of local tidal currents.

5. Can underwater kites replace solar and wind energy?

They are unlikely to replace solar and wind energy. Their more realistic role could be as a complementary renewable source, adding predictable generation to a broader clean-energy system.