Blue Energy: Can the Power of the Seas Become a New Pillar of the Energy Transition?

As global energy systems are reshaped around solar and wind power, seas and oceans are emerging as testing grounds for a new generation of renewable energy technologies. Blue energy systems—which generate electricity from waves, tides, marine currents, temperature differences and salinity gradients—offer the prospect of predictable, low-carbon power generation. However, high investment costs, harsh marine conditions and uncertainties concerning their environmental effects continue to restrict their widespread deployment.

What is blue energy?

In its broadest sense, blue energy refers to renewable energy generated from the natural movements and physical properties of seas and oceans. It encompasses five main technology groups:

• Wave energy
• Tidal energy
• Marine and ocean-current energy
• Ocean thermal energy conversion
• Salinity-gradient or osmotic energy

In a narrower definition, “blue energy” refers specifically to energy generated from the difference in salt concentration between freshwater and seawater. Blue energy should therefore be understood not as a single technology but as a family of technologies with different operating principles and levels of maturity.

According to the International Renewable Energy Agency, global installed ocean-energy capacity reached approximately 494 MW at the end of 2024. Compared with worldwide solar and wind capacity, this figure illustrates that the sector remains at a very early stage of development. (www.irena.org)

How are waves and tides converted into electricity?

Wave-energy systems convert the movement of the water surface into mechanical energy, which is then transferred to a generator. Some devices use floating structures that move vertically with the waves, while others employ the air compressed by incoming waves to drive a turbine. Developers are experimenting with numerous designs installed onshore, near the coast or on floating offshore platforms.

Tidal energy is primarily harvested through two methods. Tidal-range plants use the difference between high and low tide, normally through a barrage or lagoon. Tidal-stream turbines resemble underwater wind turbines and generate electricity from flowing water.

Because water is much denser than air, marine currents can contain considerable mechanical energy even at relatively low flow speeds. Tidal cycles can also be predicted years in advance, making tidal generation more predictable than wind and solar power. However, projects are economically feasible only in locations with sufficiently strong currents or large tidal ranges.

The difference between saltwater and freshwater can also generate power

One of the most innovative forms of blue energy is osmotic power, which exploits the difference in salinity where rivers meet the sea. Two principal technologies are being developed.

In pressure-retarded osmosis, or PRO, freshwater passes through a semi-permeable membrane into a pressurised saltwater chamber. The resulting increase in pressure drives a turbine and generates electricity.

In reverse electrodialysis, or RED, salt ions pass through alternating ion-selective membranes, creating an electrical potential that can be converted into usable power.

Salinity-gradient technologies in the European Union remain largely at the pilot and demonstration stages. A reverse-electrodialysis demonstration plant was commissioned in the Netherlands in 2014, while a newer pilot facility was established where the Rhône River meets the Mediterranean Sea in France. The European Commission estimates the technology’s readiness at approximately TRL 5–7. (blue-economy-observatory.ec.europa.eu)

Blue energy could complement wind and solar power

One of blue energy’s principal advantages is that its generation profile differs from those of wind and solar. Tides are highly predictable, while ocean waves may continue producing electricity after local winds have weakened. Salinity-gradient power could provide relatively continuous generation at suitable river estuaries with stable water flows.

This makes blue energy a potential complement to established renewable technologies rather than a direct replacement for them. Island communities, offshore facilities, aquaculture farms, remote monitoring equipment and communities without reliable grid connections are among its most promising early markets.

Ocean energy may also be integrated with desalination plants, potentially combining clean-water and electricity production. IRENA estimates that ocean-energy resources possess a theoretical annual generation potential of between 45,000 and 130,000 TWh. However, only a fraction of this theoretical potential is likely to be technically, economically and environmentally accessible. (www.irena.org)

The hidden costs of blue energy

Although blue energy is renewable and potentially low-carbon, it is neither impact-free nor free of operational difficulties.

High investment and maintenance costs

Seawater creates an exceptionally demanding operating environment for energy equipment. Saltwater corrosion, severe storms, wave loading and constantly changing mechanical forces can shorten the service life of components.

Biofouling—the accumulation of microorganisms, algae, barnacles and other organisms on underwater surfaces—can reduce system efficiency and interfere with moving parts. Even relatively routine offshore maintenance may require specialised vessels, divers or remotely operated underwater vehicles.

These requirements increase operating expenses and may leave a device out of service for extended periods following a failure. The US Department of Energy identifies corrosion and biofouling among the principal materials challenges that must be addressed before marine-energy technologies can reach commercial maturity. (www.energy.gov)

Technologies have not yet reached full commercial maturity

Many blue energy systems remain at prototype or demonstration scale. No standard wave-energy design has yet emerged that can operate efficiently under widely differing coastal and offshore conditions.

Although numerous devices have completed successful tests, long-term field evidence concerning capacity factors, reliability and maintenance costs remains limited. This creates substantial technological risk for investors.

Electricity generated from most blue energy systems remains more expensive than electricity from solar photovoltaics and onshore wind. The sector consequently finds it difficult to obtain finance without public grants, revenue guarantees or long-term power-purchase arrangements. IRENA notes that ocean-energy projects remain expensive and high-risk, making large-scale deployment through market forces alone unlikely at the present stage. (www.irena.org)

Effects on marine life

Underwater turbines may create a collision risk for fish and marine mammals. Construction and operating noise may also affect the communication, navigation or feeding behaviour of certain species.

Electromagnetic fields generated by subsea cables are being studied for their possible effects on animals that use electrical or magnetic signals to navigate. Large arrays may alter currents, sediment movement and habitats on or around the seabed. The allocation of maritime areas to energy generation can also conflict with fishing, shipping, tourism and marine conservation.

Existing monitoring has not established that every marine-energy installation necessarily causes serious ecological damage. However, much of the available research concerns single devices or small arrays. Evidence about the cumulative effects of commercial farms containing many devices remains limited.

The 2024 OES Environmental State of the Science report identifies collision, underwater noise, electromagnetic fields, habitat change, displacement, entanglement and changes to oceanographic systems as major areas requiring continued research and monitoring. (www.oceanenergysystems.org)

Osmotic energy is not environmentally neutral

Membranes used in salinity-gradient systems can become clogged by organic material, microorganisms and mineral deposits. This reduces water flow and power production while creating additional cleaning and replacement costs.

Facilities may need to extract large volumes of freshwater and seawater. Smaller organisms can be drawn into intake systems, while discharged water may have a salinity, temperature or chemical composition different from the receiving environment.

Estuaries are particularly sensitive ecosystems. Changes in salinity distribution could therefore affect local habitats. The chemicals used to clean membranes and the disposal of membranes at the end of their service lives must also be included in life-cycle assessments.

Osmotic power should consequently not be assumed to have zero environmental impact simply because it consumes no conventional fuel.

Which countries and companies are leading blue energy development?

The blue energy market has not yet become a mass industry comparable to wind and solar power. Nevertheless, the 2024–2026 period has seen a gradual shift from individual pilot devices towards pre-commercial, multi-device projects.

Across Europe, 15 publicly supported wave and tidal farms with a combined planned capacity of 165 MW are expected to be deployed over the coming five years. (www.oceanenergy-europe.eu)

According to the European Commission’s Joint Research Centre, just 1.8 MW of new ocean-energy capacity was installed worldwide in 2024, of which 0.5 MW was installed in the European Union. The limited volume confirms that the sector has not yet reached commercial scale, while also pointing to an emerging industrial opportunity. (setis.ec.europa.eu)

United Kingdom: The strongest tidal-stream market

The United Kingdom is one of the sector’s principal centres, particularly because of tidal-stream projects around Scotland and the Orkney Islands. Its position results not only from favourable marine resources but also from the government’s Contracts for Difference auctions, which provide dedicated revenue support for tidal-stream projects.

More than 120 MW of tidal-stream capacity is scheduled for deployment by 2029, in addition to approximately 8.3 MW already operating in UK waters. (www.research.ed.ac.uk)

Scottish company Orbital Marine Power operates the 2 MW O2 floating tidal turbine in Orkney. The company secured a further £7 million investment in late 2025 and holds government-backed contracts for six turbines with a total capacity of 14.4 MW.

Orbital plans to procure approximately 70% of an estimated £200 million equipment programme from the UK supply chain. (www.lse.co.uk)

Other important British initiatives include MeyGen, one of the world’s largest tidal-stream projects; Nova Innovation, which develops systems for islands and smaller grids; and the European Marine Energy Centre, an internationally recognised testing and demonstration facility.

France: Combining tidal-stream and osmotic energy

France has a long history in conventional tidal-range energy through the 238 MW La Rance power station. New investment, however, is increasingly focused on marine-current turbines and salinity-gradient systems rather than major tidal barrages.

French developer HydroQuest is working on the FloWatt project, which is expected to use six turbines off the coast of Normandy. France’s energy programme envisages the allocation of 250 MW through the country’s first commercial tidal-stream tender by 2030. (www.hydroquest.fr)

In osmotic energy, Sweetch Energy has established a demonstration project where the Rhône meets the Mediterranean. In 2025, the company signed a lease for a 3,000-square-metre industrial building intended to accommodate its first osmotic-generator production lines.

Commercial viability has not yet been demonstrated, but France is one of the first countries attempting to move osmotic power from pilot operation towards equipment manufacturing. (blue-economy-observatory.ec.europa.eu)

Portugal and Spain: Testing grounds for wave energy

Strong Atlantic wave resources have made Portugal and Spain natural testing grounds for wave-energy developers.

Swedish company CorPower Ocean has tested its C4 wave-energy converter near Viana do Castelo in Portugal. In 2025, the company was awarded up to €17.5 million by the European Innovation Council, comprising grant finance and an equity commitment.

CorPower also secured a €40 million EU Innovation Fund grant to support its proposed 10 MW VianaWave project off northern Portugal. (corpowerocean.com)

The company employs approximately 100 people across Sweden, Portugal, Scotland and Norway. Its recruitment activity demonstrates the variety of jobs being created in composite manufacturing, CNC operation, mechanical and electrical engineering, subsea cables, marine operations and project management. (careers.corpoweroceanjobs.com)

The Oceanic Platform of the Canary Islands, or PLOCAN, provides testing and grid-connection infrastructure for international wave-energy developers. Dutch company Wavepiston has installed a system there that combines wave-power generation with pressurised water production and potential desalination applications. (op.europa.eu)

Sweden, Denmark and the Netherlands: Technology developers take the lead

Northern European countries stand out more for technology development, patents and specialised engineering than for installed capacity.

Swedish company Minesto develops underwater “kites” that travel in a figure-eight pattern through tidal currents. CorPower Ocean, also founded in Sweden, concentrates on wave-energy converters.

Danish companies Wavepiston and Wave Dragon, together with Finnish developer AW-Energy, are developing different types of wave-energy system. Dutch company REDstack uses reverse electrodialysis to generate electricity from salinity gradients, while Slow Mill Sustainable Power develops wave-energy equipment.

According to the European Commission, Sweden, France, Denmark, the Netherlands and Germany are among the ten largest recipient countries for venture-capital and private-equity investment in ocean energy. (setis.ec.europa.eu)

Canada and the United States: Testing infrastructure and remote applications

Canada’s Bay of Fundy contains exceptionally strong tidal currents, making it an important location for tidal-energy trials. The Nova Scotia-based Fundy Ocean Research Centre for Energy, or FORCE, provides marine sites, environmental monitoring and grid-connection facilities for technology developers.

In 2025, Orbital Marine Power and Canadian company Eauclaire Tidal secured an additional 12.5 MW allocation from the Province of Nova Scotia, together with 15-year power-purchase contracts. The plan involves deploying six Orbital O2-X turbines at the FORCE site. (www.lse.co.uk)

US investment is concentrating not only on utility-scale generation but also on defence facilities, ocean-observation systems, remote communities and offshore equipment.

Ocean Power Technologies develops PowerBuoy systems for marine surveillance and offshore-energy applications. CalWave, C-Power and Oscilla Power are among the other US companies developing wave-energy devices.

The grid-connected PacWave South facility off Oregon has been established to test full-scale wave-energy devices. The US Department of Energy has invested approximately $150 million in the facility since 2016. (apnews.com)

China, South Korea and Japan: Industrial capacity with different priorities

China and South Korea have some of the world’s largest conventional tidal-range facilities. South Korea’s 254 MW Sihwa Lake plant is one of the most prominent examples.

However, major tidal barrages are now less frequently pursued because of their environmental effects, limited suitable locations and high capital costs. Current attention is shifting towards modular tidal-stream turbines and wave-energy technologies.

China supports wave and tidal research through universities, public research institutes and large energy companies. Japan is investigating wave energy, strong ocean currents and ocean thermal energy conversion.

Activities in these countries are frequently organised through publicly supported demonstration programmes. Consequently, fewer independent technology developers have emerged than in Europe.

How much is being invested in blue energy?

The European Union leads public research and development expenditure in this field. It accounted for approximately 58% of global public ocean-energy R&D investment over the most recent decade for which comparable information was available.

Half of this share originated from national programmes in EU member states, while the other half came from EU-level research programmes.

Since 2014, more than €365 million has been allocated to blue energy through Horizon 2020 and Horizon Europe:

EU-based companies invested approximately €948 million of private capital in ocean-energy technologies between 2010 and 2022. Europe accounted for 53% of global ocean-energy investment deals between 2022 and 2024.

Nevertheless, annual public R&D spending in the EU declined by 37% in 2023 to €30.6 million. Europe therefore remains the sector’s leading investment centre, but funding has not followed a consistent upward trajectory. (setis.ec.europa.eu)

How much employment has blue energy created?

Employment figures must be treated cautiously. Companies and industry organisations frequently publish projections of thousands of future jobs based on planned capacity. These figures do not represent current employment; they estimate the direct and indirect employment that could materialise if deployment targets are achieved.

According to the European Commission Joint Research Centre’s latest comprehensive estimate:

• The global ocean-energy industry employed approximately 1,000 full-time-equivalent workers in 2023.
• At least 415 of these jobs were in EU-based companies.
• The estimate covers developers and related supply-chain activities in wave and tidal energy.
• Because there is no standard industrial classification for ocean energy, some employment is recorded under shipbuilding, marine engineering, research or professional services. (setis.ec.europa.eu)

It would therefore be inaccurate to claim that blue energy already employs tens of thousands of people. Current direct employment remains comparable to the workforce of a small number of large industrial facilities.

Future employment potential is significantly greater. The UK tidal-stream workforce has been projected to reach approximately 4,000 jobs by 2030 and 14,500 by 2040. These positions would be distributed across manufacturing, installation, maintenance, electrical systems, welding, marine operations and project management.

However, the estimates depend on whether deployment targets, industrial investment and supply-chain localisation are realised. (www.gov.uk)

France’s FloWatt initiative estimates that industrialisation of the tidal-stream sector could support 6,000 direct and indirect jobs in France from 2030. Once again, this is a projection rather than an existing employment figure. (www.flowatt.fr)

What kinds of jobs does blue energy create?

Employment is not limited to operators working at power plants. The emerging value chain requires:

• Mechanical, electrical, control and materials engineers
• Naval architects and marine-technology specialists
• Welders, CNC operators and composite-manufacturing technicians
• Subsea-cable and grid-connection specialists
• Corrosion, coating and cathodic-protection engineers
• Divers and remotely operated underwater-vehicle operators
• Maintenance technicians and vessel crews
• Oceanographers, marine biologists and environmental-monitoring specialists
• Data analysts, software engineers and predictive-maintenance specialists
• Permitting, finance and project-management professionals

One of the sector’s potential economic advantages is its ability to use existing shipyards, steel-fabrication businesses, energy-equipment manufacturers and offshore-service companies.

Whether employment remains within local economies will depend on where turbine bodies, foundations, cables, power systems and other components are manufactured. Installed capacity alone will not guarantee substantial local employment if equipment and maintenance services are imported.

What does the current market tell us?

Blue energy technologies are progressing at different rates:

Europe remains the centre of the emerging industry. The United Kingdom leads in tidal-stream projects, Portugal and Spain provide major wave-energy test and deployment sites, while France is investing in both tidal-stream and osmotic power.

Canada and the United States are developing strong testing infrastructures, while China, South Korea and Japan are pursuing larger publicly supported research and demonstration programmes.

At present, the industry is driven more by technology development, prototype manufacturing, marine testing and the construction of initial pre-commercial farms than by conventional electricity sales.

The global workforce of approximately 1,000 people may appear modest, but it represents highly specialised and potentially high-value industrial expertise. Actual employment growth will ultimately depend on how many of the announced project pipelines secure finance and proceed to construction.

What potential does Turkey offer?

Turkey’s extensive coastline offers opportunities for blue energy research. However, its seas do not generally experience tidal ranges comparable to those of the Atlantic coast. Large tidal barrages are therefore unlikely to represent the most realistic option.

Greater attention could be directed towards wave energy in selected coastal areas, marine currents and salinity-gradient systems near suitable river estuaries. The Black Sea coast may warrant investigation for wave-energy applications, while the currents in the Bosphorus and Dardanelles appear theoretically attractive.

Nevertheless, current speed alone cannot determine the feasibility of a project. Heavy shipping traffic, migratory fish routes, navigational safety, grid connections and maintenance requirements would all have to be considered.

The most realistic starting point for Turkey would be small-scale pilot projects jointly developed by universities, shipyards, machinery manufacturers and energy companies rather than immediate investment in large commercial farms.

Corrosion-resistant materials, composite structures, underwater sensors, power electronics, subsea cables and predictive-maintenance systems could provide technology-development opportunities for Turkish industry.

Turkey already possesses significant capabilities in shipbuilding, fabricated metal products, electrical equipment, cables and industrial machinery. If an early domestic market were combined with university research and marine test infrastructure, these capabilities could be adapted to the blue energy supply chain.

However, Turkey should avoid approaching blue energy simply as another field in which imported equipment is installed. Its greatest economic value would arise from domestic engineering, component production, testing and maintenance services.

Conclusion: Substantial potential, but expectations should remain realistic

Blue energy is an important area of energy-transition research, but it has not yet proved itself as a mainstream commercial power source. The theoretical scale of the resource is impressive, yet there is a considerable gap between theoretical potential and economically recoverable energy.

The sector’s future will depend not only on how much electricity its devices generate but also on maintenance requirements, material durability, grid connections, maritime spatial planning and cumulative ecological effects.

Blue energy projects should therefore be evaluated through life-cycle costs and regional environmental carrying capacity rather than through the simplistic assumption that the sea represents an unlimited source of clean energy.

When deployed at appropriate locations, supported by rigorous environmental monitoring and integrated with domestic industry, blue energy could complement solar and wind power while providing specialised solutions for islands, coastal communities and offshore facilities.

However, for this potential to become commercially meaningful, the technical, financial and ecological costs of operating in the marine environment must first be measured—and reduced—with much greater certainty.