The Growing Importance of Ocean Energy

Tidal and wave energy represent one of the largest untapped renewable resources on the planet. Oceans cover more than 70% of the Earth’s surface and carry an enormous store of kinetic and potential energy. Unlike solar and wind, which vary with weather and time of day, ocean energy is highly predictable. Tides follow precise lunar cycles, and wave patterns can be forecasted days in advance. This predictability makes tidal and wave power uniquely valuable for grid stability — a critical advantage as grids integrate higher shares of variable renewables.

Globally, the technical potential for ocean energy is estimated at over 300 gigawatts (GW) of installed capacity for tidal energy alone, while wave energy could exceed 10,000 terawatt‑hours per year — roughly equal to global electricity demand. Currently, installed capacity is less than 1 GW, but the sector is accelerating. The International Renewable Energy Agency (IRENA) projects that ocean energy could reach 350 GW by 2050, supplied by a mix of tidal barrages, tidal stream devices, wave energy converters, and other innovative systems. As countries strive to meet net‑zero targets, ocean energy offers a reliable, complementarity source to solar and wind, especially in coastal regions.

Technological Innovations Driving Integration

Recent breakthroughs in materials science, power electronics, and hydrodynamics are making ocean energy technologies more efficient, durable, and cost‑effective. Below we explore the key innovations currently reshaping the sector.

Advanced Turbines and Energy Converters

Tidal stream turbines — often compared to underwater wind turbines — have evolved dramatically. Early designs were heavy, fixed‑pitch systems prone to corrosion. Modern turbines use variable‑pitch blades, direct‑drive permanent magnet generators, and composite materials that resist saltwater and biofouling. Companies like Orbital Marine Power have developed floating tidal turbines that can be towed into deep water, avoiding costly offshore construction. For wave energy, point‑absorber buoys and oscillating water columns now incorporate adaptive control algorithms that tune the device’s response to real‑time sea states, increasing capture efficiency by 20–30%.

Grid Connection and Subsea Cabling

One of the biggest hurdles to integration has been transmitting power from offshore arrays to onshore grids. Modern high‑voltage alternating current (HVAC) and high‑voltage direct current (HVDC) cables reduce transmission losses over tens of kilometres. Dynamic cables — capable of flexing with wave motion — are now deployed alongside floating devices. New grid‑side inverters allow ocean energy plants to provide ancillary services like voltage support and frequency regulation, making them active participants in smart grids rather than passive generators.

Energy Storage to Smooth Intermittency

While tidal energy is predictable, it does produce a lull twice daily. Wave energy fluctuates with swell patterns. Pairing ocean energy with storage — whether lithium‑ion batteries, pumped hydro, or emerging technologies like hydrogen electrolysis — ensures a steady dispatchable power supply. In the UK, the MeyGen project uses onshore batteries to smooth output, while hybrid projects in Europe combine wave energy with offshore wind and floating solar, sharing a common storage asset to maximise utilisation of underwater cables.

Digital Twins and Predictive Maintenance

Operational costs have been a barrier to deployment. Digital twin technology — creating a virtual replica of each device — allows operators to simulate performance under different conditions, detect wear before failure, and schedule maintenance during calm weather. Machine learning models trained on years of ocean data now forecast wave heights and currents with over 90% accuracy, enabling real‑time power scheduling that aligns with market demand.

Challenges and Opportunities

Despite rapid progress, large‑scale integration faces serious hurdles. High capital costs, permitting complexity, and environmental uncertainties remain. However each challenge also presents an opportunity for innovation and policy leadership.

Environmental and Ecological Impacts

Marine ecosystems are sensitive. Tidal barrages can alter sediment transport and fish migration; turbines pose collision risks to marine mammals; wave devices may create noise and electromagnetic fields. Yet research shows that properly sited and designed arrays can coexist with marine life. New turbine designs incorporate fish‑friendly blades with rounded edges and lower tip speeds. Artificial reef effects from submerged structures can enhance local biodiversity. Rigorous environmental impact assessments (EIAs) and adaptive management plans — such as the ones used at the MeyGen tidal stream project — help minimise harm and build public trust.

Economic Viability and Policy Support

Levelised cost of energy (LCOE) for tidal and wave power historically exceeded €300/MWh, but costs are falling. For tidal stream, LCOE in Europe has dropped below €150/MWh, and the 2030 target for wave energy is €100/MWh. Scaling up arrays, standardising designs, and leveraging manufacturing supply chains from offshore wind can drive further reductions. Government mechanisms — feed‑in tariffs, contracts for difference, and dedicated auctions (e.g., Portugal’s wave energy auction) — are essential de‑risking tools. The European Commission’s Ocean Energy Strategic Research and Innovation Agenda aims to deploy 1 GW by 2030, sending a strong policy signal.

Technical and Logistical Complexities

Installing devices in harsh, corrosive saltwater is expensive. Vessel costs, weather windows, and mooring system failures have plagued early projects. However, innovations in self‑installing platforms — ballasted foundations that sink into place without heavy lift vessels — and autonomous underwater inspection robots are reducing these costs. Shared infrastructure, such as offshore energy hubs that combine wind, solar, and ocean energy, also spreads installation and O&M expenses.

Emerging Projects and Case Studies

Several pioneering projects worldwide are demonstrating the feasibility of integration at meaningful scale.

MeyGen (Scotland)

Located in the Pentland Firth, the 6 MW MeyGen tidal array has been generating since 2016. It uses four 1.5 MW turbines and has exported over 60 GWh to the UK grid. MeyGen’s success lies in its phased approach, meticulous seabed monitoring, and grid connection via an existing onshore substation. It is now expanding to 80 MW, with plans to integrate battery storage and provide balancing services to the national grid.

Sihwa Lake Tidal Power Plant (South Korea)

Built in 2011, the 254 MW Sihwa barrage is the world’s largest tidal power installation. It generates electricity using 10 submerged turbines that capture energy as water flows through the barrage gates. Sihwa’s integration into South Korea’s grid is straightforward because its output is predictable and it operates as a baseload plant. However, environmental concerns (reduced water exchange in the lake) led to design adaptations that improved water quality over time — a lesson for future barrage projects.

WaveRoller (Portugal)

The WaveRoller device, installed off Peniche, uses a hinged panel that oscillates with near‑shore waves to drive a hydraulic generator. The project has been connected to the Portuguese grid since 2019 and is part of the European Marine Energy Centre’s testing network. Its innovative bottom‑mounted design avoids collision risk for marine life and simplifies mooring. The developers aim to scale up to commercial arrays by 2027 with LCOE targets below €100/MWh.

The Role of Policy and International Cooperation

Integration of ocean energy cannot happen in isolation. National energy strategies must explicitly include marine renewables in grid expansion plans, and regulatory frameworks need to streamline permitting while protecting marine environments. The Ocean Energy Europe trade association advocates for a dedicated ocean energy target in the European Union’s Renewable Energy Directive. Similarly, the UK’s Marine Energy Council has called for a ring‑fenced budget for tidal and wave R&D. International collaboration — such as the Ocean Energy Systems (OES) initiative under the International Energy Agency — facilitates information sharing on resource assessment, device testing, and environmental monitoring, which accelerates learning and reduces duplication.

Future Outlook: A Blue Energy Revolution

Looking ahead, the integration of tidal and wave energy into national grids will follow a trajectory similar to offshore wind: from single‑device demonstrations to multi‑device arrays, then to large‑scale farms connected via offshore energy hubs. By 2035, we may see hybrid platforms combining wind turbines, solar panels, wave energy converters, and even hydrogen electrolysers, all linked to shore via one subsea cable. This co‑location approach dramatically improves utilisation of transmission infrastructure and reduces intermittency.

Grid operators will increasingly rely on ocean energy’s predictability to balance the variability of solar and wind. Tidal power, with its persistent daily cycles, can serve as a “renewable baseload” resource when paired with a small amount of storage. Wave energy, which often peaks in winter when solar is low, provides a valuable seasonal complement in temperate latitudes.

Investment forecasts from Bloomberg NEF suggest that cumulative global investment in ocean energy could reach $30–50 billion by 2040, supporting hundreds of thousands of jobs in coastal communities. Manufacturing clusters could emerge in regions with strong marine engineering heritage — Scotland, France’s Brittany, the Pacific Northwest of the US, and Japan. As climate pressures mount, the ocean’s energy resource is too vast and too dependable to remain on the sidelines. With continued innovation, sensible policy, and careful environmental stewardship, tidal and wave energy will become a cornerstone of the 21st‑century renewable energy portfolio.