The Role of Marine Energy in the UK’s Net-Zero Transition
The United Kingdom is already a global leader in offshore wind power generation, as demonstrated by an installed and consented capacity of over 40 GW. Offshore wind energy is therefore becoming the backbone of the UK’s efforts to provide clean electricity to its homes, industry and other sectors. However, beyond the large numbers of turbines turning in the North Sea, there is one large area of opportunity in terms of renewables that has remained untapped: marine energy.
What Is Marine Energy?
Marine energy refers to electricity generated from the natural movement of the ocean. In the UK, this mainly includes tidal stream energy and wave energy.
Tidal energy captures power from fast-moving tidal currents using underwater turbines, operating in a similar way to wind turbines but driven by seawater. Because tides are governed by lunar cycles, output is highly predictable years in advance, a major advantage for system planning.
Wave energy is produced by the motion of the surface waves (up and down) by floating or submerged devices that convert this motion into electrical energy. Since the output from wave energy varies with weather, there is typically less of an overlap in the output peak time of wave energy with its peak time of wind energy, thus providing additional balancing support for the wind energy.
When combined, wave and wind technology are able to produce firm, renewable power, which can provide added stability across the broader mix of energy generation.
Why the UK Is Exceptionally Well Placed?
Few countries have the marine resources the UK does. With over 19,000 km of coastline and some of Europe’s strongest tidal currents, the UK is ideally positioned for marine energy deployment.
Regions include:
The Pentland Firth and Orkney Waters contain some of the world's fastest and strongest tidal streams worldwide (i.e., tidal flow).
The Severn Estuary – massive tidal range potential
Cornwall and the South West – strong Atlantic wave resource
Welsh coastal waters – suitable for tidal stream arrays
Industry and government studies consistently show that the UK’s theoretical tidal resource alone could meet a substantial share of national electricity demand. Wave energy potential along the Atlantic-facing coastline is also significant, particularly during winter months when electricity demand is highest.
Despite this, marine energy deployment has lagged behind offshore wind, not due to lack of resources, but because of technology maturity and financing challenges.
Progress in the UK Marine Energy Sector
In the last several years, the marine energy sector has progressed beyond just showing off what can be done:
The development of tidal array projects (as seen in the multi-megawatt tidal array demonstrations that took place in Scotland & Wales) has shown us that tidal Turbine-Driven Arrays (TDAs) have proven to work reliably over many years, even when subjected to the difficult marine conditions found in both the Hebrides and Yorkshire.
The European Marine Energy Centre (EMEC), located in Orkney, Scotland, is still mainly seen as a global leader and as a location to test new products and technologies before they can be commercially available.
Through funding provided by the UKRI, Ofgem and the devolved administrations, the marine energy sector has seen many of its projects transition from being pilot projects to being early-scale commercial projects.
The amount of installed marine capacity is small but is in the tens of megawatts per state, and the uptake of marine energy technology in the UK should begin to see the costs reduce over time as its supply chain develops further and its deployment and operational knowledge continue to grow.
Why Marine Energy Matters Now
1) Clean Power With Predictability
Tidal generation has very high accuracy when it comes to forecasting power generation. This predictability will reduce costs for balancing generation and help system operators while decreasing reliance on gas-fired flexible generation.
2) Stability of the Grid in a System Dominated by Renewables
As the UK begins working towards an electricity grid that is primarily powered by renewable energy, the need for diversification will be more pronounced. Marine-based energy generation will complement both wind and solar power generation in such a way as to increase the resiliency of the overall system.
3) Creating Economic Value in Coastal Communities
Marine energy creates high-skill jobs, primarily in marine engineering, fabrication, operation, and maintenance of equipment, particularly in coastal areas where maritime technical skills are prevalent.
4) Collaboration With Offshore Wind
Tidal and wind projects can use the same infrastructure that has been developed for offshore wind. The equipment, vessels, ports, and underwater cabling development of offshore wind power can be used for tidal and wave energy deployment, which will lower the overall deployment cost and deployment time.
Challenges to Overcome
Even with this promise, there are numerous challenges to overcome in the marine energy sector:
High capital costs compared to mature renewables
Complex consenting processes in marine environments
Limited revenue certainty for early-stage projects
Competition for investment with lower-risk technologies
These barriers are typical for emerging energy technologies, and many mirror the challenges offshore wind faced a decade ago.
Looking Ahead
By the mid-2030s, marine energy could deliver:
Hundreds of megawatts of predictable tidal power.
Commercial wave energy farms along the Atlantic coast
Exportable UK expertise in marine engineering and technology.
Greater energy resilience for island and remote communities.

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