Roadmaps helping to drive the global marine energy sector forward into the future estimate the technologies could contribute 300GW of renewable capacity by 2050, with a value of over US$340 billion. Indeed, as the Energy Industries Council (EIC) acknowledges, the wave and tidal sectors have the potential to provide a huge amount of renewable energy and could drastically aid in the goal of net zero.
In its recent Wave and Tidal insight Report, the EIC says the UK is at the forefront of testing for both wave and tidal stream projects. Of the 74 schemes the EIC tracks in its global data-base, 28 projects in the pipeline are in the UK – 22 tidal and 6 wave. All of which will contribute towards a target from the Marine Energy Council of achieving 1GW of tidal energy and 300MW of wave power by 2035.
Across Europe there are 13 projects in the pipeline, although the EU is described as lagging behind the UK in both scale and policy clarity. France and Portugal are leading the European assault, but other countries need to catch up.
And waking up to its marine energy potential of an estimated 63MW, Indonesia has eight sizeable projects in the pipeline. However the country’s main challenge isn’t resources but regulations, with overlapping agencies and a lack of feed-in tariffs slowing progress.
Then with 12 projects underway, although it has the resources and the markets have funding available to push for innovation, North America is described as not having the urgency for widespread deployment.
Nabil Ahmed, author of the EIC insight report, says governments need to stop treating marine energy as a science project and realise that the ocean’s power is more than just a drop in the renewable energy bucket.
More established sector
According to the EIC, at the current time, the tidal sector is considered to be more established and closer to commercialisation than the wave sector, with the latter still predominantly in its testing and demonstration phase. While a new study carried out by the European Marine Energy Centre (EMEC) and the Offshore Renewable Energy (ORE) Catapult on behalf of Crown Estate Scotland, Scottish Enterprise, and Highlands and Islands Enterprise, says the UK has the opportunity on world leadership in tidal stream energy. Indeed, with more than11GW of potential tidal stream capacity, over 130MW of tidal stream projects are due to become operational by 2029 in the UK – 82MW of which are planned to be deployed in Scotland.
Estimates suggest that tidal stream can support energy capacity and reduce energy systems costs by £1 billion per year. And through economies of scale and volume, learning by doing and technology innovation, the report believes tidal stream will follow a similar cost reduction pathway to solar and wind with costs forecast to fall to £50 per megawatt hour by 2050.
Identifying a range of opportunities to help coastal communities access cleaner, and potentially cheaper energy, the report says a more creative approach to using power generated locally by tidal energy projects could help businesses and homes around Scotland’s coastline become less reliant on expensive and polluting oil and diesel sources of power. It investigates how communities could connect directly to tidal power projects, allowing green energy generated locally to be supplied to users without relying on a connection to the national grid. Turning tidal-derived electricity into green hydrogen is also explored, identifying major opportunities for decarbonising industries, and manufacturing clean fuels.
Called Alternative Offtake Routes for Tidal Stream Energy, the report highlights that energy resilience for remote areas could be improved by reducing reliance on diesel and oil, which are often transported long distances, and notes the economic potential for local tidal projects to employ more people and generate revenues via community-funded projects.
As Carolyn MacPhee, Development Manager at Crown Estate Scotland, says: “Scotland has an enviable natural resource in the form of tidal power, which provides a consistent and predictable source of renewable energy. However, securing a connection to the national grid is an acknowledged obstacle to making full use of the tidal stream power available. This report sets out the opportunities to make greater use of our country’s natural power. In so doing it highlights the potential to provide clean energy within local communities, create jobs, and help reduce the costs of generating a range of energy types.”
Thirty tidal stream locations around Scotland’s coast were examined, of which 20 were identified as being close enough to potential end users. Various off-take routes were considered viable, including:
- The Islay Project, where green hydrogen company Protium is helping whisky distilleries to be carbon-neutral by 2040.
- Using the Pentland Firth’s tidal energy potential to produce green hydrogen to develop synthetic fuels on the Orkney island of Flotta.
- Replacing diesel generators on Barra and Vatersay with a battery storage system to utilise tidal generated electricity.
The study emphasises that accessing tidal-derived energy in this way is not a substitute for a connection to the national grid, but an additional way to maximise the use of such energy resources.
“Alternative offtake routes for tidal stream generation across Scotland could play an important role in enabling the sector’s development, given existing grid constraints,” Eileen Linklater, Corporate Affairs Director at EMEC, adds. “To realise this potential, key recommendations focus on strategic planning around best use of resources adjacent to industries in need of decarbonisation, reducing risk for community scale projects, and increasing thresholds for consenting requirements to better support projects at different scales. These insights aim to inform future leasing design and identify practical approaches to resolving deliverability constraints.”
Marine energy and seal safety
As a predictable and persistent source of renewable power, unlocking the full potential of tidal stream energy will strengthen energy security and bolster economic growth, which is imperative for Scotland and the UK to deliver their long-term net zero ambitions. So with this in mind, the sector has also called for collaborative action to resolve consenting challenges around the potential for seal collision in the vicinity of projects.
Home to some of the world’s strongest tides, the Pentland Firth and Orkney Waters region is the epicentre of the UK’s tidal energy sector. More technologies have been demonstrated, and more tidal power produced from its seas, than anywhere else in the world. This unique setting offers a testbed for developing marine energy at meaningful scale, shaped by local knowledge and environmental context.
However, commercial-scale project development is facing challenges in progressing responsibly given the complexity, uncertainty and long lead-times encountered with the current regulatory framework. Although extensive monitoring to date has found no evidence of seal-turbine collisions, a high level of precaution is still applied to the perceived risk – particularly in the context of ongoing harbour seal decline in the region. This highlights the need for science-led, proportionate approaches that uphold environmental protection while keeping pace with readiness for scaled deployment.
Funded by Crown Estate Scotland and Highlands and Islands Enterprise, the Tidal Industry Seal Project (TISP) report has been developed with input from leading organisations in tidal energy and environmental assessment. The consortium included Xodus Group Ltd, Carronside Consultancy Ltd, SAE Renewables Ltd, European Marine Energy Centre Ltd, Eurona Consultancy Ltd, Burges Salmon LLP, Orbital Marine Power Ltd, and Nova Innovation Ltd. And their report, Called Managing the Consenting Risk of Harbour Seal Collision in the Scottish Tidal Energy Industry sets out key recommendations to underpin robust consenting to enable the growth of tidal stream energy in Scotland while addressing environmental concerns – particularly the potential impact on harbour seals.
The tidal energy industry has formed a regional developer group and says it is committed to working together with regulators and research institutions to strengthen the evidence base on the seal collision risk with tidal turbines and increase the reliability and accuracy of impact assessments. This could involve the development of effective mitigations, better use of existing evidence, exploring opportunities to enhance the environment and trialling new monitoring technologies.
“We recognise that for the tidal energy to grow, a collaborative effort is required to better understand whether the potential for seals to collide with turbines is an issue,” Donald Leaver, Environment and Consents Manager at EMEC says. “Pioneering projects led by MeyGen, Nova Innovation and Orbital Marine Power have investigated this over several years and, so far, haven’t seen any evidence of seal-turbine collisions.
“With various new projects in the Pentland Firth and Orkney Waters due to be built out over the coming decade, supporting Scottish and UK government policy ambitions for energy security and climate resilience, it is vital this consenting uncertainty is resolved in a collaborative, science-led manner to enable sustainable development alongside the protection of our marine ecosystems.”
TISP sets out a series of recommendations calling for coordinated action across government, industry, regulators and key delivery bodies to strengthen policy, planning, evidence and monitoring frameworks for marine energy.
Realising this coordinated approach will require proportionate, solutions-focused regulation, developed in partnership with key actors including NatureScot, that actively supports the responsible deployment of tidal stream energy in line with national goals. This approach should be underpinned by statistical methods and regional frameworks that better reflect population-scale ecological processes and long-term environmental change.
As Dr Ewan Edwards, Environmental Specialist at Xodus explains, harbour seal populations around Orkney and the north coast of Scotland have been in sharp decline for around 20 years but is generally attributed to factors such as competition for food with other species, predation by killer whales or grey seals, and potentially biotoxins from algal blooms.
“Extensive monitoring of operational tidal projects in Scotland has found no evidence of seal-turbine collisions,” he states. “On the contrary, data suggest that seals actively avoid operating turbines, especially during peak flows. The project team strongly believe that the weight of evidence suggests that collisions between harbour seals, or any other marine mammal, and tidal turbines are thankfully incredibly rare, and the risk of collision is a hypothetical one, rather than a realistic threat.”
Although the report demonstrates the significant progress the marine energy sector has made to unlock its full potential, it realises it must continue to work collaboratively, share its learnings, and maintain the momentum.
“At MeyGen, we’re committed to environmental stewardship but the consenting system must evolve to reflect both the latest evidence and ensure the scale of this vital technology is realised,” Fraser Johnson, O&M Manager at MeyGen, commented. “Tidal stream energy has proven that it can be key in providing predictable, scalable renewable power, creating a thriving sector in the process. We must ensure we put in place a framework that enables responsible growth, builds trust, and delivers long-term value across communities, the environment, and those investing in a more resilient energy future. This work is part of our long-term commitment to the region, and we look forward to continuing the dialogue to support practical solutions.”
Italian assessment
With tidal currents reaching speeds up to 3m/sec in the Messina Strait, recent research on this area has described it ‘as a highly intriguing location for energy generation’. According to researchers from the Department of Engineering at Italy’s University of Palermo, this phenomenon is primarily attributed to the tidal excursion between the Ionian and Tyrrhenian seas, resulting in currents that demonstrate high predictability and relative stability over time.
The Messina Strait is a narrow strip of water that separates the island of Sicily from mainland Italy and is characterised by a semi-diurnal tidal current. An energy assessment undertaken by Michele Agueci and Emiliano Pipitone focuses on open flow tidal turbines, and the total energy produced was calculated by integrating current velocities over a whole year with 15-minutes time intervals.
The coastal profile and the bathymetry of the location selected led to the development of a theoretical tidal energy park consisting of 113 horizontal axis tidal turbines, with a total installed capacity of 271MW and an annual production of nearly 145GWh.
The authors say these results show that tidal turbines present a viable option to increase the share of the region’s renewable energy production. Although currently theoretical, they claim their work lays a solid foundation for further investigation into tidal energy exploitation. Future studies will focus on optimising this generation park and its technology, focusing on a better exploitation of the current energy and turbine technology. In conclusion, they add that tidal energy represents a promising renewable energy source for Italy, with the potential to significantly contribute to the country’s energy and climate goals with targeted investments and further research to help promote its development.
Thailand
The coast of the Andaman Sea in Southern Thailand has recently been assessed for its technical and economic potential for tidal power generation.
Four areas along the coast were studied and the results show that the highest annual energy production could reach 160MWh per year, while the annual energy production from a ten-unit cluster of the most efficient tidal current turbine was 79 MWh/year.
As Klompong et al explain in their research published in Energy Reports, the spatial measurements of the tidal current speeds in four target areas showed that the Krabi and Trang provinces are characterised by relatively strong tidal currents, with the maximum tidal current speeds of approximately 1.15m/sec. For its part, the Phuket-Phang Nga provinces have maximum tidal current speeds of 0.87m/sec, while the Ranong province shows the lowest tidal current speeds, at a peak speed of 0.44 m/sec. These values were consistent with the mathematical simulations showing that the southern part of the Andaman Sea coast, from Phang Nga to Trang, has the highest power densities due to the tidal current speeds being the most important in the area studied.
The Pak Phra Strait in the Phuket-Phangnga Provinces was identified as a potential site for a tidal current power plant. The estimated economic indices showed that the benefit-cost ratio was 1.32, the net present value was US$0.09 million, with the payback period 12 years under the fixed internal rate of return of 7 % and an appropriate FiT of 0.39 USD/kWh.
However, as the authors conclude, under the available present technologies and costs, ‘a tidal power investment in Thailand is not economically viable without financial subsidies or incentives by various levels of government’.
Scottish policy recommendations
Delivering policy recommendations with the capability to progress both the tidal stream and wave energy sectors is a complex and urgent task, researchers from The University of Edinburgh have recently admitted. However as tidal stream projects are being built now, with the first phases to be commissioned in 2026/27 and a growing pipeline beyond, Scotland needs to be ready. So decisions must be made now to address developmental challenges and deployment timelines facing the tidal sector and future wave energy capacity.
Such recommendations include:
1. Long-term market support – Continuation and expansion of a well-funded UK market support mechanism, such as the CfD, is the foundational step to ensuring a market for Scottish tidal stream developers to supply and deploy their devices. It also provides a potential long-term funding source for the wave energy sector.
2. Sustained technology innovation – Targeted and sustained research and innovation support for both tidal stream and wave energy technology developers is essential to ensure Scottish companies continue to innovate, reduce costs, win projects, and deploy their devices in both domestic and international markets.
3. Increase supply chain competitiveness – Modernisation of Scottish supply chain capabilities should be implemented at all levels to support the imminent pipeline of tidal stream and future wave energy projects
4. Develop skills for a Just Transition – Investment into device innovation and supply chain capability should be coupled with an equal investment into domestic workforce capacity and skills. This should not solely target higher education graduates from a STEM background, who are an important consideration of any future skilled workforce. It should also consider apprenticeships and existing workers transitioning from the oil and gas and other relevant sectors, who often have transferable skillsets and exposure to the challenges of working in a marine environment.
5. Cross-sector collaboration – The maturity of the offshore wind sector, in terms of fabrication facilities and supply chain depth, should serve as both an inspiring template and a serious opportunity for collaboration with the tidal stream and wave energy sectors.
6. Prioritise infrastructure upgrades – Significant grid upgrades will be required alongside the continued development of renewable energy in Scotland, to avoid transmission bottlenecks and potential curtailment of renewable output. Port and harbour infrastructure upgrades across the country, currently being planned for offshore wind, should also factor in the additional requirements from the growing pipeline of tidal stream projects and potential for wave energy.
7. Delivering innovation support in Scotland – Tasking and funding existing innovation and support organisations to oversee the well-coordinated and accelerated delivery of recommendations, in particular innovations in tidal stream and wave energy device development, and improvements in Scottish supply chain capabilities. This will help to ensure that Scotland maintains its position as a world leader in the delivery of tidal stream and wave energy projects with high Scottish supply chain content
