
As published in Materials World, October 2024
To view the online article, click HERE.
If you stand on the shores of Orkney in Scotland’s far north, or indeed any coast around the world, it is hard not to be impressed by the power of our oceans.
Various studies have highlighted the huge untapped energy potential of our seas. The Intergovernmental Panel on Climate Change puts potential annual global wave energy production at 29,500TWh. This is almost 10 times Europe’s annual electricity consumption of 3,000TWh.
The size of the prize for commercialising ocean energy (which also includes tidal energy) is huge. In Europe alone, the ocean energy industry plans to deploy 100GW of production capacity by 2050, meeting 10% of the continent’s electricity demand. That’s enough to meet the daily electricity needs of 94 million households.
Wave energy in particular offers an exciting future, not only to generate clean power, but to create jobs and economic opportunities in remote coastal communities where prospects are often scarce. Yet, so far, very few companies have succeeded in harnessing this vast natural resource.
But now a new wave of data-driven technology firms are making strides in successfully deploying wave energy technology aimed at a variety of market sectors.
A new wave
Orkney is a great place to begin. For more than a decade, these Scottish islands have been home to the European Marine Energy Centre (EMEC), where pre-consented, grid-connected, wave and tidal berths have offered ocean energy pioneers the opportunity to try out new technologies in some of the most powerful waves and tides in the northern hemisphere.
After some false starts (and high-profile failures) around a decade ago, companies have emerged applying past lessons to computational modelling and a strong R&D focus to design and deploy a new generation of wave energy machines.
Mocean Energy was one of a number of firms that received significant support through the Scottish Government’s Wave Energy Scotland programme.
Using numerical modelling and optimisation, rapid prototyping and tank testing, we have wave energy machines that produce high levels of power in some of the world’s harshest environments. Furthermore, using onboard solar panels and battery-storage capabilities gives the technology a hybrid approach.
Blue X is a 20m-long, 38t, 10kW, prototype wave machine, which was deployed successfully at EMEC’s Scapa Flow test site in summer 2021. Following positive tests, Blue X then became a core element within the pan-industry Renewables for Subsea Power (RSP) programme, which combines wave power with subsea energy storage to power subsea equipment for oil and gas projects.
RSP is an ocean energy project that combines wave power and solar with subsea energy storage to power subsea equipment completed a 13-month offshore test programme earlier this year. The £2million Renewables for Subsea Power (RSP) project connects the Blue X wave-energy converter – built by UK firm Mocean Energy in Edinburgh – with a Halo underwater battery storage system developed by Aberdeen-based Verlume.

Located 5km east off Orkney mainland, the project has shown how wave energy can be combined with other renewable technologies to provide reliable and continuous low-carbon power and communications to subsea equipment. This offers a cost-effective future alternative to umbilical cables, which are carbon intensive with long lead times to procure and install.
The pan-industry initiative has been led by Mocean Energy and Verlume, alongside participants, including energy majors TotalEnergies and Shell Technology – Marine Renewable Programme, the Thai national oil company PTTEP, Serica Energy, Harbour Energy, Baker Hughes, Transmark Subsea and the Scottish Net Zero Technology Centre.
The at-sea phase of the RSP initiative commenced in spring 2023 and operated successfully for more than a year, demonstrating the potential of wave energy to decarbonise existing oil and gas programmes. The next step will be to seek new destinations for Blue X and Blue Star – a 20kW machine that builds on Blue X’s learnings.
In parallel, in the autumn of 2023, Swedish wave energy developer CorPower Ocean successfully installed its first commercial wave-energy converter (WEC) off the shores of northern Portugal.
The CorPower C4 system was launched at the port of Viana do Castello, then towed to the Aguçadoura site 4km offshore.
It was then connected to a pre-installed anchor on the seabed and linked to Portugal’s national grid through a subsea export cable.
Both projects demonstrate that wave energy devices can be deployed successfully, and our ambition now is to build bigger arrays and larger machines that can make a significant contribution to net-zero goals.
At Mocean Energy, we are also developing Blue Horizon – a grid-scale machine that can deliver power to the grid and to remote and island communities. The technology was recently selected as finalist in the EuropeWave project, securing close to €4mln to develop and deploy the product offshore in Scotland.
We ultimately envision Blue Horizon machines being deployed in large farms, potentially alongside other renewables such as offshore wind, or floating solar, maximising the utility of offshore projects, and providing diverse and balanced renewable power.
Riding the waves
However, as any technology developer will attest, it takes time, money and several iterations before a new, large-scale, energy technology can become competitive against other energy forms.
Early wind projects were costly, and the first solar panels, developed for use in space, delivered tiny amounts of power at an astronomical cost. But look where we are now – solar photovoltaics are the cheapest form of energy, bar none.
So, the challenge for wave energy is to demonstrate to policymakers and investors that we can – with the correct support – deploy multiple devices to bring down cost over time and deliver reliable ocean energy, with potentially transformational impacts on our broader energy systems.
I believe wave energy has some unique aspects that will make it extremely valuable in the years ahead.
In oil and gas, the business case is clear. We have already demonstrated through our RSP programme that wave energy, combined with solar-power capability and battery technologies, can offer a reliable and cost-effective alternative to costly umbilical cables. And we will see an increasing number of deployments of this type.
A greater whole
Grid-scale power is more of a challenge. As highlighted above, early grid-scale machines will require significant first-of-a-kind investment and support (such as EuropeWave), alongside some form of revenue mechanism, such as a feed-in tariff (FIT) or a contract for difference (CfD), to enable the sector to deploy numerous machines and bring down costs.
This is the model that has allowed solar power and onshore and offshore wind to deploy at scale and deliver affordable green power – and wave power will be no different.
However, where wave power is different is that it delivers system-wide benefits when generating as part of an increasingly intermittent grid. The value in any type of renewable energy is not just its cost, but in when that power is delivered – power needs to be available when people need to use it. Ocean energy provides power at times when other renewables are not available, and this can be extremely valuable.
Recent studies in Applied Energy have shown that even small amounts of wave and tidal energy in a grid can have disproportionate positive impacts on reducing gas turbine usage and costs to the consumer.
For example, by 2030 in the UK, an energy system that includes 0.6% of capacity coming from marine energy would reduce CO₂ emissions by 3%. This is compared to a system with the same total renewable capacity, but without marine energy.
The €1million EU-funded EVOLVE initiative – completed in 2023 – aimed to build a firm evidence base to support the introduction of ocean energy in Europe. The initiative’s country-scale modelling covered three regions – Great Britain, Ireland and Portugal – all located on the west coast of Europe with some of the highest ocean energy resources.
For each region, the study found that increasing the proportion of ocean energy within the renewable mix results in higher renewable dispatch for the same availability, due to the offsetting of wave and tidal with wind and solar generation.
The ability to dispatch more renewables results in lower fossil fuel and peaking plant dispatch (such as gas). So, scenarios including higher proportions of ocean energy result in lower dispatch costs and lower carbon emissions. The study calculates annual cost reductions of up to £1.46billion from 10GW of wave in Great Britain in 2040, with annual carbon reductions of up to 1.06MtCO2.

Island benefits
When it comes to islands, the benefits can be even stronger. The EVOLVE project found that the integration of wave and tidal stream energy can lead to significant benefits for 100% renewable islanded systems, compared with only making use of more established technologies such as solar and wind.
Looking at the Orkney Islands, it found that scenarios including wave and tidal stream required up to 30% less installed capacity and 50% less storage to meet demand, compared with scenarios only including wind and solar.
Overall, this would lower system costs by up to 20%, despite wave and tidal having the highest cost of all renewable sources, due to the additional value of their complementary generation profiles.
And on islands dependent wholly on diesel generation, or in offshore industries – such as fish farms or oil and gas platforms – the cost and environmental benefits could be stronger still.
Many also consider that there are strong synergies between the fast-expanding offshore wind sector and wave energy.
Combining wave farms with offshore windfarms, either by deploying wave-energy converters in the 1-2km gaps between wind turbines or in adjacent farms, presents several advantages.
It reuses expensive infrastructure like the cable, maximises the energy produced from a given space of sea, creates potential efficiencies in processes like consenting and operations and maintenance, and provides the project owner with two forms of renewable energy at different times.
A recent study by Wave Energy Scotland shows that combined wind-wave farms could reduce the cost of energy of the wave and wind farms.
Although combined wind-wave is a popular concept within the wave energy industry and offers a lot of potential, it is still in its early stages. More work and engagement with the offshore wind energy industry and demonstration of hybrid projects are needed.
It’s also worth comparing wave energy to floating wind. Within floating wind, existing technology is being deployed with an existing supply chain on very large and innovative structures. Floating offshore windfarms will consist of dozens of structures the size of oil platforms. This brings real challenges around the port infrastructure to build the floating wind turbines and the vessel availability to install and maintain these technologies.
In contrast, wave energy technologies are new and innovative with a not-yet-established supply chain, but they have inherent advantages. For one, the structure is the energy producer itself.
Also, they will be smaller – around 1MW rather than 10MW – and higher, and weighing hundreds-of-tonnes rather than thousands. This means that they could be built in smaller ports and installed with smaller, much more available vessels.
Plus, there are many other combined offshore project concepts – wave and wind could be combined with offshore solar, hydrogen production, aquaculture, electric vessel charging and more.
Water, water everywhere …
Ultimately, nothing replaces ‘learning by doing’. If Britain wishes to become a world leader in ocean energy, more innovation funding and a more uniform approach is needed.
Designing and developing any type of device that will be subjected to the harsh environment of the sea for long periods of time has never been an easy feat.
Numerous factors must be taken into account and addressed appropriately, otherwise risk of failure is anything but abstract.
There will be different types of wave-energy converters that have their own unique advantages, dependent upon their location.
We have already shown we can make technologies that work, so we can definitely get there. But governments and investors will need to step up too.
