Launchpad Leaders: Porpoise Power – The Future of Tidal Energy

Tidal energy is one of the most dependable low-carbon energy sources, offering a constant and predictable supply of power driven by the gravitational pull of the sun and the moon. 

Porpoise Power was co-founded by Adrian Thomas, Professor of Biomechanics at the University of Oxford, alongside John Kennedy, Hillary Struthers and Martin Hall. Bringing together expertise in biology, renewable energy and mechanical engineering, the team is exploring new possibilities for tidal energy. 

Backed by funding from Innovate UK, they have developed innovative fin technology inspired by one of nature’s most powerful swimmers. 

In conversation with Adrian Thomas, JOMEC students uncovered how the technology works, why Wales is leading on the future of tidal energy, and what’s next for Porpoise Power…

What is tidal energy, and why is it such a promising renewable resource? 

If you stand on the seashore, the tide rises and falls. For that to happen, vast amounts of water have to flow in and out, creating strong tidal streams. That moving water contains enormous amounts of energy. 

What makes tidal energy so promising is its predictability. Unlike wind or solar, tides follow gravitational cycles, so we know exactly when and how much energy will be available. 

How does Porpoise Power capture energy from these tidal streams? 

We place a device directly into the tidal stream, where it extracts the kinetic energy — the energy of movement — from the flowing water and converts it into electricity. 

Rather than using a rotating turbine, our device moves in a flapping motion like an aquatic fin. That allows it to work efficiently across a wider range of tidal conditions, particularly in shallower coastal waters.

Your technology is inspired by a whale’s tail. Why take that approach? 

A whale’s tail can be around 10 metres wide and flaps once every 3 to 4 seconds, producing roughly 100 kilowatts of power as it swims. Our full-scale device is about 12 metres wide and flaps slightly slower, around every 4 to 5 seconds. Slower movement actually means greater power extraction. 

Flapping is also a very natural behaviour in fluid flows. If you look at seaweed in a river or ocean current, it flaps naturally without any mechanical input. We design our device to work in harmony with that natural motion, rather than forcing the water to behave in a certain way. 

How does this differ from traditional tidal turbines? 

Most existing tidal systems use underwater turbines, similar to wind turbines adapted for water. Because water is around 800 times denser than air, these turbines need to be short and very robust and usually require deep water and fast flows. 

Our device — the flapping fin — works well in shallow water and slower flows. It naturally slows down near the seabed, and the surface, and moves fastest in the middle of the water column. The blades are also much simpler and cheaper to manufacture, which opens up more potential tidal sites. 

What does this mean in terms of cost and environmental impact? 

Cost is critical. Even at prototype stage, our electricity costs around £100 per megawatt, roughly a third of the cost of gas. Our goal is to make tidal energy cheaper than fossil fuels. 

Environmentally, we limit the maximum speed of the device to eight metres per second —which is the speed fish are known to escape from. We don’t harm marine life, in fact, fish often swim alongside the device as if it’s part of their school. It’s a very benign system, and that is incredibly important to us. 

Why is Wales such a strong location for tidal energy development? 

Wales is miles ahead of the game when it comes to tidal energy. It has one of the best tidal resources in the world, particularly along the west coast. 

Pembroke Dock, where we carried out testing, is home to established marine energy organisations and a tidal test centre. The conditions are well understood, which makes testing far more efficient. We also received fantastic local support throughout the process. 

How has funding from InnovateUK supported Porpoise Power’s early growth? 

The initial £50,000 grant allowed us to test our device in Pembroke Dock for three weeks, accelerating our development by around six months. It gave us access to facilities we wouldn’t otherwise have had. 

That success helped us to secure a follow-up grant of £680,000 and supported us in raising £4.3million for the next phase of testing. 

What is the next milestone for Porpoise Power? 

We have just successfully closed a £4.3million funding round and are currently testing our 1/4 scale (3m) device locally in order to build a larger device during Q2 of this year. The larger device will use data gathered to validate our digital twin models of the flapping tidal energy system. These will be deployed in Morlais as soon as our licenses and contracts with them allow.

Finally, what excites you most about the future of tidal energy? 

It’s a reliable, home-grown source of clean energy. It’s predictable, environmentally benign, and has the potential to improve people’s lives. 

Throughout history, when new energy sources emerge, standards of living tend to rise. Tidal energy has the potential to do that again, and it could be a real game changer for the UK.