Caudal Energy raises £4.3m led by Oxford Science Enterprises and Empirical Ventures
This article covers Caudal Energy, an Oxford University spinout and energy startup, which has raised £4.3m in a growth funding round to advance a fin-based tidal generator and fund full-scale testing at Strangford Lough in Northern Ireland, with commercial deployment targeted by 2028. The funding supports demonstration of a modular, surface-mounted device intended to open mid-flow sites to tidal power and support wider deployment of tidal technology in the UK and beyond.
Caudal Energy, an Oxford University spinout and energy startup, has raised £4.3m in a growth funding round to advance a fin-based tidal generator and fund full-scale testing at Strangford Lough in Northern Ireland, with commercial deployment targeted by 2028. The cash injection aims to demonstrate a modular, surface-mounted approach intended to open mid-flow sites to tidal power.
Why it matters
Tidal energy is prized for its predictability but has lagged behind other renewables because of high costs and technical complexity. The global tidal market was valued at about $1.4 billion in 2025 and is forecast to expand, increasing interest in designs that reduce capital and deployment barriers. If Caudal’s approach can reliably operate in mid-flow locations, it could materially increase the number of sites suitable for tidal projects and lower the levelised cost of energy for tidal projects.
Inside the product
Caudal’s device uses an oscillating fin inspired by the caudal fins of marine mammals. The system is modular and surface-mounted, designed to operate where peak flows exceed about 3 knots, compared with many conventional tidal systems that require peak flows above 5 knots. That lower-flow threshold is central to the company’s case for wider, lower-cost deployment.
The company began life as Porpoise Power. Co-founders Hilary Struthers and Professor Adrian Thomas combine commercial energy experience with academic research. The funding will pay for a full-scale test campaign at Strangford Lough, with the company aiming to move to commercial deployments by 2028 if tests validate performance and survivability.
Who are the investors?
The £4.3m round is led by Oxford Science Enterprises and Empirical Ventures, with participation from Zero Carbon Capital and Oxford Innovation Finance.
Oxford Science Enterprises is known for backing university spinouts and deep-tech companies, while Empirical Ventures focuses on early-stage hardware and energy innovation. Zero Carbon Capital and Oxford Innovation Finance are investors that back low-carbon and innovation-led ventures. The funding is earmarked for full-scale testing and to progress engineering validation that underpins commercial plans.
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Founder perspective
The leadership frames the project as a response to a narrow set of commercially viable tidal sites today. By aiming for a simpler, surface-mounted design and operation in mid-flow conditions, Caudal’s founders argue the technology could reduce installation complexity and increase the addressable market for tidal deployment. John Kennedy is listed as CEO, overseeing the next phase of trial and demonstration activity.
The bigger picture
Caudal enters a market where a handful of early entrants — including Orbital Marine Power and Minesto — have shown technical promise but faced difficulties in translating prototypes into profitable commercial rollouts. Demonstrating reliable, lower-cost tidal generation would strengthen the case for tidal power as a complementary, predictable resource in UK and European grids.
Testing in Northern Ireland also highlights regional testing facilities and supply chain opportunities across the UK. Success for Caudal would provide a tangible example of university spinouts moving from lab concept to sea trials, a pathway investors and policymakers have been keen to see more of as the UK pursues diversified routes to net zero.
They've invested in Caudal Energy
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