Caudal Energy (formerly Porpoise Power) raises £4.3M seed for bio-inspired tidal generators
What's the deal? Caudal Energy, an Oxford University spinout formerly known as Porpoise PowerDealroom has a profile for this one. Try Dealroom →, has raised £4.3M in a seed round co-led by Oxford Science EnterprisesDealroom has a profile for this one. Try Dealroom → (OSE) and Empirical VenturesDealroom has a profile for this one. Try Dealroom →. Zero Carbon CapitalDealroom has a profile for this one. Try Dealroom →, Creator FundDealroom has a profile for this one. Try Dealroom →, Kibo InvestDealroom has a profile for this one. Try Dealroom →, and Oxford Innovation FinanceDealroom has a profile for this one. Try Dealroom → also participated. Total funding now stands at £5.5M.
The company has built a modular, surface-mounted fin-based tidal generator inspired by the caudal fins of marine mammals. The money will fund full-scale testing at Strangford Lough in Northern Ireland, with first commercial deployment targeted for 2028.
Caudal was co-founded in 2024 by CEO John Kennedy (former MD at Wayfair), chief commercial officer Hilary Struthers (ex-Shell), Professor Adrian Thomas, whose Oxford hydrodynamics research underpins the technology, and marine systems engineer Martin Hall.
Why now? Tidal energy is the only renewable source that is completely predictable — it runs on lunar cycles, not weather. Yet it remains a rounding error in the global energy mix because conventional turbines need peak flows above 5 knots, limiting deployment to a handful of extreme sites worldwide.
Caudal's system operates at sites where peak flows exceed just 3 knots, dramatically expanding the addressable market. The global tidal energy market stands at $1.4B in 2025 and is forecast to reach $3.66B by 2030, growing at a 21.1% CAGR, according to The Business Research Company.
"We founded Caudal to challenge the assumption that tidal energy has to remain complex, costly and niche," Kennedy said. "By unlocking the potential of mid-flow tidal sites, we believe Caudal can dramatically expand where tidal energy can be deployed."
What could go wrong? The technology currently sits at Technology Readiness Level 5 — meaning it has been validated in a relevant environment but not yet proven at commercial scale. The jump from lab to ocean is notoriously difficult for marine energy hardware, and the 2028 deployment target leaves little margin for delays.
Tidal energy startups have a long history of promising breakthroughs that never reach grid scale. Caudal's simpler architecture and lower flow-speed threshold are advantages on paper, but full-scale marine testing will be the real proof point.
The signal: Caudal's investor syndicate pairs a climate-specialist seed fund (Zero Carbon Capital, which led the pre-seed and returned for this round) with Oxford Science Enterprises, one of the UK's largest university-linked investment funds. That combination — deep-tech patient capital plus climate-native conviction capital — reflects a maturing funding stack for hardware-heavy energy startups that would have struggled to attract institutional backing even five years ago. If Strangford Lough testing validates the lower flow-speed threshold, Caudal could reframe tidal energy from a niche curiosity into a scalable, predictable baseload source.
Read more: Tech Funding News
