Technology

Pliosaur Energy has developed a floating marine renewable-energy platform that combines tidal-stream and wave-energy generation within a single offshore structure. By capturing energy from both resources simultaneously, the technology has the potential to increase the amount of electricity generated from a given site while improving overall project economics.

Rather than developing every component from first principles, the technology applies proven engineering from the offshore oil and gas, civil engineering and wind energy industries wherever practical. Innovation is focused on the areas that provide genuine commercial advantage, reducing technical risk while accelerating the route to deployment.

The platform is designed as a semi-submersible floating structure that supports a single horizontal-axis turbine beneath the water surface. An integrated overtopping system captures wave energy within an elevated reservoir, allowing the same turbine to convert both tidal-stream kinetic energy and stored wave energy into electricity. The overtopping screen also provides an opportunity to intercept floating plastic waste and other marine debris before it enters the reservoir, enabling the platform to contribute to cleaner oceans while generating renewable electricity.

The floating architecture offers significant operational advantages over conventional seabed-mounted systems. Installation can be simplified, routine maintenance is more accessible, and major components can be serviced offshore without recovering the complete structure from the seabed. The modular platform concept also allows generating capacity to be increased by adding additional sections as projects expand.

Reinforced concrete construction further improves durability by eliminating many of the corrosion and coating-maintenance requirements associated with conventional steel structures. Combined with an electrical architecture designed to minimise dynamic cable fatigue, the overall system aims to reduce lifetime operating costs while improving long-term reliability.

The prototype has a nominal generating capacity of 1 MW, but the underlying platform architecture has been developed with scalability in mind. Construction techniques routinely employed for large offshore structures provide a practical pathway towards significantly larger generating platforms suitable for commercial deployment.

The following Technology pages describe each major engineering system in more detail, including the turbine, wave-energy system, electrical architecture, mooring system, environmental considerations and the platform's modular design philosophy. Together, these technologies have been developed to deliver commercially viable marine renewable energy while contributing to healthier marine environments.

Building on measured research data

Pliosaur's technology development builds on the EU-funded HYLOW research programme, coordinated by the University of Southampton.

HYLOW developed and tested a large-scale floating Free Stream Energy Converter under controlled and natural river conditions in Germany. The programme generated measured data covering power output, conversion efficiency, hydrodynamic behaviour, stability and operating performance.

It also produced environmental-impact data covering fish behaviour and passage, flow velocities, underwater acoustics and changes to riverbed morphology.

Pliosaur is extracting and analysing relevant performance and environmental data from the HYLOW programme to inform the design, modelling and future validation of its floating marine renewable-energy platform.

This evidence provides an important research foundation for Pliosaur's development programme. The current Pliosaur architecture—including its horizontal-axis turbine, wave-energy system, wave impact mitigation device and offshore operating environment—will nevertheless require its own detailed testing and full-scale validation.

Lynmouth turbine general assembly

The general-assembly schematic illustrates how the principal structural, generation and marine systems are integrated within the floating platform.

Engineering schematic of the Lynmouth turbine general assembly.

Turbine cross-section

Cross-sectional view of the turbine.

Ten-turbine array

Isometric view of a ten-turbine array.

Plan view of the turbine array.