Combining wind turbines with wave, solar and tidal devices on shared platforms reduces construction costs, improves stability and generates more reliable power, according to researchers from the University of Surrey.

The comprehensive review, published in Energy Conversion and Management, examined hybrid offshore renewable energy harvest systems that integrate multiple technologies on a single foundation. These systems could help countries meet ambitious climate targets whilst minimising impact on marine ecosystems.

Dr Liang Cui, primary supervisor and co-author of the study from the School of Engineering at the University of Surrey, said:

"Offshore wind farms currently occupy thousands of square kilometres of ocean, but the turbines themselves use less than 1 per cent of that area.

"By adding wave energy converters, tidal turbines or solar panels to existing wind turbine platforms, we can generate far more power from the same ocean footprint."

The research team analysed data from demonstration projects, including Norway's W2Power wind-wave system and the NoviOcean platform that combines wind, wave and solar energy. Studies showed that hybrid systems could reduce the cost of electricity by 10 to 15 per cent compared with standalone offshore wind farms. Power generation increased by up to 70 per cent when tidal turbines were added to wind installations.

The research team also found that adding wave energy devices to floating wind turbines improved rather than compromised structural stability. The additional equipment reduced unwanted platform motion by 15 per cent and lowered stress on tower foundations.

Yukun Ma, PhD student and co-author of the study from the University of Surrey, said:

"These cost reductions could translate directly to lower consumer energy bills as offshore wind expands.

"The European Union aims for renewable energy to account for at least 42.5 per cent of final energy consumption by 2030. Hybrid offshore systems that generate steady power around the clock could be crucial for meeting these targets."

The review identified wind-wave integration as the most mature hybrid technology, with several systems reaching demonstration stage. Wind-solar and wind-tidal combinations show significant promise but remain at earlier development stages.

Systems combining three or more energy sources are emerging, with NoviOcean's platform achieving a capacity factor of around 40 per cent.

However, critical gaps prevent immediate large-scale deployment. Most research has focused on ideal conditions, leaving major questions about how these systems survive hurricanes, earthquakes or tsunamis. Long-term foundation performance after decades of cyclic loading remains poorly understood.

Professor Suby Bhattacharya, co-supervisor and co-author of the study from the University of Surrey, said:

"More efficient use of ocean space means less disruption to marine organisms that inhabit or migrate through these areas. But we need demonstration projects with long-term monitoring to prove these systems can withstand extreme weather and deliver reliable power over 20 to 30-year lifespans."