CorPower Ocean and OPS Solutions have created a novel pre-tension cylinder (PTC) prototype, forming the basis of a breakthrough design for a critical wave energy component.
The Scandinavian firms recently joined forces through the COMPACT (COMposite Pressure cAsing for CosT- and energy-effective wave power generation) Project.
By combining sector leading wave energy technology with low-cost composite design and fabrication processes from the offshore industry, the firms now believe the development has potential to significantly reduce cost and mass of wave energy technology.
The project involved developing, testing, manufacturing and certifying an innovative light-weight pressure casing (cylinder), which is a key component of CorPower Ocean’s WEC system. By making the WEC significantly lighter and using cost-effective materials and production technology, the COMPACT solution aims to increase energy efficiency while decreasing cost of energy.
CorPower Ocean Senior Technical Project Manager and COMPACT Project Lead Ross Harnden said the cylinder pressure reached almost 700 bar during the first attempt at ‘burst testing’ – which is 2.3 times the maximum operating pressure.
“This validates the COMPACT cylinder design philosophy,” said Mr Harnden. “With small modifications to the composite layup it is expected that it will be possible to reach the 900 bar required to obtain PED certification of the design, which is required for type certification. The results from the COMPACT project will now be fed into future design iterations of the CorPower Ocean WEC and contribute to bringing viable wave energy to market.”
A major challenge identified during the course of the project was the need for a suitable cylinder liner material. Extensive material testing conducted in COMPACT with various combinations of polymers showed an insufficient range of solutions for a cost-effective liner material meeting the pressure and temperature requirements of the PTC cylinder. This will be a focus for further research within the company, in collaboration with external research institutes.
OPS Composite Solutions General Manager Reidar Anderssen said: “We’re thrilled with the outcome of the COMPACT Project delivered in partnership with CorPower Ocean. By combining our areas of expertise we have been able to drive real industry advances taking wave energy ever closer to commercialisation.”
Financial backing came from Iceland, Liechtenstein and Norway under the EEA Grants ‘Blue Growth Programme’ – which is committed to stimulating ‘blue economy’ innovation, creating jobs and driving growth for SMEs.
The COMPACT Project has actively contributed to the Portuguese Industrial Strategy for Ocean Renewable Energies. Ocean renewable energy has the potential to supply 25pc of Portugal’s annual power consumption, while the sector could generate €254 million in investment, €280 million in gross value added, €119 million in trade and 1,500 new jobs, according to the strategy.
Critical developments from the COMPACT Project include:
- Development of efficient and innovative bottle-neck design of pre-tension cylinder (PTC) barrel which will be used in CorPower Ocean’s next-generation C5 device.
- Developing winding techniques and understanding for manufacturing the new bottle shape design of the PTC barrel.
- Developing and understanding the possibilities and drawbacks for the flange connection of large bolts embedded within a pressurized wound structure.
- Developing the solution for minimizing bolt yielding/fatigue due to bending moments from expansion of the vessel
- Getting hands on experience with fabric backed HDPE as a liner material (previously we have used other fabric backed materials).
