Corpower Ocean AB (Sweden)

Partners(s): Corpower Ocean Portugal Lda, Portugal

Industrial-scale wave energy converter enabled by an innovative mobile filament winding factory for composite hull manufacturing at scale.

Material, manufacturing processes and design for WECs are essential to unlock cost-reduction mechanisms and achieve a competitive cost of energy. The WEC mass influences CapEx due to material and manufacturing costs, OpEx due to the complexity of offshore operations, and impacts the WEC behaviour in the sea and its energy harvesting capacity, thus its annual energy production (AEP). Early in the design phase, CorPower performed a cost analysis comparing steel, aluminum and composite hull options for the full-scale CorPower WEC hull, looking at AEP and cost-effective manufacture.

After evaluating several subscale models, glass-fibre proved to be the lightest material with filament winding being the most cost-effective manufacturing process. The WEC hull has been designed with a low-cost sandwich structure made of filament-wound composite skins for the inner and outer layer separated by a core material. The inner skin combiness glass fiber rovings and specially developed 141-millimeter-wide bands of fabric – a layer of Diab (Helsingborg, Sweden) Divinycell H structural PVC foam core designed for strength and to adapt to the curvature of the hull – and an outer skin also comprising filament-wound rovings and fabric. The hull is wound around the 10-meter-long mandrel of the filament winding machine, with an automated carrying system to apply fibres onto the mandrel and wind the hull layer-by-layer.

The machine can be packed and transported in 3 standard containers, taking only a few days to assemble once delivered to a new site and easily integrated in port. This “mobile factory” concept enables composite hulls to be built rapidly on customer sites, with additive manufacturing dramatically reducing lead times, cost, and CO2 footprint by eliminating transportation of the finished product. When delivering wave farms to customers, we will be moving these factory cells from site the site to produce the hulls needed for a given customer project.

Key benefits

• 20-30% increase in annual energy production (AEP) yield vs. steel
• 70% reduction in end-to-end hull production costs vs. steel
• 15-20% improvement in levelized cost of energy (LCOE) vs. steel
• Increased reliability, robustness and durability in harsh oceans
• Highly scalable onsite WEC hull production via mobile winding factory concept