High performance pultrusion for advanced composites (HIPPAC)

Using pultrusion to manufacture wind turbine (WT) components -- such as spar caps -- will make operations significantly more efficient and will enable the development of much larger WT blades. Wind energy continues to grow in importance, generating 3.5% (960TWh) of the total electricity produced worldwide in 2018 - up from 0.8% in 2008. The UK -- with 57TWh (17%) of total electricity generated -- is leading figure in the industry. In 2018 the UK started running the world's largest offshore wind farm -- the £1 billion Walney wind farm off the coast of Cumbria, which generates enough energy to power 600,000 homes.

This fantastic progress is made possible because wind energy is getting ever cheaper due to advances in the WT supply chain and life cycles. The main factor is that WT blades are getting larger and taller. GE Renewable Energy announced a turbine blade over a 100m long. They were only 50m long five years ago. Larger blades harvest more wind power and taller structures are subject to stronger and more constant winds. This improves their power harvesting capacity and availability of energy; this dramatically reduces the wind energy cost (UK offshore: £150/kWh in 2015 down to £57.5kWh today). However, larger blades present their own technical challenges: chiefly the stresses that blades and the supporting structures experience.

Advanced composites technologies are becoming critical in wind turbine blades production. Pultrusion is a continuous manufacturing process for polymer composites where the part/profile formed is pulled through a heated die. Pultrusion improves the efficiency of manufacturing blade components, lowers costs and improves composite quality. Weight savings and stronger parts have a positive knock-on effect as it allows other components such as gear boxes, the nacelle and tower to be downsized. The spar cap is a key structural element inside a WT blade. They run along both sides of the blade to provide crucial reinforcement and take-up most of the mechanical load.

The industry is turning to pultrusion based manufacturing, however pultrusion currently only represents 5% of the composite parts produced. HIPPAC aims to improve the spar cap pultrusion process by developing a digital tool to allow for the rapid design of the pultrusion line prior implementation, in-line quality control and improved process control in a tailored and original way. This will enable the production of more cost-effective stronger and lighter parts.