Environmental assessment of a novel generator design in a 15 MW wind turbine

Report, 2024

The demand for renewable electricity generation is increasing worldwide as fossil energy sources are phased out due to climate change mitigation targets. Wind power plays a key role in this transition. However, wind turbines still impact the natural environment through emissions from various stages in turbine production, including extraction of metal resources from the ground. Hagnesia AB has developed a permanent magnet-based electrical generator design with high electrical and material efficiency, and potential to lower the environmental impacts compared to today’s conventional wind turbine generators, not only for the generator as such, but also for the complete turbine.

This study uses life cycle assessment to investigate how the generator design influence climate change and resource use impacts of a 15 MW wind turbine. The reference designs of IEA Wind task 37 (Gaertner et al., 2020) for a 15 MW floating wind turbine for offshore installation, and a 15 MW monopile wind turbine for shallower sea installation, are included int the study as two reference options. These are compared to two alternative turbine options, instead using the generator proposed by Hagnesia. For the floating option with the Hagnesia generator design, the model also captures the effect of lowered tower and foundation masses, which are allowed for by the load reduction that follows from the shift of generator.

Resource use is evaluated using an indicator for long-term mineral and metal scarcity. The study draws its system boundary at the point in the life cycle when the turbines are commissioned at sea and ready to generate, but it excludes the operation. In line with recommendations from previous literature, to provide transparency and replicability, all unit process-level data compiled specifically for the study is reported in Appendix A.

The conclusion is that Hagnesia’s generator design is able to reduce the greenhouse gas emissions and resource use of the 15 MW wind turbine significantly in comparison to IEA Wind task 37 reference design. The largest impact reduction potential can be identified for the generator subparts, for which the sum of greenhouse gas emissions is more than one order of magnitude lower compared to the reference design.