Variable Geometry Turbines Industrialization for a Circular Economy of Distributed Wind Energy

In this work we present a novel VAWT with passive variable geometry (PVG), which combines variable radius and variable pitch of the free blades. The turbine was optimized through extensive numerical simulations, with a final design featuring short start-up time, high steady-state efficiency, low construction complexity, and low material costs. A crucial reduction of nearly 50% in the blades' mass was obtained through the use of compression moulded composites. A full-scale physical prototype was tested in a dedicated wind tunnel facility, where the typical intermittent air flow of the UBL was replicated. The turbine was connected to standard power electronics found in the solar photovoltaic market. The measured electrical power output closely matches the numerical simulations, suggesting that our PVG design can achieve a 64% increase in the capacity factor compared to a fixed-geometry turbine. Thanks to this engineering breakthrough we believe that, for the first time, wind installations in the UBL can be competitive on the energy market. We conclude our contribution by discussing industrialization and sustainability aspects of our PVG-VAWT technology, and by projecting a deployment scenario towards the uptake of a distributed urban wind market.