Techno-economic optimisation of small wind turbines using co-design on a parametrised model

Wind turbines are one of the most rapid growing and promising technologies for renewable power generation today. However, the share of wind energy in the global energy mix is almost entirely attributed to large turbines. Despite their unique merits, small wind turbines remain a marginal phenomenon, as they lack the technological maturity of their large counterparts. They often have a disappointing energy yield, and consequently, poor economic viability. However, it was observed from test field data that turbines with a higher ratio of rotor size to drivetrain power perform better. This rises the question whether a different design methodology, tailored to the specifics of small turbines, would result in a performance improvement. Therefore, this article presents a techno-economic optimisation method specifically for small wind turbines. Parametrised technical and economic models are integrated within a co-design optimisation process, with maximum economic performance as primary goal. A cost model of the turbine was constructed by collecting price data from wind turbine manufacturers and manufacturers of their main components. The results of the optimisation process confirm that the economic performance can indeed be greatly increased by significantly increasing the ratio of rotor size to drivetrain power.