Increasing popularity of individualised electricity generation from wind by prosumers creates a strong demand for profitable and highly efficient small wind turbines. This paper investigates the influence of rotor blade solidity parameter on device efficiency in hope of determining its optimal value as a part of the development process of the GUST small wind turbine. The study involved experimental analysis in the wind tunnel and numerical simulations performed in QBlade software. Different solidities of the rotor were achieved by alteration of (1) number of blades and (2) chord distribution along the blade span. The increase of rotor solidity resulted in augmentation of the aerodynamic efficiency in both approaches. The elongation of the chord by 33% in a 3-bladed rotor resulted in a bigger power coefficient increment than addition of a 4th blade with original chord distribution. Even though the solidity was the same, the 3-bladed rotor performed better, possibly due to lower form drag. The results emphasize the importance of the rotor solidity optimization during the small wind turbine rotor development and may significantly influence overall power output.

One of the increasingly important criteria, when constructing a Small Wind Turbine (SWT), is its sustainable design. It means constructing the SWT in such a way that it can provide a cheap, easy and safe access to clean energy at a specific location for predicted number of consumers. This paper highlights three issues. First, benefits from the application of the rapid prototyping technology are discussed. 3D printers can be used as a durable and relatively cheap means of SWT components production. Also, the possibility of using recycled plastic for 3D-printed components is of big importance. Secondly, the modular construction of the small wind turbine is outlined. This facilitates the product versatility, proneness to adjustments and ease of maintenance. Last but not least, the production costs for individual units as well as multi-unit production are reviewed to show the financial benefits of SWTs and the payback of such investments over the years. The article concludes with a set of recommendations for wind turbine design, conformal with the suggestions of the UN Sustainability Report and Sustainable Development Goal 7.1. The utilization of described concepts is demonstrated basing on the GUST 1.6 m diameter horizontal axis SWT.

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