Selection of Nepalese Timber for Small Wind Turbine Blade Construction

Abstract

The paper describes the selection of Nepalese timber for development of small wind turbine blades on the basis of locally based low cost timbers, along with the selection of coatings to protect the timber from weathering. The selection criterion of timber includes timber mechanical properties, weathering effect on coatings, price, growth and availability of the timber. Mechanical properties such as Young's modulus of elasticity, breaking strength, breaking strain and Brinell's hardness of selected Nepalese timbers are presented. The effects of weathering on timbers without coating, and with different coatings, are analysed on the basis of the change in weight of the timber due to the effect of humidity and rainfall over a period of nineteen months. Degradation of different coatings of timber are compared.

Sustainable End-of-Life Management of Wind Turbine Blades: Overview of Current and Coming Solutions

“…In the simplest version, the blades can be carved from wooden parts, fully or in parts. Mishnaevsky Jr., Sinha et al [ 147 , 148 ] demonstrated the applicability of Nepali timber for low cost wind blades. The turbines with timber wind blades were installed on several locations around Nepal, and their usability was demonstrated (see Figure 10 ).…”

Materials for Wind Turbine Blades: An Overview

“…In a number of works, the strength and damage mechanisms of hybrid composites were studied [ 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ]. It was reported, among others, that the incorporation of glass fibers in carbon fiber reinforced composites allows the improvement of their impact properties and tensile strain to failure of the carbon fibers.…”

“…An interesting option for developing countries is small turbines, producible on-site, and made from “natural composites”, i.e., from locally available timber [ 47 ]. In a series of investigations, a group of Nepali, Danish and Australian scientists studied the applicability of different timbers for wind turbines, and demonstrated that the turbines with wooden blades represent a reliable and low cost option for the developing countries [ 48 , 49 , 50 , 51 ]. Figure 5 shows a test of a timber wind turbine blade and small wind turbines installed in a village school in Nepal.…”

Design, manufacture and testing of small wind turbine blades

“…These blades were hand-carved and have large variations in mass and inertia, J . The limitation on length of solid timber blades is the cost of knot-free blanks, (Peterson and Clausen, 2004;Sinha et al ., 2010). There are complications; it is best, for example, to use timber quarter-sawn from well-seasoned logs (the main cuts being in the radial direction after the log has been quartered), which is not standard practice.…”

“…Sinha et al (2010) tested a range of blade coating materials primarily for use in Nepal and found that enamel paint with a primer undercoat offered excellent surface protection.…”