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Currently, wind turbine blades are manufactured from a combination of glass and/or carbon fiber composite materials with a thermoset resin such as epoxy, which requires energy-intensive and expensive heating processes to cure. Newly developed in-situ polymerizing thermoplastic resin systems for composite wind turbine blades polymerize at room temperature, eliminating the heating process and significantly reducing the blade manufacturing cycle time and embodied energy, which in turn reduces costs. Thermoplastic materials can also be thermally welded, eliminating the need for adhesive bonds between blade components and increasing the overall strength and reliability of the blades. As well, thermoplastic materials enable end-oflife blade recycling by reheating and decomposing the materials, which is a limitation of existing blade technology. This paper presents a manufacturing demonstration for a 9-m-long thermoplastic composite wind turbine blade. This blade was constructed in the Composites Manufacturing Education and Technology facility at the National Wind Technology Center at the National Renewable Energy Laboratory (NREL) using a vacuumassisted resin transfer molding process. Johns Manville fiberglass and an Arkema thermoplastic resin called Elium were used. Additional materials included Armacellrecycled polyethylene terephthalate foam from Creative Foam and low-cost carbonfiber pultruded spar caps (manufactured in collaboration with NREL, Oak Ridge National Laboratory, Huntsman, Strongwell, and Chomarat). This paper highlights the development of the thermoplastic resin formulations, including an additive designed to control the peak exothermic temperatures. Infusion and cure times of less than 3 hours are also demonstrated, highlighting the efficiency and energy savings associated with manufacturing thermoplastic composite blades.

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Tidal turbine developers and researchers use small scale testing (i.e. tow tank and flume testing) as a cost effective and low risk way to conduct proof-of-concept studies and evaluate early stage device performance. This paper presents experimental performance data for a three-bladed 1/20 th scale NREL S814 tidal turbine rotor, produced at the 4.6 x 2.5 m and 76 m long Kelvin Hydrodynamics Laboratory tow tank at Strathclyde University. The rotor performance was characterised from very low tip speed ratios to runaway for four carriage speeds. A maximum C P of 0.285 and a maximum C T of 0.452 were recorded at tip speed ratios of 3.53 and 4.45 for a carriage speed of 1m/s. The uncertainty in the instrument calibration and experimental measurements was quantified, allowing accurate representation of the experiments in numerical models. The methodology behind the uncertainty calculations is described in this paper. The uncertainty in the experimental measurements was found to be less than 5% for over 87% of the tests. Reynolds number scaling effects were found to be influential on the rotor performance in the range of velocities tested.