Marine current turbine blades are commonly made using composites such as epoxy fiberglass, which have been shown to have reduced static and fatigue strengths when saturated with seawater. In contrast, novel two-part reactive thermoplastic resin composites have been shown at a small-scale to have improved seawater performance and are also recyclable at the end of their lives [1-3]. While these thermoplastic materials have potential advantages for marine renewable energy applications, it is critical to better understand their applicability and value to marine energy at larger scales. Therefore, the objective of the work presented here was to validate thermoplastic materials in a full-scale tidal environment to build confidence in a novel material that has the potential to be a game changer in the marine industry.
In April 2021 a tidal turbine with NREL-built thermoplastic composite blades was deployed on Verdant Power’s 5-m diameter turbine in the East River, New York. The thermoplastic turbine operated successfully on the TriFrame for three months, contributing 31.8 MWh of energy into the NY electric grid. In October 2021, the TriFrame including the turbine with the thermoplastic rotor and NREL-built data acquisition system (NDAQ) were retrieved from the East River.
This paper will discuss the lessons learned from this deployment, including pre- and post-deployment structural validation of thermoplastic and epoxy blades, power analysis of the turbines during the deployment, and the design and lessons learned from a data acquisition system. This work validated a new material that can lead to a step-change improvement in the materials and structures used in marine renewable energy systems, ultimately leading to cost reductions and improved structural reliability in harsh subsea environments.