Abstract
In October 2023, we deployed a small-scale (1 m2 swept area) cross-flow turbine in a vertical orientation on a gravity foundation. This was subsequently recovered 141-days later, in March 2024. The deployment site at the inlet to Sequim Bay (WA, USA) is a shallow, narrow channel (< 10 m) with mixed semi-diurnal tides and peak currents on the order of 2.5 m/s. This deployment was the first long-term test of the system, referred to as the “Turbine Lander”, which was a laboratory-to-field effort to design, test, and deploy a system capable of generating on the order of 100 Watts (time averaged) of electrical power. During this deployment, the Turbine Lander achieved high uptime (> 90%) with downtime driven primarily by shore power and networking issues. An integrated environmental monitoring package deployed on the gravity foundation operated with even higher uptime, capturing acoustic and optical images of biological activity near the rotor, measurements of sound from the operating system, and velocity profiles used to control the Turbine Lander.
While this presentation includes some high-level performance metrics and environmental observations, it focuses primarily on considerations that informed the mechanical and electrical design, pre-deployment characterization of the system, and post-deployment analyses of system components. These include holistic considerations for the blades, rotor shaft and struts, seals, the bearing pack, housings, and cables. Specific contributions of the environmental monitoring to engineering analysis are also considered. Lessons learned from the first endurance test of the system provide a clear pathway to improving the Turbine Lander’s performance and reliability in future deployments as it transitions towards fully autonomous operation.