Open-Source Tidal Energy Converter (OSTEC) Test Bed – Enabling In-Water R&D for Current Energy Conversion

The Open-Source Tidal Energy Converter (OSTEC) is an instrumented reference turbine designed to serve as a test bed for foundational R&D and data generation in real open-water tidal flow conditions. It was funded by the U.S. Department of Energy to advance our understanding and to identify knowledge gaps in the techno-economic performance of tidal energy converters (TEC). This marine turbine test bed also enables testing, demonstration, and improvement of recommended best practices in international standards, including the IEC TC 114 technical specifications on marine energy.

A 3-bladed axial-flow turbine was selected as it is the most common marine turbine archetype. The OSTEC diameter is 2.5 m, which is sufficiently large scale to enable Reynolds number independence and to allow upscaling of material and component, load response and stress-strain behavior, and fluid-structure-interactions. The DOE marine hydrokinetic family 1 (MHKF1) advanced reference blade geometry was selected as the initial blade configuration since its design is well-documented and its power performance was demonstrated in scale model testing. The OSTEC test bed is extensively instrumented for measurements of tidal energy resource, power performance, environmental monitoring, loads, including mooring, thrust and blade loads, operating parameters, and many other measurements.

The OSTEC test bed will be deployed from a 15 m x 6 m Turbine Deployment Platform (TDP) at the UNH-AMEC Tidal Energy Test Site at Memorial Bridge in Portsmouth, NH, an easily accessible, cost-effective open-water test site. Tidal currents up to 2.8 m/s (2-minute average) were measured at the site with an ADCP during spring ebb tides. The TDP has survived tropical storms and Nor’easter storm surges. A tidal turbine has been successfully deployed at the site since 2018.

This contribution to UMERC+METS 2024 will give an overview of the OSTEC and then focus on the research and development enabled by this test bed.

The OSTEC capabilities were compared to the DOE Water Power Technology Office’s Muli-Year Program Plan (MYPP) for marine energy, and numerous opportunities exist in all four MYPP focus areas: Foundational R&D, Technology-Specific Design & Validation, Reducing Barriers to Testing, and Data Access and Analytics. Studies enabled by the OSTEC test bed include: Blade R&D (geometries, materials, coatings, sensors), blade failure modes (pitch misalignment, damaged blades, missing blade, etc.) and health monitoring, model Verification and Validation (TurbSim, OpenFAST, CFD-FSI, etc.), digital twinning of CECs, advanced controls research utilizing rotor speed or torque regulation, debris detection and mitigation using acoustic imaging and turbine control, concurrent environmental studies, turbine wake studies, gearbox lubricant research, blade/component coatings for corrosion protection or biofouling mitigation, process monitoring using dedicated sensors (e.g., accelerometers) or generator output analysis, novel power electronics development, IO&M process studies, CapEx, OpEx, LCOE benchmarking studies. The OSTEC test bed was designed with modularity in mind, within reason. Some parts of the OSTEC can readily be exchanged, e.g., blades, while other sections or assemblies can be adapted if needed. There are significant opportunities for research on and documentation of Operation and Maintenance costs, examples of what worked well and what didn’t, and lessons learned.