Hydropower and Hydrokinetic R&D in 2025

At the 2025 European Wave and Tidal Energy Conference, an NLR researcher showcased new marine energy updates to OpenFAST, a free, open-source tool that simulates turbine performance in ocean and river environments. The latest features—such as buoyancy and added mass forces, combined wave and current simulation, and cavitation detection—could assist developers design more efficient, reliable, and cost-effective underwater turbines. The OpenFAST team also released two instructional YouTube videos: one on the OpenFAST installation process and another that demonstrates several example use cases. These updates could support marine energy developers expedite the design of more efficient, cost-effective, and longer-lasting underwater turbines and generate more affordable electricity from ocean and river currents.

Two new publications offer insights on material properties and manufacturing processes for the marine energy industry. In one study, NLR researchers investigated how long-term exposure to heat and moisture—typical conditions for marine energy devices—affects thermoplastic glass fiber composites. These composites are valued for their high strength-to-weight ratio, but researchers found that mechanical strength decreased after aging, which could impact recyclability and reuse. In the second study, researchers demonstrated that 3D printing expedited the development of a tidal turbine blade component. The findings suggest that 3D printing could support the marine energy industry in reducing costs and speeding up prototype development and testing.

The team behind the original Modular Open-source Data Acquisition (MODAQ) system released MODAQ 2.0 on GitHub. Marine energy developers use NLR's customizable MODAQ systems to collect and process field data and remotely monitor deployed technologies. MODAQ 2.0 offers greater flexibility, allowing developers to choose a MODAQ model that fits their specific needs. MODAQ 2.0 can adapt to a wide range of missions, including those that require low power demand and lightweight equipment, while continuing to deliver the same high-quality data expected from MODAQ 1.0. The new version also incorporates more widely used programming languages and tools.

In September 2025, the Marine and Hydrokinetic Toolkit (or MHKiT) team released version 1.0 of MHKiT Python and MATLAB, offering equivalent functionality across the two code bases. MHKiT is an open-source software tool designed to assist marine energy researchers and developers process, visualize, and assess data collected during technology testing. The toolkit also enables users to evaluate marine energy resources—including waves and tides—at different ocean sites and assess device performance. The MHKiT MATLAB version on GitHub now supports new data types, including acoustic Doppler current profiler data—which measures the speed and direction of water currents—and acoustic Doppler velocimeter data—which measures water velocity. The MATLAB version also allows users to perform turbulence and mooring analysis and acoustic measurement evaluation.

Researchers released updated versions of two wave energy modeling tools: Capytaine and the Wave Energy Converter Simulator (WEC-Sim). Capytaine, a free, open-source tool developed by NLR and Mews Labs, enables developers to model how waves interact with floating devices, including wave energy technologies. Version 2.3 offers more accurate results in deep or shallow water, eliminates irregular frequencies data, adds export file format options, and includes other improvements. WEC-Sim, also open-source, simulates wave energy converter performance. WEC-Sim 7, available on GitHub, delivers more efficient and accurate results thanks to bug fixes and system enhancements.

NLR researchers investigated various power electronics topologies—electrical configurations used to convert and control electricity flow—and evaluated their performance for wave energy technologies. The team tested the most promising topologies using a generator and power hardware-in-the-loop setup, which connects virtual simulations with real hardware to create a more realistic test bed. This test bed, along with the top-performing topologies, could support researchers and industry members in designing hardware more efficiently and optimizing it for specific wave energy devices.

The marine economy—which includes coastal communities and ocean-based industries such as shipping, ocean observation, and seafood farming—generated more than $500 billion and 2.6 million jobs in the U.S. in 2023. But powering this ocean-based economy remains a challenge. In 2025, NLR researchers investigated and advanced three different technologies that could provide reliable and affordable energy for ocean-based workers and communities. One team partnered with the Hawai'i National Marine Energy Center to evaluate an oscillating surge wave energy converter using an NLR-designed power take-off unit. The study focused on long-term deployment, performance, and maintenance. Another team designed an economical floating marine turbine platform, which will be tested in NLR's wave tank using hardware-in-the-loop simulations to study current-induced turbine loads and improve the design for long-term deployment. A third team built a thermal ocean gradients test facility to study the feasibility of thermoelectric generators that harness energy from thermal ocean gradients. These three efforts could allow marine energy developers to understand the benefits and challenges associated with various wave energy technology designs.

NLR experts developed a new open-source wave energy converter modeling framework called SEA-Stack. Researchers and developers depend on computer models to evaluate design potential in a low-risk, low-cost virtual environment. But existing software has limitations. SEA-Stack addresses these gaps by integrating low-, mid-, and high-fidelity simulation tools, along with HydroChrono, a GitHub tool that simulates how ocean devices respond to waves and hydrodynamic forces. This comprehensive, user-friendly modeling framework supports the development of more efficient and robust wave energy technologies, which could deliver reliable energy to coastal communities and ocean-based industries.​

NLR researchers supported the development of PacWave, a grid-connected, open-ocean wave energy testing facility off the coast of Oregon. PacWave is one of the world's only accredited, pre-permitted, multi-berth wave energy test sites. NLR engineers will conduct accredited testing of deployed wave energy devices at PacWave. Independent and third-party accreditation increases confidence that wave energy converters perform as stated by the manufacturer. NLR waveriders are deployed at PacWave to characterize wave conditions. These efforts could help PacWave operators and wave energy developers accelerate progress toward certified, market-ready marine energy technologies.

NLR researchers built and tested a full-scale generator that produces electricity from temperature differences between the ocean and the air. The prototype—a thermomagnetic generator—demonstrated its ability to provide reliable, consistent energy for ocean-based technologies, including sensors used to monitor ocean conditions. Marine thermal energy technologies generate energy from heat that is typically wasted, but harvesting ultra-low temperature differences has been a difficult engineering challenge. In a paper published in Nature Communications Engineering, the team explains how their generator successfully powered an internet-connected sensor while operating in an ultra-low temperature difference of about 13.5°F (7.5°C). In another paper published in Device, the team demonstrates a fully passive, self-sustained underwater thermomagnetic generator for remote marine thermal energy harvesting. The work can bring thermomagnetic generators closer to commercialization by demonstrating their potential to support ocean-based operations and land-based applications, such as data centers.

NLR experts supported the latest Testing Expertise and Access for Marine Energy Research (TEAMER) program by working with 16 successful applicants for technical assistance. The lab partnered with various startups, national laboratories, universities, and developers, including iProTech, Littoral Power Systems, Pterofin, CalWave, Equinox Ocean Turbines, NWEI/Azura Wave Power, Ocean Inertia, BladeRunner. These projects span a wide range of marine energy research, including advanced numerical modeling and techno-economic analysis, open-water testing, resource assessment, power take-off characterization, hybrid system integration, and wave, tidal, and river energy device development. Beyond direct project support, NLR representatives helped strengthen TEAMER's potential impact by supporting Sandia National Laboratories to develop new training for the program's team leads and reviewers, contribute to the rollout of a new commercialization track, and participate in technical board meetings, facility summits, and international outreach. NLR experts also received approval to begin work on its first open-water award and helped clarify design guidelines for future TEAMER projects.

NLR researchers have two patents pending for a novel thermal ocean gradient energy system that converts natural temperature differences in the ocean into reliable, low-power electricity. This year's work focused on optimizing a buoyancy-driven submersible, known as the Thermopod, which uses thermoelectric generators and a phase-change material to produce electricity from ocean thermal gradients. The system is designed to support technologies such as autonomous underwater vehicles, profiling floats, offshore sensors, and low-energy aquaculture operations. Researchers also identified potential national security applications where persistent, maintenance-free underwater energy generation could power sensing and surveillance systems.

Marine energy researchers began redesigning NLR's hydraulic and electric reverse osmosis wave energy converter (HERO WEC), which uses wave energy to pump seawater through an onshore reverse osmosis system to produce fresh drinking water through desalination. To improve the device's reliability, researchers upgraded the winch line with a polyurethane flat belt that overperformed in initial lab tests. They also redesigned the WEC's outer body using more durable materials and relocated the power system components for easier access. These changes slightly modified the WEC's shape, which the team validated using modeling tools and the lab's wave tank to confirm efficiency and survivability. The HERO WEC design and test results are available on OpenEI for other researchers and developers. Through a refined, standardized testing process, NLR is assisting the marine energy industry in developing reliable, cost competitive energy conversion devices. NLR's refined, standardized testing process could guide the marine energy industry in developing reliable, cost-competitive energy conversion devices.

Marine energy developers now have access to more data on wave, tidal, ocean current, river, and ocean thermal energy resources in the United States, thanks to updates to the Marine Energy Atlas tool. The free Marine Energy Atlas tool now features an improved user interface, easier download options, and access to Puerto Rico datasets. A cross-laboratory team also posted more than 12 terabytes of data to the cloud, including detailed wave metrics such as wave power, significant wave height, and energy period. Through an ongoing collaboration with Pacific Northwest National Laboratory and Sandia National Laboratories, NLR enables users to conduct more in-depth analyses of marine energy resources and identify optimal sites for deploying emerging technologies.