Project Spotlight: Sandia’s SWEPT Lab offers specialized testing, builds relationships with marine industry

WECs are unique because they convert the oscillatory mechanical energy from ocean waves to generate electricity. This differentiates them from other technologies that harness a relatively steady input of mechanical energy, such as wind turbines or hydroelectric power technologies. Because of the unique way they convert energy, WEC power take-off systems require specialized methods and facilities for their design and testing. 

Sandia National Laboratories’ Water Power Technologies Program studies ocean wave energy technologies, which gather energy from waves using wave energy converters, or WECs, to harness wave motion and generate carbon-free electricity. This renewable power source has major production potential to help meet the nation’s energy needs and climate goals. Ocean wave energy technologies are still in the early stages, and testing a WEC in a wave tank or the open ocean is complex due to challenges such as location and weather.  

In 2017, Sandia invested $1.2 million to design and build the Sandia Wave Energy Power Take-off (SWEPT) Lab to test WEC power take-off systems in a controlled environment. Since then, bench testing of control systems, sensors, robotics, and other components before testing at sea has allowed Sandia and its industry partners to increase device efficiencies. Testing at the Lab has also increased WEC developers’ confidence that their designs will work properly when deployed.    

The SWEPT Lab is capable of testing a WEC’s multiple degrees-of-freedom of movement with independent control. The Lab can simulate the dynamics (inertia, damping, stiffness, multi-body links) of full-scale WECs, as well as the input from waves and wave-body interactions. The SWEPT Lab can provide accelerated life testing, dry tests, and bench tests, and allows for system identification, real-time control, reliability analysis, and grid interface simulation.  

AquaHarmonics was the first company to use the SWEPT Lab to test its WEC. In 2016, the U.S. Department of Energy awarded the company the Wave Energy Prize for the design of a model-scale WEC. AquaHarmonics used the $1.5 million award to manufacture and test several iterations of its device up to and including the 1/7^th-scale version of its power take-off system at the SWEPT Lab.

AquaHarmonics’ single-body WEC is designed to be tethered to a mooring with a power take-off on the sea floor. Successful component and sub-system level testing at Sandia helped to confirm that the power take-off will perform as predicted when it is moved to the U.S. Navy Wave Energy Test Site at Mōkapu Peninsula in Hawaii.    

AquaHarmonics co-founder Alex Hagmüller said working with Sandia at the SWEPT Lab has helped to reduce the risk involved with going directly to the water without testing. Otherwise, “it would be hard to have such a high degree of confidence,” he said.  

“Ocean deployments of WECs are expensive and have high levels of risk for a number of reasons. Anything we can do to reduce the risk of these deployments has a big potential to pay dividends,” said Ryan Coe, Sandia co-Principal Investigator.  

While Sandia continues to partner with companies that want to test and validate their WECs, it is also leveraging its expertise to develop and standardize testing procedures for the wave energy industry. These standards will help developers be certain their devices are working properly when they are installed. 

To learn more about the SWEPT Lab, contact Giorgio Bacelli and Ryan Coe.  

Read more about Sandia’s Water Power Technologies program.  

Featured Image: Co-PI Ryan Coe opens the mobile Sandia Wave Energy Power Take-off  (SWEPT) Lab, that tests wave energy converter power take-off systems.