Aquaharmonics co-founders stand in front of a computer while their wave energy converter is being tested in a flume.
Alex Hagmüller and Max Ginsburg, co-founders of Aquaharmonics, test their wave energy converter in a flume at Oregon State University.

In 2016, AquaHarmonics took home the $1.5 million grand prize in the Energy Department's Wave Energy Prize, an 18-month design-build-test competition to increase the energy capture potential of wave energy devices. Now, more than two years later, the Oregon-based company is planning to test a larger version of the winning device in the open ocean. The Water Power Technology Office (WPTO) recently sat down with AquaHarmonics co-founder Alex Hagmüller to learn about their recent device testing and plans for future deployment.

What actions have you taken to build off your success in the 2016 Wave Energy Prize?

We wanted to continue developing our 1/20th scale wave energy converter (WEC), so we applied for and were awarded funding through the Water Power Technology Office's 2017 Marine and Hydrokinetic Technology Development and Advancement funding opportunity. The award will enable us to ultimately deploy a 1/7th scale version of our device at Hawaii's Wave Energy Test Site (WETS) in 2021. We currently are optimizing our numerical models and control systems to leverage both the data that we generated during the Prize as well as new data drawn from recent wave tank testing at Oregon State University's O.H. Hinsdale Laboratory.

We also are part of a Wave Energy Scotland (WES) award that was granted to us around the same time as our WPTO project. We are primarily working to improve WEC-based controls that can be applied toward reinforcement learning—a type of machine learning that basically connects a computer's actions with outcomes and develops a control policy that maximizes long-term efficiencies. The goal of the project is to reduce the levelized cost of electricity of wave energy via a more accurate evaluation of the trade-offs between reliability and performance.

What are some of the most complex challenges in scaling up a device?

In the industry, extensive planning and coordination is devoted to hardware testing, which is challenging for wave energy due to both the expense and preparation needed for effective tank and open ocean deployment. Each testing iteration must be markedly more efficient than the last, so there is a tendency to prioritize modular designs where components can be more easily separated and combined. AquaHarmonics has tank tested for five times now—pushing the boundaries of what our model can accurately predict with each test. The more we understand about our device, the more improvements we can make at each component level, which can equate to months of preparation for tank tests to be successful.

What tools or approaches have helped develop your technology?

You have to not only consider how to accomplish your primary testing goals, but also how to quickly make any modifications during your experiment. Because tank testing is expensive, we have refined our testing approach to reduce downtime and maximize efficiency. For example, we've added automated solenoids (electro-hydraulic valves that controls fluid flow) to remotely drain the water lines running to our pressure sensors instead of having to manually enter the tank to make adjustments. We have also constructed an innovative mooring frame that allows us to make precise changes to our mooring lines without having to get into the water. Our entire setup sometimes resembles a marionette puppet, where the mooring lines and different pulley paths are all visible outside of the tank. We have also made significant improvements to the individual components of our device to accelerate the process for removal and inspection.

Repeatability of testing is another key aspect of successful technology development. In situations where a developer is pulling a device in and out of a tank for modifications, it's important to return to a baseline where performance inputs and outputs can be examined. We conduct simple tests at the beginning of every day, and throughout testing as required, in exactly the same way to show cross calibration between instrumentation. Regardless of performance, confirming that a device is operating in an expected manner is a step that should be built into the timeline of tank testing.

What kind of onshore testing milestones does your device need to meet prior to open ocean testing?

After we conclude numerical modeling and control system optimization tasks, we will need to successfully manufacture and test the 1/7th scale version of our Power Take-Off (PTO) system—the hardware that takes absorbed WEC energy and transforms it into useable electricity—at the Sandia Wave Energy Power Take-off Laboratory, or SWEPT Lab. Successful component and sub-system level testing will confirm that our PTO performs within the operational bandwidth predicted by our numerical models, which are based on the Hawaiian wave and climate conditions at WETS. The more accurate our models become, the easier it will be to scale up our device and move to open ocean testing.

Could you see AquaHarmonics testing at PacWave in the future?

It's definitely on our radar. There is a lot of potential value in PacWave providing a United States-based, pre-permitted WEC test site that's grid connected for the testing of large-scale devices. The site also can test device arrays that could vary in design and power output, so we are certainly interested. The first deployment at PacWave will represent an incredible milestone for the industry as well as an important investment in the future of wave energy.  

In your opinion, which technological innovations are most needed for wave energy to become cost competitive?

I see PTO advances being key to enable devices to become more cost competitive. Wave energy presents a unique resource challenge in terms of power generation. With wind power, turbines are conventionally designed to spin in one direction, which allows power generators to operate around a positive average velocity. Due to the oscillatory nature of waves, WECs need generators to operate efficiently around a zero velocity—something that most generators are not designed to do. So I would focus efforts on not only improving the efficiency of wave energy-specific oscillating generators, but would also look to improve energy storage systems. Developing an oscillating, high energy density mechanical energy storage system would allow certain WECs to more efficiently store and use energy from the rise of waves rather than relying on generators to provide reactive power in the system.

Advanced gearboxes can also help drive the entire WEC system. Whatever your base method is for extracting rotational power, you need to be able to translate it to both your generator and your energy storage system in an efficient, reliable manner. Having some kind of gearbox in the system also allows for a reduction in the size of your generator, which can be beneficial both in costs and complexity. Looking at where the marine energy industry is, it can be difficult to find gearboxes that have the ability to work within the high torque requirements of WECs. One of the reasons why we've settled on the 1/7th scale model for our WPTO project is because many of our components can be found off the shelf. When developers are looking at ramping up to full scale systems, off-the-shelf components are often not an option, so making innovations within WEC-specific gearboxes is an area that will need to evolve.

The marine energy industry has not yet settled on a singular WEC design—why does AquaHarmonics focus on point absorbers?

The decision to concentrate on point absorbers was based on our core design approach of prioritizing simple and economical concepts. While there are more complex WECs that have potential to capture greater amounts of energy than our system, factors such as power production, tank testing, and open ocean deployment only rise in complexity as any technology scales up. Our design strategy was also informed by the Wave Energy Prize, which was geared toward advancing designs that can produce more power per unit structural cost, instead of the traditional focus on outright power production. Research into controls analysis has reinforced our understanding that point absorbers can economically produce power while remaining lightweight and reliable.

We've also considered whether the marine energy industry's evolution will be centered around the device level, or on the array level. Deploying one highly tuned, power intensive WEC may not be the right path for the industry—a developer would not only be putting all of their resources in one basket, but there could also be issues with things like maintenance and long-term material reliability. Until more research is conducted into the long-term survivability of WECs, it might be a better idea to focus on deploying a greater number of small, economical devices that can gather data that the industry could then use to inform future decisions.

Since the conclusion of the Wave Energy Prize, AquaHarmonics has worked with several different types of stakeholder groups including the Energy Department, the national laboratories, Oregon State University, and with other companies in private industry—can you elaborate on the importance of partnerships for advancing the state of the art in marine energy?

As a small startup with minimal resources, partnerships are key enablers to the growth of AquaHarmonics. There isn't any room for dead weight in terms of concepts that may or may not work, so we have had to be precise in onboarding and aligning the right people with the right tools during every development stage. Our operating status as a company now and going into the future is different than when it was just the two of us competing in the Prize—the quicker you scale up technology, the greater the need is for seeking out additional expertise and partnership opportunities. We are very proud of the team we have assembled to date, so if we are to be successful with our current testing, it will be due in no small part to our partners.

There are multiple ocean industries within the Blue Economy. Is AquaHarmonics interested in potentially powering any of those markets? If so, which ones?

Since the 2017 Energy Department forum, we've been thinking a lot about how we can apply marine energy within a number of different markets in the ocean economy of the future, commonly referred to as the Blue Economy. Removing power constraints could accelerate growth and create new opportunities for sustained economic development in the ocean.

For instance, there are significant costs in maintaining aquaculture systems—especially through diesel transport—so there's incentive within the market to look for alternatives. A viable approach might be to develop a WEC system that is directly integrated into the aquaculture system. System integration may mean redesigning WECs to meet different goals for supporting blue economy infrastructure vs. traditional grid scale WEC operations. WECs that are integrated within an aquaculture setup may not need to be as efficient as originally intended in order to still provide a cost-competitive and reliable power option. The ecosystem for device deployment is another consideration. Instead of highly energetic wave environments where WECs would normally be placed, aquaculture farms are better suited to docile wave conditions. Less harsh coastal conditions could even enable smaller point absorbers to be built at lower costs and at bigger array scales since the materials wouldn't have to be as durable.

What are some key goals for AquaHarmonics during the next five to ten years?

After completing our Energy Department project—which includes design, manufacture, dry testing, open water deployment, and recovery of the point absorber—finding an industry partner to help us with larger scale device testing and deployment will be our next step. Using PacWave as a testing platform for the next generation AquaHarmonics grid scale device or array is certainly on our radar. There are a lot of questions we still need to answer for how our company will evolve and who our future customers will be.