When was the last time you looked up at the Moon on a clear night? What ran through you mind? I often think of the Apollo missions and the monumental, nationally concerted effort it took to reach the Moon ahead of the Russians. That’s what I thought up until a few weeks ago. Now, I’m exploring how enterprising individuals are attempting to harness the Moon’s influence on Earth through tidal forces and the wind’s influence on ocean waves.
Tidal and wave energy are in the early stages of becoming viable as commercial power sources. However, each come with their own unique set of challenges in order to make these technologies progress to the point that they’re powering the lights in your house. Tidal energy, which draws its power from the gravitational pull of the Moon on the Earth, is plagued by environmental concerns including disrupting native species’ habitat and adversely affecting shoreline ecosystems. Wave energy has similar challenges to tidal energy, albeit on a smaller scale but it also differs from similar alternative energy strategies in one important aspect - the engineering masses haven’t landed on what form of wave energy device the industry will be defined by. Wave energy devices, more specifically the wave energy converters, can take the form of attenuators, point absorbers, or oscillating wave surge converters, among a myriad of other devices. How is an industry as fragmented as wave energy going to decide what technology is best?
To answer that question, I met with Alex Hagmuller, the CEO of AquaHarmonics, Oregon State Alum and co-inventor of a unique point absorber wave energy buoy which won his team a $1.5 million grand prize from the Department of Energy. We discussed his history of innovation, why his recent endeavors seek to move wave energy in a cohesive direction and what lies ahead for the technology.
Innovation in the Bathtub
“I have given this some thought and always seem to end up on analogies within the automobile or similar industries,” says Alex. “You are building a device to be cost competitive with other technologies. Ultimately, a successful device is determined by the market. The one that gets purchased and installed in quantity is the one that we will converge on. So far that hasn't happened. And there will always be niche market applications, or even devices that work best near shore and devices that work best in deep water. "
Alex developed his innovative idea like most inventors - by tinkering. While he was working the late shift and his wife was working the day shift, Alex occupied his free time by taking apart the family Roomba to use as a power takeoff coupled with some foam pieces in his bathtub to try to see how water motion can be captured. After repeated tinkering, Alex found that the bathtub model worked - the mechanical wave motion can be captured to drive a small generator. Alex began uncovering a potentially innovative and unique solution to producing clean, renewable energy.
The drive behind experimenting with his bathtub and Roomba (RIP) is a fundamental concern to emphasize a people-focus with technology - what is being hailed as appropriate technology. This movement believes that technology should be used to make people's lives better and alleviate the common hardships and challenges people the world over experience. Examples include hand and bike-powered water pumps, self-contained solar lamps and streetlights, and passive solar building designs. “Doing good” by way of appropriate technology isn’t something new to sustainable energy and has considerable impact on developing regions. However, it hasn’t seen the renaissance one would expect in a nation which espouses sustainable prowess.
Bringing Disparate Technologies to a Confluence
The difficulty with enabling sustainable, alternative energy to bring power to the people is the intermittency of electrical transmission and delivery. The sun doesn’t always shine, the wind doesn’t always blow and ocean waves don’t always arrive with regularity or predictable periodicity. Baseload power from fossil fuels is still required to keep the lights on. Alex’s team, along with other energy pioneers in the Pacific Northwest, Norway, Ireland, the UK, and Australia are working tirelessly to develop innovative technologies to meet this challenge. With point absorber buoys, the technical challenge comes twofold: they are traditionally massive, and and try to capture energy from both the rising and falling wave. “The problem we see with point absorbers, or buoys in our case is that to make them structurally cheap, they need to be small” says Alex. “This means that they will also have a low mass. If we consider the problem in it's simplest form, as a mass damped spring system, the buoy would have a high natural frequency relative to that of the excitation force, which are the ocean waves. This means that it is operating out of resonance.”
By definition, if a device were operating at resonance, or having the same natural frequency as the excitation force, it would have the highest displacement as well as highest velocity. If resonance can be achieved, there are significant gains for power output, perhaps 2-3 times as much power as a device operating out of resonance. This can result in the same device making 2-3 times more power for the same capital expenditure. This is where control for wave energy conversion takes the stage. Many possible approaches exist in the application of a control system to a low mass point absorber that will force the system into resonance. Some are very complex, others are simpler and more robust - there are benefits and drawbacks to each.
“Our approach is to design the device topology to maximize the benefits of a control system, while at the same time being able to take advantage of the simplest forms of control, which can translate to a robust control system.” Control then has to be designed in parallel from the inception of the device. The intent is to arrive at a device that can operate with bidirectional power flow, meaning it has some amount of on board storage, and it can operate the generator as a motor in part of the cycle.
The Future for Marine Energy
Alex, and his team at Aquaharmonics, are currently refining their innovative technology to build a 1/6th scale prototype (the previous prototype was at 1/20th scale) to be tested in Hawaii, and if all goes well they would build a larger scale to test off the coast of Oregon. In the midst of designing the prototype, Alex has been making visits to Washington DC to show our elected representatives how marine energy can solve our energy crisis and promote a secure energy future - with their help. Recently, the team earned up to $5M dollars from the Department of Energy to ensure their buoy gets the chance to be tested in real wave environments. Like the space race in the ‘60s, taking a technological leap forward often requires the support of an entire nation. Funds in the form of energy grants which support Alex’s venture, among countless other responsible use energy initiatives, can only be realized with the backing of our elected officials and, by extension, the nation as a whole.
We need explorers like Alex. Our energy future is far from secure and we’ve inherited an uphill battle in ensuring we have a livable planet for the future. Advances in marine energy and responsible energy pioneers will help us secure that future. Clean, sustainable, renewable energy can be drawn right off the shores of almost any country. In our country, the target of the space race was to land on the Moon. It took a nationally concerted effort to accomplish and we’re still reaping the rewards. Our next race is one in which the target is not as straightforward but just as critical to our current quality of life and that of the next generation. Next time you gaze up at the moon in the night sky, remember what it took to get there and what the human spirit can achieve - what we have to achieve to preserve the planet for generations to come.