Power vessel navigates to wave energy cost-effectiveness

Flying deliberately under the media radar over the past decade, and in the meantime developing a giant 9MW wave energy device, American wave energy company GWave has recently lifted the lid on its well-kept secret by announcing the plans to deploy a full-scale device at the Wave Hub test center in Cornwall, UK.

Tidal Energy Today has talked to GWave’s Chief Executive Officer, Robert Stoddard, to learn more about this ‘dark horse’ of wave energy generation whose nameplate capacity of 9MW is larger than that of the biggest offshore wind turbine currently available on the market.

Mr. Stoddard can you tell us more about the GWave company and its collaboration with Wave Hub?
We have been flying under the radar quite intentionally. GWave is a company based in Portland, Maine, USA, founded in 2006, when our founder Glenn Beane started working on the design of the power generation vessel which is currently in the final stages of development. He received principal funding for that in 2011, and we’ve been working with the same venture capital fund to support the operation – which is entirely privately funded.

GWave has been talking to Wave Hub for about two years, reaching the initial commitment agreement about a year and a half ago. We have been renewing and extending that, while at the same time GWave made a major capital contribution to the infrastructure completion that Wave Hub conducted last year.

The working principles, as well as the dimensions of the GWave device are unknown to the public – so can you give us some more details on the GWave wave energy device itself?
The power generation vessel is currently under construction in the United States. The internal power take-off and insulating systems are well along in construction. The vessel is 72 meters long, 22 meters high, with the weight little under 13,000 tons. It has a nameplate capacity of 9MW.

The working principle of the device is simple to describe, yet tricky to execute. Basically, it is a floating sealed tube, so the sea water doesn’t engage with any of the internals. The tube is aligned pointing into the waves, and as swell passes under it, the tube pitches fore and aft. Within the tube, we have large weights that roll on tracks. We set up the timing to ensure that as the vessel pitches downward, the weights roll downhill, and then as the swing of the buoyancy pushes that end of the vessel back up, the weights are once again positioned to roll back downhill. Then we just convert the kinetic energy of the rolling weights into electricity. It’s a fairly straight forward linear generation.

The goal is to complete the construction of the power generation vessel by the end of this year. It is being built in Louisiana, where we’re using the skillsets of the oil and gas fabrication industry. We plan to test it in the nearshore water environment in the Gulf of Mexico in 2018, and then bring over the device to Wave Hub for the installation in the summer that same year.

Why did you choose to make a full-scale device as a first unit as most developers tend to start small to test the technology first?
The scientific principles underlying the vessel are very challenging to scale, and we would have spent substantial amount of time and money having to re-engineer a device that could work with small waves to work with higher waves. Instead, we relied on very extensive numerical modeling utilizing some excellent models that our naval architect used for decades with very high profile clients including the US Navy and the Israeli Navy.

We were also free of the constraints that most developers face – they have to start with smaller devices because they are seeking public money which is available in small amounts and on milestone basis. Our board and our investor made the decision that it was better to move forward with full-scale device so that we could get to market more quickly.

Obviously, there are always technology risks, but the fundamental principles that could be demonstrated at small-scale were not where the primary risks lay. The primary risks lie with the scale itself – so until we’ve built it at full-scale we really wouldn’t have de-risked the project sufficiently.

How long do you plan on keeping the device at Wave Hub?
Our commitment agreement with Wave Hub is for a period of 10 years. The period of installation could be shorter, or longer, but 10 years is what we’re aiming for right now.

Do you have plans to add more devices at Wave Hub to see how devices behave in an array?
We have been in preliminary discussions with Wave Hub to moor a second vessel should the first one prove successful. We want to make sure we gain as much performance data and knowledge as possible from the deployment of the first device that could be incorporated into the development of the second device, before we decide to add it to Wave Hub.

What markets do you target for the application of GWave wave energy device?
We see GWave as a global company. We have been in discussions with major utilities and governments around the world and have identified potential projects in nearly every continent, so we have a very broad vision for GWave’s application in the future. Also, we view GWave technology as directly competitive in the utility market space, so we envision that, once we have proved the core technology, to be installing dozens or scores of these in clusters and using them as primary source of power for electricity grids. The goal is to have plants in hundreds of megawatts in 5 to 7 years time.

Interview prepared by Amir Garanovic from Tidal Energy Today.

Instagram Posts from the IIMS @iimsmarine