Harnessing wave power in Tasmania

Scarlett Evans 3 August 2020 (Last Updated August 4th, 2020 11:39)

While previous attempts have run into maintenance issues - having to vie with the eroding and powerful force of the very waves they are attempting to capture – Wave Swell Energy has developed an oscillating water column design that promises to turn Australia’s coastline into one giant energy source. We talk to co-founder Dr Tom Denniss.

Harnessing wave power in Tasmania
“It’s the only technology that we’re aware of in the world that serves as both a climate mitigation measure and as a climate change adaptation measure,” said Dr Tom Denniss. Credit: Wave

Founded in late 2016, Wave Swell Energy is a renewable energy technology development company, which has developed a proprietary technology to convert wave energy into electrical energy that the company hopes could transform wave power in Australia. Other systems have faced significant challenges, from maintenance of projects located in deep water to the potential harm such projects could do to their local ecosystem. Wave Swell Energy aims to prove these challenges need not stop wave power.

The Australian-developed system is to begin generating electricity from ocean waves later this year, with a pilot project set up on King Island, located in the Bass Strait between the Australian mainland and Tasmania.  find out more about Wave Swell’s technology, and how it could succeed where other wave power companies have failed.

Scarlett Evans (SE): Tell me about your company and your technology – what motivated its initiation?

Tom Denniss (TD): We had a lightbulb moment back in 2016 when we came up with this technology. We had it tested and the results actually surpassed our expectations, and since then we’ve just been working on furthering the technology, testing it at a wave tank facility, and getting the King Island project up and running.

The King Island project is the first real ocean demonstration of the technology, and is partially funded by the Australian Renewable Energy Agency (ARENA). Getting ARENA on board, raising the private capital ourselves, as well as the design and construction – it’s all taken the best part of the last three years.

SE: And it’s set to begin operating later this year?

TD: Yes. With COVID-19, we’ve had some minor issues in that Tasmania – where it’s been built – has closed its borders, so we can’t go down and do anything there until the border restrictions are lifted. It’s more than 95% complete at this point, there are just a few small things to be done before it’s towed from Launceston to King Island and installed on site.

The way it’s designed is with a main structure with a ‘super structure’ on top, and it’s this super structure that actually contains all of the high-tech components – the turbine and generator. That super structure still needs to be placed on top of the main structure that’s in the water, so we need to hook that up.

SE: Your site mentions the design mitigates damage to marine life, and can even act as a protection against coastal erosion. Can you tell me more about this?

TD: Yes, the technology has a dual function. One is to generate electricity and all that comes with that – desalinating water, producing hydrogen etc. But the structure also naturally acts as a barrier to the waves eroding the coastline. Particularly when you place multiple units side by side, they act as a harbour breakwater, or can just simply be there to prevent coastal erosion.

It’s the only technology that we’re aware of in the world that serves as both a climate mitigation measure, in its production of green electricity, and as a climate change adaptation measure, in that it can protect coastlines from erosion. In doing so, it would be an asset to coastal communities wanting to adapt to changes occurring due to a level of climate change – shifts that are now somewhat unavoidable.

Remote islands in the Pacific (and even the state of Hawaii) predominantly generate electricity from diesel fuel, which is the most expensive form of electricity generation. We can undercut that, as diesel generated electricity is around ten times more expensive than traditional baseload electricity in major grid connected regions. By instead using wave technology in a place like that, electricity becomes cheaper, greener, and can also adapt seawalls to become something that generates revenue. Rather than putting these in as a sunk cost, they more than pay for themselves.

SE: Where would be an ideal site for this technology?

TD: While the technology is not specifically intended for islands, that’s where it will make its mark most obvious. If you are a remote island you’ll almost certainly use diesel, so you can potentially cut costs quite drastically.

Tasmania has one of the best wave climates in the world, so it’s an ideal focus for us and anyone else who wants to use this technology to produce not only electricity but also hydrogen, which is just a more compact way of storing electricity.

SE: Is ocean power something that is still relatively untapped?

TD: Yes, very much so. There’s still no real commercial operating units in the world at this stage. While there’s been a lot of attempts to harness it commercially, most have failed to some extent, if not completely.

In my opinion, the reason for this failure is because so many of these technologies have moving parts in the water. The sea is a very unforgiving environment, and having bits of high tech componentry in the ocean (and in some cases very deep in the ocean) not only means the ocean destroys it, but when there are problems, it’s almost impossible to access the parts to fix them. Any maintenance becomes very difficult and very expensive. While prior attempts have had moving parts in the water, and deployed in deep water often between 30 and 50m, ours is in about 6m of water, and all our moving parts – the turbine and valves – are above the water line.

SE: What’s next for your company?

TD: The technology has global applications, so we hope that after demonstrating its potential at the King Island project, we will see it proliferate and become widespread. The more of the technology that’s deployed throughout the world, the more it will drive the cost of generation down, and we hope to see it competitive with wind and solar on price.

We do have some advantages over wind and solar already, in that wave energy is much more predictable. You can predict with a high degree of accuracy at least 3 days out, sometimes even up to 10 days. As such, its time frames of variation are low enough that the traditional baseload can react quickly to provide a seamless supply of power when the two are combined.