Australian company Wave Swell Energy is developing a new system that harvests wave energy, a renewable form of energy.
The system is a giant hollow chamber that sits partially submerged on the seabed, funneling waves in and out of an underwater opening and generating electricity via a turbine.
The use of renewable sources of energy, such as wave energy, could play an important role in reducing greenhouse gas emissions to achieve the Paris agreement goal of preventing temperatures from rising more than 2° C (3.6° F) above pre-industrial levels by the end of the century.
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The use of renewable sources of energy, such as wave energy, could play an important role in reducing greenhouse gas emissions to achieve the Paris agreement goal of preventing temperatures from rising more than 2° C (3.6° F) above pre-industrial levels by the end of the century. Pictured is a prototype of the system in use
Solar power use hit record highs in 2016, and renewables overall overtook coal to become the world’s largest source of installed power capacity.
However these sources of energy aren’t always easy to harness: For example, wind and solar energy are only effective when the wind is blowing and the sun is shining.
So, the more diversified renewable energy sources are, the more reliable they can be.
The motion of the ocean is a renewable energy source, and there have been different methods to tap into that energy.
For example, buoys can be used to drive underwater hydraulic systems and wave energy stations have been mounted onto jetty’s, where they convert the rise and fall of waves into energy.
Wave Swell’s ‘artifcial blowhole’ – called an ‘Oscillating Water Column (OWC)’ is a large hollow concrete chamber, sitting partially submerged on the seabed.
It funnels waves in and out through an underwater opening, and it also has a small opening above the water, which houses an air turbine.
As waves pass the column, which measures 20 x 20 x 18 m (66 x 66 x 59 ft), water enters and leaves the chambers, rising and falling inside the column – causing the air above it to change pressure.
These changes in pressure force the air to pass by the turbine, generating electricity as they do.
‘So the water wants to fall, and that creates a partial vacuum inside the chamber, and it sucks air back through past our turbine, and that's what generates the electricity,’ CEO Dr Tom Deniss told NewAtlas.
What makes it different to other OWC’s is that its turbine is only exposed to air flow from one direction .
The only moving parts in the entire technology are the turbine and some simple off-the-shelf valves, all of which are well above the water line.
There are no moving parts in or below the water.
This means maintenance is only ever required to be performed on the easy-to-access regions well above the ocean.
The device uses ‘resonance’ to make the most energy out of the moving water.
So the motion of the water inside the chamber get amplified because it’s resonating at the same frequency as the waves – it does this by modifying the surrounding wave field.
That gives it a capacity factor – which is the ratio of the average power a system can generate to its peak – of about 47 percent, compared to the 30 percent that other wind and wave energy systems usually manage.
The company claims its system should be able to produce electricity for a cost of about $0.07 per kWh, which is roughly the same price as coal.
The technology is set to be trialed off the coast of King Island, which lies between Tanzania and Australia.
The technology is set to be trialed off the coast of King Island, which lies between Tanzania and Australia. It has a tiny population of 2,000, which is why it’s been a testing ground for other renewable energy sources before
It has a tiny population of 2,000, which is why it’s been a testing ground for other renewable energy sources before.
Energy organizations have collaborated on a project to combine wind and solar energy to supply about 65 per cent of the island’s energy.
In 2015, the island was run off 100 per cent renewable energy for a period of 33 hours.
This combined strategy can help with the fact that renewable energy sources like waves being intermittent.
One of the goals of the team is to increase the amount of time the island’s population can run fully on renewable energy.
As waves pass the column, which measures 20 x 20 x 18 m (66 x 66 x 59 ft), water enters and leaves the chambers, rising and falling inside the column – causing the air above it to change pressure
So far the company has completed the design and a prototype of the system and a unit should be up and running off King Island by mid 2018 – in the future, they hope to install more in other areas, and Hawaii could be a possible target.
Because Hawaii is isolated, its energy is mostly powered by diesel and electricity is expensive - even though the Island has waves which can be used as an energy resource.
But cost isn't the only issues - using diesel increases reliance on foreign oil, and if there's an oil supply problem in the world, Hawaii could find itself unable to afford the cost of generating power, or they may just be cut completely.
'It's one thing to not be able to run cars when that happens, but it's another to not have any power at all, for refrigeration and in hospitals,' said Dr Denniss.
Wave Swell Energy plans to scale up quickly, and Dr Denniss says he'd like to see projects on the scale of 100 MW or more running within five years.
The larger the scale, the cheaper the energy becomes to produce, and in the long run, the company believes it will be possible to get the price down to $0.04 per kWh.