Waves horizontal motion

Carnegie C​ETO

Off Fremantle a piston is fixed to the ocean floor and goes up and down as waves pass overhead. This forces high pressure sea water ashore into a desalination plant.

Carnegie has just completed a year long trial on Bermuda and will be installing a 20 MW wave power station.

Carnegie Wave Energy, which is currently working on the installation of the 2MW installation near Fremantle, says its CETO technology will shortly have a levellised cost of energy of around 35c/kWh, which means it will be able to compete with the cost of diesel on island grids – hence its focus on opportunities in places such as Reunion Island, Bermuda, and in the Pacific – and also in the UK, which offers a 5 times multiplier on renewable obligation certificates (the local equivalent of RECs).

According to this graph below, made in a presentation to a Sydney conference last week, over the medium term, Carnegie expects its costs to fall to around 25c/kWh, making it cost competitive with offshore wind, and making it an interesting proposition for other wave-rich European countries such as Ireland, Portugal and France, while over the longer term, the aim is to bring the cost down to match that of onshore wind, or around 10c/kWh, where it will be competitive in countries such as Chile.

Carnegie Wave Energy expects to begin construction of its Perth Power Project – near the naval base at Garden Island – in the first quarter of 2013 and make its first power sales into the grid in the fourth quarter of 2013. The project recently attracted a $9.9 million grant from the federal government’s Emerging Renewables Program and a $5.5 million grant from the WA government, and the company is currently negotiating a power purchase agreement with local offtakers.

Later this year, the company is expecting that a pilot unit of its CETO 4 technology will be deployed on Reunion Island by French energy giant EDF and French construction company DCNS.

Renew Economy

2012 to 2014 - Grid Connected Demonstration

Perth Wave Energy Project
50% Government grant funded
First grid connection
First revenues from CETO power
Demonstration of CETO grid connected array

 

Website

 

Perth-based Carnegie Wave Energy has unveiled the latest design of the CETO technology it proposes to use in its 2MW demonstration project off Garden Island near Fremantle – the first in the world to deploy multiple machines.

After 12 months of research, Carnegie has bumped the size of its submerged buoy to 11m in diameter for CETO 5 (see image below), up from 7m in the CETO 3 version that was used in a trial off Garden Island last year.

Carnegie Wave Energy says this will triple the capacity of the machine to 240kW, and it says that further refinements of the hydraulics will ensure that it can produce power more than 97 per cent of the time in the best wave sites. The hydraulics are complex but crucial, as the buoy is designed to move with the motion of the ocean, driving pumps that pressurise water and then send it to hydro-electric turbines located onshore.

The company expects to begin construction of its Perth Wave Energy Project in the first quarter of 2013 and make its first power sales into the grid in the fourth quarter of 2013. The project recently attracted a $9.9 million grant from the federal government’s Emerging Renewables Program and a $5.5 million grant from the WA government, and the company is currently negotiating a power purchase agreement with local offtakers.

Later this year, the company is expecting that a pilot unit of its CETO 4 technology – which has a 10m diameter – will be deployed on Reunion Island by French energy giant EDF and French construction company DCNS.

Video

Ceto 6 - 6 M diam. with a rated capacity of approximately 240 kW. 

Oyster

The Oyster wave power device is a buoyant, hinged flap which is attached to the seabed at depths of between 10 and 15 metres, around half a kilometre from the shore.  This location is often referred to as the nearshore.

Onshore electricity generation
Oyster's hinged flap, which is almost entirely underwater, pitches backwards and forwards in the nearshore waves.  The movement of the flap drives two hydraulic pistons which push high pressure water onshore via a subsea pipeline to drive a conventional hydro-electric turbine.

In the future, subsea pipelines will connect multiple Oyster wave energy devices to a single onshore plant.  Ultimately Oyster will be installed in wave farms of several hundred connected devices generating hundreds of megawatts of electricity.

Website

 

Click to play video

Wave roller

Very similar to the Oyster. Website

 

Laminaria​

Website

Langlee​

"The 132 kW Langlee Robusto™ is a semi-submersible floating installation meassuring 30x50 metres. It is floating at the water surface but most of the unit is under water, not visible from shore. The four mooring lines keeps it in position. Normal installation site is at 40-100 meter water depth."   Website

Ocean star - Bourne E​nergy

"OceanStar captures the underlying pressure wave, amplified ocean wave to accelerate and collapse through a series of small turbine generators." Website

Nearshore waves

There are advantages in using waves just outside the surf zone.

• Amplified wave force in the surge direction due to 'shoaling'. Orbital particle motion in deep water is largely circular. However, this motion is distorted in the nearshore region due to sea bed interaction. This results in an amplification of forces by up to 50% in the surge (beach) direction in the nearshore area as illustrated in the diagram.

• Filtering of the largest ocean waves. The largest storm and rogue waves are filtered out before reaching the nearshore area, largely due to the action of wave breaking. Therefore extreme forces on a wave energy converter are significantly reduced in the nearshore area enhancing survivability.

• Narrower directional spread. While waves in deep water are omni-directional, waves in the nearshore region are largely directed in a beach-ward direction with a tight directional spread. 

• Lower power transmission losses. A typical nearshore site with a 10-15m water depth is only 500m from the shore when compared to several km for a typical deep water (50m) site. This means that transmission losses are less for an equivalent nearshore site.

Biowave

"The bioWAVETM is mounted on the sea floor, with a pivot near the bottom.  The array of buoyant floats, or "blades", interacts with the rising and falling sea surface (potential energy) and the sub-surface back-and-forth water movement (kinetic energy).  As a result, the pivoting structure sways back-and-forth in tune with the waves, and the energy contained in this motion is converted to electricity by an onboard self-contained power conversion module, called O-DriveTM.  The O-DriveTM contains a hydraulic system that converts the mechanical energy from this motion into fluid pressure, which is used to spin a generator.  Power is then delivered to shore by a sub-sea cable."

"The bioWAVETM prototype currently under development will operate at a depth of 30m, while the planned 1MW commercial model will operate where the depth is 40-45m"

Biowave website

http://40SouthEnergy40South Energy

The 40South is made of two sections, upper and lower.

The upper part is just below the surface and moves with the waves.

The lower section, is about 15 metres lower and is relatively stationary.

The extension and contraction of the connecting rods generates electricity.

Ref.. See animation..

In rough weather the machine goes deeper to avoid damage.

AguaGen SurgeDrive