Beyond Zero talks to Greg Allen of Western Australia wave power developer Carnegie Corporation

Posted on 29 Jan 2010

Based in Fremantle, Western Australia, Carnegie Corporation has developed the CETO II wave power device that produces zero emissions energy. Their unique system involves pumping a working fluid from the ocean floor to drive a conventional pelton wheel hydro turbine back on land. The high pressure fluid operates in the same way that the falling water of a conventional hydro dam would act. The technology was developed by the inventor back in the mid 70s yet it is only since 2006 that most of its commercial development has occurred. There is enough wave resource available in proximity to population centres to supply more than half of Australia's current average annual energy demand. Greg Allen is the Chief Operating Officer and joins the Beyond Zero team to discuss the latest developments and implementation of their zero emissions wave power.

The Carnegie Corporation is currently testing technology in Fremantle (approx quarter scale) moving to a full scale unit off Garden Island to be expanded out to a 5MW facility in 2011.

The CETO Unit was conceived by Alan Burns, the original Chairman, and was developed by Carnegie over a number of years (CETO 111 is the current model). In 1975, while diving, Burns was watching the movement of kelp at the bottom of the ocean and realised that rather than restraining the energy of the ocean we could design something that mimics its motion and extract the energy thus created.

It uses plumbing technology (works like a bike pump attached to the sea floor) with a flexible tether attached to a 'pump', which is attached to a buoyant actuator. This entraps a mass of seawater which mimics the molecules of water in their motion in a wave, just below the surface of the ocean. On an upwards movement it pulls through the tether and actuates the pump on the upstroke. The pump is a positive displacement pump. This means any movement enables it to pressurize the fluid in the system and it pushes that fluid ashore.

The pump sits at one to two metres (at lowest tide) below the surface of the ocean. (The closer to the surface, without breaking the surface, the more energy is collected from the wave). Connected to the CETO device are pipelines which take the generated energy back to shore. Conventional hydro electric power generation equipment ( a pelten wheel turbine) is then utilised. (Carnegie tries to leverage existing technology in the market as much as possible).

In a conventional hydyo electric dam, the higher the dam, the more energy is generated. This technology (the CETO device) is equivalent to a 1200m dam in its power generation. (At the higher end of this technology there is equivalence to an 1800m dam).

Can it provide baseload power?

The wave resource itself is inherently baseload as it is highly consistent and highly predictable. There is 100% availability of one metre waves (the CETO unit starts operating with one metre waves and 'flatlines' in output at four metres) therefore it is possible to extract energy from the waves with a CETO device 100% of the time.

Locations for this technology

Any south-western exposed site around the southern half of Australia. The first priority of this technology's development is to extract energy from the wave environment that typically comes off the southern ocean. The wave energy up to Eden is significant (one to three metres) but has no 'higher end' waves. It is necessary to adapt the technology for such locations with 'lower end' environments.ie. it is still highly consistent but at a lower level.

The northern hemisphere licensee is the renewable energy division of EDF (Energie du France) who have purchased the rights to exploit the technology in the northern hemisphere. EDF are interested in developing sites in Europe, USA and further afield. Europe has been interested in wind and wave energy and diversifying from coal for many years. It is a great vote of confidence in Carnegie and the CETO units that EDF has chosen to go with this technology after a worldwide scan. Carnegie have looked at sites in Costa Rica, New Zealand, Chile etc.

Scaling potential

Sites need to be 20MW or greater for an installation. Larger costs are in the mooring and pipeline systems which bring the fluid back to shore so economics dictates a reasonable scale of facility.

Carnegie are targetting 50 MW wave facilities. They have licences for a number of sites around Australia for this size facility. The vision is for 1700MW generation by 2020.

A 50MW facility occupies about 30 hectares of sea bed.

Asked how many sites around SW'n Australia have the right wave height and right conditions on the sea shore, Allen stated that the real question is how much of the resource is readily accessible? There are approximately 17 GW of accessible wave energy sites across the southern half of Australia, from Geraldton to Eden.

Costs

The installation cost for the first 5MW is approx. $10 million per MW. This first plant will be the most expensive. Due to the mass producable nature of the device, scale is necessary and therefore they need to be rolling out about 150MW per year to achieve the economies of scale envisaged by the technology ie. bulk purchasing of equipment, consitent workload etc. will push the capital costs down to $6-7 million per MW. (This does not translate into $/MWhour) The forecast is for 150MW/year - to be competitive with wind ie. $120 - 140/MWhour - to justify investment.

(CETO units themselves are a small proportion of the cost. Most of the cost is the pipeline and onshore facilities).

Jobs

Many jobs will be created in manufacturing the CETO units and in maintaining the plants ie. operating, maintenance, offshore and onshore support. CETO unit attachments are currently being manufactured in Victoria; pump units in Melbourne, Geelong and France; tethers in the UK and actuators in W.A.

Seasonal variation

The energy generation is slightly winter-biassed (25% variation).