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Published on April 21st, 2013 | by Giles Parkinson

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Solar Energy In The Australian Outback – At 8c/kWh



This article first appeared on RenewEconomy.

An Australian solar thermal technology developer says it can provide concentrated solar thermal energy to outback and remote locations for just 8c/kWh, and hopes to sign for its first two commercial projects within the next few months.

Graphite Energy, an Australian company privately owned by an un-named “entrepreneurial family”, has been operating a 3MW solar thermal power plant at Lake Cargelligo, in western NSW, for the last couple of years.

Concentrating solar thermal technology differs from solar PV because it captures the sun’s heat and uses it to generate steam – just like fossil fuel generators. The key to its success comes in its ability to do this efficiently, at high temperatures, and at low cost. graphite

Various technologies exist, such as parabolic troughs, power towers and flat-mirrored linear fresnel. The distinguishing feature of Graphite Energy’s technology (seen at right) is that it uses graphite receivers that are mounted on towers to collect heat reflected from a field of heliostats (mirrors), and its ability to store energy via  heat exchangers gives it an “in-built” storage option that delivers “dispatchable” energy.

And the company is about to take this technology to market, but not in the way that most would expect.

One thing it has learned is that, unlike other CSP technologies, it does not have the cost structure to be able to install more stand alone power plants. “It’s an expensive way to boil water,” Gary Baddlock, the chief operating officer of Graphite Energy, told an international symposium on concentrating solar power at the CSIRO Energy Centre in Newcastle on Wednesday.

But it does offer a cheap way of doing what he calls the “high end” of the technology, by “superheating” waste heat, for instance, and using this to produce energy.

Baddlock notes that this has attracted the interest of two potential customers in remote areas of Western Australia. The details are being kept confidential for the moment, but they are most likely mining related, as the load requirements of the client need to be at least 15MW to be worthwhile.

Baddlock says that by adding the solar technology, and its storage ability which can provide stable output over a 24 hour period – diesel consumption at a remote location could be reduced by 15 to 30 per cent.  Given that diesel-fired power plants cost at least 30c/kWh, and sometimes more than 40c/kWh depending on location, the option to replace at least some of this with an 8c/kWh power source should be attractive.

Baddlock says by integrating waste heat and solar thermal, and focusing on the “last 20 per cent” of the heating process, this will deliver thermal to electrical efficiency of more than 50 per cent, and a solar to electricity efficiency of around 30 per cent, and explains the dramatically cheaper levellised cost of energy” over other applications. (Most solar thermal technologies are bracketed around 25c/kWh)

He says the technology can be used as a booster to lift the temperature of steam, and the efficiency of steam cycle turbines by between 7 and 15 per cent.

The company’s initial target markets are for boosting combined cycle gas turbines where the avoided cost of fuel is greater than $10/GJ (and has some spare land), and on remote mining locations which burn high cost diesel, which is offering the best short term opportunities. Indeed, there are a number of projects combining solar with diesel or gas in remote locations that could be announced in the coming year, some with help of funding from institutions such as the Australian Renewable Energy Agency, which has identified hybrid systems as one of its priorities.

Overseas opportunities for Graphite Energy are seen in the US, where the company would focus on integrating its technology with CCGT and cogeneration plants, or even to extend geothermal plants; and in Saudi Arabia, where it would look at hybrid facilities or stand alone solar thermal plants acting as superheaters.

“We believe we have got a compelling solution for solar thermal,” Baddlock says. “We feel  we have found the essence of where the true value is. Now it’s about getting out there and getting projects.”

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About the Author

is the founding editor of RenewEconomy.com.au, an Australian-based website that provides news and analysis on cleantech, carbon, and climate issues. Giles is based in Sydney and is watching the (slow, but quickening) transformation of Australia's energy grid with great interest.



  • Bob_Wallace

    Eight cents is not low enough if the new PV farm in Spain really comes in at six cents.

    • Ronald Brakels

      This comes with storage.

      • Ronald Brakels

        But low cost PV could make this uneconomic. It would be possible to rely on PV during the day while one of these just heats graphite for use during the evening and night. Or surplus PV electricity could simply be used to heat a block of graphite or other thermal energy storage medium without heliostats. This wouldn’t be an efficient way to run things but still might be the cheapest way to store energy for an off grid mine.

      • Bob_Wallace

        If it has storage. I read the piece a couple of times and it wasn’t clear to me that it did. There’s ““in-built” storage option” but I didn’t see anything specific about storage actually included.

        • Ronald Brakels

          In this design sunlight is concentrated onto a big graphite block in the tower and that block stays hot for quite some time. Water takes heat from the graphite block, so storage is built in. This design was going to be built in the outback town of Cloncurry a few years back, but it ran into problems with glare and now Cloncurry now has a fair bit of PV instead.

          • Bob_Wallace

            If the block of graphite is large enough and well-enough insulated.

            Someone worked up a thermal solar design a few years back in which the heliostats would be aimed at a concentrating mirror suspended above them. The light beam from that mirror would be aimed on a very large block of graphite stored underground in an insulated chamber. When the Sun dropped in the sky a set of insulated doors would seal off the graphite.

          • Ronald Brakels

            It works. This is like ancient technology from 4 years ago. The Cloncurry project design had 8 hours storage but glare and low cost PV killed it. Here they seem to be ressurecting it as a hybrid solar/fossil fuel system that makes use of waste heat. This may work, or low cost PV/wind etc. might mean it would be more economical to skip the heliostats and just use electrical resistance heating thermal storage. It will be interesting to find out what works best.

  • jburt56

    Aye mate, that’s one sweet array you have there!!!

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