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CSIRO sets world record in generating "supercritical" steam using solar power

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June 3, 2014

The CSIRO has generated 'supercritical steam' at a pressure of 23.5 MPa (3,400 psi) and 57...

The CSIRO has generated 'supercritical steam' at a pressure of 23.5 MPa (3,400 psi) and 570° C (1,058° F) in what it claims is a world record for solar thermal energy (Photo: CSIRO)

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In what it is claiming as a world record and breakthrough for solar thermal energy, researchers at Australia's CSIRO have used solar energy to generate "supercritical" steam at its solar thermal test plant in Newcastle, Australia. Using a field of more than 600 directional mirrors (heliostats) directed at two towers housing solar receivers and turbines, the researchers generated steam at a pressure of 23.5 MPa (3,400 psi) and 570° C (1,058° F).

Generating supercritical steam, an ultra-hot, ultra-pressurized steam that’s used to drive the world’s most advanced power plant turbines, has previously only been possible using fossil fuels, such as coal or gas. The CSIRO is touting its generation using solar technology as a breakthrough for solar energy production, with Dr Alex Wonhas, CSIRO's Energy Director, seeing it as a potential revolution for the renewable energy industry.

"It's like breaking the sound barrier; this step change proves solar has the potential to compete with the peak performance capabilities of fossil fuel sources," Dr Wonhas said. "Instead of relying on burning fossil fuels to produce supercritical steam, this breakthrough demonstrates that the power plants of the future could instead be using the free, zero emission energy of the sun to achieve the same result."

Commercial solar thermal power plants that currently exist use subcritical steam that is generated at similar temperatures to the CSIRO experiment, but at lower pressures. The difference between subcritical and supercritical power plants is that the former operate at lower pressures, which allows bubbles to form when heating takes place, leading to inefficiencies.

However, by increasing the pressure, the boiling temperature also increases and the latent heat of vaporization decreases. Supercritical steam powerplants operate at such high pressure that the latent heat of vaporization is zero; in other words, liquid water is converted directly to steam. Modifying subcritical plants to operate on supercritical steam would vastly increase their efficiency and could help significantly lower the cost of generating solar electricity while negating the need to use fossil fuels to achieve the same result.

Supported by the Australian Renewable Energy Agency (ARENA) the research program is part of a wider collaboration with one solar thermal electricity supplier, Abengoa Solar. ARENA CEO Ivor Frischknecht in recognizing the importance of the realization of CSIRO’s work, said, "this breakthrough brings solar thermal energy a step closer to cost competitiveness with fossil fuel generated power."

The CSIRO says that although commercial development of the technology could still be a fair way off, the breakthrough is a big step in paving the way for a low cost, low emission energy future.

The video below shows the setup at its Energy Centre in Newcastle used to achieve the breakthrough.

Source: CSIRO

About the Author
Colin Jeffrey Colin discovered technology at an early age, pulling apart clocks, radios, and the family TV. Despite his father's remonstrations that he never put anything back together, Colin went on to become an electronics engineer. Later he decided to get a degree in anthropology, and used that to do all manner of interesting things masquerading as work. Even later he took up sculpting, moved to the coast, and never learned to surf.   All articles by Colin Jeffrey
9 Comments

An exciting acheivement. The critical question is how long the supercritical steam state can last.

Bruce H. Anderson
4th June, 2014 @ 08:59 am PDT

Not sure why anyone is surprised as solar makes the hottest, cleanest heat you can get.

Fact is because you can collect/transfer more energy at lower temps at a lot higher flow rate, thus much more total energy, easily beats the less flow, higher temp eff gain is likely why no one else bothers.

jerryd
4th June, 2014 @ 10:07 am PDT

I am not familiar with supercritical steam behavior so, can this step more readily crack water into oxygen & hydrogen? Or, can it desalinate itself in a steady process fashion better than at subcritical temperatures? In scaling this up can it be placed relatively close to urban areas in Australia and other warm areas around the world? More application info would be appreciated.

StWils
4th June, 2014 @ 11:05 am PDT

What portion of the day does it work? If only between 11am and 1pm why bother?

The solar hybrid plants generate electricity when need whether the sun is shining or not.

Slowburn
4th June, 2014 @ 11:32 am PDT

@Slowburn, it helps if you RTFA before dropping into auto-cynic mode. It's a research project that has shown that you can generate supercritical steam through solar heating, something which had apparently not been done before. That means that you can get higher efficiency out of your solar input. When that happens is not important (this is an experiment), and it could help any solar generator increase efficiency, including hybrid plants that are only a stop-gap anyway.

Synchro
4th June, 2014 @ 03:42 pm PDT

@ Slowburn. Given the temperatures being achieved here (& I doubt very much it'll be just 11-1 once it becomes commercial) I think it's pretty reasonable to assume that excess heat can be stored in chemical form-whether molten salt or the break-down of methane, ammonia, sulphur trioxide or even water. As Synchro has said, why are you so quick to drop into "auto-cynic" mode....do you just not *want* the technology to succeed?

Marcus Hicks
4th June, 2014 @ 06:22 pm PDT

Why are people so harsh on people asking questions about cost effectiveness?

There are ways other than by using a steam engine to turn an external heat source into electricity.

Also concentrated solar is real susceptible to clouds. A little haze can significantly reduce the output.

Slowburn
5th June, 2014 @ 02:51 pm PDT

SHEC Energy out of Saskatoon has patented a complimentary set of CSP technologies that also process hear at much higher temperatures than current CSP in the field.

Zorba
8th June, 2014 @ 11:34 pm PDT

Wonderful research! I have similar questions regarding feasability of coastal location, de-salination capabilities and applicability to the energy-hungry northern hemisphere? Any prospects of these?

Best wishes from "Sunny South Africa".

Regards, JohnnyB

JohnnyB
13th June, 2014 @ 01:24 am PDT
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