AsianScientist (Jun 9, 2014) – Power stations of the future could run on solar-generated supercritical steam instead of fossil fuels, following a proof of concept demonstration by Commonwealth Scientific and Industrial Research Organisation (CSIRO) scientists.
Current power generators typically operate at pressures below critical pressure (22 MPa), an inefficient process because of the need to separate steam from water. Switching to supercritical steam, water heated to 570 degrees Celsius and pressurized to 22 MPa or more, could lead to as much as 42 percent improvement in overall plant efficiency, lower emissions and reduced boiler room explosions. However, the generation of supercritical steam has so far only been possible through the burning of fossil fuels.
Scientists at CSIRO have now found a way to use solar energy to generate supercritical steam. Using an array of 600 directional mirrors (heliostats) directed at towers housing solar receivers and turbines, they have been able to generate steam at temperatures above 570 degrees Celsius and at the record-breaking pressure of 23.5 MPa.
CSIRO’s Energy Director, Dr. Alex Wonhas said this milestone is a game-changer 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. 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,” Dr. Wonhas said.
The AUD$5.68 million (~ US$5.3 million) research program is supported by the Australian Renewable Energy Agency (ARENA) and is part of a broader collaboration with Abengoa Solar, the largest supplier of solar thermal electricity in the world. CSIRO and Abengoa Solar, with support from ARENA, are developing advanced solar storage to provide solar electricity at any time, day or night.
Although there is still work to be done before this technology is ready for commercialisation, ARENA CEO Ivor Frischknecht acknowledged the significant achievement saying it demonstrates the importance of research and development.
“This breakthrough brings solar thermal energy a step closer to cost competitiveness with fossil fuel generated power,” said Mr. Frischknecht.
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Source: CSIRO.
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