Supercritical Solar Steam Could Rival Fossil Fuels

A breakthrough by CSIRO scientists could see solar energy replace fossil fuels in the most advanced power stations in the world.

A research program at the CSIRO Energy Centre in Newcastle focused on using solar power to create supercritical steam – super-hot, pressurised steam – to drive electric turbines in large-scale power plant.

The CSIRO team broke a world record for heating and pressurising steam using only solar thermal power in May.

The work has been hailed as a coup for the renewable energy industry. Previously, only coal or gas-fired plants could achieve temperatures high enough generate supercritical steam.

Conventional solar thermal power plants currently generate subcritical steam – but CSIRO believes if these plants could be converted to supercritical steam power, the overall cost of solar electricity would be significantly lowered.

“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,” said CSIRO Energy Director, Dr Alex Wonhas.

“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.”

Researchers used CSIRO’s test solar thermal plant in Newcastle to break the world record for solar steam, reaching temperatures of 570 degrees Celsius, at a pressure of 23.5 megapascals (a measure of force per unit area). It is this combination of enormous pressure and heat that makes the breakthrough such an important milestone for solar technology.

The CSIRO says the breakthrough was made possible through a $5.68 million research program supported by the Australian Renewable Energy Agency (ARENA) and collaboration with researchers from solar thermal giant, Abengoa Solar.

ARENA CEO Ivor Frischknecht said that while work remained before supercritical solar steam technology would rival fossil fuels, “This breakthrough brings solar thermal energy a step closer to cost competitiveness with fossil fuel generated power.”