Researchers have developed a material that can be used to harvest electricity from the sun's heat, which paves the way for generating less expensive solar power during cloudy days and at night.
Innovation is an important step towards solar thermal electricity generation in direct cost competition with fossil fuels, researchers say.
"Storage of solar energy as heat can already be cheaper than saving energy through batteries, so the next step is to reduce the cost of generating electricity from the sun's heat with the added benefit of greenhouse gas emissions," says Kenneth Sandhage, a professor at Purdue University in the United States.
Concentrated solar power plants convert solar energy to electricity using mirrors or lenses to concentrate a lot of light on a small area that generates heat transferred to a molten salt.
Heat from the molten salt is then transferred to a "working" fluid, supercritical carbon dioxide, which expands and works to rotate a turbine to generate electricity.
In order to make the electricity supply of solar energy cheaper, the turbine engine would generate even more electricity to the same amount of heat, which means the engine must run warmer.
The problem is that heat exchangers, which transfer heat from the hot melt salt to the working fluid, a presently made of stainless steel or nickel-based alloys that become too soft at the desired higher temperatures and at elevated pressure of supercritical carbon dioxide.
Researchers thought of a ceramic zirconium carbide composite and tungsten tungsten for more robust heat exchanger.
They made ceramic metal composite plates. The plates are customizable channels to customize heat exchange.
Mechanical tests and corrosion tests showed that the composite material could be tailored to cope with the higher temperature, high-pressure supercritical carbon dioxide needed to generate electricity more efficient than current heat.
An economic analysis also showed that the scaled production of these heat exchangers could be carried out at comparable or lower cost than for stainless steel or nickel-based.
"In the end, with continued development, the technology would enable large-scale penetration of renewable solar power into the grid," said Sandhage.
"This would mean dramatic reductions in human CO2 emissions from electricity generation," he said. The story has not been edited by Business Standard staff and is automatically generated from syndicate flow.)