New Material to Make Concentrated Solar Power Cheaper

Sunlight is vitally important for many things from making plants grow to allow solar panels to make electricity and it is also a source to heat stuff up to enormously high temperatures, which also makes concentrated solar power (CSP) possible.

In this context, a Purdue University-led team developed a new material and manufacturing process that would reportedly make one way to use solar power, as heat energy, more efficient whilst generating electricity. The innovation is a significant step for facilitating solar heat-to-electricity generation in direct cost competition with fossil fuels, which generate electricity to the tune of 60% in the US.

Kenneth Sandhage, Purdue’s Reilly Professor of Materials Engineering reiterated that storing solar energy as heat could be cheaper than storing energy via batteries. He added that the next step would be to reduce the cost of generating electricity from the sun’s heat with the benefit of zero greenhouse gas emissions. The research conducted at Purdue was in collaboration with the Georgia Institute of Technology, the University of Wisconsin-Madison and Oak Ridge National Laboratory, and was published in the journal Nature. Please see the video below.

In the context of concentrated solar power plants, conversion of solar energy into electricity is done by using mirrors or lenses to concentrate a lot of light onto a small area. This is said to generate heat that is then transferred to a molten salt. Next, the heat from the molten salt is transferred to a working fluid, supercritical carbon dioxide that expands and also works to spin a turbine for generating electricity.

The critical elements in this process are the heat exchangers. They transfer the heat stored in the molten salt to the carbon dioxide working fluid. So, if the process is made to operate at higher temperatures, CSP systems could generate more electricity from a given amount of sunlight.

Currently, the heat exchangers are made of stainless steel or from alloys that are nickel-based. And, Professor Sandhage has been working with a team of researchers to develop new materials that could be used in the heat exchangers to operate at higher temperatures. The team has created new heat exchangers from zirconium carbide (ZrC) and refractory metal tungsten that could withstand the high temperature, high-pressure supercritical carbon dioxide needed for generating electricity more efficiently.

Professor Sandhage concluded that it would mean dramatic reductions in human-made carbon dioxide emissions from electricity production. So, in the near future, carbon dioxide responsible for global warming could facilitate in reducing carbon emissions from the energy generation sector.

Image credit: Purdue University illustration/Raymond Hassan

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