Researchers from the USA’s Purdue University have released details of a new system that uses solar energy to generate electricity while simultaneously producing and storing hydrogen for round-the-clock, emissions-free power production.
The concept is called “hydricity”, a theoretical closed system in which solar concentrators produce superheated steam to drive electricity-generating turbines and solar reactors for splitting water into hydrogen and oxygen.
Hydrogen is stored and used to run the steam turbines overnight, providing what lead researcher, Professor Rakesh Agrawal, believes could be a potential breakthrough for humanity.
“The concept provides an exciting opportunity to envision and create a sustainable economy to meet all the human needs including food, chemicals, transportation, heating and electricity,” Professor Agrawal said.
The findings, “Hydricity: A Sunshine Route to Sustainability”, were published Monday in the online early edition of Proceedings of the National Academy of Sciences (PNAS).
“In the round-the-clock process we produce hydrogen and electricity during daylight, store hydrogen and oxygen, and then when solar energy is not available we use hydrogen to produce electricity using a turbine-based hydrogen-power cycle,” said Mohit Tawarmalani co-author of the findings.
“Because we could operate around the clock, the steam turbines run continuously and shutdowns and restarts are not required.”
While using solar power to produce hydrogen from water isn’t a new concept, by integrating and improving the overall solar-and-hydrogen-to-electricity of their hydricity process the researchers were able to develop a system capable of producing more energy than conventional renewable energy technologies.
“The overall sun-to-electricity efficiency of the hydricity process, averaged over a 24-hour cycle, is shown to approach 35 percent, which is nearly the efficiency attained by using the best photovoltaic cells along with batteries,” said chemical engineering doctoral student Emre Gençer.
“In comparison, our proposed process stores energy thermo-chemically more efficiently than conventional energy-storage systems, the coproduced hydrogen has alternate uses in the transportation-chemical-petrochemical industries, and unlike batteries, the stored energy does not discharge over time and the storage medium does not degrade with repeated uses.
