The Sun, roughly 93 million miles away, is what powers everything for us on Earth in one way or another. Unfortunately, we haven’t been very good at efficiently using its vast amounts of energy. Coal and oil work as decent energy sources, but if we could cut out the middle man to get hydrogen directly from sunlight on a meaningful scale, humanity would have it made. That’s what Erik Koepf, a doctoral candidate at the University of Delaware, is working on. His solar reactor project produces hydrogen from a chemical reaction causing sunlight to split water, but its efficiency is still unknown. In March, he’ll be traveling to Zurich, Switzerland to test the reactor at full power for the very first time. From there, we’ll be able to see if this solar reactor will serve as a stepping stone to better solar technology, or if it’s a complete dud.
This reactor uses zinc oxide powder on a ceramic surface that is then exposed to massive amounts of focused sunlight. From there, a therm o chemical reaction happens that splits water apart into oxygen and hydrogen. It sounds rather complex at first, but it’s beautifully simple in a way — using the Sun’s effectively infinite power to do the heavy lifting for us. No greenhouse gases are being produced, so this is an environmentally friendly power solution. Better yet, this line of research has the potential to make renewable and reliable energy a reality. That means no more bending to the whims of OPEC.
To get the reaction needed for everything to work properly, the reactor needs to get unbelievably hot. The thermometer needs to hit between 1750° to 1950° Celsius (3182° to 3542° Fahrenheit), so it will need a lot of concentrated sunlight. A mirror that fits the needs of this project just didn’t exist, so Koepf and his research associate Michael Giuliano had to develop their own. This inch-thick water-cooled 45-inch by 45-inch mirror is flawlessly flat and 98% reflective. Effectively, this system focuses the solar energy into a tiny six centimeter circle that has to be precisely aimed. If the light is just a millimeter or two off to one side, the entire reactor could be damaged. Considering this ton-and-a-half monster has to be moved back and forth from the US to Switzerland, nobody wants to have to go back to the drawing board.
The first tests were successful in creating small amounts of hydrogen, but the real test is happening next month when the system will be running at full bore. While expectations are obviously quite high, it’s still too early to know how effective this reactor will end up being. “We want to analyze the reactor under different conditions to determine how our production rates vary under different levels of zinc oxide dispersal, temperatures and flow patterns,” says Koepf. This single project isn’t the be-all and end-all of solar power, but it is promising. In the coming decades, we’ll have to stop labeling solar power as “alternative power,” and start thinking of it as our best way forward.