Sunlight and manure is a combination most people would likely try to avoid.
But at the University of Illinois Chicago, researchers have found a way to make hydrogen fuel using sun rays and biowaste, including droppings and husks.
Importantly, the technique cuts the energy requirement to make the fuel by a whopping 600%.
"We are the first group to show that you can produce hydrogen utilizing biomass at a fraction of a volt," research team lead Meenesh Singh said in a lab summary. "This is a transformative technology."
Hydrogen is considered by many experts to be a clean-burning fuel, producing mostly water vapor as a byproduct, the National Renewable Energy Laboratory reports. As such, scientists around the world are trying to find better ways to make it, as well as to create machines that can be powered by it. There's even a big, government-backed proof-of-concept project in Texas that's examining ways to produce and use the alternative fuel.
The Chicago research, which is a multi-institutional effort, tackles one of the big knocks against hydrogen — the use of fossil fuels and high energy during production.
A common way to make hydrogen includes natural gas.
Electrolysis is a cleaner option that splits hydrogen from water using electricity. It can be powered by renewables.
The Chicago team's breakthrough came by introducing a carbon-rich substance the USDA calls biochar to the electrolysis chamber, decreasing the amount of electricity needed to break hydrogen from water, per the research summary. They created their version of biochar by mixing agricultural waste, manure, or sewage with sulfuric acid. The slurry is packed with needed carbon and is well-suited for the task.
Cow dung produced the best results. The experts said that an AA battery — they used a single solar cell — would provide more than enough power for hydrogen production. Since they use renewable energy and recycled waste streams, the technique could become "net zero." To hit that goal, the team must capture the carbon dioxide generated from the process. Singh suggested using it to carbonate beverages, as one example of a productive use for it.
"It's very efficient, with almost 35% conversion of the biochar and solar energy into hydrogen" study co-author Rohit Chauhan said in the report. "These are world-record numbers; it's the highest anyone has demonstrated."
Hydrogen has some other concerns, according to the Sierra Club. The environmental group notes that the fuel emits nitrogen oxides when burned. The gas is a potent polluter that can cause health problems, per the EPA. But the U.S. Energy Department reports the pollution is "comparable" to natural gas when burned to power a turbine, for example.
In fact, the federal government considers hydrogen to be a viable fuel alternative to help the country reduce world-heating pollution in the coming decades. Public health would benefit if it can be safely rolled out to replace fossil fuels. That's because air pollution is linked by many health experts, including the WHO, to increased risk for stroke, heart, lung, and other diseases.
The Chicago experts also see benefits from their tech being realized even on farms. They plan to test ways to scale the now-patented research.
"This cheap way of making hydrogen could allow farmers to become self-sustainable for their energy needs or create new streams of revenue," study co-lead author Nishithan Kani said in the report.
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