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Here's How Artificial Leaves Could Produce Zero-Emissions Fuel

Researchers in Australia have developed a solar-powered process for producing hydrogen that mimics photosynthesis.

by Aaron Cantú
Aug 24 2015, 9:45pm

Photo by Patrick Pleul/EPA

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A new study from Monash University in Melbourne, Australia is a reminder that even if the political will to ditch fossil fuels is in short supply, the technology to produce energy that generates zero greenhouse gases is growing more advanced. Scientists there have developed the most efficient means yet of producing hydrogen-based fuel from solar power, a process that mimics natural photosynthesis.

The man-made photosynthesis uses sunlight to separate hydrogen atoms from water molecules in a solar-powered "leaf." Researchers used inexpensive materials to convert solar energy into a current that split apart hydrogen and oxygen atoms in the water.

The Monash researchers were able to convert 22 percent of the incoming solar energy into hydrogen — the highest ever recorded. The first artificial leaf developed in 2011 had conversion efficiency of only 4.7 percent. 

They suggest an even better conversion rate is possible as the photosynthesis process became more refined.

Their findings were published in the journal Energy & Environmental Science.

Related: This Material Can Remove Carbon Pollution From the Atmosphere

The researchers hope to convert the hydrogen into a fuel source that could provide an alternative to fossil fuels, adding another technology to the mix of clean-energy sources like wind and solar that are becoming increasingly cost competitive with natural gas and oil.

Leone Spicca, the lead researcher of the study and a professor at the School of Chemistry at Monash, said that most of today's technologies that are powered by hydrogen, such as electric cars with hydrogen fuel cells, still rely on carbon-spewing fossil fuels to produce. 

"The majority of the hydrogen is currently made from carbon-based feedstocks, and only on the order of 5 percent is made by water electrolysis (water splitting)," he wrote in an email to VICE News. Unlike traditional methods of producing hydrogen, water electrolysis emits zero carbon.

The Monash study highlights the possibility of using abundant materials, including sunlight, water, and cheap metals, to generate hydrogen-based fuel without emitting any carbon dioxide. The UN's Intergovernmental Panel on Climate Change says that in order for the world to keep temperatures from rising 2 degrees Celsius above what they were prior to the Industrial Age  —  an increase that could trigger dangerous changes to the Earth's atmosphere, land, and oceans — humanity must reduce its carbon emissions between 40 and 70 percent by 2050, based on 2010 emissions rates.

But for artificial photosynthesis to become a mainstream technology, governments need to change their energy policies to favor zero-carbon fuel sources, said Douglas MacFarlane, another professor at Monash University who worked on the study. The IMF estimates that global subsidies for fossil fuels amount to $5.3 trillion a year, including direct government subsidies as well as hidden health and environmental costs generated by burning dirty fuels.

"Until there is a way of pricing in the cost of carbon emissions, these technologies will struggle to compete at a broad level," he told VICE News. "Socially, there are only the challenges of changing over domestic and automotive technologies to this kind of approach; nothing that isn't possible given the right economics."

Related: Obama's Steep New Emissions Rules Praised as 'Great Advance,' Scorned as 'Power Grab'

While the researchers hope that their findings become part of a foundation for a sustainable new economy, MacFarlane added that their research has yet to have much traction with policy makers.

A global economy powered by photosynthesis may be a political pipe dream now, but if it did become a reality, we likely wouldn't need to worry about the water running out, said Peter Gleick, a climatologist and expert on water issues at the climate and international security think-tank Pacific Institute.

Although large-scale artificial leaves would theoretically consume vast quantities of water—which is predicted to become scarcer as the planet warms and populations rise — Gleick said the leaves could be even more water efficient than current carbon- and nuclear-based energy production.

"I don't think [large-scale artificial photosynthesis] would cause water problems unless we are taking water from a water-poor area when we make the hydrogen," he told VICE News. "It's just a question of designing the system."

"I think people should be skeptical about silver bullet solutions to our energy or water or climate problems," Gleick said. "There are no easy solutions. But that's not the same as saying there are no solutions."

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environment
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photosynthesis
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greenhouse gas emissions