For some energy researchers, it’s the holy grail: How can technology cheaply and sustainably recreate photosynthesis, nature’s way of making fuel, which works way better at taking energy from the sun than anything we’ve been able to invent?
A new “artificial leaf” is close to being viable for use at home, say scientists from Monash University in Australia. Using cheap, readily available materials, solar power, and water, the system pumps up out hydrogen with more efficiency than anything that’s gone before. That hydrogen can then fill up fuel cells.
“We’re not at all the first to tackle this problem,” says Doug MacFarlane, a chemistry professor at Monash University. “But what was behind our work was a realization that by separating the two main functions in the device–gathering solar energy as efficiently as possible, and using that energy to generate fuel–we could optimize the pairing of the two.”
They took a super-efficient solar panel, and then tweaked equipment that splits water into hydrogen so that it used the maximum voltage that the solar panel could create.
The system can provide solar energy for a home, and when gadgets inside don’t need the power, it can switch to making hydrogen.
“It effectively becomes an energy storage solution,” MacFarlane says. “That hydrogen can then be used in a fuel cell to regenerate the electricity–so we just effectively stored the energy and regenerated it again.”
It can also be used in a fuel cell hybrid car, like Toyota’s new Mirai. Though some have argued that hydrogen cars won’t succeed–Elon Musk has called them “mind-bogglingly stupid“–one of the challenges in the past was that hydrogen is usually extracted from natural gas, better than oil, but not the most sustainable
Hydrogen created with solar power, like the process performed by the artificial leaf, have had other problems; some systems aren’t stable, and other require expensive, scarce metals to run. But the system from Monash uses nickel as a catalyst–something that’s both abundant and cheap.
It’s close to technically ready for use at houses or gas stations. “The technical challenges are not great,” says MacFarlane. “It’s simply scaling up, prototyping, optimizing. The challenge is economic–various other forms of energy are rather cheap at the moment. Oil is cheaper than it’s been in a long time. So this won’t happen, especially for vehicles, until the cost of [gas] rises once again. Then something like this becomes much more favorable.”