Yang, a professor of energy and chemistry at the University of California, Berkeley, is one of this year’s MacArthur Foundation “genius” grant recipients. His lab has developed a “leaf” that uses nanowires between 100 and 1,000 times thinner than a human hair to capture sunlight. Bacteria cultured among the nanowires then use that sunlight to convert CO2 into oxygen and fuels like methane and butanol.

The Los Angeles Times recently caught up with Yang to discuss the technology and his hopes for the future:

How close are you to being able to use artificial photosynthesis on a large scale?

This year, we finally came up with a first-generation, fully-functional system — and that’s after 10 years of research. We demonstrated its feasibility, but in terms of robustness and cost and efficiency, it is not close to being commercially viable.

To do basic research, we have to be patient. I’m a big believer that discovery cannot be planned. It requires support from the government and industry. It will take the work of one or two generations of talented people to solve this problem.

Do you think artificial photosynthesis can ever compete with natural photosynthesis?

We want to learn from nature, but we have to be better than nature.

It took evolution millions of years to get green plants and leaves to their current stage, but their solar-to-chemical-energy efficiency is not that high. All they need to do is make enough energy to survive. To come up with a commercially viable technology, we have to do better than that.

Is that possible?

Theoretically, it is certainly possible. In solar panels the energy conversion efficiency is above 20%, much higher than what is happening in leaves. So in terms of design, we have the advantage — nature doesn’t have silicon to use. We do.

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