No single new technology can deliver limitless and clean energy, but Daniel Nocera and Angela Belcher are optimistic that they can harness the physical and natural worlds to move toward this goal.

Belcher looks to ancient ocean organisms for her inspiration. The biocomposite materials that make up abalone shells or diatoms, which evolved over millions of years, are durable and exquisitely designed at the nano level. Belcher poses an “interesting question: Why didn’t the organism make other materials, like solar cells, batteries, or traditional fuel cells? ....We say, they haven’t had the opportunity yet, let’s give them the opportunity.”

Her goal is to engineer these organisms so that their DNA codes for the synthesis of an efficient battery or solar cell, for instance. “It seems crazy,” admits Belcher, but she points to a photo of her son, to whom she’s passed on the genetic information that’s given rise to his flesh and bones. Why not take the same principles and direct a microorganism to construct itself into a useful machine, Belcher suggests. “With the right ingredients, it would assemble itself,” she says. Using natural materials would ensure “environment-friendly processing” that produces little waste. Indeed, the yeasts used in beer could “brew semiconductors for solar cells as well,’ says Belcher.

“What will be the oil of the future, my nirvana?” asks Daniel Nocera. The answer is deceptively simple: water plus light. Nocera is trying to emulate plants, which story the energy of sunlight: “Every time you eat a green leafy vegetable, you’re literally chewing photons of the sun, releasing photons of the sun.” Nocera “does artificial photosynthesis”, which he believes “our future has to evolve to.”

The challenge lies in how to capture and convert the energy created by splitting water with sunlight. Nocera says “We don’t know how to make photovoltaics cheaply,” but we must learn quickly.

Right now humans globally require 13 trillion watts (or terawatts) of power. By 2050, we’ll need 28 terawatts. Nocera pokes holes in some hypothetical scenarios offered to achieve this objective. If you gave over every square inch of cropland on the face of the earth to biomass production, you’d only get 7 additional terawatts. Plus, “you couldn’t eat anymore.” You’d still need to add 8,000 nuclear power plants, by building a new plant every 1.6 days for the next 45 years; put wind turbines everywhere; and dam every available river, to approach the 28 terawatt goal.

These technologies don’t scale up realistically, says Nocera, so we must look to the sun, which in one hour puts out as much energy as humans use during an entire year.