A recipe for solar energy: learning from nature
For the past 20 years, MIT Professor Daniel G. Nocera of chemistry has been working on a novel system for producing pollution-free energy in real time without adding fuel. In his system, a tub of water containing specially designed chemicals sits in the sunshine. Gaseous hydrogen and oxygen rise from the water, pass through a power-producing fuel cell, then recombine to replenish the water in the tub.
Sound too good to be true? Nocera thinks not. While practical systems may be another 20 years away, recent events in his MIT lab suggest that his vision is not as implausible as it may seem.
Much discussion now focuses on a cleaner energy future based on hydrogen rather than fossil fuels. But where are we going to get all the hydrogen? The obvious answer is electrolysis, which splits water into hydrogen and oxygen, the feed stocks for clean and efficient power-generating fuel cells. But conventional electrolysis is driven by electricity mostly made using fossil fuels, just what we need to get away from.
Nocera and others believe that in the long-term we must get our energy from the sun. Even if we crowd the earth with biomass farms, windmills, solar power facilities and nuclear plants, we won’t be able to satisfy the world’s appetite for energy in 2050. Yet the daily dose of sunshine on the earth’s surface is enough to power our energy needs for 30 years.