Energy: Cheap, Clean, and Forever
If you ask thoughtful people what the long term solution to our energy needs is, you would probably hear about a judicious combination of solar, wind, geothermal, biofuels, and nuclear slowly replacing fossil fuels. This isn’t a bad solution—assuming we had the societal will to get to it—because it relies on largely replaceable sources and lessens greenhouse gas emissions.
But what if we had a source of power that generated no greenhouse gases and was essentially limitless?
We do. It’s called hydrogen, and every molecule of water on earth contains a molecule of H2, just itching to be combusted for energy.
The problem, of course, is using less energy to strip the water of its hydrogen than is produced when the product is burned in a fuel cell. A recent publication from Dan Nocera’s lab at MIT takes a big step towards solving this problem. The approach is to simulate a natural process—photosynthesis—that uses the energy of sunlight to drive the heavy chemical lifting. Water electrolysis is already known, but relies on expensive rare metal catalysts and highly acidic or basic conditions. The new work deploys silicon cells to absorb light and two catalysts of cheaper transition metals. The final device mimics what happens in the leaf of a photosynthetic plant: direct sunlight splitting water into hydrogen and oxygen.
Difficult problems remain, including capturing, storing, and transporting hydrogen in a world almost completely lacking the appropriate scale of infrastructure, and engineering fuel cell/electric motor combinations that would replace the internal combustion engine. But at least we now know it should be possible, and possibility is surely what drives innovation.
Tom Tritton is President and CEO of CHF.
Video Monday: Artificial Leaf [Periodic Tabloid]
Small Molecule, Big Promise [Periodic Tabloid]