Scientists at Oxford University have come up with a way to make electricity biologically. It’s not an English version of Ed Begley, pedaling his stationary bike attached to a turbine to make tea and crumpets. Nope, two different enzymes (hydrogenase and laccase) work together to kick start the chemical reactions that make electricity from hydrogen. It’s a biological fuel cell.
Traditional fuel cells generally use platinum to catalyze the reactions. The precious metal is scarce and toxic, making it expensive and hardly eco-friendly. The enzymes in bio-fuel cells are ubiquitous, found in plants and micro-organisms. They are pretty much infinitely renewable and completely biodegradable. They effectively make biological batteries that never run out as long as there is some hydrogen around. And what’s more, the hydrogen stream does not have to be pure, as it does for chemical catalysts. The enzymes simply pick and choose the hydrogen atoms from a smorgasbord of gases that would render the traditional fuel cell utterly impotent.
Ain’t life grand!
The university’s commercialization company, Isis Innovations has a couple of bio-fuel cells running a digital watch as a demo, reminiscent of, but a jot more sophisticated than sticking electrodes into a spud. The company hopes the invention will juice up all kinds of small electronics, and eventually more power-hungry gizmos.
However, the Oxford profs have a nagging little problem in common with traditional fuel cell developers. They still need to get the hydrogen from somewhere, which is generally from burning some sort of fossil fuel to split water into its components, hydrogen and oxygen. So, while people like to call the energy from fuel cells clean power with zero emissions, they usually do so ignoring the feedstock production.
Way across The Pond at Stanford University, another group of scientists is using enzyme-based reactions to tackle just that blight on the hydrogen economy. They have harnessed hydrogenase to make hydrogen. The input energy is none other than the sun itself. Photosynthetic bacteria house the hydrogenase, and the energy from the sun drives the chemical reactions.
There’s only one teensy weensy catch – oxygen stops hydrogenase dead in its tracks. That’s a bit of a problem when oxygen is a byproduct of the reaction that makes the hydrogen.
The researchers have, of course, come up with several work-arounds that include making hydrogenase that tolerates oxygen. If that doesn’t solve the problem, they hope that cyanobacteria will. Just like the enzyme, the ancient photosynthetic blue-green algae make hydrogen in the absence of oxygen. A bunch of universities and R&D companies are working feverishly to come up with what’s called biohydrogen production, including the University of Hawaii. If Stanford doesn’t figure it out, someone else surely will.
Put the biohydrogen production technology together with the biological fuel cell, and you’ve got sun, water and enzyme-made power. It would truly be clean energy every step of the way from making the hydrogen, to firing up an iPod.
The elegant power generation systems of the future are going to make our current filthy technologies seem positively Neolithic.