Hi Maurice,
I thought you'd be interested in the following fuel cell story. At minimum, it's entertaining.
Best,
hiker
newscientist.com
Food scraps could help power homes
By Duncan Graham-Rowe
A battery that runs on scraps of food could fuel a battery
providing electricity to top up your home's supply, say UK
researchers.
Although such "microbial
fuel cells" (MFCs) have been
developed in the past, they
have always proved
extremely inefficient and
expensive. Now Chris
Melhuish and technologists
at the University of the West
of England (UWE) in Bristol
have come up with a
simplified MFC that costs as little as £10 to make.
Right now, their fuel cell runs only on sugar cubes, since
these produce almost no waste when broken down, but they
aim to move on to carrot power. "It has to be able to use raw
materials, rather than giving it a refined fuel," says Melhuish.
Inside the Walkman-sized battery, a colony of E. coli bacteria
produce enzymes that break down carbohydrates, releasing
hydrogen atoms. The cell also contains chemicals that drive a
series of redox, or reduction and oxidation reactions, stripping
electrons from the hydrogen atoms and delivering them
steadily to the fuel cell's anode. This creates a voltage that
can be used to power a circuit.
Robot power
To prove the MFC works, the researchers are using it to power
a small light-sensitive robot. And when a number of the cells
are connected in series, they could power domestic
appliances, running a 40-watt bulb for eight hours on about 50
grams of sugar.
Earlier MFCs were inefficient because they relied on
energy-hungry filters and pumps. By experimenting with
different anode materials, the UWE team have figured out how
to make their system work: they dump the bacteria and redox
chemicals directly into the cell.
In its current form, the UWE team says its organic battery can
produce eight times as much power as any previous MFC. But
Melhuish wants to improve this, both by scaling it up and
finding a better mix of redox chemicals.
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