Copying nature
If you want to create a sustainable source of carbon-free fuel, find something that can do this already and just copy it19/11/2008
Copying nature might sound like an overly simplistic approach, but it’s exactly what researchers in the growing field of biomimetics are attempting. Biomimetics is an emerging branch of nanotechnology that, enthusiasts say, could develop exciting new discoveries to a host of seemingly intractable problems. The underlying philosophy is simple: plants, bacteria and other biological organisms have, through eons of evolution, developed some highly effective ways of doing things that would be very useful to us humans – so why not copy them?
Plants, for example, are able to use the energy in sunlight to split water into electrons and protons, thereby providing a stream of energy to fuel their growth. The process, as every schoolboy knows, is called photosynthesis. Scientists working in biomimetics say it is possible to build microscopic machines that can do the same thing.
An artificial human-made system that copied the process of photosynthesis could produce hydrogen, a carbon-free fuel. With a little tweaking it could produce fuels such as alcohol or even hydrocarbons that do contain carbon molecules but recycle them from the atmosphere and therefore make no net contribution to carbon dioxide levels above ground.
Biomimetics has other applications too. It could also solve the longstanding problem of how to store large amounts of electricity efficiently. This would knock down the barrier that has hindered the development of electrically powered vehicles. A biomimetic battery could enable an electric car to travel as far as a petrol or diesel-based counterpart.
To achieve this, scientists are trying to mimic a type of virus that infects E.coli bacteria. The virus can coat itself in electrically conducting materials, such as gold, to make microscopic ‘nanowires’. Because these wires would be so small, they could be tightly packed together, meaning a far greater amount of electrical charge could be held in the same space, slashing the size and weight of a battery. What’s more, the virus has a natural ability to replicate itself, which means that a battery could potentially self-assemble. This might sound all very far-fetched. Indeed, the commercial realisation of biomimetic technologies lies far in the future. But it is not science fiction. Nanotechnology is already improving the efficiency of existing energy-generating systems that use carbon fuels. Nano-scale catalysts, for example, can be used to improve the efficiency of engines or systems consuming fossil fuels.
Other nanotechnologies offer new ways of capturing and storing solar power. “If solar energy is harvested where it is most abundant, and distributed on a global net, it will be enough to replace a large fraction of today’s fossil-based electricity generation,” says Professor Bengt Kasemo of Chalmers University of Technology.
