Researchers at The University of Glasgow are attempting to mimic the process of photosynthesis to artificially produce a carbon-neutral biofuel that could potentially solve the problem of finding a liquid fuel suitable for a post-oil society.

Easy access to a relatively inexpensive source of liquid or gaseous fuel is indispensable to the functioning of a modern society. Inexpensive fuel means inexpensive transportation costs and the latter is one of the baseline assumptions of a global economy. Without the ability to ship goods around the world at low cost, the economy, as we have constructed it, will fail.  Thus, we need fuel.

Currently, our fuel of choice is oil and we can be sure of two things: (1) if we keep using it then we are going to run out and (2) the combustion of oil releases carbon dioxide into the atmosphere. Carbon dioxide emissions are, of course, the main culprit behind global warming. It then seems there are at least two good reasons to look at other liquid/gaseous fuel alternatives.

Two alternatives currently being researched are probably familiar to the educated layperson, namely, biofuels and hydrogen gas. Biofuels take organic matter and then chemically process it to get a liquid or gaseous fuel. One example is the production of ethanol from corn.

Hydrogen gas doesn’t occur in natural deposits and therefore, must also be produced. It can be made via electrolysis (ie. passing electricity through water), gasification of biomass, or other more advanced processes.

It is important to note that both biofuels and hydrogen gas require an energy input. If the energy input is from renewable resources than either could be a carbon-neutral liquid/gaseous fuel but if not, then their use could be doing more harm than good.

A different approach is currently being developed by researchers at The University of Glasgow and other universities around the world. The idea is to mimic photosynthesis, the process that allows plants to grow. In photosynthesis, water and carbon dioxide react under solar illumination to produce carbohydrate molecules and oxygen. Solar energy is converted into chemical energy and stored in chemical bonds of the carbohydrate molecule.

6CO2 + 6H2O (+ light energy)  C6H12O6 + 6O2

Photosynthesis is already exploited in the production of biofuels, during which the carbohydrate molecules (ie. corn) are further processed to produce ethanol.  However, using novel approaches, it may be possible to produce a useful biofuel like methanol directly from an artificial photosynthetic process rather than having a carbohydrate intermediary that needs further processing.

2CO2+4H2O → 2CH3OH + 3O2

The result could be an artificial solid-state “leaf” that uses solar energy to directly produce useful biofuels. This could have several benefits. The energy-intensive processing necessary for traditional biofuel production would no longer be needed. Issues with traditional biofuels, such as their effect on world food prices or climate sensitivities, could be avoided as the artificial photosynthetic process would not require anything to actually grow. The artificial leaf would be a fabricated self-contained unit. Furthermore, the process could be carbon neutral.

The field of artificial photosynthesis is relatively new but certainly has great promise as the potential benefits of such a technology are far-reaching. You can learn more about artificial photosynthesis at The University of Glasgow’s Solar Fuels webpage:  http://www.glasgowsolarfuels.com/proj.bio-insp.html.

-Erik Janssen

(Engineering Physics, MASc, Year 2 at McMaster University)

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