Artificial Photosynthesis Powering Up

By: Sheila Moorcroft

Photosynthesis is ubiquitous, but not easy – for humans. Although plants do it, humans find it more of a challenge: but we are making progress on a number of fronts. The potential long term is almost limitless supplies of low carbon energy; clean fuels for cars, planes and ships; and fundamental change to the nature of the global economy.

What is changing?

Swedish researchers have developed a molecular catalyser that can oxidize water to oxygen at speeds not far off those of natural photosynthesis. Speed has until recently been a major obstacle.

Research to develop an artificial leaf aims radically to improve the conversion ratios of ‘natural’ photosynthesis which at present has an estimated conversion ratio of between 1% and 5%.

A start-up company has developed a process which could convert the carbon dioxide emissions from industrial processes and wastewater into natural gas, using solar power.

An ‘artificial leaf’ could, it is claimed, produce enough electricity to power an American home for a day using three gallons of water and a large solar panel.

Another experiment aims to use ‘vats of bacteria’ to produce fuel using sunlight to drive the process. The aim is to modify cyanobacteria, so they can power themselves with electricity rather than sunlight direct. The resulting fuel can then be stored – overcoming one of the major obstacles of renewable energies.

Why is this important?

Energy demand is expected to double over the next 40 years if we do not find more efficient ways to use it; and even if we do demand may still continue to increase. Not only that, oil supplies are becoming more difficult to find and extract; although again, technology and price rises are making new sources feasible. Then there are carbon emissions and climate change, and the need to find low carbon options for processes. Artificial photosynthesis could benefit all of these and more.

The variety of research and the cumulative effect of progress on so many fronts may mean that we are getting nearer to a breakthrough. If we are, it could radically change the nature of the global economy – our dependence on oil could go – reducing production costs for almost every process from food to transport in the process; desert areas could become the power houses of the future; distributed power in poor countries could bring a revolution in every aspect of the economy as the lights go on.  Oil rich nations could however face difficulties as their economies shifted. What used to be a pipe dream, may be reality sooner than we think.

We first discussed artificial photosynthesis in 2008.

By Sheila Moorcroft