Humans have been struggling for years to create clean, renewable energy that doesn't decimate the planet. What's even more infuriating is that plants, waving gently in the breeze all the while, have been creating 'green' energy before mankind even existed. During plant photosynthesis, water and carbon dioxide is turned into glucose and oxygen. Recently, mankind has been trying to learn from plants to produce our own clean, green machines – in this case, artificial leaves.

The latest advancement in the artificial leaf comes from Monash University in Melbourne and brings us another step closer to a commercially viable method of turning water into fuel. Instead of creating glucose, the artificial leaf uses water and sunlight to produce hydrogen and oxygen. This process of "electrochemical splitting" is achieved by running an electric current through the water. The hydrogen can then be used for fuel production.

The make or break for any energy production technology is the all-important level of efficiency. If the energy output is too low, then artificial leaves will never stand a chance at replacing our current sources of energy, including things such as fossil fuels and nuclear power. In the past, the highest efficiency achieved in an artificial leaf was 18%. However, the scientists from Melbourne have increased this to an impressive 22%, the highest efficiency ever seen in artificial leaves. You can read about the details of this new device in Energy and Environmental Science.

While this level of efficiency is the best yet, it is still not quite good enough to make the process financially viable. However, the researchers note that they are aware of the parameters that need fine-tuning and which components need tweaking for the next generation of tests.

“Electrochemical splitting of water could provide a cheap, clean and renewable source of hydrogen as the ultimately sustainable fuel. This latest breakthrough is significant in that it takes us one step further towards this becoming a reality,” Professor Leone Spiccia, the lead researcher, said in a statement. Creating energy without waste is one of the biggest issues the world is facing in the 21st century. Just recently, President Obama set an ambitious goal of reducing emissions by more than 80% by 2050, relative to 2005 levels. This target could be much more easily achieved with the assistance of something like the artificial leaf.

If the artificial leaf can be improved to a marketable level, then we could be seeing forests of them powering our houses, cars and maybe even entire cities. 

“Hydrogen can be used to generate electricity directly in fuel cells. Cars driven by fuel cell electric engines are becoming available from a number of car manufacturers. Hydrogen could even be used as an inexpensive energy storage technology at the household level to store energy from roof-top solar cells,” Professor Doug MacFarlane, co-author of the study, summarized.