The demand for fuel is ever increasing as the world becomes more and more industrialized. Thankfully, the investments in green energy are also escalating. Many are the experts that have referred to solar power as the most promising technological field with regards to creating sustainable and economically viable options to fossil fuels. We are daily bombarded with news about the increased efficiency and dropping costs of solar panels, which is of course quite pleasant for those of us who care about preserving our planet, but it might be interesting to look at other utilizations of the power from the sun as well.
As it turns out, Harvard researchers have managed to create what they call a “bionic leaf”. As CleanTechnica points out, some of us vaguely recall having stumbled upon this term before. The last time we heard about a bionic leaf, it involved making hydrogen fuel from sunlight and water. However, there are many skeptics criticizing hydrogen and say that it is not a fuel source worthy to the future of green tech. Even if we do not know much about the future, these skeptics might have a point for now. The reality is that hydrogen has failed to catch on as a practical fuel for cars and for power generation in a world designed around liquid fuels, as for instance noted by R&D Magazine. There are some things hydrogen is very good at though, and one of them is that it offers a way to store energy for later. And that is where the new and improved bionic leaf solution comes in.
The researchers have built the “leaf” from a silicon strip coated with catalysts on each side. The Daily Mail writes that when placed in water and exposed to sunlight, the strip split the water molecules to release oxygen and hydrogen with the help of voltage from a solar panel. This part is in the invention is taken from the previous bionic leaf solution mentioned earlier, but the scientists have added a new twist. The Weather Network reports that the researchers at Harvard have taken use of common soil bacteria to create the solution, making a type of liquid fuel called isopropanol. This type of fuel has many uses, for example in aviation. In nature, the bacteria use hydrogen and carbon dioxide for reproduction. Here, it converts the hydrogen into protons and electrons, and when carbon dioxide is added to the mix one can create the isopropanol. Researcher Pamela Silver stated in the Harvard press release:
“This is a proof of concept that you can have a way of harvesting solar energy and storing it in the form of a liquid fuel”
Scientific American reports that the bionic leaf can pump out 216 milligrams of isopropanol per liter of water—an efficiency that rivals that of a corn plant making starch-rich kernels out of sunlight. This might sound good considering that the solution reaches the level of nature itself, but one should remember that the photosynthesis is a quite inefficient process. Therefore, as Science Daily notes, the team’s immediate challenge is to increase the bionic leaf’s ability to translate solar energy to biomass by optimizing the catalyst and the bacteria. Their goal is 5 percent efficiency, compared to nature’s rate of 1 percent efficiency for photosynthesis to turn sunlight into biomass. Daniel Nocera, one of the scientists and a Professor of Energy at Harvard University, gave this confident statement in the press release:
“We’re almost at a 1 percent efficiency rate of converting sunlight into isopropanol. There have been 2.6 billion years of evolution, and Pam (Silver) and I working together a year and a half have already achieved the efficiency of photosynthesis.”
Despite the modest efficiency, and bearing the words of Professor Nocera in mind, the invention is actually quite interesting, and who knows, maybe the scientists could be on to a serious discovery in terms of complementing technologies within solar power. For instance, Tech Times writes that one day, homes and businesses might regularly be powered by solar cells, while vehicles are powered by liquid fuel generated by bionic leafs. Whether the solution will bring us something with serious potential or not, green energy innovation is always welcome.