Scientists create bionic leaf that's more efficient than natural photosynthesis, secretly hoping this new process will be used for fuel and eliminate major greenhouse gases. (image not related)
We all remember plant week in grammar school biology and learning about photosynthesis. It's something so common we don't really think about it, unless you're a scientist. It seems researchers have been thinking about it a lot lately since they have used the process for a new system that aims to be more efficient at converting solar energy. Researchers at Harvard University have created a new system that allows them to store the sun's energy, converting solar energy into chemical energy using a leaf like system.
They refer to the invention as a “bionic leaf” or “artificial leaf” and it's supposed to be more effective than other similar systems including natural photosynthesis. The goal of this new system is to store the energy of the sun instead of just converting it for immediate use and building something useful from carbon dioxide in the atmosphere as a way to reduce major greenhouse gases. So how does it work? The simplified version is a jar containing bacteria (Ralstonia eutropha), which is a cobalt water splitting system and a pair of electrodes. When electricity is sent through this biological system, the electrodes change the water into hydrogen gas that can be used for fuel and carbon based materials.
“You can use hydrogen as a source of energy, burn it,” says co-author Pamela Silver of Harvard University. “Instead, we decided to take advantage of bacteria that take in hydrogen and carbon dioxide and use them to grow.” Silver goes on to explain as they grow, organisms produce specific compounds. This allows the bacteria to be genetically engineered to make useful things like alcohol and plastic precursors.
This is a big breakthrough for scientists, who have been trying to grow bacteria off water-splitting electrodes for a long time, but as with most new things the system isn't perfect. Right now, it's only ten percent efficient, but it's an improvement over the widely established eight percent baseline for real world performance. Also, researchers still have to find a way to connect the system to solar cells to take away the biggest draw back to solar energy – inability to store energy to use for hours of darkness. It's also not sure how the system will work in different climates. It may work well in a mild environment, but it probably wouldn't survive in extreme temperatures. It's an issue scientists are trying to remedy during these testing phases.
“I think this is actually quite exciting research,” says Johannes Lischner of Imperial College, London. “Converting sunlight into chemical fuels with high efficiency is something of a holy grail for renewable energy.” Once the system gets the kinks worked out, it could prove to be a cheap, eco-friendly way to produce energy and store it even if the sun isn't shining high.
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