Scientists have studied plant photosynthesis for centuries, but an international team believes they have unlocked new secrets to nature’s great machine that could provide sustainable energy and combat climate change.
The team says they have determined that it is possible to extract electrical charges at the optimum possible point of photosynthesis. This means harvesting the maximum amount of electrons from the process for possible use in the power grid and some types of batteries. It can also improve the development of biofuels. Although it is still early days, the results, Reported in the journal Naturecan reduce greenhouse gases in the atmosphere and provide insight into improving photovoltaic solar panels.
The key breakthrough came when researchers observed the process of photosynthesis on very fast time scales.
“We can take photos at different times that allow us to see the changes in the sample really, really fast — a million billion times faster than your iPhone,” Dr. Tommy Becky, of the University of Cambridge’s Cavendish Laboratory, told CNET.
The team used a technique called ultrafast transient absorption spectroscopy, which is most simply understood as illuminating a sample with laser pulses and recording what happens in extremely short intervals. This makes it possible to see the electrons as they go through the entire photosynthesis process.
Previous demonstrations attached cyanobacteria, algae and other plants to electrodes to create so-called Bio-photoelectrochemical cells which taps into the photosynthesis process to generate electricity.
Baikie said they were surprised to discover a previously unknown path of energy flow early in the process that might be able to extract charge in a more efficient way.
“We depend on plants for everything we eat and the air we breathe, and we can probably use their electrons as well.”
Scientists have found that electrons “leak” at the site of the cell where photosynthesis begins. In nature, it can protect plants from the damaging effects of sunlight.
The discovery of new, leaky pathways could also have major implications for the production of renewable biofuels, typically derived from plants or algae. Biofuels can be carbon neutral because they both take in carbon dioxide when plants grow and release it into the atmosphere when burned, versus fossil fuels that release carbon stored deep in the earth over long periods of time. How much carbon biofuels add or subtract from the atmosphere depends on how the plants grow and how the fuel is produced.
This research can be used to develop more efficient processes for making biofuels.
“This is a completely new approach to biofuel production. We’re harvesting electrons from the most primitive and powerful point of photosynthesis and re-routing them there.” Research Coordinator Dr. Jenny ZhangAlso from Cambridge, said via email.
Zhang said that others had tried to harvest electrons from earlier points in the photosynthesis process but concluded that this was impossible. He says that at first, the team was convinced that they had made a mistake.
“It took us a while to convince ourselves that we did it,” Zhang said In a statement.
This breakthrough in turning sunlight into energy promises to make greater use of the incredible efficiency of photosynthesis.
“What makes photosynthesis really special is the nearly 100% efficiency of converting light into electrons,” explained Becky. “By understanding our photosynthesis process, we can use this knowledge to motivate us to improve existing solar cell technology.”
In addition to producing energy more efficiently, fine-tuning the photosynthesis process can help combat climate change, allowing plants to better absorb and store carbon dioxide.
Zhang envisions a future where tapping into photosynthesis allows us to “farm our energy the same way we farm our food,” but to do so with organisms like cyanobacteria, which don’t need to compete with food production.
In fact, he says new insights from this research could actually make crops more tolerant of intense sunlight.
“In the long term, if we can create self-generating, self-recycling, renewable energy and fuel from living materials, that will be one of the greenest options imaginable moving forward for sustainability.”