For those of us interested in cleantech solutions to humanity’s need for renewable energy, today’s solar panels are miracles of technology. In the past 30 years, solar panel efficiency has increased exponentially while costs have plummeted. But as the kids riding in the back seat always say, “Are we there yet?” The answer to that, at least according to many researchers, is no. Solar panel technology still has a long way to go before the promise of abundant, low cost energy for all people is achieved.
“Most silicon panels have to run for eight to 10 years before they recover the energy it took to make them,” Barry Bruce, a professor of biochemistry and cellular and molecular biology at the University of Tennessee and a biosolar pioneer, told Salon. “So there’s room for improvement.”
Today’s solar panels use small amounts of expensive and toxic elements like ruthenium, cadmium, and indium. Silicone is abundant in nature but converting it into a form that solar panels can use to make electricity requires lots of energy. Plus, the silicon wafers that result require silver electrodes. The best solar cells available are only 30% efficient, meaning that 70% of the sunlight that falls upon them is wasted. Most commercial panels are between 15% and 20% efficient.
Researchers at, Bruce’s lab at the University of Tennessee think they can do a lot better by mimicking the photosynthesis process that occurs in nature, which has an efficiency ratio of nearly 100%. Wouldn’t it be great if they could find a way to incorporate that ultra-efficient process into devices that provide clean, affordable and sustainable energy?
“There are two billion people living without electricity right now,” says Bruce. “If they had, say, the light to read at night, they could learn to treat their water, learn to use vaccines, practice birth control, and learn to implement better agricultural practices. We could help overcome the world’s illiteracy obstacle.”
The researchers are trying to find ways to extract the protein centers that are responsible for photosynthesis from plants and bacteria. If they can do so efficiently and at low cost, it may be possible to make a thick paste of enriched green material — like a pesto sauce for energy generation, according to Salon — that can be painted onto sheets of transparent material like mylar to make low power solar cells for charging cell phones and powering LED lights.
There are only about 20 labs worldwide pursuing such research. Last year, researchers at Binghamton University in New York were able to assemble nine cyanobacteria-powered solar cells into a solar panel. The device they created produced 5.59 microwatts — the most by existing small-scale biosolar cells. That’s not a lot but science has to start somewhere. 30 years ago, solar panels were less than 1% efficient.
Seokheun “Sean” Choi, director of Binghamton’s Bioelectronics and Microsystems Lab, says “Biological systems have the advantages of being self-assembling and self-repairing. Also, they are extremely cheap and environmentally friendly to manufacture and scale up compared with traditional solar cells. But there is a long way to go,” he says. “First of all, the power density must be increased significantly. There are many potential solutions for this. Genetically engineered bacteria will be one of them.”
Jellyfish are also being studied as a possible source of biological solar power. Six years ago, Swedish scientist Zackary Chiragwandi put thousands of the Aequorea victoria species in a blender in order to isolate the creature’s green fluorescent protein (GFP) — the stuff that makes it glow.
This year, Iranian researchers built a solar cell using GFP coupled with light activated proteins from bacteria to achieve a voltage of 690 mV, about the same as traditional dye sensitized solar cells. According to Iran’s MEHR News Agency: “With further optimization of energy conversion, these cells can replace the older generations of solar cells in the near future.”