Scientists report in the American Chemical Society journal Environmental Science & Technology Letters a first-of-its-kind development toward that goal: a rechargeable battery driven by bacteria.
A discovery like this might be refreshing news following a recent Economist headline questioning whether lithium is now an equivalent to precious metals.
“Worldwide sales of lithium salts are only about $1 billion a year. But the element is a vital component of batteries that power everything from cars to smartphones, laptops and power tools. With demand for such high-density energy storage set to surge as vehicles become greener and electricity becomes cleaner, Goldman Sachs, an investment bank, calls lithium “the new gasoline”.”
Storage for renewable electricity
Solar, wind, and other renewable energy sources are gaining ground as nations work to lower greenhouse gas emissions and reliance on petroleum. But sunlight and wind are not constant, so consumers can’t count on them 24-7.
Storing energy can make renewables more reliable, but current technologies such as lithium-ion batteries are limited by safety issues, high costs and other factors.
Sam D. Molenaar and his colleagues from Wageningen University and Wetsus (The Netherlands) wanted to come up with a less expensive, more sustainable solution.
As reported by ACS, the research team combined, for the first time, two separate microbial energy systems. One system used bacteria to form acetate from electricity, while the other one converted the produced acetate back into electricity. The researchers were then able to charge the battery over a 16-hour period and then discharge it over the next 8 hours. This timing was intentional, mimicking the day-night pattern typical for solar energy production.
Importantly, the team repeated this cycle 15 times in as many days. With further optimization, they say the energy density of the microbial battery could be competitive with conventional technologies. Someday it could help us store energy from local renewable sources safely and at a lower cost than current options.
We look forward to future reports on the progress of this exciting storage discovery.
Image: Battery pack closeup via Shutterstock