Scientists used a common species of blue-green algae to power a microprocessor continuously for a year—and counting—using nothing but ambient light and water. Your system has the potential to provide reliable and renewable power to small electronic devices.
The system, which is comparable in size to an AA battery, contains a type of non-toxic algae called Synechocystis which naturally obtains energy from the sun through photosynthesis. The tiny electrical current generated then interacts with an aluminum electrode and is used to power a microprocessor.
“Our photosynthetic device doesn’t discharge like a battery because it continuously uses light as its energy source.” — Chris Howe
The system consists of ordinary, inexpensive and mostly recyclable materials. This means it could easily be replicated hundreds of thousands of times to power large numbers of small devices as part of the Internet of Things. The researchers say it’s likely to be most useful in off-grid situations or remote locations where small amounts of electrical power can be very beneficial.
“The growing Internet of Things requires more and more energy, and we believe that this needs to come from systems that can generate energy, rather than simply storing it like batteries,” said Professor Christopher Howe of the University of Cambridge’s Department of Biochemistry. joint senior author of the paper.
He added, “Our photosynthetic device doesn’t drain like a battery because it’s constantly using light as its energy source.”
In the experiment, the device was used to power an Arm Cortex M0+, a microprocessor commonly used in Internet of Things devices. It was operated in a domestic and semi-outdoor environment under natural lighting conditions and associated temperature fluctuations, and after six months of continuous power generation, the results were submitted for publication.
The study will appear in the journal on May 12, 2022 Energy and Environmental Sciences.
“We were impressed by how consistently the system worked over a long period of time – we thought it might stop after a few weeks, but it just kept going,” said Dr. Paolo Bombelli from the University of Cambridge’s Department of Biochemistry, first author of the paper.
The alga does not need to be fed as it makes its own food through photosynthesis. And although photosynthesis requires light, the device can continue to produce electricity even in times of darkness. The researchers believe this is because the alga processes some of its food when there is no light, which continues to generate electricity.
The Internet of Things is a vast and growing network of electronic devices, each of which consumes little power and collects and exchanges real-time data over the Internet. Many billions of devices are part of this network via inexpensive computer chips and wireless networks – from smartwatches to temperature sensors in power plants. This number is expected to grow to one trillion devices by 2035, requiring a large number of portable power sources.
The researchers say it would be impractical to power trillions of Internet of Things devices with lithium-ion batteries: it would require three times more lithium than the world produces annually. And conventional photovoltaic devices are made of hazardous materials that have adverse effects on the environment.
The work was a collaboration between the University of Cambridge and Arm, a company at the forefront of microprocessor development. Arm Research developed the high-efficiency Arm Cortex M0+ test chip, built the board and set up the data acquisition cloud interface presented in the experiments.
Reference: “Powering a microprocessor by photosynthesis” by P. Bombelli, A. Savanth, A. Scarampi, SJL Rowden, DH Green, A. Erbe, E. Årstøl, I. Jevremovic, MF Hohmann-Marriott, SP Trasatti, E. Ozer and CJ Howe, May 12, 2022, Energy and Environmental Sciences.
The research was funded by the National Biofilms Innovation Center.