We use them in agriculture, cooking, as a biological filters capable of mitigating CO2 emissions and even to make cosmetics and sportswear. Over the years we have known make good use of algae, but maybe we can do it even more. And in an unexpected way and field: generating energy for the internet of things (IoT).
It sounds outrageous, but maybe it’s not. Although on a very modest scale, researchers at the University of Cambridge has already shown that the idea is not unreasonable.
What Christopher Howe and his colleagues at the British university have just done is make a small device—similar to an AA battery—with plastic and aluminum and in which they introduced a colony of Synechocystis, a type of freshwater cyanobacteria commonly known as “blue-green algae.” The piece was in turn connected to an Arm Cortex MO+ microprocessor, a common component in devices integrated into the Internet of things.
The key: photosynthesis
When the device was ready, they placed it on the windowsill of one of the windows of Paolo Bombelli, another member of the team, and… they waited for half a year, from February to August 2021. The test coincided with one of the lockdowns due to COVID-19, so they had time. What did they discover? The great game that can be drawn from the photosynthesis of the algae.
Taking advantage of this chemical process, scientists developed a kind of biological photovoltaic cell with which powered a microprocessor. “Here we describe a system that generates biophotovoltaic energy using photosynthetic microorganisms on an aluminum anode and that can power an Arm Cortex M0+ microprocessor”, details the equipment in your report.
To get an idea of the capacity of their invention, the Cambridge team tested their peculiar “computer” with very basic calculation cycles that required a power of 0.3 microwatts.
The experiment found some interesting data. For example, that the device provided a continuous current of electricity, both during the day and at night. Yes, photosynthesis needs light; but the scientists have verified that -since the algae process part of their food in the dark- the device emitted energy even during the early mornings.
Ever wondered if you can power a computer with photosynthetic bacteria and recycled aluminium ? In our last paper we show that it is possible ! https://t.co/IEEr5aqYrM
– Alberto Scarampi (@scaralbi) May 12, 2022
Beyond the curious fact that a small “computer” works thanks to a container with water and a few algae, why is the experiment relevant? The key is that it can help us generate energy, and with less environmental impact than conventional batteries or solar energy. To make their device, in fact, they used common, cheap and recyclable elements, in addition to water and Synechocystisa type of seaweed quite widespread.
“The growing Internet of things needs more and more energy and we believe that this will have to come from systems that can generate it, instead of just storing it like batteries,” Professor Howe points outfrom the Department of Biochemistry: “Our photosynthetic device does not run out like a battery does because it continually uses light as an energy source.”
“we were impressed the consistency with which the system worked over a long period of time. We thought it might stop after a few weeks, but it kept going.” recognizes Bombelli. His team recalls that the likely spread of the IoT over the next few years will mean that there are more and more connected devices, a challenge for lithium-ion batteries.
“Powering trillions of Internet of Things devices with lithium-ion batteries would not be practical: three times more lithium would be needed than is produced worldwide annually. And traditional PV devices are made from hazardous materials that have adverse environmental effects.” abound from the University of Cambridge.
Perhaps one of the solutions goes through energy sources like the one explored by Howe and Bombelli.
For now, the team already points out its advantages to produce small amounts of energy in rural areas or with low income. “Even There is much to do“, they acknowledge.
Cover Image | University of Cambridge