A colony of Synechocystis, better known as blue-green algae, trapped in a case the size of an AA battery, powered an Arm chip for more than six months, thanks to the energy of photosynthesis. This study was carried out by researchers from Cambridge and published May 12 in the journal Energy Environmental Science.
Photosynthesis works, even at night!
No, the blue algae computers will not arrive in stores tomorrow, nor the day after tomorrow. Nevertheless, the performance is there.
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The algae were enclosed in a plastic and steel case with an aluminum anode. The whole thing was placed on the windowsill of one of the study participants, from February to August 2021. They managed to power an Arm Cortex-M0+ chip performing simple calculations and verifying them in a 45 minute cycle, with 15 minutes standby.
In the study published by Energy Environmental Science scientists found that energy production continued at night. They estimate that the micro-organisms stored part of their “food” recovered during the day to continue to feed. ” We were impressed with how consistently the system worked over a long period of time. We thought it would stop after a few weeks, but it kept working “, rejoiced Dr. Paolo Bombelli, first author of the article via communicated.
This experience is part of a booming field, biophotovoltaics. This consists of studying possible methods to exploit the electricity generated by biological micro-organisms by transforming light during the process of photosynthesis. The goal is, unsurprisingly, to find a new source of energy with a very low environmental impact.
The Internet of Things, the ideal outcome of biophotovoltaics
Biophotovoltaics is not intended to become an alternative to other means of producing electricity on a large scale. The Verge recalls that photosynthesis is very inefficient, since a plant absorbs on average 0.25% of solar energy, where a solar panel recovers 20%.
In the study by the Cambridge researchers, it is specified that the chip used is very low consumption, around 0.3 microwatts per hour. A low consumption LED bulb, represents about 10 watts, an average desktop computer 100. Blue algae are far from the mark.
Scientists, perfectly aware of this limit, nevertheless imagine a major utility for their discovery, the Internet of Things. In the abstract of the article they note that ” The power consumption of a single IoT device is modest, ranging from μW to mW “.
Professor Christopher Howe, co-lead author of the paper, notes, ” The expanding Internet of Things needs an increasing amount of energy, and we believe it will need to come from systems that can generate energy, rather than just store it like batteries. “.
Minerals such as Lithium or Cobalt used in batteries are already the subject of a race between China and the United States, as their number is likely to explode in the years to come. According to the statement from the University of Cambridge, to power IoT with batteries “ it would take three times more lithium than is produced annually in the world “. The promise of biophotovoltaics is to minimize the environmental impact of powering IoTs. Extremely attractive prospects.