Blue-green algae can keep the processor of a small device running for more than a year, a team of researchers has shown. And those algae need nothing but sunlight for that.

By 2035 we should have an estimated trillion devices connected to the Internet of Things. But where do all those devices get their energy from?

Batteries are not useful, biochemist writes Paolo Bombelli from the University of Cambridge and colleagues in the journal Energy & Environmental Science, because they contain hard-to-win materials and eventually run out. And many of the current ways of collecting energy on site, such as solar cells, can have environmental disadvantages.

The alternative proposed by Bombelli and his team: let a collection of algae do the job. Using the energy these micro-organisms get from nothing but sunlight, Bombelli and his team managed to keep an (albeit very frugal) computer processor running for a year.

‘He just kept working’

The whole system is the size of an AA battery and uses blue-green algae of the genus Synechocystis† Using the process of photosynthesis, which many plants also use, these single-celled organisms generate energy. That produces a tiny electrical current – ​​on which you can nevertheless run a processor of the type Arm Cortex-M0+which is in many Internet-of-Things devices.

After that processor had functioned that way for six months, Bombelli wrote a scientific paper detailing their results up to that point. And, as the University of Cambridge states in a press release: the processor has been running for over a year now. “We thought he would stop after a few weeks, but he kept working,” says Bombelli.

From idea to useful technology

It is also interesting that the ‘algae battery’ did not work under sterile lab conditions. This also allowed other microbes to take up residence in the system, such as bacteria of the genera Halomonas and Pseudomonas. Those uninvited guests turned out not to get in the way of power generation.

biochemist Kevin Redding of Arizona State University, not involved in the study, is impressed by the stability of the whole. “This study shows that a microbial cell can use photosynthesis to provide a processor with sufficient energy for a long time,” he says. opposite Chemistry World† “That may convince the industry to develop the idea into a usable technology.”