A multinational team of researchers have managed to extract useful, photosynthesis-based energy from an algae-powered system, opening up the door for truly sustainable edge computing. The system, similar in size to an AA battery, was used to continuously power an Arm-based Cortex M0+ (the same CPU as in the Raspberry Pi Pico) test board for over a year with nothing more than ambient light in a domestic environment. It's being hailed as a potential enabler for future scaling of IoT (Internet of Things) devices.
The system was built around a common species of blue-green algae, Synechocystis, which are capable of photosynthesizing their own nutrients from ambient lighting - whilst producing a minute-but-significant-enough electrical current that's proven stable throughout a one-year-plus operation (and counting). It's essentially a "set-it-and-forget-it system - so long as there's sufficient ambient lighting to provide the algae with sustenance.
“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 in the University of Cambridge’s Department of Biochemistry, first author of the paper.
According to the researchers, the system is made from common, inexpensive and mostly recyclable materials, opening up the door to economies of scale - due to how inexpensive and easily replicable it is. Eventually, the researchers hope their solution could be used to scale the needs for IoT devices, whose typical power supply methods - read, lithium-ion batteries for energy storage - are deemed too expensive for the expected one trillion devices by 2035.
A trillion devices consuming the world's highly-sought-after lithium reserves would not only push costs up across the board, but would also make them dependent on increasingly loaded energy grids - whilst putting pressure on an already spread-thin logistics and rare metals management. Due to the algae batteries being self-contained production and power delivery systems, initial applications are expected to concern off-grid or remote locations - but they could also be used to reduce dependency on energy grids.
“The growing Internet of Things needs an increasing amount of power, and we think this will have to come from systems that can generate energy, rather than simply store it like batteries,” said Professor Christopher Howe in the University of Cambridge’s Department of Biochemistry, joint senior author of the paper. “Our photosynthetic device doesn’t run down the way a battery does because it’s continually using light as the energy source,” he added.
Luckily, algae are common-enough lifeforms and in theory, this solution could also be scaled enough to power an enthusiast-class gaming PC - perhaps even upcoming high-performance graphics cards and their reported thirst for power.