Credit: Paolo Bombelli, used under Creative Commons Attribution 4.0 International License

A microprocessor powered by algae has now been running continuously for a year. Researchers at the University of Cambridge say the approach could help power Internet of Things devices.

The system uses Synechocystis, a common blue-green algae, in a device around the size of a AA battery. It harvests solar energy through photosynthesis, creating an electrical current that powers an Arm Cortex M0+ microprocessor. The testing was in real-world conditions including natural light and temperature fluctuations.

The researchers say they were uncertain if the device would prove durable. As it has, it should theoretically now run indefinitely. That’s because the algae also generates its own food supply as part of the photosynthesis. The power generation even works in the dark as the algae generates a current while processing food.

Because the algae is common and the other materials in the system recyclable, the researchers say it should be easy to mass-produce the devices. They say it would be most suitable for situations that need a small but reliable and sustainable power source.

They also note the algae approach may overcome problems with the two main power options for Internet of Things devices at the moment: the world supply of lithium is nowhere near enough for batteries for the trillion devices forecast by 2035, while existing photovoltaic approaches have environmental downsides.