Cambridge engineers power computer with algae

Engineers from the University of Cambridge have successfully powered a computer using just algae, ambient light and water.

The system, which is just about the size of an AA battery, takes advantage of a type of non-toxic algae called Synechocystis. This algae harvests energy from the Sun through photosynthesis. An aluminium electrode then takes the tiny electrical current that’s produced and uses it to power the Arm Cortex M0 microprocessor.

Moreover, the algae didn’t just power the microprocessor for a few hours or days. In fact, it’s been continuously powering the CPU for over a year and counting.

The engineers say their experiment could lend itself to future Internet of Things (IoT) developments, reliably and renewably powering devices and sensors in remote locations that don't have other power sources. That’s because Arm CPUs, like the one powered by the algae, are widely used in IoT devices.

“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 from the University of Cambridge’s Department of Biochemistry, joint senior author of the paper.

He added: “Our photosynthetic device doesn’t run down the way a battery does because it’s continually using light as the energy source.”

The beauty of the setup is that the algae never needs feeding because it obtains everything it needs through photosynthesis. More amazing is that the researchers found that the algae produced energy even during periods of darkness. They believe this is possible because the algae still processes some of its food when there’s no light, generating an electrical current.

“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 from the University of Cambridge’s Department of Biochemistry, first author of the paper.

The research was funded by the National Biofilms Innovation Centre and the study is published in the journal Energy & Environmental Science.

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Image credit: Paolo Bombelli