Scientists Have Powered a Basic Computer With Just Algae For Over 6 Months

In a ghastly vision of a future cut off from sunlight, the machine overloads in the Matrix movie series turned to sleeping human bodies as sources of electricity. If they had had sunlight, algae would undoubtedly have been the better choice.

Engineers from the University of Cambridge in the UK spent more than six months running a microprocessor using nothing more than the power generated by a common species of cyanobacteria. The method aims to power huge swarms of electronic devices.

“The growing Internet of Things needs more and more power, and we think this will have to come from systems that can generate energy, rather than simply storing it like batteries,” said Christopher Howe, a biochemist and (we assume ) non-mechanical human.

Unlike the side of the Internet we use to tweet and share TikTok clips, the Internet of Things connects less quirky objects like washing machines, coffee makers, vehicles, and external environmental sensors.

In some cases, these devices operate far from a power grid. Often they are so remote, or in such inconvenient places, that there is no easy way to put in a new battery when they run out, or repair their power source if it deteriorates or breaks.

For technology that runs on just a flicker of current, the solution is to simply take energy from the environment, waste motion, carbon, light or even heat and use it to bring out a voltage.

Photovoltaic (solar) cells are an obvious solution in today’s world, given the rapid progress made in recent years to extract more power from every ray of sunshine.

However, if you want power overnight, you’ll need to add a battery to your device, which not only adds mass but also requires a mix of potentially expensive and even toxic substances.

Creating a “living” power source that converts material in the environment, such as methane, creates a greener, simpler energy cell that doesn’t weaken when the sun goes down. On the other hand, they will run out of juice the moment their food supply runs out.

Algae could be the solution that provides an intermediate solution, as a solar cell and living battery to provide a reliable power without the need for replenishing nutrients. Algae are already being explored as an energy source for larger operations, but can also supply power to countless small devices.

“Our photosynthetic device doesn’t drain like a battery because it constantly uses light as a source of energy,” Howe says.

Their bio-photovoltaic system uses aluminum wool for an anode, mainly because it is relatively easy to recycle and less of an environmental problem compared to many other options. It also gave the team the opportunity to explore how living systems interact with energy-generating aluminum-air batteries.

The ‘bio’ part of the cell was a strain of freshwater cyanobacteria called Synechocystisselected for its ubiquity and the fact that it has been studied so extensively.

Under perfect lab conditions, an AA battery version of the cell managed to produce just over four microwatts per square centimeter. Even with the lights off, the algae continued to break down food reserves to generate a smaller but still significant current.

That may not sound like much, but if you only need a little bit of power to work, algae power could be just the ticket.

A programmable, limited-instruction 32-bit processor commonly used in microcontrollers was given a series of sums to chew on for a 45-minute session, followed by a 15-minute rest.

Left in the ambient light of the lab, the processor performed the same task for over six months, showing that simple algae-based batteries are more than capable of running rudimentary computers.

“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 just kept going,” says biochemist Paolo Bombelli.

Given the speed at which we are finding new ways to incorporate electronics into everyday objects, it is clear that we cannot continue producing lithium-ion batteries to power them all.

And frankly, it’s just overkill to use sleeping human bodies to power huge swarms of computers. Isn’t that so, machines?

This research was published in Energy and Environmental Sciences

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