Scientists have made a computer that uses algae and will never run out of battery.
The breakthrough uses a species of blue-green algae called synechocystis that has been powering a microprocessor continuously for a year using only light and water as fuel.
The system is approximately the size of an AA battery and uses photosynthesis to generate a tiny electrical current, which interacts with an aluminium electrode and to maintain a working Arm Cortex M0+ microprocessor.
“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.
“Our photosynthetic device doesn’t run down the way a battery does because it’s continually using light as the energy source.”
Even though the computer system is based on photosynthesis it does not always require light to work, and can continue producing power even when it is dark. This is because the algae processes its food even in dark conditions and therefore continues to generate a current, researchers believe.
The Arm Cortex M0+ processor operated in under semi-outdoor conditions – with natural light and associated temperature fluctuations –and after six months of continuous power the results were submitted for publication in a journal article that has now been published in the journal Energy & Environmental Science.
This system could be used to power small, Internet of Things devices – an umbrella term for smart technology that includes meters, lights, speakers, and other gadgets that connect to the internet. It is estimated that there will be one trillion of these devices by 2035.
Researchers say it is likely to be most useful in off-grid situations or remote locations where getting large amounts of power is difficult. Moreover, using conventional lithium-ion batteries for these products would be impractical as it would require three times more lithium than is produced across the world every year.
“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.