An algae energy harvester that alone powers the electronics for a year

As the number of electronic devices increases, we’re going to have to get creative with our power sources. Cambridge researchers have shown how an algae energy harvester can use sunlight to power a microprocessor for over a year without human help.

Algae are of great importance in the green technologies of the future, in many respects. They show promise for producing hydrogen, purifying wastewater, removing carbon dioxide from the atmosphere, forming the basis for biofuels and generating electricity through photosynthesis.

The Cambridge team focused on this last point. Algae is an efficient natural solar cell that converts sunlight into chemical energy and water and carbon dioxide into organic molecules. The process produces electrons that can be collected and used to power electronic devices.

The new algae harvester placed a species of blue-green algae in a small container with water, the whole unit being as big as an AA battery. Electrons are collected by an aluminum electrode and transported to power an Arm Cortex M0+, a low-power microprocessor commonly used in Internet of Things (IoT) devices.

The researchers let the system operate in a “domestic” environment under “semi-outdoor” conditions (like on a porch), where it reliably generated power for the microprocessor over the long term. The article only describes the first six months, but the team says it’s still running after a year of inactivity.

We were impressed with how consistently the system performed over a long period of time; we thought it would stop after a few weeks, but it kept working.

Dr. Paolo Bombelli, first author of the study.

The team says the device was even able to continue generating electricity for some time in the dark, suggesting that the algae could be storing some of its “food” for later processing.

The algae-based energy harvester doesn’t generate much power, but it’s enough for the growing number of Internet of Things devices.

Made from inexpensive common components and with a much longer lifespan than traditional lithium batteries, these devices could provide a more environmentally friendly source of energy, especially in remote areas.

More information: (English text).

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