Algae-fueled power cells offer a carbon negative energy source – Interesting Engineering

According to researchers, when set up properly, their micro-photosynthetic power cells (µPSC) cells have the capacity to produce enough energy to run ultra-low- and low-power gadgets, like Internet of Things (IoT) sensors.

“The integration of µPSCs into the realm of sustainable energy sources represents a significant stride forward, potentially impacting various sectors reliant on low-power solutions,” said the team in their research paper.

Harnessing algae power

In a µPSC setup, a proton exchange membrane in the form of a honeycomb divides the anode and cathode chambers of the micro photosynthetic power cell.

The researchers constructed microelectrodes on both sides of the membrane to gather the charges that the algae release during photosynthesis. Each chamber is quite small, measuring just two centimeters by two centimeters by four millimeters.

The anode chamber contains a two-milliliter solution in which the algae are suspended, while the cathode is filled with potassium ferricyanide, an electron acceptor of some kind.

According to researchers, when the algae start to emit electrons due to photosynthesis, the electrons are gathered through the electrodes in the membrane and conducted, resulting in a current.

Protons, however, cross the membrane and enter the cathode, oxidizing and reducing potassium ferrocyanide. The process also functions without direct sunlight, albeit at a lower intensity.

“Just like humans, algae are constantly breathing — but they intake carbon dioxide and release oxygen. Due to their photosynthesis machinery, they also release electrons during respiration.” said Dhilippan Panneerselvam, a PhD candidate at the University and the study’s co-author, in a statement.

“The electricity generation is not stopped. The electrons are continuously harvested,” he added.

Efficient and eco-friendly

Researchers tested the performance of micro-photosynthetic power cells (µPSCs) in various configurations. In one set, configurations included two µPSCs in series with three sets in parallel, three in series with two sets in parallel, four in series with another two in series and both sets in parallel, and five in series with one in parallel.

According to researchers, performance variations were normalized for voltage, current, and power due to fabrication differences and changing conditions.

The tests showed that combining series and parallel arrays of micro-photosynthetic power cells (µPSCs) generates more power than using only series or parallel connections.

The team acknowledges the system’s inability to compete with alternative power generation methods, such as solar cells. One micro photosynthetic power cell has only a maximum terminal voltage of 1.0V.

However, with sufficient research and development, including AI-assisted integration technologies, researchers believe the technology could become a viable, affordable, and clean power source in the future.

The team highlights that their system does not use any hazardous gases or microfibers required for the silicon fabrication technology that photovoltaic cells rely on.

“Furthermore, disposing of silicon computer chips is not easy. We use biocompatible polymers, so the whole system is easily decomposable and very cheap to manufacture,” said Muthukumaran Packirisamy, professor in the Department of Mechanical, Industrial and Aerospace Engineering and the paper’s corresponding author.

The details of the team’s study were published in the journal Energies.