Algae-based power cells provide a carbon negative energy source

Researchers at Concordia University in Quebec have developed a way to harvest energy from the photosynthesis process of algae, aiming to provide a sustainable source of energy.

The team at the University’s Optical-Bio Microsystems Lab produces energy by suspending algae in a special solution and putting it into tiny energy cells.

Their model captures electrons to generate electricity, making it not only a zero-emission but carbon-negative technology.

According to the researchers, when properly installed, their photovoltaic power cells (µPSC) are capable of producing enough energy to power low- and low-power devices, such as Internet of Things (IoT) sensors.

“The integration of µPSCs in the field of sustainable energy sources represents a major step forward, which could affect various sectors that rely on low-power solutions,” the team said in their research paper.

Integrating the power of algae

In the µPSC configuration, a proton exchange membrane in the shape of a honeycomb separates the anode and cathode compartments of the small photosynthetic power cell.

The researchers created microelectrodes on both sides of the membrane to collect the charge that the algae produce during photosynthesis. Each chamber is very small, measuring two centimeters by two centimeters by four millimeters.

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

According to the researchers, when the algae begin to produce electrons due to photosynthesis, the electrons are collected through electrodes in the membrane and conducted, causing a current.

Protons, however, cross the membrane and enter the cathode, oxidizing and reducing potassium ferrocyanide. The process also works without direct sunlight, although to a lesser extent.

“Like humans, algae breathe all the time – but they take in carbon dioxide and release oxygen. Because of their photosynthesis mechanism, they also release electrons during respiration,” said Dhilippan Panneerselvam, PhD candidate at the University and co-author of the study, in information.

“Electricity production has not been stopped. Electrons are always harvested,” he added.

Efficient and environmentally friendly

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

According to the researchers, performance differences were adjusted for voltage, current, and power due to manufacturing differences and changes in conditions.

Experiments showed that combining series and parallel arrays of micro photosynthetic power cells (µPSCs) produces more power than using series or parallel connections alone.

The team acknowledges the system’s inability to compete with alternative energy generation methods, such as solar cells. A single small photosynthetic energy cell has a maximum terminal voltage of 1.0V.

However, with enough research and development, along with AI-assisted integration technology, researchers believe that the technology could become a viable, cheap and clean power source in the future.

The team highlights that their system does not use harmful gases or the micro-fibers required for the silicon manufacturing technology on which photovoltaic cells are based.

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

Details of the team’s research were published in the journal Energy.