Energy cells powered by algae are a source of energy with negative carbon dioxide emissions

Scientists from Concordia University in Quebec have developed a way to obtain energy from the photosynthesis process of algae, with the aim of providing a sustainable energy source.

A team from the university’s Optical-Bio Microsystems Lab produces energy by suspending algae in a specialized solution and placing them in small energy cells.

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

According to the researchers, if configured correctly, their micro-photosynthetic power cells (µPSC) can produce enough energy to power ultra-low and low-power gadgets such as Internet of Things (IoT) sensors.

“The inclusion of µPSCs in the sustainable energy field represents a significant step forward, potentially impacting various sectors dependent on low-power solutions,” the team said in their research paper.

Harnessing the power of algae

In the µPSC system, a honeycomb proton exchange membrane divides the anode and cathode chambers of a microphotosynthetic power cell.

The researchers built microelectrodes on both sides of the membrane to collect the charges released by the algae 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 algae are suspended, while the cathode is filled with potassium ferricyanide, a type of electron acceptor.

According to scientists, when algae begin to emit electrons through photosynthesis, the electrons are collected by electrodes in the membrane and conduct, creating a current.

Protons, however, pass through the membrane and enter the cathode, oxidizing and reducing potassium ferrocyanide. This process also takes place without direct sunlight, although with less intensity.

“Like humans, algae constantly breathe, but they take in carbon dioxide and release oxygen. Through the mechanisms of photosynthesis, they also release electrons during respiration. Dhilippan Panneerselvam, a PhD student at the university and co-author of the study, said in a statement.

“Electricity generation is not stopped. Electrons are collected continuously,” he added.

Efficient and ecological

Scientists tested the performance of microphotosynthetic power cells (µPSC) in various configurations. In one set, the configurations included two µPSCs connected in series with three sets in parallel, three in series with two sets in parallel, four in series with another two sets in series and both sets in parallel, and five in series with one in parallel.

According to the researchers, performance differences were normalized in terms of voltage, current and power due to differences in production and changing conditions.

Tests have shown that combining series and parallel arrays of microphotosynthetic power cells (µPSC) generates more power than using only series or parallel connections.

The team admits that the system cannot compete with alternative energy generation methods, such as solar cells. One microphotosynthetic power cell has a maximum terminal voltage of only 1.0 V.

However, scientists believe that with sufficient research and development, including AI-powered integration technologies, the technology could become a viable, affordable and clean energy source in the future.

The team emphasizes that their system does not use any of the hazardous gases or microfibers required in the silicon manufacturing technology on which photovoltaic cells are based.

“Furthermore, getting rid of silicon computer chips is not easy. We use biocompatible polymers, so the entire system is easily degradable and very cheap to produce,” said Muthukumaran Packirisamy, professor at the Department of Mechanical, Industrial and Aerospace Engineering and co-author of the paper.

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