Research shows that algae offer real potential as a renewable source of electricity

The need to transition from fossil fuels to more sustainable energy production is crucial. So a team of Concordia researchers are looking for a potential energy source that not only produces no carbon emissions but also removes carbon as it operates: algae.

Scientists at the Optical-Bio Microsystems Lab recently published a new paper on this topic in the journal Energies. They describe their method of obtaining energy from the photosynthesis process of algae suspended in a specialized solution and placed in small energy cells. Properly configured, these cells can generate enough energy to power low- and ultra-low-power devices such as Internet of Things (IoT) sensors.

“The idea of ​​a microphotosynthetic power cell is to extract electrons produced in the process of photosynthesis,” says Dr. Kirankumar Kuruvinashetti, currently a Mitacs PhD student at the University of Calgary.

“Photosynthesis produces oxygen and electrons. Our model captures electrons, which allows us to generate electricity. So it’s not a zero-emission technology, but it is a carbon-negative technology: it absorbs carbon dioxide from the atmosphere and produces electricity. The only by-product is water.”

Energy produced day and night

A microphotosynthetic power cell consists of an anode and a cathode chamber separated by a honeycomb-shaped proton exchange membrane. The researchers fabricated microelectrodes on both sides of the membrane to collect the charges released by the algae during photosynthesis. Each chamber measures only two centimeters by two centimeters by four millimeters.

The algae are suspended in a two-milliliter solution in the anode chamber, while the cathode is filled with potassium ferricyanide, a type of electron acceptor. Once the algae undergo photosynthesis and begin to release electrons, the electrons will be collected by the membrane electrodes and conducted, creating a current.

Meanwhile, protons will pass through the membrane to the cathode and cause oxidation, resulting in the reduction of potassium ferrocyanide.

This process also occurs without direct sunlight, although with less intensity – explains Dr. Hab. candidate and co-author of the paper Dhilippan Panneerselvam.

Panneerselvam says, “Like humans, algae constantly breathe, but they take in carbon dioxide and release oxygen. Through the mechanism of photosynthesis, they also release electrons during respiration. Electricity production does not stop. Electrons are captured continuously.”

Muthukumaran Packirisamy, professor at the Faculty of Mechanical, Industrial and Aerospace Engineering and co-author of the article, admits that the system is not yet able to compete in energy production with other systems, such as photovoltaic cells. The maximum possible terminal voltage of a single microphotosynthetic power cell is only 1.0 V.

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

It also provides a significant production advantage over other systems, he says.

Packirisamy adds: “Our system does not use any hazardous gases or microfibers needed in the silicon technology on which photovoltaic cells are based. Moreover, disposing of silicon computer chips is not easy. We use biocompatible polymers, so the whole system is easily degradable and very cheap to produce.”