Tiny algae offer hope for renewable energy with negative carbon emissions

As climate change forces society to consider alternatives to fossil fuels, a potential new source of renewable energy has emerged in a somewhat unusual form: algae.

Algae are a very diverse group of organisms that are also photosynthetic, which means they use sunlight, water and carbon to produce oxygen and energy. If scientists can somehow harness this process, it could potentially mean not only a new source of renewable energy, but also one that removes carbon dioxide in the process.

And that’s exactly what scientists at Concordia University’s Optical-Bio Microsystems Lab recently achieved. “The process of photosynthesis produces oxygen and electrons. Our model captures electrons, which allows us to generate electricity,” Kirankumar Kuruvinashetti, first author of the study describing the discovery, said in a statement.

The model in question is known as a microphotosynthetic power cell, or µPSC for short. It consists of two chambers, one anode and the other cathode, each measuring just 2 centimeters by 2 centimeters and just 4 millimeters thick, separated by a specially designed membrane.

The algae are suspended in a solution in the anode chamber and after photosynthesis, they begin to release electrons, which are captured by microelectrodes running on both sides of the membrane. Microelectrodes conduct electrons, generating electricity.

Currently, energy production is not sufficient to compete with other renewable energy sources such as photovoltaic cells – although it is sufficient for low and very low power devices. However, scientists believe that this process still has great potential for three main reasons.

First, it would be a particularly “clean” energy source. Not only does the process produce no carbon dioxide emissions, but “it is a carbon-negative technology: it absorbs carbon dioxide from the atmosphere and produces electricity. The only by-product is water,” Kuruvinashetti explained.

This method also does not require direct sunlight to work – which is great news for its potential customers in the UK – although it is slightly less intense.

Scientists also believe that using algae in this way is safer and more sustainable than other existing renewable energy production processes. “Our system does not use any hazardous gases or microfibers needed in the silicon technology on which photovoltaic cells are based,” said correspondent Muthukumaran Packirisamy.

“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.”

You see, algae isn’t that bad after all.

The study results were published in the journal Energies.