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In a world increasingly hungry for sustainable energy sources, scientists are turning to some unlikely heroes: microscopic algae. Researchers at Concordia University have developed a promising new technology called micro-photosynthetic power cells (μPSCs) that harness the natural processes of these tiny organisms to generate electricity. Now they say they’ve found a way to dramatically increase the power output of these miniature green energy factories.
At the heart of this innovation is a deceptively simple idea: connecting multiple μPSCs together, much like linking batteries in a flashlight. By arranging these biological power sources in various configurations, the team has unlocked new levels of performance that bring us one step closer to practical applications for this eco-friendly technology.
What makes this technology particularly exciting is its potential to not only produce clean energy but actually remove carbon from the atmosphere in the process. “More than being a zero-emission technology, it’s a negative carbon emission technology: it absorbs carbon dioxide from the atmosphere and gives you a current. Its only byproduct is water,” says Kirankumar Kuruvinashetti, PhD, now a postdoctoral associate at the University of Calgary, in a statement.
So how do these microscopic power plants work? μPSCs tap into the fundamental processes that algae use to survive: photosynthesis and respiration. During photosynthesis, algae use sunlight to split water molecules, releasing electrons in the process. Even in darkness, the algae continue to produce electrons through respiration. The μPSC is designed to capture these free electrons and channel them into a usable electric current.
The real magic happens in the cell’s structure. Picture a sandwich: the bread slices are two chambers, one containing the algae (the anode) and the other holding a special solution that accepts electrons (the cathode). Between them is a thin membrane that allows protons to pass through while directing electrons along a path where they can be harvested as electricity.
Dhilippan Panneerselvam, a PhD candidate and co-author of the study, highlights an important advantage of this system: “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. The electricity generation is not stopped. The electrons are continuously harvested.”
What makes μPSCs particularly exciting is their potential for long-term, maintenance-free operation. Unlike traditional batteries or solar panels, these living power sources can repair and maintain themselves, potentially providing stable energy output for extended periods.
However, a single μPSC produces only a tiny amount of electricity – not nearly enough for most practical applications. The maximum possible voltage from a single cell is just 1.0V. This is where the current study comes in. The researchers explored various ways of connecting multiple μPSCs to boost overall power output.
They tested several configurations: connecting cells in series (like a string of Christmas lights), in parallel (like lanes on a highway), and in combinations of both. By carefully analyzing the performance of these different arrangements, the team identified optimal setups that significantly increased both voltage and current.
The most promising configurations were those that combined series and parallel connections. These hybrid arrangements allowed researchers to fine-tune the balance between voltage and current, opening up possibilities for powering a wider range of low-power devices.
This breakthrough could pave the way for the μPSCs to find real-world applications in the burgeoning field of the Internet of Things (IoT). Imagine networks of tiny, self-powered sensors monitoring environmental conditions, tracking wildlife, or optimizing agricultural practices – all powered by colonies of industrious algae.
While μPSCs may never replace large-scale power plants or high-output solar arrays, they offer unique advantages for specialized applications. Their ability to operate continuously with minimal maintenance, coupled with their eco-friendly nature, makes them ideal for remote or sensitive environments where traditional power sources are impractical.
“Our system does not use any of the hazardous gases or microfibers needed for the silicon fabrication technology that photovoltaic cells rely on,” explains corresponding author Muthukumaran Packirisamy, a professor with Concordia’s Department of Mechanical, Industrial and Aerospace Engineering. “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.”
As we face the mounting challenges of climate change and seek to reduce our reliance on fossil fuels, innovations like μPSCs remind us that solutions can come from unexpected places. By looking to nature’s time-tested energy harvesting methods, we may find new ways to power our future – one tiny algae cell at a time.
Paper Summary
Methodology
The researchers created arrays of six individual μPSCs and connected them in various configurations. Each μPSC consists of two tiny chambers (2cm x 2cm x 4mm) separated by a honeycomb-shaped proton exchange membrane with microelectrodes on both sides. The anode chamber contains algae in a 2mL solution, while the cathode chamber is filled with potassium ferricyanide. They tested pure series connections, pure parallel connections, and several mixed arrangements combining both series and parallel. For each setup, they measured the voltage, current, and power output under different electrical loads. They also developed a computer model to predict the performance of these arrays, which they then compared to real-world experimental results.
Results
The study found that combining series and parallel connections offered the best overall performance. For example, one effective arrangement connected three pairs of cells in series, with those three pairs then connected in parallel. This configuration produced a maximum power of around 985 microwatts – a significant improvement over single cells. The computer model generally predicted higher outputs than were achieved experimentally, suggesting room for future optimization.
Limitations
While promising, μPSCs still produce relatively small amounts of power compared to conventional energy sources like photovoltaic cells. The experimental results often fell short of the model’s predictions, likely due to variations in individual cell performance and losses in the system. The technology is also in its early stages, with challenges in scaling up production and ensuring consistent performance across cells.
Discussion and Takeaways
This study demonstrates that strategic arrangement of μPSCs can significantly boost their power output, bringing them closer to practical use in low-power applications like IoT sensors. The ability to tailor voltage and current through different configurations offers flexibility for various device requirements. The research also highlights the importance of optimizing not just individual cells, but entire systems of biological power sources. Future work may focus on improving consistency between cells and reducing internal losses to close the gap between theoretical and actual performance. The researchers believe that with further development, including AI-assisted integration technologies, μPSCs could become a viable, affordable, and clean power source for certain applications.
Funding and Disclosures
This research was funded by the Natural Sciences and Engineering Research Council of Canada. The authors declared no conflicts of interest.
