The concentration of carbon dioxide in the atmosphere is steadily rising, and it is seriously impacting the environment. Elevated CO₂ levels contribute to higher global temperatures, which drive climate change. While there is broad agreement on the need to cut emissions, putting those reductions into practice often requires significant time and financial investment.
In response to this challenge, French biochemist Pierre Calleja developed a technique using algae to help remove carbon dioxide from the air. His work highlights the potential of natural systems to address one of the world’s most pressing environmental issues.
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Why is Algae Important?
Algae are large, diverse groups of microorganisms that have lived on Earth for billions of years.
Although algae are commonly seen as thin green sludge accumulated on the surface of a stagnant pond, kelp and seaweed are also members of the algae family. Algae can produce more oxygen than all the other plants in the world combined. They produce energy through photosynthesis by combining water, carbon dioxide, and sunlight. In recent years, algae's potential as an energy source has received enormous attention.
For instance, microalgal species like Nannochloropsis oceanica exhibit high lipid productivity (158.76 mg/L/d) with substantial neutral lipid content, producing biodiesel with favorable properties— low iodine number (104.85 gI2/100 g), high cetane number (54.61), and a cloud point of 3.45 °C. Species like Dunaliella, Spirulina, Chlorella, and Chlorococcus also yield biodiesel meeting ASTM D6751 and EN 14214 standards, though high polyunsaturated fatty acid content may affect fuel quality.3
Carbohydrate-rich species like Spirogyra, Chlorella vulgaris, Chlorococcum, and Chlamydomonas reinhardtii are better suited for producing bioethanol, bio-H₂, and biogas. Microalgae excel in carbon dioxide fixation with 40% to 93.7% efficiencies. Chlorococcum, Scenedesmus, Synechococcus, and Chlorella can tolerate over 30% carbon dioxide concentrations. Microalgae like Chlorella, Desmodesmus, Botryococcus, and Spirulina thrive under optimized temperature, pH, and light conditions.3
Microalgae Lamps as a Sustainable Alternative
Calleja spent several years developing a lamp that feeds on the atmosphere's huge amounts of carbon dioxide.
The key ingredient to this lamp is a single-celled algae, known as microalgae.
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Unlike any other crop on Earth, microalgae can be grown and cultivated in extremely adverse conditions. They can produce more biofuel than comparable energy crops, which makes them the target of most of the research on future power sources.
How Do Microalgae Lamps Work?
Calleja's lamp, developed in 2012, contains a tube containing microalgae-filled water and a battery system.
The lamp can charge during the day through photosynthesis, which is driven by the sun and nutrients. The stored power is then used at night to power lights. However, as algae can also produce energy from carbon, sunlight is not required for the lamp to operate.
The lamps represent a viable electricity-free lighting solution even for locations with less natural light, such as underground parking garages. They work by absorbing all the carbon dioxide emissions from the cars in the parking garages.
A microalgae lamp that absorbs CO2!
Video Credit: ScottFree Digital Design/YouTube.com
Benefits of Microalgae Lamps
Carbon dioxide molecules have been proven to trap and retain heat. This emulates the greenhouse effect of trapping heat energy inside Earth’s atmosphere. Trees naturally consume approximately one ton of carbon dioxide in their lifetime.
Calleja has taken advantage of microalgae's properties to develop a microalgae lamp that produces light and consumes carbon dioxide.
The lamp releases light energy stored in the battery only when needed. It produces an eco-friendly byproduct: oxygen. One microalgae lamp can suck up one ton of carbon dioxide per year, which means one lamp absorbs as much carbon dioxide in one year as a tree does in its lifetime.
An entire city equipped with these green lamps will have the ability to absorb enough carbon dioxide equivalent to that absorbed by a big forest. Another key benefit of this lamp is that algae can act as a biofuel when separated from the water. Hence, every time the water in the lamp needs changing, the waste algae can still be used as fuel, and the water can be recycled and used for other purposes.
Challenges Facing Microalgae Lamp Adoption
Despite its promise, microalgae lamp technology has faced hurdles that may explain its limited adoption.
Dense algae growth can block light, reducing efficiency, while maintenance issues such as murky buildup on lamp surfaces raise practicality concerns.
Experts note that scaling such systems requires advanced bioengineering and significant investment. High costs and technical complexity also pose barriers to widespread use.
However, with continued research and improvements, such eco-friendly systems could see niche or future urban applications.
The technology’s success depends on resolving these challenges while balancing performance, aesthetics, and affordability for real-world environments.4
Sustainable Developments Involving Algae
A paper recently published in the AIP Conference Proceedings evaluated the effectiveness of photovoltaic systems using Spirulina sp. and developed an eco-friendly streetlight prototype. Spirulina sp., a microalga with high photosynthetic efficiency, was used in anolyte biophotovoltaic devices due to its potential for power generation. The prototype generator incorporated 21 pairs of Spirulina sp. microalgal fuel cells. Using 21 pairs of series circuits, the voltage obtained was 17.6 V.5
It differs from lamps using microalgae as the prototype has an aeration system to sustain the algae's life and a light-dependent resistor (LDR) sensor to automate the system based on sunlight availability.
The study demonstrated that Spirulina sp. microalgal fuel cells effectively generate electricity, offering a unique advantage. However, the prototype’s size is currently unsuitable for typical streetlight applications. While promising as a bioelectrochemical energy solution, further research is necessary to scale and commercialize this technology, making it viable for widespread use.5
Similarly, researchers from the Centre for Research in Agricultural Genomics (CRAG) and the International University of Catalonia (UIC) have launched the BioLumCity project, aiming to develop advanced real bioluminescence using bacteria and algae for architecture and urban design applications.
The project seeks to create natural lighting systems powered by living organisms, which would provide sustainable, renewable lighting without relying on electricity and reduce light pollution.
One key microalgae being used is Chlamydomonas reinhardtii, which contains proteins, carbohydrates, and beneficial pigments like chlorophyll and carotenoids. These qualities enhance the economic value of the biomass, making its cultivation more commercially viable.6
Using microalgae for sustainable technology presents challenges, as upstream and downstream processing are energy-intensive. To overcome these obstacles, novel technologies and further research are needed to optimize efficiency and reduce energy consumption.1
The Future of Microalgae Lamps
Microalgae lamps offer a sleek, modern aesthetic with a distinctly futuristic feel. Their design can be customized with various colors and styles, which could help accelerate the adoption of this eco-friendly technology.
That said, questions remain to be addressed, such as the cost and practicality of widespread use, their overall impact, and whether they could reduce the Earth’s excess carbon dioxide. Still, it is an exciting prospect: a future where the lights illuminating our cities also help clean the air we breathe.
References and Further Reading
- GreenMuze. (2012) Algae Street Lamps. [Online] Available at: https://www.greenmuze.com/algae-street-lamps/
- Buczynski, B. (2012) Algae Street Lamps Suck Up CO2, But How Exactly? [Online] Available at https://earthtechling.com/2012/04/algae-powered-street-lamps-suck-up-c02/
- Piyatilleke, S., Thevarajah, B., Nimarshana, P. H. V., & Ariyadasa, T. U. (2025). Microalgal biofuels: Challenges and prospective in the framework of circular bioeconomy. Energy Nexus, 100338. DOI: 10.1016/j.nexus.2024.100338, https://www.sciencedirect.com/science/article/pii/S277242712400069X
- Nguyen, T. C. (2013) Can an Algae-Powered Lamp Quench Our Thirst For Energy? [Online] Available at https://www.smithsonianmag.com/innovation/can-an-algae-powered-lamp-quench-our-thirst-for-energy-3509307/
- Israyusnita, F., Hasanah, N. R. P., Febriani, I., Septian, F. R. D., Saputra, I. K. (2023). Increasing the efficiency of photovoltaic streetlight through microalgal fuel cell Spirulina sp. series circuit prototypes. AIP Conference Proceedings, 2634, 1. DOI: 10.1063/5.0112084, https://pubs.aip.org/aip/acp/article-abstract/2634/1/020029/2871149/Increasing-the-efficiency-of-photovoltaic
- Bioluminescent bacteria and algae for illuminating cities [Online] Available at https://www.cragenomica.es/crag-news/230929_JaeSeong_BioLumCity
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