In the picturesque French town of Rambouillet, south west of Paris, a series of cylindrical tubes illuminate a path with soft turquoise light. It’s pretty, but maybe won’t strike you as a bold experiment in the future of street lighting. But it is. Because the path is alight thanks not to electricity, but to bacteria.
The phenomenon is known as bioluminescence – light produced and emitted by living organisms. Fireflies, fungi and deep-sea creatures use it to find mates and confuse predators, but now one company has found a way of harnessing it to illuminate our cities.
French start-up Glowee, which is behind the project in Rambouillet, collects a bacteria called Aliivibrio fischeri and stores it in tubes filled with saltwater. Recharging them simply requires occasionally feeding the bacteria a mixture of basic nutrients and oxygen. ‘Instead of replacing the bulbs in street lamps, we created a whole new approach,’ says Sandra Rey, who founded Glowee in 2014. ‘With this new approach, we found the solution we have today.’
Unlike LEDs, bioluminescent bacteria have a potentially infinite lifespan and are completely natural, so could pave the way for an energy-efficient and sustainable way to light our cities. Rambouillet is the first city to test the process, with the aim of becoming ‘a full-scale bioluminescence laboratory’.
It’s not just Glowee that has succeeded in harnessing bioluminescence in recent years. In 2017, researchers at MIT injected luminescent chemicals used by fireflies into leaves, while the Glowing Plant project designs flora that light up.
A world where street lamps are replaced by luminous trees may still be the stuff of sci-fi, but Glowee’s turquoise tubes could be popping up in more streets and parks. The company is working with 40 cities in France and beyond (they won’t reveal which ones) that are interested in testing the technology between 2023 and 2027. ‘We’re seeing a real shift in the awareness around sustainability,’ says Rey, ‘but also around urbanism: how to make cities attractive while increasing quality of life. Street lighting has a very important role to play.’
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