Algae are a large, diverse group of simple microorganisms that have lived on Earth for billions of years.
Although we typically associate the term algae with the slimy green stuff that accumulates on the surface of a stagnant pond, seaweed and kelp are also member of the algae family.
In the right situations, algae can be very useful to humans, and their potential as an energy source has received lots of attention over the past few years.
Like most plants, many varieties of algae are photosynthetic, which means they feed on sunlight and produce oxygen as a byproduct. Some species are algae are also mixotrophic, meaning they are able to derive energy both from photosynthesis and uptake of organic carbon.
It is this last characteristic that was of particular interest to French biochemist Pierre Calleja, who has spent several years developing an algae-powered street lamp that feeds on the vast amount of carbon emissions swirling around in our atmosphere.
The lamps are really more like massive tanks filled with water and algae. During the day, the algae feed on sunlight and C02 in the air and the resulting energy is stored in batteries connected to the tank. The stored energy is then used to power the lights at night.
As this review points out, Calleja’s lamps can also be illuminated artificially, such as in dark underground parking lots, where the algae go to work absorbing all the CO2 emissions from the cars. Above ground or in homes, they use natural daylight.
There’s no denying that the street lights are cool, and if they became a regular fixture in densely populated cities, they could have a massive impact air pollution in urban areas where trees are scarce.