Calleja has developed a lighting system that requires no electricity for power. Instead it draws CO2 from the atmosphere and uses it to produce light as well as oxygen as a byproduct.
During the day the algae produce energy from sunlight that is then stored in the batteries. Then at night the energy is used to power the light. However, as the algae can also produce energy from carbon, sunlight isn’t required for the process to work. That means such lights can be placed where there is no natural light and the air will effectively be cleaned on a daily basis.