Look at a satellite image of a city at night and one thing is clear: we produce a lot of light. Streetlights, cars, houses, offices and factories all illuminate an otherwise dark Earth. There is no doubt that our lives are far more comfortable than they were before the invention of electric lighting some 200 years ago, but all that light has its cost.
“Modern illumination is not only much more efficient, but increasingly responsive to the rhythms of human life.”Edwin Cartlidge
Another innovation is to make better use of the light that is produced. Dutch company Tvilight has developed a set of sensors that allows streetlights – whether using LEDs or more conventional techno- logy – to emit at full power only when a person or car, say, passes by. The sensors maintain output at a lower level for the rest of the time, and are able to distinguish passers-by from other sources of movement such as animals or rustling leaves. The system reduces energy consumption by up to 80%, according to Tvilight CEO Chintan Shah, and has so far been installed in a number of cities in the Netherlands, Germany, Ireland and Korea.
By Edwin Cartlidge
First published on http://www.technologist.eu/a-revolution-in-lighting/