Buildings and Cities
LED Lighting (Commercial)
The origin of LEDs (light emitting diodes) dates back to the 1874 invention of the diode—a crystal semiconductor. Under certain conditions, diodes emit light. In 1994, three Japanese scientists invented high-brightness LED bulbs, for which they were awarded the Nobel Prize in Physics in 2014.
LEDs work like solar panels in reverse, converting electrons to photons instead of the other way around. They use 90 percent less energy than incandescent bulbs for the same amount of light, and half as much as compact fluorescents, without toxic mercury. On top of that, an LED bulb will last much longer than either other type.
Lighting accounts for 15 percent of global electricity use. LEDs transfer 80 percent of their energy use into creating light—rather than heat, like older technologies—and reduce electricity consumption and air-conditioning loads accordingly. LED streetlights can save up to 70 percent of energy and significantly reduce maintenance costs.
The question about LEDs is not whether they will become the standard in lighting fixtures; it’s when. The price (per watt equivalent) is two to three times higher than incandescents or flourescents, but falling rapidly. Virtually any bulb currently in use can be replaced by LEDs.
Technical summaries for each solution will be available May 1, 2017.