...AND CHEAPER...:

The blue LED light was finally created in the early 1990s by the three Nobel-winning Japanese physicists who took the painstaking route of growing gallium nitride crystals to do the job.

Since then LEDs have been associated with state-of-the art devices like Blu-ray DVDs, smart-phone screens and TV screens. The intensity of tiny red, green and blue LED pixels can be adjusted to produce sharp images of any colour.  But the real revolution is still to come, from the simple lighting of households, offices and streets.

According to the International Energy Agency 19% of all global electricity is used for lighting. The incandescent bulbs developed by Edison in 1879 run hot, wasting most of the electricity pumped into them. The fluorescent tubes that criss-cross the ceilings of today's offices are about five times more efficient than incandescents. Today's commercially available white LEDs have the same efficiency as fluorescents, but, while fluorescent technology has plateaued, LEDs just keep getting better and better. They're expected to both double in efficiency and halve in price over the next 15 years. Added to this they have a useful lifetime of over 50,000 hours, meaning they need to be changed less than once a decade.

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