Thursday, January 29, 2009


from the grauniad

Cheap new LED eco-lights promise price breakthrough
Scientists have hit on the holy grail of eco-friendly lighting – low-cost LED lights for use in the home. Even compact fluorescent bulbs' days are numbered
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low energy lightbulb

New LED lights will beat even energy-efficient domestic lightbulbs. Photograph: Graham Turner

As one technology fades, so another starts to shine. Excuse the pun but what better way to mark the imminent demise of incandescent light bulbs than with the news that an ultra-low-power way to light up your home has been developed by scientists?

You're familiar with LEDs, of course, from scrolling dot-matrix signs, Christmas decorations to streetlamps – their intense points of light turn up everywhere, from lighting up public buildings to camera flashes. But the new LEDs are something different – they're meant for your home and could reduce lighting bills by 75%.

Colin Humphreys of Cambridge University led a team that has successfully made white LEDs from gallium nitride. This semiconductor has been around for decades but it has been expensive to produce (grown on wafers of sapphire) and the light it can produce is usually blue or green.

Humphreys has found a way to grow the gallium nitride on silicon wafers, making it 10 times cheaper. And by applying a phosphor to the LED, they can shine more useful white light. Within five years, Humphreys hopes to have commercially-produced versions of his LED in use around homes and offices.

His calculations show that, if we replaced all our lights at home and work with something like gallium nitride LEDs, the share of UK electricity used for lighting would drop from 20% to 5%, ending the need for up to eight big power stations.

"We are very close to achieving highly efficient, low-cost white LEDs that can take the place of both traditional and currently available low-energy light bulbs," says Humphreys. "That won't just be good news for the environment. It will also benefit consumers by cutting their electricity bills."

By making brilliant white LEDs so much cheaper and more easily available, the new invention, or something like it, might also one day kill off the trade in light bulbs (incandescents and the more environmentally-frendly compact fluorescents) entirely. The scientists reckon they can get 100,000 hours of light out of their LEDs so, on average, they would need replacing only every 60 years. Plus they don't contain mercury and are dimmable.

There is still work to be done in making the white light from current and future LEDs less harsh – in the same way that some people will cling to incandescent light bulbs for some time to come, citing their more-appealing light, no doubt there will be some reticence from some in moving wholeheartedly into using LEDs in their lounge or bedroom.

And other user complaint should also be addressed: modern LED lamps for home use tend to be low-powered and the light is often intensely focused in a single direction – not so useful in hallways or bedrooms where a more diffuse light might be needed.

Still, that sort of practical technological problem doesn't seem so complicated to fix. The harder part is doing what the Cambridge scientists have done – bringing down the costs of the semiconductor manufacturing that makes LEDs cheaper in the first place. Here's to a brighter future.

1 comment:

Improvedliving said...

My dear wife has stashed away 5 years worth of conventional bulb