Research leads to affordable LED bulbs then “smart lighting”

Researchers at the University of Cambridge have developed a new technique that paves the way for manufacturing affordable LED light bulbs that will have a dramatic impact on carbon emissions.

The process will be utilised by Plessey, a semiconductor manufacturer based in Plymouth, UK that involves growing gallium nitride crystals on silicon that could drastically reduce the cost of making LEDs for lighting in offices and homes. The company may eventually be able to develop “smart lighting” from LED light bulbs.

Light-emitting diodes, or LEDs, are the small, coloured lights currently used in electronic equipment, bicycle lights and roadside signs. Many scientists see them as the ideal replacement for old-fashioned tungsten filament light bulbs, which are being phased out by the EU because of the amount of electricity they waste and the consequent impact on carbon emissions.

Researchers estimate that a worldwide switch to LEDs, which are far more energy-efficient, would enable the closure of 560 power plants and result in annual CO2 savings equivalent to the output of all the cars on the planet.

LEDs are also being designed to give off a more natural quality of light, which will be better for people’s health. They could potentially be used as “smart lighting” that can switch itself on or off when a person enters or leaves a room, or adjust its brightness according to the amount of daylight.

Until now, however, they have been very expensive to produce. LED light bulbs currently cost as much as £40, but this could be reduced to below £8.

The potential return on value for money is high. LEDs last for 100,000 hours at a time, compared with the 1,000 hour lifetimes offered by tungsten filament light bulbs and the 10,000 hours claimed for fluorescent lighting. The average light bulb in Britain is on for four hours every day. So, on average, LED light bulbs would only have to be changed once in every person’s lifetime.

More significant, however, are the likely benefits for the planet. Because tungsten filament light bulbs lose much of their energy as heat, just 5% of the energy they consume is used as light. Fluorescent tubes range from 20% to 25% efficiency. LEDs, however, are currently about 30% efficient and Humphreys hopes to raise that figure to 60% in time.

This means that they require far less energy than conventional bulbs. In the UK alone, the researchers estimate that the nationwide use of LEDs would save 15% of the electricity generated by power stations, resulting in a similar reduction in CO2 emissions. There are also potential cost savings: a recent (2010) US Department of Energy report estimates that savings of $20 billion per year would result if LED light bulbs became widespread in the US.

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