Visibly efficient

Visibly efficient

Tiny indicator bulbs evolve into energy-saving lightings

They have been around for over 50 years. First in colour red, orange, yellow, blue, green. Then sheer white. Light emitting diodes, or leds, have come a long way from being tiny indicator lights that tell you when an electronic appliance is switched on. They are beginning to get noticed in India as an energy-saving option for lighting buildings and streets, though still a speck on the horizon.

Early this year, Delhi replaced 150-Watt solar vapour lamps in streetlights with 50-Watt leds in a residential locality. "They are zero-maintenance. Humidity and temperature do not affect them," said O P Gupta, chief engineer of the New Delhi Municipal Corporation. The new lights are saving it energy but the corporation wants to be sure of their lighting efficiency before using them on a large scale.The capital is following the Bengaluru example, where leds were used in traffic signals in 2001. The signals became brighter and lasted longer. Hyderabad and Chennai followed suit. The switchover to leds is more visible in corporate houses, railway stations, showrooms and heritage sites.

leds shed straight beams of light suitable for highlighting objects in museums, shops and monuments, and for aviation obstruction warning lights and underwater lighting.

Two things helped led graduate to a lighting option introduction of white leds five years ago and increase in energy efficiency. leds have taken over compact fluorescent lamps (cfls), promoted as the most advanced lighting device, in energy efficiency. A five-Watt led can replace a 15-Watt cfl, saving Rs 77 on the electricity bill a year (see led v cfl).

LED v CFL
A five-Watt LED can replace a 15-Watt CFL, and save money

leds score over incandescent bulbs and cfls in life span as well. An led lasts three to five years; an average cfl lasts about 250 days and an incandescent bulb, 41 days. Long life makes it a fit-and-forget fixture, saving cost of maintenance and replacement.

Although no official data is available, India imported four million leds last year, says the Society of Lighting Engineers (isle). The current led market in the country is US $25 million (Rs 120 crore), and is growing at the rate of 20 per cent in the organized sector, according to industry estimates. But it is still a small fraction of the US $4.8 billion world market.

Use of leds in the automobile component segment has grown at 25 per cent in the past three years, according to Kailash Singh, business development manager at osram, one of the four main players in the international led market. "Tail lamps, fog lamps and dashboard lights are already leds. Headlights are next," said Singh. "They are small and can be customized to suit the car design." led makers claim these use less fuel compared to the bulbs used earlier in car lights, though there are no studies.

led lights can be dimmed, can absorb shock and are perfect for traffic signals. What's more, they do not distort power in transmission lines to an extent cfls do."They are also safe since led beams do not emit radiation. Unlike cfls, they do not contain mercury (a neurotoxin), so disposal is not a problem," said Ajay Goel, chief executive officer, Goldwyn led, an led assembling firm in Noida near Delhi. With no disposal system in place, cfl is likely to collapse, Goel said. He expects led prices to reduce enough in three years for it to replace cfls.

The Bureau of Energy Efficiency (bee), an autonomous regulator under the Union power ministry, agrees leds are the future of lighting. "But zeroing down on efficiency standards would require the technology to be put in practice more rigorously," said Sandeep Garg, energy economist with bee. Before that led has to overcome its drawbacks.

Cost barrier
"As a new technology, led faces many challenges initial investment cost and heat management," said S Mukhopadhya, additional general manager (sales) at Instapower that makes led light fixtures. High costs have restrained Indian households from buying leds. A 10-rupee, 40-Watt incandescent bulb is replaceable by a cfl that costs Rs 100. But an led for the same light output will cost Rs 800 (last year the cost was Rs 1,200).

Manufacturers claim high prices are offset by savings, but recovering the cost takes five to 10 years. "Consumers are comfortable with a payback period of a maximum of two years. So despite energy efficiency and long life, led remains unaffordable," explained H S Mamak president emeritus of isle. The price of an led bulb should be brought down to Rs 300, at least, he said.

The manufacturers are looking to the government for subsidies to promote leds. "The government will have to prepare a tax structure similar to that for solar photovoltaic panels. The current tax structure is high," said Goel. The solar photovoltaic industry pays no excise duty and four per cent vat. The led industry pays 28 per cent import duty and 12 per cent vat, said Singh.

With no representation in either of the industry bodies, cii and ficci, led makers have got together to draw guidelines under the Bureau of Indian Standards (bis). Setting standards, they hope, will help the government decide on subsidies to the led industry.

bis has set up a technical committee to draw guidelines for performance, safety and mechanical specifications of leds. The bis Electro Technical Committee for Lamps and Lighting Products comprises led manufacturers, non-profits and government officials. isle and elcoma (Electric Lamp and Components Manufacturers Association of India) are also part of the committee. Their priority is to draw specifications that will ban the entry of cheap quality leds made in China.

Another way to bring down the cost is to scale up production. leds are made in three stages the chip stage, packaged stage (chip with electrical components) and the luminaire stage with the lighting fixture. India imports leds either at the packaged stage or the luminaire stage. "If India can set up packaging units, we can save up to 30 per cent on the cost. But it is a volume game and demand has to be created," said Mamak.

Not easy to maintain standards
The technical challenge in popularizing leds is to manage the heat generated. "If the heat is not dissipated properly the light will begin to dim and the life of the bulb will be reduced," said H C Kandpal, head of the optical radiation standards department of the National Physical Laboratory, Delhi. Although leds have much higher lighting efficiency than cfls and incandescent bulbs, the efficiency decreases with use.

"Unless high standards are maintained in mass production, the output of light and lifespan will be affected," said Mamak.

A step towards setting standards is bee's plan to light a kilometre of road in 16 states with leds. "We want to test the lighting and energy efficiency of the product. Since there are varying claims, we want to be sure of the technology we endorse," said Garg. bee also has a project in the pipeline to convert the lighting system to led in one village in each state. This would also perk up demand for leds in the states.