Lighting | Centre for Science and Environment


Lighting

How do I light my home?

Do you know lighting accounts for almost 20 per cent of the monthly electricity bill in many households? Energy saving can make a considerable difference to our household budget. Do you know the yellow incandescent bulbs that we have got so used to is extremely energy inefficient? Only 5 per cent of the electricity is converted into light in these bulbs, the rest is lost as heat. How can we adopt efficient lighting that can help to reduce energy consumption, thereby save energy and money, without compromising on the quality of light?

Lighting constitutes almost 10% of the total Residential Energy Consumption (Survey, 2001). Residential sector accounts for 13.3% of total commercial energy generated in India. But, depending up on the end-use energy consumption and building functions, lighting could be responsible for up to 60% of total energy consumption at Commercial Building level. This act as capital intensive affair for most small and bigger building owners.

Use of new lighting technologies can reduce energy use in the house by 50 to 75 per cent – that’s enormous in terms of monetary savings. In addition, lighting controls offer further energy savings by reducing the amount of time that lights are on without being used. Consumers have a bigger role to play in order to save the energy.  Most home lighting products are usually energy intensive in nature and cost too much. Due to the asymmetric information about energy conservation and its economic and environmental benefits available at consumer demand and supply side, it is often difficult to perceive right choice for energy efficient lighting. Here, are some of the basic information about Lighting-ways and primitive information about know-how principles of energy efficient lighting for our homes and offices.

 

 

Compact fluorescent lamp (CFL)?

What is it and why it helps?
A Compact fluorescent lamp (CFL) is an energy efficient alternative and are much more efficient than incandescent bulbs. A CFL uses only one-fifth as much electricity as an incandescent lamp to provide the same level of illumination. A 15 W and 20 W CFL can replace a 60 W and 100 W incandescent bulbs respectively.

The lighting efficiency in case of CFL, ranges from 45 lumen per watt to 60 lumen per watt. Since an incandescent bulb converts about 95 per cent of electricity into heat and only five per cent is converted into light, it generates only 14 to 16 lumen per watt. In case of Delhi, where the domestic consumers pay Rs. 4.5 per unit of electricity (kilo watt hour -- kWh), a 60 W incandescent bulb burning for 4 hours a day will consume 87.6 kWh in a year, whereas a 15 W CFL in a similar condition will use 21.9 kWh, saving Rs. 296 to a consumer. Similarly, comparison of 20 W CFL and a 100 W incandescent bulb shows that the CFL will consume 116.8 kWh less saving Rs. 526. Not only savings, CFLs also save heat trapping carbon dioxide emissions. While a 60 W incandescent bulb emits 65 g/hr of CO2, a 15 W CFL emits only 16 g/hr. 

What is the life span and cost?
CFLs last up to six times longer than incandescent bulbs. The average cost of a CFL is in the range of Rs. 80 to 100 compared to Rs. 10 to 15 for an incandescent bulb. Although these cost a bit more than incandescent bulbs, the excess investment is easily paid back in a year’s time.

Where can you get it?
A consumer can buy a CFL from any electrical shop. One can get CFLs manufactured by companies such as Osram and Phillips. There are other manufacturers as well. In addition, low cost Chinese CFLs are also found. You need to check out on the lamp life.

Any concern?
Mercury, which is a proven neurotoxin, is a small but essential component of CFLs. It allows the bulb to be an efficient light source. It has no substitute but its quantity can be reduced. In developed countries like the US and Europe, CFLs with 1 mg of mercury are available but CFLs sold in India however have 3 milligrammes (mg) to 13 mg mercury. There is however no system of collection and proper disposal of used CFLs to be able to avert the risks of mercury contamination. Now collection system is evolving.

Any official policy?
The ‘Bachat Lamp Yojana’ aims at large scale replacement of incandescent bulbs in households by CFLs. It seeks to provide CFLs to households at the price similar to that of incandescent bulbs and plans to utilize the Clean Development Mechanism (CDM) of the Kyoto Protocol to recover the cost differential between the market price of the CFLs and the price at which they are sold to households.  Under this scheme, the Bureau of Energy Efficiency (BEE) is coordinating voluntary efforts to provide high quality CFLs to domestic consumers for about Rs. 15 per lamp, at a rate comparable to that of incandescent bulbs. This would remove the barrier of high CFL price (which is currently Rs. 80 to 100 per lamp) which is constraining its penetration into households. The BEE targets replacement of about 400 million incandescent bulbs in use in the country, leading to a possible reduction of about 6,000 MW of electricity demand, and a reduction of about 24 million tones of CO2 emissions every year.

 <Back to Top

 

 

Light Emitting Diode (LED) bulbs?

What is LED? LEDs have been around for over 50 years in colours red, orange, yellow, blue, green and then sheer white. These have come a long way from being tiny indicator lights that tell one 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. Delhi has replaced 150 Watt solar vapour lamps in streetlights with 50 Watt LEDs in a residential locality early this year.

What is the benefit?
Unlike incandescent bulbs, LEDs do not have filament that is heated to create light. These are illuminated by the movement of electrons in a semi conductor material (diode). Since electricity is directly turned into light, LEDs waste less energy as heat. Energy consumption is lower than CFLs that use mercury vapour to produce light. LEDs have taken over CFLs promoted as the most advanced lighting device, in energy efficiency. A 5 Watt LED can replace a 15 Watt CFL, saving Rs. 77 on the electricity bill a year.

What is the life span and cost?
LEDs score over incandescent bulbs and CFLs in life span as well. A 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.

The biggest challenge LED faces is high cost. It is 80 times as expensive as an incandescent bulb and 10 times a CFL. Manufacturers claim high prices are offset by savings but recovering the cost takes 5 to 10 years. A Rs.10, 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.

Any concern?
These are safer as LED beams do not emit radiation and unlike CFLs, they do not contain mercury.

Any official policy?
At present, there is no subsidy for LEDs. The LED industry pays 28 per cent import duty and 12 per cent VAT. The manufacturers are looking to the government for subsidies to promote LEDs. 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. 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.

 <Back to Top

 

Follow us on 
 
 
 
 
 
 
 
 
 
 

 
 
 
 
 
 
gobar times