LIGHTS

LIGHTS

Incandescent Bulbs: - Incandescent bulbs contain a filament that is heated, giving off light in the process. The filament is delicate and eventually burns out. Special gases are introduced into the bulbs to increase their useful life although this does not increase its efficiency. Regular incandescent bulbs are very inefficient as over half the energy consumed by them produced heat and not light.

 

Tungsten Halogen Bulbs: - Tungsten-halogen (or quartz) bulbs are quite similar to the incandescent bulbs but are 10-15% more energy efficient than the standard incandescent. Compared to incandescent lamps, halogen lamps produce a brighter, whiter light and are more energy efficient because they operate their tungsten filament at higher temperatures. However, they can generate excessive heat and could be a fire hazard.

 

Light Emitting Diodes (LED):- Another source of lighting that is gaining importance is LED – small, solid light bulbs, which are extremely energy efficient. Until recently, LEDs were limited to single bulb use in applications such as instrument panels, electronics, penlights, etc. Recent improvements in manufacturing technology have lowered the cost of LEDs and their range of application has increased. the bulbs are now available in clusters, from 2 to 36 bulbs and are popular especially for batter-powered items like flashlights. Their life is about 10 times that a CFL and they use a fraction of the wattage of incandescent bulbs. Moreover, because of their low power requirement, they can be lighted using solar energy thereby allowing their use in remote areas.

However, LEDs offer only focused light and are best as task specific lighting such as reading light, spotlights, signage lightening, etc. They do not radiate light in 360°. New designs using diffuser lenses with clustered bulbs are trying to address this problem. A lot more needs to be done for more residential application of LED lights.

 

Compact Fluorescent Light Bulbs:- The demand for CFL has risen sharply over the past few years. According to Elcoma (Electrical Lamp Manufacturing Association), New Delhi, the production of GLS (General Lighting Service) bulbs and FTLs (Fluorescent Tube Lights) has increased only by about 30% and 37% respectively but at the same time the production of CFLs has increased by 370% during the last five years.

The primary reason for the increase in their demand and production is their energy efficiency. Compact fluorescent light bulbs (CFLs) use fluorescent technology in a compact size that can be used in place of standard light bulbs, are much more energy efficient and last 8 -10 times longer than the ordinary bulbs. The primary difference between a CFL and FTL is in size. CFLs are made in special shapes to fit in standard household sockets, like wall fixtures, table lamps, etc. in addition, CFLs generally have integral ballast that is built into the light bulbs whereas most fluorescent tubes require separate ballast independent of the bulbs and thereby need special fixtures. Both offer energy efficient light, but an added advantage is that CFLs are available in different shapes and sizes.

The watts needed by regular incandescent bulbs and CFLs to produce the same amount of light is roughly as follows:

CFLs fill our rooms with the same amount of light using 60-75% less energy than a standard incandescent bulb. Although the initial cost of a CFL is higher, the cost saving over the life of the bulb can be striking.

So, by replacing one 60-watt incandescent light bulb by a 13 watt CFL you save about Rs. 1500/- over its lifetime; if you replace more the saving would be much greater. And don't forget the heat – the standard incandescent bulbs give away most of the energy consumed as heat thereby increasing the cooling costs of homes and offices in summer. At the same time, mercury is an essential ingredient for most energy efficient lamps. The amount of mercury in a CFL can be upto 4 mg/bulb.

Fluorescent bulbs contain low-pressure mercury vapour and argon, an inert gas, with electrodes at each end. Ultraviolet (UV) light is emitted when electric current is passed through mercury vapour. The UV light is itself invisible, however, when this ultraviolet radiation hits the white fluorescent coating inside the tube, it is absorbed by coating and emitted as visible light – the illumination we see. As CFLs do not use heat to produce light they are much more efficient as compared to regular incandescent bulbs.

 

CFLs Posing Mercury Hazard?

Mercury is found naturally in the environment and its emission can come from both natural and man-made sources. The highest source of mercury in air comes from burning of fossil fuels such as coal. Coal based thermal power plants are an important man made source of mercury. The thermal power plants may account for upto 40% of mercury emissions in the air (Thermal Power Plants in the US are required to reduce their mercury emission by 70% by 2018). A CFL uses 75% less energy than an incandescent light bulb and lasts 6-10 times longer. A power plant may emit upto 10 mg to Hg to produce the electricity to run an incandescent bulb compared to only 2-4 mg of mercury to run a CFL for the same time.

Another argument is that the mercury emissions from thermal plants are air-borne and pose a lower risk of exposure but when the same mercury is deposited in the organic dumps/water bodies through the disposal of broken or discarded CFLs, it may transform into methyl mercury which is a neurotoxin that is likely to enter the food chain. However, one has to remember that the air emission of mercury from a thermal power plant also eventually lands on the vegetation, soil, etc. thereby entering the food chain.

 

Environmental Benefits:- In addition to generating cheap electricity, coal fired Thermal Power Plants release massive amounts of carbon dioxide, the greenhouse gas linked to global warming. Every incandescent lamp replaced by a CFL helps to fight global warming. In addition to carbon dioxide Thermal Power Plants also release, sulfur dioxide (the main cause of acid rain); nitrogen oxides (cause smog and acid rain); radioactive pollutants and mercury.

The amount of mercury in CFLs compared to all other sources of mercury exposure (thermometers, emissions from coal fired Power Plants, etc.) is so little that it does not substantially contribute to the problem of mercury exposure. In fact, the amount of mercury produced from generating electricity to burn an incandescent bulb is more than that for the electricity for a CFL and the amount of mercury contained in a CFL combined. So there is still less mercury going into the environment from using CFL. It is estimated that replacing a single incandescent bulb with a CFL will keep half-ton carbon dioxide out of the atmosphere over its lifetime.

 

Limitations of CFL Bulbs:- Not all CFL can be used with dimmers since this can shorten their life. Earlier the fluorescent bulbs flickered when they were turned on; it took a few seconds for the ballast to produce sufficient electricity to excite the gas inside the bulb. Due to improvement of technology the flicker is now insignificant, although the bulbs do require a short warm up period for reaching full lighting. Moreover, it is best not to use CFLs in fixture that is turned off and on frequently as this shortens their life.

CFLs can also cause disturbance in the working of electronic devices like televisions, radios, remote controls, etc. as such devices may intercept the light coming from a CFL as a signal. In such cases it is better to increase the distance. Use in bathrooms may also shorten the life of the CFL due to humidity.

 

Disposal Options:- At present there is no substitute for mercury in the CFLs. However, manufacturers claim to have taken several steps bulb. Although CFLs used in houses are not legally considered as hazardous waste, it is in the interest of the environment to dispose off the CFLs properly upon burnout. There should be an option for its safe disposal in the treatment, storage and disposal facility and it should be regulated in the same way as used battery, used oil, etc. The best way would be to place the CFLs in a sealed plastic bag and send it to the nearest collection centre. Large commercial users of CFLs must be required to recycle it.

CFL's are safe to use in homes. No mercury is released when the bulbs are in use as the mercury content in each bulb is very small. Even when the bulb breaks there is no immediate health risk if it is cleaned up properly. The glass fragments and fine particles of the broken bulb must be collected by sweeping – not by vacuuming and then the area should be wiped with damp cloth. The damp cloth and the fragments may be placed in plastic bag before disposing. Opening the doors and windows ventilates the room. We need to pay attention to the recycling of CFLs as a little bit of mercury in each bulb can become a real problem as the production and sales are booming very fast.

It is clear, that although there are certain limitations or drawbacks of using CFLs, the benefits in terms of saving energy thereby fossil fuels), reduced greenhouse gas emissions and other environmental issues related to burning of coal are far greater. What is needed is further research for improving the CFLs and reducing / replacing the mercury in them.

Many countries are now banning or are in the process of banning the incandescent bulbs in favour of CFLs as a part of initiatives to reduce both energy consumption and greenhouse gases blamed for global warming. The Indian Government is also taking steps for introducing CFLs in preference to incandescent bulbs. In addition to the steps already taken for promoting the use of CFLs we may think of providing subsidy on them (that is. energy saving measures) in preference to providing subsidy on power itself.

But what is needed is a mass movement. Only then we could help repair the damage we have wrought on our environment.