Domestic Efficient Lighting Programme (DELP)

DELP programme has been launched in several states (Maharashtra, Rajasthan, Himachal Pradesh, Uttar Pradesh, Delhi) to replace the regular bulbs and CFL lights with LED lights. The programme is being implemented by  Discoms in association with Energy Efficiency Services Limited (EESL). LED lights are given at lower than market price in this scheme.

What fraction of electricity consumption is shared by Lightning in India?

Lightening accounts for around 15% of the total electricity consumption in India.

How ICL, CFL and LED differ in terms of efficiency?

An ordinary incandescent (ICL) bulb is an extremely energy inefficient for lighting when compared to LED. A ICL bulb requires 60 watts of power to emit 350-400 lumen of light (unit of light) while CFL lights emit 450-550 lumen of light on 14-16 watts. However, they have issues because of their hazardous mercury coat.

LED bulb can emit 600-700 lumen by consuming just 6 watts of power and it saves 90%  more energy than regular bulbs. Further, the proportion of lumens that falls in an area from an LED light source is greater than that of a conventional light sources.

How ICL, CFL and LED differ in terms of life?

The LED bulbs have the life of 15000 to 20000 hours which is more than both the ICL bulbs and CFL bulbs.

How ICL, CFL and LED differ in terms of safety and mercury emissions?

ICL has safety hazards because it has both mercury and lead. Further, the halogen lights have halogens (Bromine, Iodine) which are also harmful.  CFL has safety hazards because of mercury coating. LED has no mercury and this is what makes them versatile and popular. However, it is not correct to say that LED bulbs are totally safe. Some toxic material are used in them too.

How LED bulb works?

An Light-Emitting-Diode (LED) is a small light bulb that can easily fit into an electrical circuit. These light bulbs do not get hot and they are illuminated by the constant movement of the electrons located in the semiconductor material. The diodes are basically semi-conductors (a semi-conductor is the one whose electrical conductivity is in between that of a conductor and an insulator) that are used to control the direction of the flow of electrons.

When the electricity flow is started in a diode, the electrons in the diode change their state by losing energy in the form of photons (light) emission. The more energy is lost, the more powerful the photons of light. This phenomenon is known as “electroluminescence”, and this is different from any other kind of light emission because it provides no heat. When the traditional light bulbs emit light, that process is called “incandescence” because they emit heat along with the light (thus the name “incandescent light bulbs”).

Generally LED lights are designed to emit one colour of light, but over the past years manufacturers have come up with bi-colour light bulbs, and the most popular colours at the moment are red, green and blue. In the case of large LED displays, the manufacturers use a combination of LEDs that aim to give a wide range of colours (these displays use a 3-LED pixel).


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