PMF IAS Current Affairs
PMF IAS Current Affairs

DELP (UJALA) Scheme – Comparison: LED – CFL – Incandescent Bulb

Domestic Efficient Lighting Programme (DELP) or Unnat Jyoti by Affordable LEDs for All (UJALA) scheme

Bachat Lamp Yojana

  • “Bachat Lamp Yojana” was a launched in 2009 to reduce the cost of compact fluorescent lamps (CFLs, i.e., energy saving lights) sold to consumers.
  • Implemented through the Bureau of Energy Efficiency (BEE) in India’s Ministry of Power, the program’s goal was to deliver CFLs at the cost of normal lightbulbs.
  • The difference in cost will be covered by the sale of Certified Emission Reduction(CER) Units (Carbon Credits) under the Clean Development Mechanism of the Kyoto Protocol.
  • The Ministry of New and Renewable Energy stopped the subsidy on CFL-based solar lighting system to encourage the use of the LED version.


  • DELP replaced the ‘Bachat Lamp Yojana’ [Energy Efficient Lighting Programme (EELP)] – Scheme to offer CFL at the price of Incandescent bulbs.
  • DELP encourages the people to use LED bulbs in place of incandescent bulbs, tube lights and CFL bulbs.
  • DELP sold 9 crore LED bulbs at subsidized prices reducing the energy cost by 50 billion rupees.
  • DELP scheme is implemented by Energy Efficiency Services Limited (EESL) – Ministry of Power.

DELP - UJALA - Energy Efficiency Services Limited

Domestic Efficient Lighting Programme (DELP) or Unnat Jyoti by Affordable LEDs for All (UJALA) scheme


  • EESL is a Joint Venture company of four Central Power Sector undertakings viz. NTPC Ltd, PFC, REC, and Power Grid.
  • EESL was set up to create and sustain markets for energy efficiency in the country.
  • EESL works closely with the Bureau of Energy Efficiency (BEE).
  • It is leading the market related activities of the National Mission for Enhanced Energy Efficiency (NMEEE), one of the 8 national missions under National Action Plan on climate change.

Comparison: Light Emitting Diodes (LEDs) – Incandescent Light Bulbs – Compact Fluorescents (CFLs)

Tungsten Lamp or incandescent light bulb

Tungsten Lamp or incandescent light bulb

  • In an incandescent light bulb, a wire filament (tungsten) is heated to a high temperature by passing an electric current through it until it glows with visible light.
  • The hot filament is protected from oxidation with a glass or quartz bulb that is filled with inert gas.

Why tungsten?

  • Pure tungsten has very high melting point (3400 °C) [An electric current can heat the filament around 2000-3000 °C, which stays below the melting point of tungsten].
  • It has very low vapor pressure, and greatest tensile strength out of all the metals.



  • Compact fluorescent lamp is a fluorescent lamp designed to replace tungsten lamp.
  • Compared to incandescent lamps, CFLs are highly energy efficient.
  • Like all fluorescent lamps, CFLs contain toxic mercury.

Fluorescent lighting

  • A fluorescent lamp is a low pressure mercury-vapor gas-discharge lamp.
  • Electrons that are bound to mercury atoms are excited to states where they will radiate ultraviolet light as they return to a lower energy level.
  • This emitted ultraviolet light is converted into visible light as it strikes the fluorescent coating on the bulb (phosphor coating).

LED lamp

LED lamp

  • An LED lamp is a light-emitting diode (LED) product which is assembled into a lamp.
  • LED lamps have a lifespan and electrical efficiency which are several times longer than incandescent lamps, and significantly more efficient than most fluorescent lamps.

Light-emitting diode (LED)

  • A light-emitting diode (LED) is a two-lead semiconductor light source.
  • It is a p–n junction diode, which emits light when activated.
  • When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons.
  • This effect is called electroluminescence, and the color of the light corresponds to the energy of the photon.

Comparison: Light Emitting Diodes (LEDs) – Incandescent Light Bulbs – Compact Fluorescents (CFLs)

Type LED lampLight Emitting Diodes (LEDs)
CFLCompact Fluorescents (CFLs)
Tungsten Lamp or incandescent light bulbIncandescent
Light Bulbs
Life Span (average)  50,000 hours


8,000 hours

7.5 X

 1,200 hours


Power used  7 watts


14 watts


60 watts


Brightness in lumens 600 540 800
Annual Operating Cost    X 2X 10X
Contains the TOXIC Mercury  No Yes  No
Carbon Dioxide Emissions   

(The bulbs don’t emit CO2.

Power generation emits CO2.)
Lower energy consumption decreases: CO2 emissions, sulfur oxide, and high-level nuclear waste. 

X 2X 10X
Turns on instantly Yes No – takes time to warm up Yes
Heat output Low Medium High
Heat sensitive No Yes Yes
Moisture sensitive No Yes Yes
Durability Very Durable – LEDs can handle jarring and bumping Not Very Durable – glass can break easily Not Very Durable – glass or filament can break easily

Source: and Delp Scheme.

Insulated gate bipolar transistor (IGBT)

  • A transistor is a semiconductor device.
  • It forms the basic component of all electronic devices.
  • It is used to amplify or switch electronic signals and electrical power.
  • IGBT replaces analogue power control with digital power control with a massive increase in efficiency.

IGBT applications

  • A CFL lamp needs a switch. IGBT plays the role of a switch in a CFL.
  • IGBTs is also used to generate the (mercury) gas discharge, which lights up the bulb.
  • The IGBT’s other advantage is that it can fit in a small volume.
  • IGBT are also used in electronic components of various household appliances ranging from space heaters to refrigerators.
  • They are also used in medical products (X-ray, CAT, MRI).

Jayant Baliga

Jayant Baliga

  • Inventor of the insulated gate bipolar transistor (IGBT).
  • Alumnus of Indian Institute of Technology, Madras.
  • He won the global energy prize in 2015.
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