NaBa Green Energy

As we all know LED Lights are becoming popular due to various benefits it can offer. There has been lot of emails and questions regarding how much electricity can be saved and what will be the payback when compared to CFL and Incandescent lights.


Comparing 60 Watts of Incandescent Lights with CFL/LED that can produce same amount of light (Lumens):

	LED Light	CFL	Incandescent
Lumens/Watt	120	51	12
Life Time in Hours	50,000	6000	1200
Watts required	6	14	60
Cost of the bulb in Rupees	1,200	180	60
Kwh used for 50K hours	300	700	3000
Electricity Cost @ Rs.7.00	2,100	4,900	21,000
Replacement of bulbs for 50K Hrs	1	5	42
Replacement Expenses + bulb cost	0	1,155	3,360
Total cost in Rupees	3,300	6,055	24,360

Carbon footprint is the amount of Green house gases like carbon dioxide, methane, nitrous oxide emissions emitted by a building, organization etc. It relates to the amount of greenhouse gases we are producing in our day-to-day lives through burning fossil fuels for electricity, heating, transportation etc.

For our discussion we are taking carbon footprint for indoor lighting in our office buildings. We can increase the performance of the building by using LED lights and reduce the building carbon foot print. In this article we will calculate the carbon footprint for

1. Incandescent Light
2. Compact Fluorescent Light
3. LED Lights

Electricity



We should know, half of our carbon footprint is due to electricity and 17 % is due to lighting alone. Electricity in turn can be produced by coal, natural gas, petroleum, and other. Electricity is produced from different sources and how much GHG released is shown as below Table

Source	Million metric tones of co2 emission for 1 year	Electricity generation (Billion kWh) for 1 year
coal	1788	1882
Petroleum	106	119
Natural gas	337	562
Other	14	22
Non fossil fuels	none	1106
Total	2245	3621

Since close to 2245 million metric tones of CO2 emitted by total electricity generation per 1 year. A single kilowatt-hour of electricity will generate 619 grams of CO2 emissions.



Incandescent Light
 
Incandescent lamp is a source of light which produce light when the filament is being heated. It can release 80% electrical energy converted into heat energy. We can calculate how much CO2 will be emitted by 40 watt incandescent bulb
 

• Power Consumption- 40 watts
• Operation per day- 10 hours
• Power Consumption per annum-146000 watt
• Electricity per hour (kwh) - 0.04 (1 kWh=619g CO2 can be released)
•  Lighting Carbon Emission per year/lamp (146*619g ) -90.3 kg.

A single 40 watts incandescent bulb will generate 90.3 kilograms of CO2 for every year. The reduction of carbon footprint is none for this lamp.

Compact Fluorescent Light
As we all know CFL produce less heat and more visible light compare than incandescent lamp. We can calculate how much CO2 will be emitted by 14 watt incandescent bulb

• Power Consumption- 14 watts
• Operation per day- 10 hours
• Power Consumption per annum-51100 watt
• Electricity per hour (kwh) – 0.014 (1 kWh=619 g CO2 can be released)
• Lighting Carbon Emission per year/lamp- (51.1*619g ) - 31.6 kg.

A single 14 watts CFL lamp will generate 31.6 kilograms of CO2 for every year. The reduction of carbon footprint is none for this lamp. CFL contains harmful mercury which creates mercury emission. Estimated suggestion led lights only will reduce our carbon foot print over than other lights.


LED Lights



LED lights consumes low power and energy efficient over than other lights. Not even a single point we can’t compare led lights with other lighting.We can calculate how much CO2 will be emitted by our 8 watt LED Tube light

• Power Consumption- 8 watts
• Operation per day- 10 hours
• Power Consumption per annum-29200 watt
• Electricity per hour (kwh) – 0.008 (1 kWh=619 g CO2 can be released)
• Lighting Carbon Emission per year/lamp(29.2 *619g) - 18 kg.

A building’s carbon footprint from led lighting can be reduced by 68%.

• Reduction in Carbon Footprint (tons)-0.122(12.28 kg)

	Incandescent Bulb	CFL	LED light
Power Consumption(watt)	40	14	8
Electricity(kwh)	0.04	0.014	8.008
Hours of Operation Per Day	10	10	10
Carbon Emissions (tons) per year/lamp	0.903	0.316	0.18
Reduction in Carbon Footprint (tons) / lamp			0.12

• LED light can reduce our carbon footprint by 0.12 tones per year.
• Led light does not contain mercury; it is a big benefit for this lamp.
• CFL contain 3-5mg per bulb which is poisonous. Mercury emission is 1.2mg from power plant using CFL.
• Incandescent, it is 5.8 mg from power plant.

Based on above comparisons, LED emerges as the BEST option to requce carbon footprint.

Fluorescent Tube is a gas discharge lamp, that contains gases like Mercury. It produce short wave ultraviolet light that gets transformed into visible light, the inside of the tube has a phosphor lining. Then the 80% of electrical energy is converted into heat energy , 20 % only used for visible light. The energy produced converts into more heat than Led lights.

Light Emitting Diode is a semiconductor diode. It consist of  p-n junction diode, when it is in forward biased the electron  recombine with holes, then it release some energy in the form of photon( visible light). The electrical energy is converted into 80% light energy, remaining 20% being heat energy. LED does not contain mercury. No harmfull chemical (like mercury) are used.

T8 Fluorescent tube lights are available with different kind of rated light output and power consumption. 

For example 36 watts  fluorescent lamp, light output (Luminous Flux) is 2000 lumens, so system efficacy is 55 lm/ watt. Rated life is 5,000 hrs. Tube light efficiency comes down with time.  

Lux at the ground = 9.18, Lux/watt =0.50

If using Aluminum Reflector, it can reduce 13% of output light. Now the light output is 1566 lumens

Lux at the ground =15.71, Lux/watt =0.43

If using prismatic Refractor, it can reduce 8% of output light. Now the light output is 1656 lumens

Lux at the ground =16.62, Lux/watt = 0.46

As we all know the efficiency is very high for LED Tube Light over the other lights. So the Luminous flux is consistent for rated life and power consumption also should be low. 

Power consumption - 16 watts, System Efficacy -123 lumens/watt, So total light output( Luminous Flux) is 2000 lumens. It should be maintained for Rated life(50,000 hrs). Life span is very high for led lights over other lights. Lux at the ground =68.53, lux/watt =4.28

Reflector is not required for LED lights because of Directivity (Beam Angle).so the light output should not be wasted compare than Fluorescent lamp.

Normally the Fluorescent lights are available in 36 watt, but it runs using electronic ballast (called solid state ballast) which consume above 12 watts power.

Magnetic Ballast, the stating modes are Programmed stat, instant stat, and rapid start Lamp flicker index is 0.04-0.07; Dimming is not available for this ballast

Hybrid Ballast, the stating mode is rapid stat, Lamp flicker index is 0.04-0.07. Dimming is not available for this ballast.

Instant start Ballast supply a high initial voltage (over 400V for 4 ft Tube) to start the lamp. High voltage is required to initiate the Discharge between unheated electrodes.  

Rapid Start Ballast supply 200-300V to start the lamp, which can heating the electrodes to approximately 1470˚F(800˚C). It starts the lamp with brief delay but without flashing. And for the Fluorescent lamp, warm up time is also minimum 5 minutes.

As we all known using LED Tube Light the power Consumption should be very low. And no need to use electronic ballast because it runs by constant current and voltage. We can’t see the flickering in the range of voltage 85-285VAC and Dimming also available for the led lights. LED driver are used in LED Lamp. So LED Tube Light has a potential benefits like quick start compared to Fluorescent Tube Lights.

Beam Angle is very important in every lighting technology. For Fluorescent lamp Beam angle is 360 degree. We can calculate the beam spread only for 270 degree, 90 degree beam angle is wasted

Beam Spread = 48.6 (Recommended pole height is 10 ft)

Led lights are available with variety of Beam Angle, Beam Angle is 120 degree for our Led Tube Light, we can calculate beam spread for 120 degree

Beam Spread = 21.6 (Recommended pole height is 10 ft)

The light output is not wasted in Led Tube Lights compare than Fluorescent Tube Light.

Fluorescent tube contains mercury gas, which can discharges and emits 65% of light in 254 nm and 10-20% of light in 185 nm. It will emit the yellowish white color. It has a low Color temperature and Color Rendering Index (Color Tempreature-4100 Kelvin, CRI-80)

Led light has a high correlated color temperature of 5500k -7500k. The sunlight has a color temperature of 6500k, so led light is equivalent to the sunlight. And CRI is also very high (above 90). It can emit the cool white color in the spectrum of 380-740 nm. For Humans also the visible spectrum is 380-740 nm.