Here is the EPA link and the formula used to calculate the annual reduction in carbon emissions:
37.2 kWh/bulb/year x 1,558.8 pounds CO2/MWh delivered electricity x 1 MWh/1,000 kWh x 1 metric ton/2,204.6 lbs = 2.63 x 10-2 metric tons CO2/bulb replaced
With the new updated numbers, the calculation is as follows: .0263 x 7500=197.25 metric tons.
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Bottom Line...Since November, CLEA-N has delivered 7,500 LED bulbs to 1,100 households, which over the life of the bulbs, will reduce utility costs by over $550,000.
Here's how we calculate the cost savings on utility bills.
- Each LED bulb uses just 11 watts of energy but is 75 watt equivalent.
- Each LED bulb is expected to last 15,000 hours, or 13.6 years at 3 hours per day.
- Our Alliant Energy bill shows our local rate is $.1166/kWh.
- We used an online energy cost calculator, with 3 hours per day per bulb.
- 75 watts of energy (with incandescent) would cost $9.58 to operate a bulb for a year.
- 18 watts (75 watt equivalent CFL) would cost $2.30 to operate a bulb for a year.
- 11 watts (75 watt equivalent LED) would cost $1.41 to operate a bulb for a year.
- Since CLEA-N launched, we have impacted just over 1,100 households, with just over 7,500 bulbs given out.
When we did the swap/exchange portion of the project, we saw 64% incandescent and 36% CFL exchanged. Assuming that ratio holds true across all the households...
- 64 Watts (reduction/savings on incandescent to LED) is saving $8.18 per year.
- 7 Watts (reduction/savings on CFL to LED) is saving $0.89 per year.
- Energy cost savings for incandescent replacements is calculated at $534,000.
- Energy cost savings for CFL replacements is calculated at $32,000.
Therefore, we estimate the total cost savings, over the life of the LED bulbs, for the folks who received LED bulbs from CLEA-N, is over $550,000!!