How does my solar system make for a more green environment?

We all understand that going solar is an investment and can save a homeowner money, but how does a homeowner translate their solar system into a quantifiable metic that illustrates its environmental impact? In other words, what is the carbon trade-off between trees and a solar system? Follow the 10 quick and easy steps below to calculate you Equivalent Carbon Tree number (ETC-n) and better understand your environmental impact!



  1. P (Annual kWh of your solar system) = (X * Y * Z)*365

  2. What is the DC rating of your solar system? This value will be X as shown in Step 1.

  3. What is average solar radiation in your area? This value will be Y as shown Step 1. (Please visit NREL site (click here) to find average for you state. The national average is between 4.0 and 5.5)

  4. Z=75% As shown in Step 1, the variable Z is our miscellaneous and compounding factor that can effect efficiency, such as dirty modules, dirty air, high humidity, hot modules, wiring losses, small bits of shading, inverter inefficiency, etc. Feel free to use 80% if your system is shade-free and you are in a dry, high altitude environment.

  5. Calculate P

  6. Assume 1 kWh of electricity = 1.106 lbs of CO2 (non-baseload figure) —> B = 1.106 CO2 / kWh

  7. C (Carbon Emissions Avoided/Year) = P * B

  8. To better understand that carbon emissions relative to trees, assume a 30 year old tree absorbs approximately 193 lbs of CO2/year. So A = 193 CO2/year

  9. ETC-n (Equivalent Carbon Tree number) = C/A

  10. Now that you have your ETC-n, what does it really mean relative to your solar system? Your ETC-n illustrates the number of trees required to absorb the equivalent amount CO2 emissions that your solar system now offsets!


References

  1. https://www.civicsolar.com/support/installer/questions/how-do-i-calculate-real-world-output-my-solar-system

  2. https://newenglandcleanenergy.com/energymiser/2015/09/24/tree-math-2-solar-vs-trees-whats-the-carbon-trade-off/

  3. https://rredc.nrel.gov/solar/pubs/redbook/