I created this Excel document to try and determine exactly how much I’m saving with my PV array. This calculator takes into affect SRP’s current rates.
My main purpose for creating this utility was to determine which plan makes the most sense given that if you’re an SRP customer you can pick from EZ-3, TOU, or basic. The time frames for the higher cost and lower cost energy is as follows on these plans.
Getting to the good stuff. Here is a screenshot of the program. It is very simple to use. The orange boxes indicate cells that you should be modifying with your data received on your monthly bill from SRP. None of the other fields need to be edited.
These are real numbers from my SRP bills from 2010-2011. This is a 5kw system that cost me about $5,715,51 after the tax credits. This investment yields a 14.29% return or 7 years to pay for itself.
Once you fill out a years worth of data in this document it will calculate automatically you:
1. Your return on investment or ROI.
2. The number of years the system will take to pay for itself.
3. The amount of money you would save on EZ-3 VS. Basic or TOU VS. Basic
4. The monthly savings in your electric bill from solar.
5. The total amount of electricity that you’re paying for.
6. The monthly percent of energy that comes from solar.
*This program does not take into consideration inflation. Most installers calculate 3% inflation.