How We Got, What We Got

1. The Array: 6.86 kW STC,  (28)Trina TSM-245PA05.08 Modules, (1) SMA SB 7.0-1SP-US-40-240V, Ground Mount,Tilt Angle of 35°, Location St. Louis ,Mo, Lat 38.6270° N.

Modeled using Sunny Design 3 software.

Performance Ratio: 87.3%

Beginning annual energy yield of 10, 232.2 kWh.

Assumed output decrease of 0.7%/yr., 80% power output by year 25. (Typical power warranty)

Output of 8,244.6 kWh in year 25.

25 year yield = 231,748 kWh.

(2)The Array: 7kW STC, (26) Jinko Solar JKM270M-60B Modules, SMA SB 7.7-1SP-US-40-240V,

Roof Mount 23° (5in 12 roof pitch, shingled), Location Springfield, IL, Lat. 39.7817° N.

Modeled using OnGrid

Beginning annual solar production of 9,687 kWh

Inverter replacement @ year 15, $1,400.

System Maintenance 0.15% of gross cost.

Annual module degradation of 0.5%.

System Efficiency of 78.8%.

Installed cost of $1.95/watt, $13,689 (yr. 2018)

30% Federal Tax Credit included.

Sources:

U.S Residential Electricity Price- EIA

https://www.eia.gov/outlooks/steo/report/electricity.php

 

 

7% Investment

After Tax Inv - Electric Bill w/o Solar
7% Investment w/Solar

The Cost of Doing Nothing

Assuming a 2%/year increase in electricity rates.

897 kWh per month usage.

Solar Savings

Assuming a 2%/year increase in electricity rates.

897 kWh per month usage.

Module degradation of .5% per year,

Inverter replacement @ year 15.($1,400)