Assumptions for 6.117 kW AC PV system used in example on this web page:

- 30 SunPower SPR-230 solar modules (230 watts DC Standard Test Conditions)
- 1 SunPower SPR6500f inverter
- $52,000 total system cost before any rebates
- $9,143 California Solar Initiative solar rebate administered by PG&E (1.55/W level)
- $12,857 Federal Income Tax Credit (30% of after rebate cost)
- $316 per month old electric bill with PG&E, E1 XB rate schedule
   prior to solar as of, May 2009 in San Jose, CA
- 14,400 kWh per year electric usage before solar
- 10,501 kWh per year solar production
- With solar PG&E E6 time-of-use rate schedule used
  (25% on-peak electric usage, 25% partial peak usage, 50% off peak usage)
- South facing solar modules at 22 degree tilt above horizontal ,with no shade
- 0.25% annual PV module degradation rate
- 28% federal income tax rate, 9.3% state income tax rate (used in cash flow with loan)
- $3,670 inverter replacement cost at year 15 ($600 per rated AC kW of PV system)
- $3,569 in annual electricity savings for first year
- 5% electricity price inflation
- Environmental benefits similar to removing 2.2 cars from the road for 25 years
- Removes 411,836 pounds of CO2 over 25 year period (similar to planting 3.5 acres of trees)
- $18 remaining monthly electric bill with solar
- 536% lifecycle payback over 25 years
  [computed as ($160,926 lifecycle savings / $30,000 PV system cost) X 100 = 536%]
- $160,926 lifecycle savings over 25 years

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