Cost and Payback Calculations

•  Fourteen 230W panels gives the farm a total installed peak capacity of 3.2kWatts. 
•  The panels produce 4360 kWh of energy per year. 
• The total cost of installing the solar systems was $19,487
• Installation cost = $6.05 per watt. 
• Maine state rebate is $500 per 1000kWh estimated annual production with a maximum of $2000 for residential and $4000 for commercial (DOE, 2012). 
• The federal rules provide a 30% tax credit (US Dept of Energy), which amount to $5846.10. 
• There are also federal rules that allow accelerated depreciation on tax returns for solar installations. 
• Combining state and federal incentives the total cost of the project is reduced to $11,641.   
• Given a cost of electricity of 17 cents per kWh to get a yearly savings of $741. 
• Payback time = 15.7 years.  
• Solar panels hold a 25-year warranty.