We have 24 kW system on our farm. Since Iowa allows DIY it was installed by me and wife between end of November 2012 and February 2013. Total cost of hardware was $54000. The project was financed by a loan combined by second mortgage ($29000 @ 5.5% interest)and a loan from "Iowa Revolving Alternative Energy fond" ($25000 0% interest). When the system was completed we claimed $16500 federal tax rebate and $3000 Iowa tax rebate. Our electric power is provided by rural coop that is more or less hostile to alternative energy so no net metering. Since we have 100% electric house (with propane backup) I calculated the break even point, assuming constant cost of electric power, around 13 years. BTW Iowa is #4 state in number of sunny hours/year in the country.
We heat and AC about 3400 sqft with geothermal heat pump and 2700 sqft with two mini split units. Estimated average electric bill without the PV would be about 400-450/month. With PV it is 120/month. Cost of loan is 500/month till October 2022. We should make (if we live till 95) about $45000 net profit at the end of 30 years of operation. As of today we produced 174 MWh of energy worth $19662.
Speaking about emergency power batteries. There are many Nissan Leaf coming from leases for sale at about $10000. Having 24 kWh battery it is way cheaper to buy the Leaf than Tesla wall.
1.) You can drive it.
2.) You can add off grid inverter ($5000 ro so) and use it to power your house during outages.
In fact the Japanese version of Leaf has software (Leaf to Home) for integration it with the PV and as emergency power source since 2012. The 2018 model has a variation of Leaf to Home specifically designed for the US market.
