I think it's smart governing.
Solar panels pay for themselfs in cheaper electrical bills and if you roll up-front cost into mortgage you'll probably not be paying more than for the same house without solar.
8kW (kilowatt) solar systems typically sell in the US (as at March 2017) for between $2.95 and $3.50 per watt meaning a cost of between $23,600 and $28,000 before the 30% solar tax credit.
After the 30% solar tax credit this equates to a range of $16,520 to $19,600.
However, the price varies by state and also depending on whether the system is purchased for cash or whether the system is financed. Most solar financing offers have an origination fee of 10-12% and so systems that are financed are usually 10-15% more expensive.
8kW solar power system | How much they cost, produce and roofspace requirements