I have been a solar skeptic since the 1980’s when I went to Engineering school and learned about the math behind energy. The biggest assumptions solar advocates were always wrong on was that solar efficiency would automatically rise and that solar prices would come down automatically in the same ways that other technology, like computers did.
In fact, the gains on both fronts have been painfully slow, but even I am beginning to admit some progress. Some panels now have up to 20% efficiency, a 25 year life, and the cost has come down because of the chinese getting into the business in a big way.
At this point a system for a modern 3/2 1500 sf southern house with plenty of AC, that could produce and sell back to the utility enough energy to have a net zero power bill, would cost less than $50k. For this you probably need a system with a 20 kw size so you can keep that AC compressor running all day AND sell back the excess to cover you at night.
Knock off an extra 30% for federal tax credits and you are on to something.
> Knock off an extra 30% for federal tax credits
Take off the %30 and that messes up the entire calculation.
Or you could invest in one of these and take the savings and invest it at 8%.
The solar cost model isn’t just wrong, solar as source is wrong. It could be used for things that are intermittent, but not for house power.