I'd go for it. Prices will get cheaper (virtually guaranteed), but incentives will also go away (guaranteed, deadlines are already set).
If you only care about the financial decision, then to be honest... not much beats investing in e.g. a broad S&P 500 tracking index. 7% inflation adjusted annual returns + dividends which you can reinvest to go up to 8-9%. Over a 20 year period that's 5x. I'd tune that down to 4x given there's risks and historical returns have been better than they probably will in the future. But it still means at 4x that your $15k solar installation could also have made $60k in the same period.
And there's no way a $15k installation will generate $60k worth of energy, somewhere between $10k and $20k depending on the cost per watt, solar capacity factor and local energy prices. (California does quite nicely and is on the upper end of this spectrum). About a third you get back from the gov, so in a 20 year period in Cali, investing $15k (subsidies included) you may get $30k-$35k in savings if you go solar.
It's really nice but it doesn't beat the market, and most states have cheaper rates than California which is like 30% above average and much fewer sun hours, and less competition, too. Wouldn't be surprised if installation costs were relatively more competitive in California.
So my point being is: 1) it's a great investment and I'd personally go for it. 2) it's, purely financially, not the absolute best way to spend your money, even if it saves you money. So there's still an element of 'I think solar is important' at play. 3) solar tech will get cheaper, but subsidies will fade out.
If you only care about the financial decision, then to be honest... not much beats investing in e.g. a broad S&P 500 tracking index. 7% inflation adjusted annual returns + dividends which you can reinvest to go up to 8-9%. Over a 20 year period that's 5x. I'd tune that down to 4x given there's risks and historical returns have been better than they probably will in the future. But it still means at 4x that your $15k solar installation could also have made $60k in the same period.
And there's no way a $15k installation will generate $60k worth of energy, somewhere between $10k and $20k depending on the cost per watt, solar capacity factor and local energy prices. (California does quite nicely and is on the upper end of this spectrum). About a third you get back from the gov, so in a 20 year period in Cali, investing $15k (subsidies included) you may get $30k-$35k in savings if you go solar.
It's really nice but it doesn't beat the market, and most states have cheaper rates than California which is like 30% above average and much fewer sun hours, and less competition, too. Wouldn't be surprised if installation costs were relatively more competitive in California.
So my point being is: 1) it's a great investment and I'd personally go for it. 2) it's, purely financially, not the absolute best way to spend your money, even if it saves you money. So there's still an element of 'I think solar is important' at play. 3) solar tech will get cheaper, but subsidies will fade out.