Without the heavy incentives would you still have made the purchase? These numbers seem to show many would not.
Yes indeed (again I'm a good use case). Part of it is because the incentives often artificially inflated my upfront costs anyway (much like incentives do in other industries). So the incentives didn't save me anything.
My overall cash savings is $7,700 from 5 years ago when I installed a small solar system to test it for a year, liked it, and upgraded it the next year, which was the same year I bought the EV because my wife's gas crossover needed replacing anyway. So part of the solar upgrade math was charging the EV. Most of the $7,700 in cash savings is in the past 4 years (EV + extra solar). So call it $1,600 per year in energy cost savings.
That's net savings over costs (I pay a little extra in car insurance because the EV costs more than a comparable gas car, and a little more in homeowners insurance to have a high enough payout to replace the solar equipment as well as the house). And I pay a monthly payment to a loan I took out to hire the solar contractor and buy the equipment, hire HVAC to replace my two natural gas appliances with high efficient electric ones, hire an electrician to install two chargers for the EV, buy insulation for the house, etc. Every month that the energy project cost me more than it helped me (most notably while making car payments), I pulled the excess from the loan (adding to the balance). Now that the car (EV) is paid off, my budget pays down on the balance a lot faster.
My budget for home energy and transportation is $850/month -- the same it was in year 2019. $400 of that was the $400/month we put into a car savings account to repair and replace our existing used gas cars. The other $450/month (really it was $463/month) is what our energy costs were for our home and driving (large power bill + large natural gas bill + gasoline for driving). This was year 2019 -- the last year of Trump before covid monkeyed with energy costs. (It'd be ridiculous to bank on year 2020 gas prices lasting forever.) Now that the EV is paid off, my energy budget = small power bill + loan payment + a little extra on insurance -- below the $850/month and therefore I'm paying down the loan quickly. Think of the EV and solar project as allowing me to do away with the past 7 years' worth of energy price inflation. That was the whole point.
I calculate it every month when I get the power bill. I look at the telemetry from the solar inverters to calculate how much power I consumed, without the power company knowing because most of it didn't have to be pulled from the grid. From that I calculate what my power bill would have been without solar, based on the real world costs per kWh in the power bill. I also look at my EV odometer to see how many miles we drove that month and what gas prices are in my area (what it would have cost to drive a gas car). So it's gas savings, but with some reduction from overlap (the EV saved on gas but added to power cost, so it's not a 100% gas savings, but with solar providing 80% of my power most months it's very much a savings). I then do the same with natural gas savings.
Assuming a 3% increase in energy costs each year, and a 1.2% reduction in EV and solar efficiency per year (as per the warranties), my break even point is spring of 2032. That's when the balance left on the loan will equal the total savings. But that's only part of the savings. In reality, cash flow savings = that much more in our Roth IRAs growing tax free. I intentionally ignore that to add a little pessimism in the calculations (for things like how much to upgrade the solar again if I think about doing that).