"For the record... home solar payback period is typically now 3-5 years (improves with setup size.. but 5kW setup is standard and is ~4 years paid back) with an effective life of 25 years on the panels home battery installations are not really cost effective at all - not because of payback period, but effective life and warranty... plus costs & capacities are rapidly improving - which makes an investment now possibly superseded before payback is complete... even then.... payback can be still occur around 10 years... Plenty of good real estate data shows having solar panels on the roof actually improves resale value."
I am not sure if the statistics is the result of people actually ramping up their electricity usage to cut down on the payback period or if indeed the capital expenditure amortization conditions are better than before. You and I presumably have friends or associates who have installed solar panels, and all I see when I asked them about their panels are responses like "Oh yes, they are so good, now we can turn on the a/c all day without worrying about the bills." People seem to actually increase their electricity usage (and therefore creating a possibly retentive high carbon footprint habit) to get the payoff period to be shorter. If they had not change their habits, I doubt the payback period would be much shorter. I mean solar installation prices are still more or less the same (what's changed is the generation capacity) and electricity have crept up slowly. The numerator (costs) has stayed around the same (you used to get 1.5kw for $2500 and now you still spend $2500 but for a 3kw?) while the denominator has gone up gradually. It's like instead of burning 200kwh of electricity a month on traditional fired electricity, they are burning 400kwh of electricity a month to justify for the solar panels. Sure the homeowner can get twice the juice out of the panels but they still spent $2500 on the panels. To make themselves feel like they did the right thing, they ramp up usage.
The side effect of this is once the habit of turning the a/c on all day is formed, what happens if they move or gets into some situations where they occupy somewhere that is not their home and has no solar panels (remote worksite, hotel rooms, holiday houses)? I am pretty sure they will leave the a/c on all day while they are out of the house. Thus the self-defeating act of going green and yet having a higher carbon footprint.
As for the batteries, proven traditional methods like geothermal heating and cooling whereby you lay coolant filled cables beneath your garden to cycle and regulate indoor temperatures is probably a better solution. It's a thermal battery and it's been in used for at least 50 years[1]. No degradation of battery cells and no fire risks. Since heating and cooling represents 40% of home energy usage[2], this may be a better solution for cutting down on electricity usage at home, provided you live on your own land. The only problem with this seems to be that it is not some new age sexy tech and Elon Musk is not in it. People rather spend $20k putting on batteries that lasts 10-15 years than to put in geo heating costing $15-$40k (depending on size) that lasts for 30-50 years and is mechanically stable.
"Plenty of good real estate data shows having solar panels on the roof actually improves resale value." I can foresee houses with solar panels that are >10 years old having minor incremental improvement in resale prices due to aging panels and replacement costs. It could be worse for home utility batteries. It's like buyers asking if the batteries still retain charge on second hand Priuses because they know Priuses can't achieve the superior fuel efficiency without the batteries and those batteries are costly to replace.
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