Quote (Thor123422 @ 7 Feb 2021 10:18)
Solar is super efficient at this point. You don't need direct sunlight to get most of the benefit of solar panels, and you actually don't want them to overheat and lose efficiency anyway, so they aren't as appropriate for those hot dry places as you think. They could power the average house with power to spare on a cloudy day using just the roof space 10 years ago. They're significantly more efficient now, so they're appropriate for pretty much everywhere.
To put "efficient" in perspective: Solar panels are not "super efficient". The average panel runs roughly 18-20% efficiency. A single cell can be pretty high efficiency, but not a panel. Second, more light is better. Even the best panels aren't providing as much efficiency during clouds or rain as they are in direct clear sunlight. Heat's less of a concern than you might think. Panels are just fine in Arizona on 122F days. The problem is less the heat generation, and more the installation costs to make it safe.
At any rate, here's where solar efficiency tends to screw you: You want to go off the grid. Don't lie, you do. Not the internet grid, but the power grid. You're "green" and "self-sustaining!" The average price of a solar roof + a solar wall (battery setup) that'll not only provide enough continuous output to power a full home without being connected to the grid, AND store enough power for overnight usage of... Whatever you want, everything if need be is... Between the wiring and installation of not only the solar wall and roof, in excess of $100K for a smaller home, and much higher potentially as the size of home grows larger.
Now, $100K isn't so bad when you're thinking of buying a home that costs say $400K. Make it 500K, go green! It does sound nice. But both the wall panels (again, these are batteries) AND the roof panels (power generation) have a peak lifespan of about 25 years. You will not "save" much on reinstallation cost. Some of the framing and such, initial wiring and fuse box stuff, service off switch, shit like that, sure. But realistically, the price will still likely run near six figures for the replacements. So, let's go low end, $100K/25 years/12 months=$333.34/month average cost of your "going green" solar setup which will give you 24/7 power. On the low end. Power costs on average for household in Arizona average ~$128/month from the grid.
Now, the "off the grid" setup is controlled through the powerwall setup, and if you're not part of the grid, it shuts off the panels when battery storage is [near] full. If however, you're [sort of] hooked up to the grid, in order to sell power to the grid, then the powerwall setup would automagically switch you to the net meter output, rather than battery output for the panels. How much'll you make? Well... Being on the grid, you're going to have a monthly charge just for being on the grid, so that'll reduce it. But, without clean energy incentives from the government, and in Phoenix? Maybe $50/month could potentially be reasonable. With Incentives from the government? $200, potentially.
End result? When it comes to financial efficiency, it's simply not efficient at all. By the time it's all said and done, you spend a huge amount of money, and the best you can expect is to MAYBE reach a net zero on cost (paying out equal to what simply using the grid would cost you). Meanwhile, every 25 years, the batteries and panels have to be replaced, and the batteries and panels have no way to be recycled or "safely" disposed of. They utilize heavy metal and are extremely toxic. Selling back to the grid can make up part of the cost though, and for environmental efficiency, since the grid pays you a lower price than you'd have to pay them, there's a fair chance that in actual power generated and contributed to the grid, you may end up not only being "green" but producing enough power for multiple homes besides your own. The offset, again, being the extreme environmental hazard that defunct solar panels and batteries become.
In many ways, I think Solar (as it is today) is merely tossing off the environmental disaster to the next generation, much as coal is considered to be today's "disaster" from previous generations.
This post was edited by InsaneBobb on Feb 7 2021 01:13pm