This may just be a difference in opinion, but if knowledge is not irretrievably lost, vis-a-vis the burning of the library of Alexandra, then I believe human society can eventually adjust to a much lower carrying capacity with sustainable energy. If we manage to learn from any of the social and governmental experiments of the past, perhaps a more equitable social order can arise out of the ashes of industrialism in several generations. I guess I'm just an optimist at heart?
Here's an interesting (depressing?) question to ask yourself: How do we store knowledge today, what is required to access that knowledge, and how well will that knowledge be accessible in 20 years or 200 years?
To get yourself started, go find a paper you wrote 20 years ago (say, 1997), and access it.
We store knowledge in digital form, which requires a seriously functional industrial civilization to work, reliable electricity, and regular copying of the data to new media. "The Cloud" doesn't really change any of this - it just adds regular payment requirements and internet access as base requirements to access knowledge.
Get rid of that, we drop back to a 1970s-1980s technology base in terms of knowledge, simply because most of the newer knowledge is in digital form.
I can read a book from 100 years ago. I would struggle to read a floppy with some calculator programs I wrote in high school right now.
Let's not make the mistake of assuming that trend will continue on forever, but we're also rapidly approaching stupid cheap.
"Stupid cheap" is not a winning solution if you cannot pay for and maintain grid stability on the power grid with that cheap solar. I think the power grid is pretty neat, and if you pay attention to Hawaii, you'll see a solid case of grid defection in action (it's cheaper to put up your own solar and battery, if you have the money for that) - I expect Hawaii will lose their power grid in the next 30 years, or at least major chunks of it, because they simply cannot afford to pay for the maintenance. Grid maintenance is more or less coupled to miles of line and area covered, not power delivered. Fewer people using it, less money, less reliability or more money for the remaining people.
Meaning that without petroleum (think past direct uses) can these panels/inverters/charge controllers continue to be produced, maintained and replaced at those costs? With out significant new advances in batteries a grid also needs to be maintained, correct? So we need nuclear or coal. Can we even adequately maintain those without petroleum?
Correct, correct, and "probably not." Renewables make for great energy sources if you have intermittent demands that can work with the available energy, they make acceptable peakers if you put some batteries on, and they're dreadful base load.
Seriously, I wouldn't mind an overview on the subject. My knowledge is really limited to individual/household use and I have very little understanding of large scale grid and industrial requirements/needs (can we maintain industrial electric machines in a cost effective way without petroleum?). Unfortunately, most of the information out there for non-experts(I probably don't even know, what I don't know) has an agenda, one way or the other.
One of the big questions that is still an active research area (of which I play in, slightly) is simply grid stability - how do you maintain a stable power grid with high renewable deployment? The power generation and power production have to match, almost exactly, at every moment of every day, or things go out of whack. One of the biggest issues here is that the UN requirements for residential inverters are designed for when those inverters were owned by a few fringe hippies, not contributing meaningfully to power production, and nobody cared. They don't do a thing for grid stability, and are actually harmful - they require a fairly tight voltage and frequency band to sync up, and if that goes out of sync, they trip off. So if you have a grid transient and the frequency changes, you can drop off a bunch of residential production
in a hurry and drop the whole segment of grid. It's a pain to get those lit back up again as well, because once power comes on, you have a surge of inverters joining in at certain intervals you have to deal with. Those inverters don't have any sort of synthetic inertia in them, they just follow the grid. Fine when you have a few, a serious problem when you have a lot. Plus, you can end up with interesting flows of power through the grid when areas get clouds. The grid is designed implicitly assuming one way transmission - from generating plants to transmission lines to distribution lines. Residential solar breaks that assumption.
I'm all for commercial solar - love me that stuff. I do plan to put rooftop solar on my place, since I can, but I would love to be able to buy inverters that provide grid stability services and get paid for those (since I'll have a battery bank, I could agree to stricter requirements on what I push on the grid, and I'll have power source/sinks to push/pull frequency, but I can't in terms of inverters available or legal requirements).
It's... complex. Grid stability is heavily tied to inertia, which, historically, was literal inertia of spinning generators and turbines. Thousands of tons of spinning metal at 3600 RPM stores a lot of energy.
And then there's the storage issue, which Prairie Stash touched on quite nicely.