Electric cars are not the future, there just isn't enough lithium on earth to do this. The US might be able to, but not worldwide.
Powerwall is definitely not ever going to get off the ground - cars are more profitable, and they will never have enough extra supply to shunt some to powerwall.
"according to a 2011 study conducted at Lawrence Berkeley National Laboratory and the University of California, Berkeley, the currently estimated reserve base of lithium should not be a limiting factor for large-scale battery production for electric vehicles, as the study estimated that on the order of 1 billion 40 kWh Li-based batteries could be built with current reserves. Another 2011 study by researchers from the University of Michigan and Ford Motor Company found sufficient resources to support global demand until 2100, including the lithium required for the potential widespread transportation use. The study estimated global reserves at 39 million tons, and total demand for lithium during the 90-year period analyzed at 12–20 million tons, depending on the scenarios regarding economic growth and recycling rates."[1]
In that time period a lot of the ongoing research in batteries is going to mature and alternative or more effective ways of using materials will happen.
In the short term, though, existing reserves are mostly in Argentina, Chile, and Bolivia. I wonder how difficult it would be for a cartel to manipulate pricing?
And since lithium batteries are recyclable, we pretty much just need to extract it once.
But extra battery technologies will be good. Batteries will be a commodity, lithium ion batteries will be used both in grid storage, home storage, and car storage. Batteries are the oil of the 21st century.
I did say it's enough for the US - but the entire world is 10 times that number - not enough.
Plus using it for household storage (powerwall) would be far too much.
Extracting other deposits could come with steep costs both economic or environmental.
It's a good stopgap and worth doing! But lithium batteries should not be viewed as a longterm answer, that's all.
While I don't know the answer myself, I am inclined to think that Elon's not just planning on running the company straight into a widely foreseeable dead-end. Seems unlikely, don't you think?
Like, imagine this interview:
Interviewer: What is your plan for when lithium reserves run out?
Elon: Wait, what? There's a limited supply? Hold on, need to google this.
Take 2:
Interviewer: What is your plan for when lithium reserves run out?
Elon: Oh, I'm sure we'll figure something out, cross that bridge when we get there.
(Has he EVER given an answer like that, politician-style? No. Never.)
Seems like a safe bet that this imagined problem has a solution which hasn't been shared with us because nobody's asked him.
Why do you think this is wrong? He'll have many years to figure this out - this is a longterm problem, not a short term one.
It's not like you can't do the math yourself on global extractable lithium supply, and how many cars you can make with it.
I'm betting, not on new battery technology (any element except the big 10[0] would run into the same problem), but rather on a new engine that can burn very clean synthetic hydrocarbon fuel.
But if I did have to do research on battery tech today it would be on an aluminum ion battery.
[0] https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth... [1] https://en.wikipedia.org/wiki/Aluminium-ion_battery