Okay. So why are PowerWalls going to beat the current state-of-the-art in battery technology?
Look, for areas with resources, Pumped Hydro / Compressed Air is straight up superior. For areas without resources, getting a shipping container for a Redox Flow battery is more efficient.
Hydroelectric dams are bad for the environment, and a huge risk in areas prone to earthquakes. They're also a big terrorism risk (ever watched "The Dambusters" about the WWII dam-busting operations?)
Plus, you are ignoring the biggest advantages of the PowerWall concept-- the decentralization and small-scale aspect. I don't think homeowners in my town are going to be building hydroelectric dams in their back yard, even if it weren't an earthquake zone (and it is...)
With regard to new battery chemistries... sure, there are probably things out there much better or stabler than lithium-ion. But posting some marketing copy about a not-yet-shipped new battery product proves nothing. I'm surprised you didn't latch on to the "ultracapacitor" hype since that is also a year away from taking the world by storm (and has been for the last 5 years, at least). As a layman, none of us have any idea whether these physics breakthroughs are 5 months away or 5 years, and none of the people who do know are going to talk about it.
If new battery chemistries do take the world by storm. I don't see why Tesla wouldn't just license them, much like they are licensing lithium-ion now. Tesla has the high-current charging network that a better battery would need anyway. Traditional car manufacturers have a spotty and low-wattage charging network that might not even benefit from a better battery chemistry.
You seem to be grasping at any possible reason to be negative about Tesla. I agree they're overvalued right now, but the idea of building a big factory for batteries, and focusing on a high-end electric car is smart, and the next few years will show that. There are strong network effects in building a charging network, and major economies of scale in building the gigafactory.
And it has nothing to do with "better". Lithium Ion has more energy per watt, but Redox Flow is just so much cheaper and also has a 20+ year life expectancy. It will be very hard for Tesla to compete when they're making car batteries and trying to apply it to utility scale.
Who cares about energy density when you're just going to bury the battery into the ground? The ground can support a lot more weight than the lighter Lithium Ion batteries. The Redox Flow's heavier weight is not a disadvantage in the utility space.
Okay. So why are PowerWalls going to beat the current state-of-the-art in battery technology?
Look, for areas with resources, Pumped Hydro / Compressed Air is straight up superior. For areas without resources, getting a shipping container for a Redox Flow battery is more efficient.