You are making me rethink my position a little bit. Thanks!
If you look a the energy industry now, there's an iron triangle, if you will, between fossil fuel extraction, electric utilities, and the automobile industry. Tesla is aiming to replace all three sides with solar, batteries, and electric cars. A person could use Tesla products and, in theory, not interact with the current energy sector of the market at all. Which, if it works, would be some kind of disruption!
What advantage do they have in battery tech that say, Panasonic (who provides their batteries), doesn't?
For further comparison, the total capacity of existing pumped hydroelectric storage plants is 740 000 GWh. (This puts plans of battery-based electricity storage in a rather harsh perspective.)
I believe this number only includes dams with reverse pumping. The global production capacity for all hydroelectric power is much larger, but it's not a widely used number, since you typically don't empty a reservoir due to the lower water having less potential energy.
So this capacity number is a bit theoretical, since you wouldn't use it that way in practice. But then again, so is the capacity number for batteries, since you really want to avoid doing a full discharge.
Annual global hydroelectric production is a more useful number, and is a little more than 4 000 TWh.
Tesla is.
That is common misconception. Tesla repackages batteries bought from Panasonic.
Tesla is a battery company that just so happens to also make a couple of cars. When you look at it that way, it makes a lot more sense.