alt Hacker NewsDrill baby drill!
Seriously this would be such a dream!
Turns out that the best battery is literally 10 feet away* - and you don't even need to charge it!
*if you want to make steam its a few thousand, but for heating and cooling its literally just 10 feet!
Well, heat pumps are awesome, but ground-source is overkill for many places where the air temps don't fall too low (and it's a lot harder to drill holes behind your house).