[dalbasal]

Read on.

The counterexample is aluminium, which is a commodity. It can be stored, resold. Security cannot. You output the same number of bitcoins regardless of electricity input. There's no storage or saving that can be recovered later. With aluminium, you would have more aluminium.

The reason it's like this is because the price of bitcoin isn't affected by electricity prices and electricity prices aren't affected by bitcoin prices.

[splintercell]

You're storing and recovering capital, i. e. value across time.

[eladv]

Yes, but the amount of capital that gets stored has nothing to do with the amount of electricity that goes into the system. Bitcoin is a "battery for value" (AKA a currency). But it's not a "battery for electricity" (AKA a battery :) ).