Learn Hardcore Italian: Nonostante la batteria esausta occupi poco spazio, dobbiamo smaltirla. - Even though the spent battery takes up little space, we must dispose of it.

Because nonostante introduces a concessive idea (although / despite the fact that), and in standard Italian that often leads to the subjunctive when a full clause follows.

occupa = indicative
occupi = present subjunctive

So:

Nonostante la batteria esausta occupi poco spazio... = Although the dead battery takes up little space...

A learner will often notice this because in English we do not change the verb form in the same way.

Does nonostante always require the subjunctive?

Not always in every possible structure, but in sentences like this one, where nonostante is followed by a clause with its own verb, the subjunctive is the normal standard choice.

Compare:

nonostante la pioggia = despite the rain
- here there is no verb, so no subjunctive issue
nonostante piova = although it is raining
- here there is a verb, so the subjunctive is used

So in your sentence:

nonostante la batteria esausta occupi poco spazio

the clause after nonostante has a verb, so occupi is in the subjunctive.

What does esausta mean here? Is it the same as scarica?