Learn Dutch: Daardoor richt de uitval gigantische schade aan. - Because of that, the outage causes massive damage.

Because daardoor (because of that) occupies the first position in this sentence. Whenever a sentence starts with something other than the subject, Dutch uses V2 inversion. The conjugated verb (richt) must come second, pushing the subject (de uitval) into the third position.

Where does the word aan at the end of the sentence come from?

It is the prefix of the separable verb aanrichten (to cause, to inflict). In a standard main clause like this, the conjugated part of the verb (richt) takes the second position, and the separable prefix (aan) gets sent to the very end of the sentence.

Could I use veroorzaakt instead of richt ... aan to mean causes?

Yes, you could say Daardoor veroorzaakt de uitval gigantische schade. The verb aanrichten is mostly used specifically for causing negative things, like schade (damage) or een ravage (havoc). Veroorzaken is a bit broader but means essentially the same thing.

Why is there an -e at the end of gigantische?