When playing a card, do you need to pay the power cost, or only when reminder text specifically says so?

Ruling: When you ignore "its costs" you ignore both energy and power costs, but not additional costs. When you ignore only the energy cost, you still have to pay the power cost.

Nuances:

• If a card specifies that its power needs to be paid (like The Harrowing), it will explicitly state so
• Additional costs are separate from "its costs" and must still be paid even when ignoring "its costs"