What is the difference between paying 1 (energy) and paying a rainbow (power) for Teemo Swift Scout's ability?

Ruling: Energy is gained by exhausting a rune, while power is gained by recycling a rune (and the power has a domain matching the recycled rune). Teemo's legend ability allows you to pay an energy to hide instead of paying a power.

Nuances:

• Energy comes from exhausting runes
• Power comes from recycling runes and has a specific domain