Can Ornn's power (which converts power spent to 'use' gear into energy) be used with Hextech Anomaly's ability to pay power and convert it to energy?

Ruling: No, Ornn's power does not work with Hextech Anomaly. "Use" refers specifically to the cost paid when activating a gear's ability, not power paid as part of an ability's effect.

Nuances:

• Paying power during Hextech Anomaly's ability resolution is part of the effect, not the cost to use/activate the ability
• This same principle would apply to similar cards like Mistfall where you pay power as part of a trigger condition's effect