Do you only get to spend 1 energy for 1 shield or can you spend multiple energy to gain back multiple shields?

Don't have the exact wording handy, but I believe it has a time-related trigger, which means one user per opportunity. So 1 energy for one shield per turn.

That is how I am reading it. If it was multiple uses then the action to regain shields would be kinda useless.

Backup Shield Generator

Limited

At the end of each round, you may spend 1 energy to recover 1 shield (up to your shield value).

You may only use a card activated opportunity once. So only 1 shield for each end of round.

(I went through a lengthy discussion on a few variations of this line of thinking.)

This is basically the recover action for free, but only 1 shield, and you can chose to do another action and still recover one shield. Not to bad really.

This is basically the recover action for free, but only 1 shield, and you can chose to do another action and still recover one shield. Not to bad really.

a recover action that spends only 1 energy instead of all your energy.