Gems in your invader gear
I see players smashing Ubers while wearing invader gear adorned with gems that boost overall hero energy and energy restoration. If it is your practice to only smash invaders while refilling energy manually, stop wasting your gem slots with redundancies... Use them to boost your town's resource production or something... March speed perhaps. The energy you'll recoup is a tiny drop and will amount to nothing.
Use the energy boost gems on your extra farm gear slots ;)