In Mergedom, you gain one free energy every two minutes.

If you click the '+' icon under the energy bar, you will see a pop-up that offers you two options to refill/gain energy.

You can refill your energy by using your gold, or you can gain free energy by watching an ad.

If you choose to watch an ad for free energy, please do not close the ad before its time. Or else you can't win the free energy.