One of the main advantages that the Covenant possesses over the UNSC is that they are able to field shield equipment on infantry, vehicles, space craft and structures. The Covenant Shield Generator occupies a building slot at the Citadel and provides a powerful shield over all of the Citadel’s structures, vastly increasing the defensive strength.
Covenant shield technology is repurposed Forerunner technology and requires vast amounts of power to use. Once the shield is drained, the buildings underneath the shield begin to take structural damage. Over time though, the shield will begin to regenerate back up to full strength. Expensive, and taking up a build slot, commanders who wish to use the Shield generator must choose between a strong defense, and other options.
