Delta Rising comes with a new Reputation system and new Reputation Ground and Space sets. To purchase them you need to a specific amount of dilithium, delta marks and Ancient Power Cells.
Obtaining the power cells is a bit tricky for the fact that they only drop as reward for Adv. or Elite Delta Reputation PVEs.
So playing Borg Disconnected on Normal wont give you any Ancient Power Cells as reward.
You would need to play this mission on Adv. difficulty or elite which both is extremely hard to do.
The only other option you have is to play Bug Hunt Adv. which is a new Ground PVE mission.
The mission is less hard to do and rewards the required power cells for the reputation system.
One problem however is, that you have to unlock this mission first.
You can not play it with a toon that is below level 56.
You can not play it with a toon that has not played the Delta Rising storyline yet (at least to the point where you have finished to play “The Dragon's Deceit”).
Only then you can play this mission and obtain the power cells required for the reputation system.
Note: there is still the chance to get power cells on kobali prime IF there are T4 reward for that mission or by rare drops from delta reputation boxes.
(But well, so far ive only obtained 2 power cells this way)
It makes sense to get your chars at least to that point where you can play this mission.
The adv. bug hunt is a mission that you practically can not fail and the mission is not taking that long. So the reward is guaranteed.