As I continue to get more familiar with the broad scope of the game, I finally discovered a quick way to make EC, apart from the Ker'rat Battle Zone: the "Tour the Universe" mission. I had barely noticed it earlier, and assumed it required some long chain of system explorations, but you merely race across the different faction sectors, to see how efficiently you can make the trip. In 15 minutes (the mission clock), you stand to make >250k EC, plus Exp. points for both exploration & trade. I think you may have to start the mission the first time from the "race" NPC at the faction HQ, but for sure it is available after that from anywhere. So ideally, you take your ship to the corner of a dead-end sector, initiate the race, and work your way thru as many sectors as possible. Hitting all the sectors in an area consecutively gives you a 25-30k bonus.
I have spent a lot of my EC on fleet projects, and never got more than about 400k EC together @ once, but just this one mission can yield >1 mill EC/week; this is especially good for players early in their careers, who don't have the chops yet to handle a Borg zone solo...
