Seems there was a new change introduced. The first hit when the shields are down DOES NOT damage the bases anymore. That means that maintaining a base is now -very- easy.
Shields use up to a maximum of 15K fuel per 24, when they are on -constantly-. They turn off after 1-16 minutes, 8.5 on average. That means you need to be present 24/7, shoot it -all- the time, and destroy every transport that tries to reach the base.
And then I'm not even talking about the repair supplies you have as backup.
I don't really feel like doing the specific math right now, but destroying a base is currently impossible for any faction on the server. Nobody can keep a perfectly tight blockade for more then 24 hours.