Simply, look at the Eu/t
If I remember correctly, the advanced pump takes in 128 eu/t
therefore, you need a minimum of 5 thermal generators to generate 150eu/t and satisfy that requirement.
I believe the max speed cannot exceed 1 operation per tick, as is with any machine or mechanism in minecraft (Might be wrong, but I haven't found something that does more per tick) so that's 20 buckets per second.
The advanced part of the advanced pump is it prevents flowing liquid, so if you drain an ocean with it, you'll end up with a huge flat wall of water blocks, instead of a mass of flowing blocks. Or with the lava, the lava lakes will actually be emptied instead of being a mass of flowing blocks.