The hydraulics are controlled exactly the same as any other fly by wire aircraft like the 777 or a modern airbus. The computer takes the pilot inputs and combines them with a flight computer that controls electric motors which move the flight surfaces with hydraulics.

The big increase in electrical supply (4x over the 777 i believe) is the result of the bleedless air architecture that boeing chose. There was a big push by boeing to make the system work as it was a selling point for the public and carriers. I think that decision didn't receive the scrutiny that it probably should have.