It's basically a doubling of the power requirement. By tapping into a permanent fuel source, cable operators will be able to maintain their networks indefinitely, regardless of the power draw. It no longer becomes a question of how long the fuel supply holds out, but how long the natural gas supply contract is in force. Already a handful of natural gas and propane generators exist in the field. In rural areas, propane generators are outfitted with storage tanks, although as with batteries, this is a finite source of power.
Generators also are an expensive proposition.
However, as the industry moves more towards centralised power, the economics for natural gas improve. A single gas line essentially provides the power needs for an entire network. That's a lot of little boxes in front yards. You should expect some neighbourhood resistance. Someone needs to conduct a successful evaluation of fuel cells, and then a field trial.