Tankless Hot Water In A Power Outtage

I am considering moving from an 80 gal. natural gas water heater for a 4300 sqft. home to a tankless system. What I would like to know is, if my neighborhood had a sustained power outtage, would a natural gas, tankless water heater stil produce hot water as a natural gas, tank-type, water heater would?

They require a small amount of electricity to operate things such as the control circuits, ignition, and burner fan.
Check the electrical requirements for the unit you are considering.