Raylo

Power loss is not an issue. The new electronic WH controllers are self powered off the thermocouple just like the old style gas valves. I assume they have a similar hold-open function that senses the pilot light via a thermocouple, but the engineers must be getting good at designing low power circuitry so that they can run the IC board off that as well. Here is a link to the Sears 50 gal unit with this control. It's abour $40 more than the similar one with conventional control.

http://www.sears.com/shc/s/p_10153_1...+Water+Heaters