long exp and battery life?

while checking out Kah Kit Yoong's latest post in the landscape gallery I got to wondering about battery life and long exposures. His image was 70 minutes. I would think there isn't much power being used when the shutter is open and the LCD is dark but not really sure. I haven't got into exposures of that duration yet but it would be a tough pill to swallow if a power outage occurred well into a lengthy shot like that.

Bruce, I think the cold temperatures during the long exposure would have been more of a concern with the image you mention. I was prepared, using a new battery for the purpose of that single frame. Since I was using the in-camera noise reduction feature, the camera needed to be on for 140 minutes in total. I probably could have got away with a 90 minute exposure (which means 180 minutes including noise reduction) but wanted to play it safe to avoid a power outage.