Unless triple repetition or the fifty-move rule applies, White loses if he
exceeds the time limit in this position, even though for a decent player
this is a winning position. The only case where exceeding the time limit
is a draw is if the opponent has a bare King--the case when the opponent
couldn't win no matter how badly the other player plays. In the positon
you gave you should win but could lose if you played very, very badly--so
exceeding the time limit is a loss.
If you are in bad time trouble but haven't yet gone over the limit, it
might be a good idea to offer a draw--the opponent may well accept since
he will lose if you are able to make the winning moves quickly enough. He
might prefer to take the sure half point form a lost postion than gamble
on you going over.
