Wasted labor seems to me to fall under that goal (not that I am offering a a fully burnished economic theory here). If your need is illumination, say, a lantern or even a candle is considerably less wasteful than a fire, both in terms of externalities and the effort required to operate it - obtaining oil or a candle that lasts a week, vs armfuls of wood that last for one night which cost time and effort to gather and which are not easily portable once set on fire.