In this column Cecil cites our own Una Persson to prove that paper towels use more energy than electrical hand blowers. No offense meant, wouldn’t it have been just as easy to cite her actual calculations rather than her not inconsiderable authority? I’ve seen this factoid bandied about in the past, and in most of the calculations they assume that virgin bleached fiber is used to produce paper, but fail to take into consideration the energy produced during the recovery process.
From this cite there is a total electrical production of 655 kWh of electricity per air dry ton (ADT) of pulp produced. The actual pulping processes consume less than this amount, so pulp mills are net exporters of energy, generating 17 kWh net energy per ADT of pulp. This applies to bleached white pulp.
If the pulp produced is the unbleached kraft pulp like that used in most hand towels the net electrical production is an additional 175 kWh/ADT. Look at Table I in the linked cite and you can deduct the amount used on oxygen delignification and bleaching. In that case you would generate slightly less energy because O2 delig produces dissolved wood for the boilers, but the energy penalty is miniscule compared to the 175 kWh/ADT saved.
Paper making would use more energy than the 141 kWh/ADT than listed for the pulp machine, but most mills are integrated, so you wouldn’t have to have both, just one or the other.
I agree that all paper mills have power generation equipment using wood waste, coal, or natural gas, and sometimes all three, switching from one to the other as the price of each fluctuates. I’m just questioning what the calculations show for the net energy consumption of an integrated mill producing hand towels. As Una knows quite well, in engineering it’s often a question about where to draw the box. I just want to make sure it’s drawn in the right place.
Now, if you were talking about fine papers, bleached to 94 ISO brightness and coated to a fare thee well, that would be different, but nobody dries their hands with stationary.