Remember, only membrane pumps actually use energy. Channels like aquaphorns don't actually use ATP. Now, what exactly is the structure of an aquaphorn? Well, aquaporeans basically consist of six membrane spanning alpha helices and the inner region of these helices, the inner region of that aquaporen actually contains this relatively narrow passageway that is lined with hydrophilic amino acids. Why hydrophilic? Well, because these hydrophilic amino acids within that narrow passageway of the aquaphorn must be able to interact in a stabilizing fashion with those water molecules because water is, in fact, a polar molecule.