Some wireless network technologies have very low power usage. In some cases power requirements can be so low that equipment can operate for years on one battery, or can even draw the energy they need from their environment. So for example this creates possibilities for deploying sensors into difficult to access environments where continuous power supply and battery replacement are onerous or impossible, perhaps to transmit notifications of rare intermittent events. It also allows devices to remain switched on to receive information pushed to them and then initiate an action, such as to start a more energy intensive activity that cannot be left running - like announcing its location, or to display some information as it arrives.
Wireless battery charging at short range using induction is becoming more common, such as using the Wireless Power Consortium's Qi standard. Obtaining energy wirelessly at a distance is also possible using radio frequency technologies such as the rectenna. The combination of wireless local area networks with wireless energy will lead to increased convenience.