Energy consumption is a critical issue for battery-powered mobile devices in ad hoc networks. Ad hoc wireless networks are power constrained since nodes operate with limited battery energy. If the routing protocol is not power aware, nodes simply get drained out of energy not being able to send, receive or forward packets to the destinations, thus degrading the performance of the network and network lifetime. Thus, routing protocols should be designed along with features of power aware protocols. This paper presents 'Span' a power aware protocol which is exploited by the routing protocols to increase the lifetime of networks. © 2005 - 2013 JATIT & LLS. All rights reserved.