Requirements of IPv6 over Low Power WPAN (6LoWPAN) are energy conservation and low protocol complexity. Incorporating the desirable features, potential-field-based routing known as ALFA (autonomous load-balancing field-based any cast routing) achieves autonomous load-balancing and efficient path-length provisioning with little control overhead in a wireless mesh network (WMN), which is a hub-and-spoke type network similarly to 6LoWPAN. In this paper, we provide the protocol architecture of ALFA for 6LoWPAN to consider energy consumption. Distinct from the case of ALFA in a WMN, when the energy level of a sensor node declines to a threshold, the exchange of its potential information holds and its energy shortage is reported to a sink node.