Energy efficient and cluster based routing techniques are gaining popularity due to complexities associated with the power and maintenance factors of large Wireless Sensor Networks during transmission. An adaptive ranking based energy efficient opportunistic routing protocol- AREOR is researched in this paper. It identifies the most effective node to participate as a cluster head by using adaptive participatory criteria. A novel forwarder node selection method, based on adaptive ranking system is proposed. Node’s remaining energy and geographic position is utilized to compute the ranks. The proposed approach is verified through variable sized clustered networks to investigate the impact of opportunistic routing. Evaluation parameters such as Message Success Rate, Energy Consumption, End-to-End delay and Packet Delivery Ratio are used to demonstrate the effectiveness of the proposed energy optimization approach. AREOR reports reduction in energy consumption for the duration of the transmission. Adaptive ranking and energy optimal forwarder node selection has shown an edge over competitive peer techniques as per demonstrative simulations performed on realistic scenarios.