Wireless communications has been recognized as a key enabler to the growth of the future economy. There is an unprecedented growth in data volume and the associated energy consumption. The challenge addressed in this paper is how to meet the growth in data traffic, whilst reducing both the cost and energy consumed. The paper shows that small cell deployments can significantly reduce energy consumption (30%), but increase the network cost (14%). The novel characterization of the tradeoff between Capacity, Energy and Cost (CEC) is of importance to researchers and operators.