As the progress towards 5G wireless networks, energy efficiency (EE) has become one of the critical design criteria for future wireless communications. In this regard, the joint transmission coordinated multipoint (JT-CoMP) technique is considered as a promising technology to save energy by mitigating intercell interference and improving spectral efficiency. However, additional power for data sharing and resource information is consumed by this technology. To evaluate the EE in dense femtocell networks with joint transmission CoMP approach and capture the significant factors involved in the energy consumption process, representative and accurate models are needed. In this paper, while applying a realistic power consumption model, we develop a tractable model in a JT-CoMP downlink transmission network based on spatial fluid modeling, which reduces the analysis complexity. Moreover, the proposed model’s effectiveness and accuracy are shown by comparing the obtained results to those of Monte Carlo simulations. Afterward, our simulation outcomes point out that EE is mainly highest in free space than urban areas, and can be improved with the increase of cooperative BSs number for a constant backhauling power cost. Moreover, in the case of a variable backhauling power cost, JT-CoMP becomes beneficial when the SINR threshold is 3dB.