Abstract: The improvement of the energy efficiency and the reduction of the latency are two of the main goals of the next generation of Radio Access Networks (RANs). In order to achieve the latter, Multi-access Edge Computing (MEC) is emerging as a promising solution: it consists of the placement of computing and storage servers, directly at each Base Station (BS) of these networks. For the RAN energy efficiency, the dynamic activation of the BSs is considered an effective approach. In this paper, the caching feature of the MEC paradigm is considered in a portion of an heterogeneous RAN, powered by a renewable energy generator system, energy batteries and the power grid, where micro cell BSs are deactivated in case of renewable energy shortage. The performance of the caching in the RAN is analysed through simulations for different traffic characteristics, as well as for different capacity of the caches and different spread of it. New user association policies are proposed, in order to totally exploit the MEC technology and reduce the network energy consumption. Simulation results reveal that, thanks to this technology and the proposed methodologies, the experienced delay and the energy consumption drop, respectively, up to 60% and 40%.