Access networks are responsible for a significant part of overall telecom network energy consumption. Furthermore their demand for energy also increases rapidly with the ever-growing traffic volume they carry. Sustainability necessitates energy conserving solutions which also carefully limit the negative effects on other system qualities. It is expected that future access networks are based on a converged wireless-optical architecture. This paper examines such a hybrid small cell LTE and PON network. We analyze the impact of serving the user population with a reduced number of active cells, either due to failure or selective switch-off of chosen cells. Multiple optical topologies are considered for connecting the cells of the wireless network. We use extensive simulations to quantify the interdependence of energy consumption, network availability and the QoS experienced by the consumer.