The “Thermal Battery” offers the possibility of an inexpensive renewable energy storage system, deployable at either distributed- or grid-scale. For high efficiency, a crucial component of this system is an effective phase change material (PCM) that melts within the intermediate temperature range (100–220 °C) and is inexpensive, stable and sustainable. Here, we report on five aliphatic dicarbamate PCMs. For the first time, we demonstrate high thermal stability of the two best performing materials to elucidate their critical properties including lifetimes in this application. These results are considered alongside the origins of the raw materials and the synthetic routes to provide a preliminary “whole picture” assessment of the sustainability of renewable energy systems employing these materials.