The ongoing energy transition is expected to result in significant changes in the fuel mix, impacting the existing methods for analysing waste heat recovery. This study aims to identify the energy available in fuels, the energy losses embodied in exhaust gases, and the energy flows within the foundation industries in the UK. More than 1200 potential fuels’ composition were modelled and analysed based on typical C, H, and O ranges. The analysis shows a significant correlation between the composition of exhaust gases and the energy embodied, resulting in a heat loss of 5–20% of the fuel energy. In this context, water vapour plays a significant role in trapping heat, and its condensation can reduce heat losses up to 75%. From the energy flows in the foundation industries, natural gas and electricity account for approximately 50% and 37% of total energy consumption, respectively. These findings provide valuable insights into the energy landscape and highlight areas where the foundation industries can achieve energy savings and improve efficiency.