Energy is an inextricable part of life in the 21st century, thus its availability and utilisation will become increasingly important with the concerns over climate change and the escalation in worldwide population. This highlights the need for manufacturing businesses to adopt the concept of ‘lean energy’ based on the use of the most energy efficient processes and activities within their production facilities. The energy consumption in manufacturing facilities can be reduced by either using more efficient technologies and equipment, and/or through improved monitoring and control of energy used in infrastructure and technical services. The research reported in this paper adopts a novel approach to modelling energy flows within a manufacturing system based on a ‘product’ viewpoint, and utilises the energy consumption data at ‘plant’ and ‘process’ levels to provide a breakdown of energy used during production.