The US Environment Protection Agency (EPA) has published 'The Lean and Energy Toolkit' elaborating on the relationship between the Lean philosophy and energy efficiency and discussing Lean manufacturing tools for assessing and reducing energy use. The Lean manufacturing concept was derived from the Toyota Production System (TPS) in the nineties. It is a management philosophy with a bottom-up approach that is dedicated to eliminating all types of 'waste', including unnecessary actions.
Improving the energy efficiency of installations eliminates 'energy waste' and consequently fits into the Lean philosophy. Conversely, Lean manufacturing will in most cases automatically improve the overall energy efficiency of the plant by eliminating unnecessary actions in the production chain.
Moreover, by reconfiguring a manufacturing process with the Lean concept, opportunities arise for making additional changes to improve energy efficiency at lower marginal cost. For example, introducing Lean manufacturing can reduce the need for transport vehicles and require less building space while maintaining the same productivity. Consequently, the marginal investment of switching to fuel efficient vehicles and smart energy buildings will be lower.
The relationship between energy efficiency and Lean manufacturing is in fact so obvious that one could wonder why it still needs to be stressed. The main barrier to fully exploiting it is that energy costs are often billed to overhead accounts instead of being allocated to individual departments.
Lean manufacturing relies on the ability to make manufacturing leaders on the work floor more responsible. When the Lean philosophy is introduced, this bottom-up approach of ideas is, in most cases, possible for shop floor organisation, logistics, and maintenance, but not always for energy consumption. The EPA paper mentions this barrier in the introduction, but it could have given more attention to this important prerequisite.
Once energy use has been allocated to the various departments of the production plant, the Lean manufacturing tools are very well-suited to tackling energy efficiency. The EPA paper explains how kaizen events can be used for the detection and execution of quick, non-capital energy efficiency improvements. It discusses in detail how Lean assessment strategies such as Value Stream Mapping and Six Sigma can be used for conducting energy audits. Finally, it also explains how the energy efficiency improvement actions can be structured through Lean manufacturing tools such as Total Productive Maintenance, the replacement of over-sized equipment, plant lay-out improvement, and the introduction of Standard Work, Visual Controls, and Mistake Proofing.