Value-value load diagram: a graphical tool for lean-green performance assessment

Integrated assessment of operational and environmental performance of the production system requires mapping of all the processes and activities in the form of their resource utilisation efficiency. Prior research indicates that most lean assessment tools and techniques have studied operational dimensions ignoring environmental aspect as a part of the assessment tool. Moreover, movement towards the greener production system has become a key strategic consideration for organisations to maintain a competitive edge and to remain as market winners. Continuous assessment in both, lean and green, dimensions is crucial in improving the overall performance through efficient utilisation of the available resources. In lean environment, value stream mapping (VSM) allows assessment of operational performance through identification of non-value adding activities in time units but fails to integrate inefficiencies related to material and energy utilisation. The tool-like material flow cost accounting (MFCA) is able to assess the environmental performance through physical and monetary evaluation of material flow within the production system. This paper presents, a novel tool, value-value load diagram (VVLD), for modelling and evaluating the operational (lean) and environmental (green) performance of the production system. VVLD graphically represents resource consumption, value addition and performance improvement opportunities within the production system by integrating VSM, MFCA and pinch analysis methodology. VVLD permits evaluation of the lean-green performance in terms of the eco-leanness index and also exposes the improvement opportunities by pinch point location. Some common generic scenarios for improvement in the eco-leanness index are demonstrated using VVLD. Application of VVLD along with the developed computer-based support system (CBSS) is demonstrated for a manufacturing SME in India, allowing the managers to evaluate and tune their processes for improved resource utilisation efficiency.