CIRP Annals - Manufacturing Technology 62 (2013) 475–478 Contents lists available at SciVerse ScienceDirect CIRP Annals - Manufacturing Technology jou rnal homep age : ht t p: // ees .e lse vi er . com /ci r p/ def a ult . asp Assessment of lean and green strategies by simulation of manufacturing systems in discrete production environments Nancy Diaz-Elsayed a, *, Annabel Jondral b , Sebastian Greinacher b , David Dornfeld (1) a , Gisela Lanza (2) b a b Laboratory for Manufacturing and Sustainability, University of California, Berkeley, USA Institute for Production Science, Karlsruhe Institute of Technology, Karlsruhe, Germany A R T I C L E I N F O A B S T R A C T Keywords: Production planning Simulation Sustainable development Manufacturing is a resource-intensive and costly endeavor, yet the impacts of implementing a combination of lean and green practices in a manufacturing facility can hardly be forecasted and have typically been simulated, optimized, and valuated independently. This paper identifies an approach for incorporating both lean and green strategies into a manufacturing system; from data collection to the valuation of a system. Furthermore, a case study is presented of part production in the automotive sector, in which the implementation of a tailored combination of lean and green strategies resulted in the reduction of approximately 10.8% of the production costs of a representative part. s 2013 CIRP. 1. Motivation The cost of energy and resources are constantly increasing due to rising demand and limited supply. Furthermore, price trends can hardly be forecasted, so companies aim to successfully produce within large price ranges of energy and resources. One strategy to accommodate price fluctuations consists of passing markups to the customer. However, a price markup may require that improve- ments be made to the product. Alternatively, stable prices may be facilitated with increased production efficiency, which can be achieved by reducing resource consumption and improving the organization of the manufacturing system. This paper focuses on the latter strategy and presents an approach for the assessment of lean and green strategies by simulation of manufacturing systems. The optimal combination of strategies depends on the industry and relevant processes. For instance, the effects of reducing batch size and solvent consump- tion differs between a paint shop and an assembly line in the automotive industry. Therefore, solutions must be tailored to accommodate specific applications in order to maximize impact. scheduling [9–11] and additional process planning [12,13] techniques on factory level energy consumption. Herrmann et al. developed a simulation to analyze the effects of implementing lean and green manufacturing strategies on energy consumption and costs [14]. Extensive research has been conducted in the fields of ‘‘simulating and optimizing’’ or ‘‘simulating and valuating’’ the application of lean and/or green strategies in manufacturing systems. However, the literature lacks an assessment methodology capable of simulating, optimizing, and valuating a manufacturing system’s performance indicators while using a tailored combina- tion of lean and green strategies. Such an assessment methodology would allow companies to evaluate the effectiveness of strategies before spending funds to implement them on the shop floor. 3. Assessment of lean and green strategies by simulation The following section describes an assessment methodology for simulating, optimizing, and valuating a manufacturing system’s performance indicators while using a tailored combination of lean and green strategies. 2. Literature review 3.1. Modeling the current state This literature review focuses on simulation-based approaches, a special case of quantitative assessment. A variety of approaches have been constructed to simulate the effects of applying lean methods in manufacturing, i.e., illustrating differences between a real and ideal state [1], examining their impact on performance indicators [2–4], and bundling simulation results in Cost-time profiles [5,6]. Research in green manufacturing spans a variety of scopes within the factory, from the development of energy models of production equipment [7,8] to the assessment of machine * Corresponding author. 0007-8506/$ – see front matter s 2013 CIRP. http://dx.doi.org/10.1016/j.cirp.2013.03.066 In order to set up a simulation model of a manufacturing system and subsequently optimize it, a variety of data needs to be gathered. The required data for each product variant that is manufactured can be categorized into factory and operational data, energy and resource requirements, and employee involvement. All data needed to set up the discrete event simulation model of the current state can be measured on the shop floor or estimated with historical data. In order to create a simulation model capable of valuating the increase in a production system’s performance, installing multiple levels and building reusable modules is recommended. In a typical discrete production environment, one