Abstract
We address the problem of how to determine control parameters for the inventory of spare parts of an energy company. The prevailing policy is based on an (s, S) system subject to a fill rate constraint. The parameters are decided based mainly on the expert judgment of the planners at different plants. The company is pursuing to conform all planners to the same approach, and to be more cost efficient. Our work focuses on supporting these goals. We test seven demand models using real-world data for about 21 000 items. We find that significant differences in cost and service level may appear from using one or another model. We propose a decision rule to select an appropriate model. Our approach allows us to recommend control parameters for 97.9% of the items. We also explore the impact of pooling inventory for different demand sources and the inaccuracy arising from duplicate item codes.
Similar content being viewed by others
References
Bacchetti A and Saccani N (2012). Spare parts classification and demand forecasting for stock control: Investigating the gap between research and practice. Omega 40 (6): 722–737.
Bashyam S and Fu MC (1998). Optimization of (s, S) inventory systems with random lead times and a service level constraint. Management Science 44 (12): S243–S256.
Boylan JE, Syntetos AA and Karakostas GC (2008). Classification for forecasting and stock control: A case study. Journal of the Operational Research Society 59 (4): 473–481.
Burgin TA (1975). The gamma distribution and inventory control. Operational Research Quarterly 26 (3): 507–525.
Chen FY and Krass D (2001). Inventory models with minimal service level constraints. European Journal of Operational Research 134 (1): 120–140.
Cohen MA, Kleindorfer PR and Lee HL (1988). Service constrained (s, S) inventory systems with priority demand classes and lost sales. Management Science 34 (4): 482–499.
Cohen MA, Kleindorfer PR and Lee HL (1989). Near-optimal service constrained stocking policies for spare parts. Operations Research 37 (1): 104–117.
Cohen M, Kamesam PV, Kleindorfer P and Lee HL (1990). Optimizer: IBM’s multi-echelon inventory system for managing service logistics. Interfaces 20 (1): 65–82.
Croston JD (1972). Forecasting and stock control for intermittent demands. Operational Research Quarterly 23 (3): 289–303.
DeHoratius N, Mersereau AJ and Schrage L (2008). Retail inventory management when records are inaccurate. Manufacturing & Service Operations Management 10 (2): 257–277.
Dolgui A and Pashkevich M (2008). On the performance of binomial and beta-binomial models of demand forecasting for multiple slow-moving inventory items. Computers & Operations Research 35 (3): 893–205.
Dunsmuir WTM and Snyder RD (1989). Control of inventories with intermittent demand. European Journal of Operational Research 40 (1): 16–21.
Eaves AHC and Kingsman BG (2004). Forecasting for the ordering and stock-holding of spare parts. Journal of the Operational Research Society 55 (4): 431–437.
Ehrhardt R (1979). The power approximation for computing (s, S) inventory policies. Management Science 25 (8): 777–786.
Federgruen A and Zipkin P (1984). An efficient algorithm for computing optimal (s, S) policies. Operations Research 32 (6): 1268–1285.
Fleisch E and Tellkamp C (2005). Inventory inaccuracy and supply chain performance: A simulation study of a retail supply chain. International Journal of Production Economics 95 (3): 373–385.
Graves SC (1985). A multi-echelon inventory model for a repairable item with one-for-one replenishment. Management Science 31 (10): 1247–1256.
Guijarro E, Cardós M and Babiloni E (2012). On the exact calculation of the fill rate in a periodic review inventory policy under discrete demand patterns. European Journal of Operational Research 218 (2): 442–447.
Kalchschmidt M, Zotteri G and Verganti R (2003). Inventory management in a multi-echelon spare parts supply chain. International Journal of Production Economics 81–82: 397–413, http://www.sciencedirect.com/science/journal/09255273/81-82.
Karsten F, Slikker M and Houtum GV (2012). Inventory pooling games for expensive, low-demand spare parts. Naval Research Logistics 59 (5): 311–324.
Kennedy WJ, Patterson JW and Fredendall LD (2002). An overview of recent literature on spare parts inventories. International Journal of Production Economics 76 (2): 201–215.
Kranenburg AA and van Houtum GJ (2009). A new partial pooling structure for spare parts networks. European Journal of Operational Research 199 (3): 908–921.
Kukreja A and Schmidt CP (2005). A model for lumpy demand parts in a multi-location inventory system with transshipments. Computers & Operations Research 32 (8): 2059–2075.
Moors JJA and Strijbosch LWG (2002). Exact fill rates for (R, s, S) inventory control with gamma distributed demand. Journal of the Operational Research Society 53 (11): 1268–1274.
Muckstadt JA (2005). Analysis and Algorithms for Service Parts Supply Chain. Springer Series in Operations Research and Financial Engineering. Springer: New York.
Nenes G, Panagiotidou S and Tagaras G (2010). Inventory management of multiple items with irregular demand: A case study. European Journal of Operational Research 205 (2): 313–324.
Porras E and Dekker R (2008). An inventory control system for spare parts at a refinery: An empirical comparison of different re-order point methods. European Journal of Operational Research 184 (1): 101–132.
Ross SM (1996). Stochastic Processes. John Wiley & Sons: New York.
Schneider H and Ringuest JL (1990). Power approximation for computing (s, S) policies using service level. Management Science 36 (7): 822–834.
Sherbrooke CC (2004). Optimal Inventory Modeling of Systems Multi-Echelon Techniques. Kluwer Academic Publishers: Boston, MA.
Silver EA, Pyke DF and Peterson R (1998). Inventory Management and Production Planning and Scheduling. John Wiley & Sons: New York.
Snyder RD (1984). Inventory control with the gamma probability distribution. European Journal of Operational Research 17 (3): 373–381.
Strijbosch LWG, Heuts RMJ and van der Schoot EHM (2000). A combined forecast-inventory control procedure for spare parts. Journal of the Operational Research Society 51 (10): 1184–1192.
Syntetos A and Boylan J (2006). On the stock control performance of intermittent demand estimators. International Journal of Production Economics 29 (103): 36–47.
Syntetos A, Keyes M and Babai M (2009). Demand categorisation in a European spare parts logistics network. International Journal of Operations & Production Management 29 (3): 292–316.
Syntetos AA, Babai MZ and Altay N (2012). On the demand distributions of spare parts. International Journal of Production Research 50 (8): 2101–2117.
Tijms HC and Groenevelt H (1984). Simple approximations for the reorder point in periodic and continuous review (s, S) inventory systems with service level constraints. European Journal of Operational Research 17 (2): 175–190.
Veinott AF and Wagner HM (1965). Computing optimal (s, S) inventory policies. Management Science 11 (5): 525–552.
Vereecke A and Verstraeten P (1994). An inventory management model for an inventory consisting of lumpy items, slow movers and fast movers. International Journal of Production Economics 35 (1–3): 379–389.
Willemain TR, Smart CN and Schwarz HF (2004). A new approach to forecasting intermittent demand for service parts inventories. International Journal of Forecasting 20 (3): 375–387.
Wong H, Oudheusden DV and Cattrysse D (2007). Cost allocation in spare parts inventory pooling. Transportation Research Part E 43 (4): 370–386.
Wonnacott RJ and Wonnacott TH (1985). Introductory Statistics. John Wiley & Sons: New York.
Acknowledgements
We are grateful to discussants and audiences at ISIR Summer School Istanbul 2011, INFORMS Annual Meeting Charlotte 2011, EurOMA Cambridge 2011, Statoil Kompetansedager Bergen 2011, NHH Seminar Geilo 2012, EURO Vilnius 2012 and ILS Quebec 2012 for their valuable comments. We thank the anonymous reviewers, whose comments improved the final version of the article. We also thank Vivienne Knowles and Vegard Engeset for their help in bringing this article to fruition.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Guajardo, M., Rönnqvist, M., Halvorsen, A. et al. Inventory management of spare parts in an energy company. J Oper Res Soc 66, 331–341 (2015). https://doi.org/10.1057/jors.2014.8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1057/jors.2014.8