تحقیق در عملیات برای تدارکات سبز - مروری بر جنبه ها، مسائل، مشارکت و چالش

The worldwide economic growth of the last century has given rise to a vast consumption of goods while globalization has led to large streams of goods all over the world. The production, transportation, storage and consumption of all these goods, however, have created large environmental problems. Today, global warming, created by large scale emissions of greenhouse gasses, is a top environmental concern. Governments, action groups and companies are asking for measures to counter this threat. Operations Research has a long tradition in improving operations and especially in reducing costs. In this paper, we present a review that highlights the contribution of Operations Research to green logistics, which involves the integration of environmental aspects in logistics. We give a sketch of the present and possible developments, focussing on design, planning and control in a supply chain for transportation, inventory of products and facility decisions. While doing this, we also indicate several areas where environmental aspects could be included in OR models for logistics.

Operations Research (OR) has been described as the science of better (the slogan of the INFORMS society) as it mainly focuses on minimizing the costs of existing processes. Yet in today’s society, it is not only profits that are important as many people, companies and governments are concerned about the sustainability of our society. So can Operations Research also contribute to a better environment? In our opinion, the role of OR for the environment should get more attention. Operations Research leads to a more efficient use of resources, which is not only cost attractive, but also tends to create less emissions of greenhouse gases. Secondly, Operations Research helps to identify the trade-offs between environmental aspects and costs. Very often, much reduction in emissions can be achieved with only a marginal increase in costs. Operations Research techniques and especially multi-criteria decision analysis is therefore an important method in this respect. In this review, we will highlight its (possible) contributions to green logistics, which is the study of practices that aim to reduce the environmental externalities, mainly related to greenhouse gas emissions, noise and accidents, of logistics operations and therefore develop a sustainable balance between economic, environmental and social objectives (http://www.greenlogistics.org/, last accessed on August, 16, 2011). We deal with all aspects of logistics such as transportation, warehousing and inventories, and address the related environmental aspects such as emissions of greenhouse gases, noise and use of scarce resources. We will not differentiate between green logistics and green supply chain management. While we mainly focus on transportation, we take a broader (supply chain) perspective. However, we will not address environmentally conscious manufacturing or waste management. The purpose of this overview is to give a sketch of the present and possible developments. As many papers are presently being written, we do not claim to cover all. Instead we focus on the structure of the field and illustrate this with some representative papers, the choice of which always remains subjective. There are other overviews, such as Corbett and Kleindorfer, 2001a, Corbett and Kleindorfer, 2001b and Kleindorfer et al., 2005 on sustainable operations management, Srivastava (2007) and Sarkis et al. (2011) on green supply chain management and Sbihi and Eglese (2010) on combinatorial optimization and green logistics, but ours is more comprehensive, up-to-date and more detailed with respect to transportation. In this sense, we fill the gap in industrial ecology as observed by Sheu et al. (2005) on the integration of logistics flows in a green supply chain. A recent book by McKinnon et al. (2010) has some overlap with this review, but we take a wider perspective. Finally, we would like to mention that our structuring is also in line with the business perspectives of consultants (see Palanivelu and Dhawan, 2011). In our review, we follow to a large extent the supply chain structure given by Chopra and Meindl (2010). First we discuss the main physical drivers behind a supply chain and examine transportation in Section 2, products and inventories in Section 3 and facilities in Section 4. We investigate the main choices in these drivers which affect environmental performance. We consider these options in the three decision phases of a supply chain, namely design, planning and control, while we also discuss reverse supply chains. In Section 5, we discuss the design of a supply chain and how the combination of the drivers affects the environment. Section 6 examines the design of reverse and closed loop supply chains. Section 7 focuses on the three cross functional drivers, viz. sourcing, planning and pricing (revenue management) and in Section 8 we take a closer look at the operational planning of supply chains. Green supply chain metrics are examined in Sections 9 and 10 describes the OR methods that helps in making the trade-offs in green logistics, viz. multi-criteria decision making. Fig. 1 describes the proposed framework of this paper.

Operations Research is most often associated with cost minimization. Yet there is a substantial impact on the environment, although this is often not recognized. Environmental advocates typically plead for a technology change, e.g. going from oil-based fuel to electric cars. However in all systems, the way they are operated is an important determinant in the environmental performance. For example, container ships lowering their speed from 26 to 18 knots reduce their fuel use by 30%. Accordingly, OR has and will bring important contributions to the environment, but it is quite often implicit, a fact which has become evident from this review. It would be better if OR emphasized its value for the environment. New models will be required to address the multitude of decisions needed to improve the environment.