The link between manufacturing and its operations to the natural environment is gradually becoming recognized. Progress, profitability, productivity and environmental stewardship are now seen as needing consideration by manufacturing organizations [5
]. Improving environmental stewardship and sustainability, while maintaining profitability and productivity, are increasingly viewed as strategic goals of manufacturing companies.
3.1. Manufacturing and the Environment
Traditionally strategies for manufacturing have considered production process comparisons for the volume/variety matrix of the products [6
]. Today, manufacturing strategies generally account for products and processes, as well as other parameters like practices, so as to incorporate organizational and philosophical elements of manufacturing strategy. This yields more general viewpoint. A technological dimension is included, since manufacturing is heavily technologically driven.
Manufacturing operations and the natural environment are becoming increasingly linked. To incorporate a measure of environmental impact in manufacturing strategies, expressions for assessing the environmental impact (EI) on society can be used. One common expression for the environmental impact on society is EI = P × A × T, where P, A and T denote population, affluence and technology respectively [7
]. Population is difficult to constrain and affluence is increasingly sought by people. Thus, technology, which can be defined as the knowledge of an organization [10
], is the factor that can be improved to reduce environmental impact. The technology category relating to the environment and manufacturing is affected by the following three factors:
Product: The manufacturing strategy for environmentally benign products often involves a design process which accounts for environmental impacts over the life of the product. Consequently it is normally associated with the use of design for environment (DFE) and life cycle analysis (LCA) methods. Designing products to be environmentally benign can contribute to their successful introduction and maintenance. Product flexibility, for example, allows for environmental improvements, like materials substitution, while retaining competitiveness. The expected decrease in product life cycles with increased product customization is likely to make flexibility increasingly important.
Process: Environmental improvements related to manufacturing processes are linked to reduction, reuse, recycling and remanufacturing. Zero-emission (i.e., closed-loop) manufacturing views the manufacturing system as an industrial ecosystem, and requires the reuse of wastes or by-products within the manufacturing system. Thus, zero-emission manufacturing requires capabilities for pollution prevention (e.g., substitution) and waste reuse. Flexible manufacturing also requires the capability for material flexibility, and manufacturing equipment that can accommodate variations in material flows can assist in enhancing sustainability while maintaining competitiveness. For instance, more efficient and recyclable packaging designs can make packaging more sustainable.
Practices: An important environmentally-based influence on organizational manufacturing practices is ISO 14000 certification, which can support organizational practices but does not make environmental improvements a certainty on its own [5
]. Practices can be used strategically to improve manufacturing, through such other activities as benchmarking and performance measurement, since such schemes assist managers in developing and maintaining new environmental programs and technology.
These three factors overlap in some areas and are interdependent and synergistic. Technological advances can emanate within an organization, but most developments, especially strategic environmental ones, result from multi-organizational efforts, often with governmental input and support. For example, industry consortia, such as the European Eureka program, the National Center for Manufacturing Sciences in the US, and Ecofactory in Japan, each have a significant research focus on environmentally conscious manufacturing practices and technology. Consortia are particularly important in countries where technology transfer and diffusion throughout industry is weak, such as Canada and the U.S. [5
Environmental manufacturing strategies based on the Malcolm Baldrige criteria are recommended for organizations by the U.S. Environmental Protection Agency as effective, and include environmental leadership, strategic environmental quality planning, environmental quality management systems, human resources development, stakeholder emphasis, environmental measurements and environmental quality assurance [11
Manufacturing decision makers normally addressed only the economic aspect of sustainability in the past, whereas corporations recently have started to address environmental sustainability. Such tools are becoming increasingly common and include carbon footprint estimation, life cycle assessment [12
] and life cycle management [16
], design for the environment, and product stewardship [18
]. Numerous examples of applications of these tools have been reported [20
]. Engineers in industry now consider such measures as resource consumption, and emissions of toxic substances, greenhouse gases, atmospheric pollutants and solid and liquid wastes. Besides approaches and tools, environmentally sound practices require consideration of the extended producer responsibility principle.
3.2. Manufacturing and Sustainability
Sustainable manufacturing evolved from the concept of sustainable development, which was coined in the 1980s to address concerns about environmental impact, economic development, globalization, inequities and other factors. Sustainable production was introduced at the 1992 UNCED conference in Rio de Janeiro as a guide to help companies and governments transition towards sustainable development. Research into these areas is ongoing by many [23
]. Several definitions exist for sustainable manufacturing and production. For instance, sustainable manufacturing is defined by the U.S. Department of Commerce defines as “the creation of manufactured products that use processes that minimize negative environmental impacts, conserve energy and natural resources, are safe for employees, communities, and consumers and are economically sound,” while the Lowell Center for Sustainable Production defines sustainable production as “the creation of goods and services using processes and systems that are Non-polluting, conserving of energy and natural resources, economically viable, safe and healthful for workers, communities, and consumers, socially and creatively rewarding for all working people”.
Sustainability has been interpreted in many ways, considering various requirements for many applications and different objectives. For manufacturing applications, the definition of sustainability requires refinement. Companies have developed and applied numerous approaches for integrating sustainability into industrial operations, including people planet profits, sustainable management, ecological sustainability, and the “triple bottom line” method. The latter method is described by Elkington [24
] as a business case for sustainability, which involves a holistic approach relying on the principles of economic prosperity, environmental stewardship and corporate responsibility.
Frameworks and practices for sustainable manufacturing have been proposed and investigated. For example, a framework was developed by the Organization for Economic Co-operation and Development (OECD) [23
] to accelerate sustainable industrial production by diffusing knowledge, facilitating benchmarking of products and production processes, and promoting eco-innovation, development of new technological and systemic solutions to global environmental challenges.There are four primary categories of input resources to manufacturing organizations, as shown on the left side of Table 1
. These lead to corresponding outputs, shown on the right side of Table 1
. Business generally seeks to reconfigure physical, human, information and financial resources so that the financial resources exiting the system are larger than those that enter. Sustainability requires that corporations satisfy social and environmental objectives or constraints while undertaking this reconfiguration.
Inputs and outputs of a manufacturing entity.
Inputs and outputs of a manufacturing entity.
|Inputs ||Corresponding outputs|
|Economic resources||Wealth, profits|
|Human resources||Education, training, skills|
|Natural and artificial resources||Products, goods|
|Information resources||Knowledge, know-how|
Many aspects of sustainability in the context of manufacturing have been investigated, particularly in recent years. For instance modeling and optimization challenges to sustainable manufacturing have been examined by Jayal et al
], considering the product, process and system levels. A framework for sustainable production has been proposed by Nasr et al
], who also provide a strategic approach to remanufacturing, which the authors identify as a key enabler to sustainable production. Approaches and methodologies for design sustainable supply chains and an evaluation of their performance have been described by Shuaib et al
], as have novel approaches to reverse logistics and closed loop supply chains [28
The evolution of the sustainability of manufacturing anticipated by the authors is described in Table 2
. Traditional uses for manufacturing were developed without a focus on sustainability [30
]. Investments in plants and corresponding improvement and optimization efforts have typically been driven by increased productivity, reduced operating costs and work effort, and enforced regulatory compliance. Business decisions can increase the utilization efficiency of energy, materials, human and information resources as well as related technology and equipment. Future manufacturing systems are likely to be based on strategies that seek to optimize the capability to meet immediate facility needs in a way that enhances the environmental quality of future generations and the business prospects for the company in the future. The energy systems for manufacturing facilities have advanced to improve operating cost structures, including load curtailment and shedding, and energy monitoring, as well as control of generators, HVAC systems, and thermal plants. The anticipated approaches in Table 2
can help meet the goals of sustainability.
Possible future evolution of the sustainability of manufacturing.
Possible future evolution of the sustainability of manufacturing.
|Required environmental compliance||Enhanced environmental compliance often exceeding minimal requirements|
|Economic operational efficiency||Increased operational efficiency beyond that necessitated based solely on traditional economics|
|Communication that supports business objectives (reputation, brand recognition, etc.)||Communication to support expanded business objectives (reputation, brand recognition, corporate social responsibility, etc.)|
|Meet legal regulations for compliance, with little voluntary activity||Shift from simply meeting legal regulations for compliance to more voluntary activity, driven partly by market forces for sustainability objectives|
A business must understand how it impacts sustainability to act sustainably, and this requires the use of sustainability indicators. Metrics are needed to measure progress towards the achievement of sustainability, and identifying appropriate sustainability indicators is an important challenge. Efforts have been expended to integrate measures of sustainability into the decision-making practices in industry. For instance, Parris and Kates [31
] reviewed numerous attempts to define sustainability indicators and identified up to 255 indicators. These sustainability indicators vary greatly in terms of geographic extent (ranging from global to local), ability to be managed by business decision makers, and the effort and costs required to apply them. Also, Stokes [32
] suggests monetizing sustainability, based on incorporating the triple bottom line method into the manufacturing system and its environment. Factors such as environmental compliance, communication and operational efficiency provide measurable outcomes supported by traditional business objectives, but to measure the results they are “monetized” based on outcome priorities and business performance [30
]. Such performance measures are critical to improving the environmental sustainability of industrial systems, as such efforts rely on metrics to be judged [33
The successful implementation of sustainability into manufacturing organizations is dependent on many factors. Some examples follow:
Information: The quantitative and qualitative information required to make assessments is needed, e.g., the quantity and type of metal a process uses, the quantity and type of pollutants emitted. However, such information is not always readily available and can be sometimes be difficult if not impossible to acquire.
Management and culture: Sustainability issues, e.g., environmental stewardship efforts, tend to be dealt with in specialized departments rather than holistically by management. This can lead to inconsistent application and tends to discourage the development of a sustainability-oriented culture in the organization.
Procedures: Decision makers and staff are often not provided with the methodologies and procedures needed to ensure an organization’s sustainability objectives and strategies are applied effectively, efficiently, consistently and robustly. One reason for this problem is that the number of variables to be taken into account in decision-making is usually very large. Employees need to take sustainability issues into account effectively in decision making and actions if sustainability objectives are to be achieved.
3.3. Models for Manufacturing and Improved Sustainability
Various models have been developed for implementing sustainability in manufacturing by improving the sustainability of manufacturing. Recently, frameworks for sustainable manufacturing, production and supply chains have been put forth [26
], and modeling and optimization tools have been developed [25
]. Harland et al
] propose an environmental health and safety technology engagement model (Table 3
) that illustrates the potential for implementing sustainability objectives during the development of a product or process. This model includes three phases: research, development and commercialization. A significant time period, often lasting years, is normally involved in designing a new manufacturing product or process, and Table 3
shows the potential for implementing sustainability objectives differs with the time and phase of development. Manufacturing engineers and designers need to recognize this dependence to integrate sustainability effectively into processes or products.
Rather than considering the environmental factors only at one point in the product or process development cycle, a long-term commitment over the entire design process, from early research to process development, is usually more effective for integrating sustainability into manufacturing [34
]. Sustainability can be addressed in each of the three phases of the model:
Research: The first significant opportunity to influence the design process for sustainability is during the research phase at the pre-competitive level. At this phase, specific sustainability requirements and not-yet regulated concerns can be evaluated and examined, e.g., energy and resource use, pollution and climate change impacts. Early evaluation helps to ensure appropriate attention to sustainability at a time when it can be affected greatly, e.g., research can focus on solving manufacturing environmental issues.
Development: During the development phase, effort to improve environmental performance is focused on system design and equipment selection using appropriate methods tools and methods, e.g., design for environment, environmental footprint assessment, and life cycle analysis. Collaboration with vendors helps promote environmental improvements. The potential for modifications that enhance sustainability characteristics is high during this phase.
Commercialization: The efforts introduced during the development phase are extended and refined during commercialization activities, and involve cooperation with suppliers, vendors and customers.
Model for potential for implementing sustainability in manufacturing *.
Model for potential for implementing sustainability in manufacturing *.
|Development phase||Potential for modification||Time before commercial manufacturing||Cost benefit of proper decision|
|* Based in part on model of Harland et al. .|
The semiconductor equipment company Intel is an example of a company that strives to build sustainability into its products and processes prior to commercialization [34
]. Intel operates under a two-year model for new product development, alternating between silicon manufacturing technology one year and microprocessor architecture the next. This model introduces a new manufacturing process technology in the first year, allowing, for instance, reductions in semiconductor size and the subsequent manufacture of more semiconductors on a single wafer or placement of more transistors in an equivalent space. In the second year, this model introduces a new chip architecture or design with the same manufacturing technology. Each step provides the opportunity to establish objectives and strategies to reduce environmental impact, and Intel has worked with suppliers of semiconductor manufacturing equipment and materials to improve the environmental performance of various technologies using this approach.
3.5. Importance of Manufacturing Sustainability
The importance of adopting sustainable manufacturing measures and strategies by companies are numerous and are becoming increasingly recognized. For instance, climate change is increasingly seen as caused by anthropomorphic activities and potentially having very serious consequences, while resources (e.g., energy, materials, water) are now seen as subject to scarcities and in many cases non-renewability that can affect operations. Also, the global economic crisis of the last several years has raised questions about the viability and ultimately sustainability of existing business practices that aim for economic growth, but pay little attention to mitigating the negative impacts beyond the company. As a consequence, pressures for sustainable manufacturing have become increasingly put forward by many stakeholders, e.g., employees, investors, suppliers, customers, competitors, communities, governments, regulatory bodies.