Combine the word green with practically any noun to generate a phrase that connotes something – from a government policy to a cleaning service – that a reader or listener assumes to be environmentally benign in some way. Going from a vague concept to a useful definition of “green transportation” or “green laundry detergent” frequently presents a challenge, however. Ask several people to define green this or that and the results will reflect each person’s knowledge base and biases.

Since the concept of green manufacturing was first articulated about a decade ago, however, a growing consensus among theoreticians and practitioners is clarifying what it is, and how manufacturers can institute appropriate goals and practices to turn green, or at least less brown. The benefits, both tangible and intangible, are also becoming clearer, changing the concept into a concrete and useful set of parameters and principles.

Green manufacturing and its relatives

In general, definitions of green manufacturing refer to the environmentally responsible production and use of manufactured goods. One succinct and comprehensive description of green manufacturing was suggested in 2008, at a green manufacturing expo held in New York:

… the creation of manufactured products that use processes that are non-polluting, conserve energy and natural resources, are economically sound, and safe for employees, communities and consumers.

Figure 1: OECD’s Sustainable Manufacturing Toolkit lays out “seven steps to environmental excellence.”Figure 1: OECD’s Sustainable Manufacturing Toolkit lays out “seven steps to environmental excellence.”The U.S. Department of Commerce’s Sustainable Manufacturing Initiative embraced this description, and the Organisation for Economic Cooperation and Development (OECD) repeats it in the introduction to their Sustainable Manufacturing Toolkit. The OECD further calls this concept “an exciting new way of doing business and creating value.”

Does sustainable manufacturing mean the same thing as green manufacturing? The two terms appear to be used interchangeably in both the popular press and industry publications, and both embrace the breadth of the concept, focusing it squarely on manufacturing, on making physical products. Some related terms include green technologies, green chemistry, zero waste, energy-efficient manufacturing, and often “green” or “sustainable” combined with something else. This article equates green and sustainable manufacturing but sticks with green for consistency.

Elements of green manufacturing

The OECD Toolkit sorts what it describes as quantitative indicators for environmental performance into three phases of manufacturing: inputs, operations and products. These indicators provide a good outline of the effects these components of the manufacturing process have on the environment.

Inputs

The three input indicators refer to materials consumed in the manufacturing process that typically form part of the product.

Quantity of non-renewable materials used: The supply of non-renewable materials is finite, and for materials like rare earth minerals, supply is severely restricted. Using these materials in one product prevents their use in another product. Production and delivery of these materials could also have secondary impacts on the environment.

Restricted substances: These are materials known to be harmful to people, the environment or both. Examples include damaging chemicals that leach from plastic food containers and substances that taint the environment when the product is discarded, like heavy metals in obsolete electronic devices.

Recycled and reused content: The more recycled content a product contains, the fewer new non-renewable or damaging materials are used in its manufacture. Reusing materials also reduces trash in landfills.

Figure 2: A “sustainable edition” T-shirt. Source: Scoobyfoo / CC BY-NC-ND 2.0Figure 2: A “sustainable edition” T-shirt. Source: Scoobyfoo / CC BY-NC-ND 2.0

Operations

Manufacturing processes have an environmental impact both through consumption of energy and water and through byproducts or wastes.

Water use and discharge: If the local water supply is insecure, the amount used for manufacturing could threaten the local population’s well-being. Untreated water returned to the environment can contaminate water sources, including groundwater and surface sources like lakes and rivers.

Energy sources and energy use: Energy-intensive processes can affect the environment directly, through consumption of fossil fuels like coal in a blast furnace, or indirectly, by using electricity produced by fossil fuels or by nuclear fission. Fossil fuels are non-renewable and the source of well-known polluting by-products, including greenhouse gases. Substituting solar- or wind-produced power and implementing energy conservation measures reduces environmental impact.

Waste output: The OECD model’s definition of waste products sums up wastes already mentioned, like greenhouse gases and runoff water, and material deposited in landfills or sent for recycling, sewage and solid wastes, and carbon content of direct energy sources. Reducing waste byproducts is both good for the environment and for a company’s bottom line.

Land with natural cover: Rather than pave over an entire factory site, facility operators can have a positive effect on the environment by planting natural cover. The choice of plants can range from low-growing cover crops that need little or no maintenance to trees and shrubs that provide habitat for wildlife. Any kind of plant cover will create an artificial lung that converts carbon dioxide to oxygen. New facility planning should preserve as much of the existing plant cover as practical.

Products

In addition to the impacts of inputs and operations, products can affect the environment over years or decades. Product recyclability can be as important a consideration as the use of recycled ingredients for manufacturing the product. Product design is another factor: a product with replaceable parts encourages the owner to use it longer rather than tossing the entire thing into a landfill.

Be sure to check out Part 2 of this article, which will address the question: "Why should a manufacturer bother with green practices?"