Material Input per Service Unit (MIPS)

Material input per service unit is a measure of ecoefficiency, developed at the Wuppertal Institute for Climate, Environment, and Energy, a German sustainability research institution that focuses on the intersection of ecology, economy, and society. The basic idea behind the concept is that, at some point down the line, every material input (natural resources, energy) becomes an output in the form of waste or emissions. The subsequent argument is that measuring the inputs thus allows for a rough approximation of the overall environmental burden. The Wuppertal Institute defines MIPS as “an elementary measure to estimate the environmental impacts caused by a product or service. The whole life cycle from cradle to grave (extraction, production, use, waste/recycling) is considered. MIPS can be applied in all cases where the environmental implications of products, processes, and services need to be assessed and compared.”

As a concept, in short, the method can be used to estimate the environmental burden caused by a product, service, or even a lifestyle, and can be performed on a macroeconomic scale (examining national economies) or on a microeconomic level (evaluating a single product, industry, or service).

MIPS is the reciprocal of resource productivity, which would be expressed as service units per material input (analogous to the familiar formulation of an automobile's mileage). A lower MIPS means a greater degree of ecoefficiency. MIPS values are calculated for the entire life cycle of the product or service—production, use, recycling, or disposal—with the service units varying according to the nature of the product. A common example given by Wuppertal is an automobile, the service unit of which would be passenger miles traveled over the course of its life. The fewer material inputs required per passenger mile across that life span, the greater the environmental efficiency of the car. The material input includes the raw materials and energy used to produce the product or service, to operate it, and to dispose of it. Reducing any of those obviously increases the efficiency and MIPS. Using recycled raw materials, for instance, brings the number down, as does a more energy-efficient factory or production process. Efficiency gains can also result from reducing the waste in the production process—whether caused by errors (products discarded when they fail quality inspection), an unnecessarily excessive use of material (such as vehicles larger than they need to be), or material that is wasted in the production process but is neither recycled nor part of the final product (such as the scraps of material left after the process).

[Page 354]Wuppertal and other sustainability advocacy groups promote the MIPS figure because they seek to encourage reducing materials consumption—a necessity in order to achieve sustainable manufacturing sectors. One of the concepts promoted by Wuppertal is the “Factor Four” goal (from the book of the same title by Ernst Ulrich von Weizsacker et al.), which calls for “doubling wealth, while halving resource use.” This is sometimes called “dematerializing” the economy. MIPS considers the use of a resource—a material input—to begin at the point it is extracted from nature. Such material inputs include biotic resources (living and renewable, such as plant materials), raw materials, abiotic resources (nonliving and nonrenewable, such as mineral ore), water, air (including the air consumed by combustion and chemical reactions), and earth (i.e., the soil used in such things as agriculture). Energy used for manufacture and transport is also measured. The focus on inputs reflects the institute's desire to reflect the fact that all inputs eventually become outputs, in the form of waste or emissions, and that measuring inputs thus provides as accurate an understanding of eventual environmental impact as measuring outputs does. An automobile's environmental impact is not limited to its exhaust emissions—a car that is never driven still represents a use of energy to manufacture it, the materials taken out of the Earth to build it, and the scrap it becomes when it is no longer usable. The use of a car certainly leads to its greatest environmental impact, and more gains are made by focusing on fuel efficiency and lower emissions than on dematerialization; but that does not negate the impact of the manufacturing phase. Likewise, though putting clothes through the laundry has obvious environmental impact and consumers have awakened to the desirability of environmentally friendly washing machines, dryers, and the environmental gains of returning to air-drying, the consumer is largely unaware that the resource consumption required to manufacture clothes can be as high—or even greater—as the cumulative resource consumption of laundering over their life span.

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