11 November 2006
11 November 2006
With a grant from the National Science Foundation, Timothy G. Gutowski, MIT professor of mechanical engineering is reviewing energy use in manufacturing processes.
The goal is to compare the environmental performance of traditional methods to alternative processes, alternative product designs and proposed new processes.
The work is important because manufacturing plays a big role in energy use. Industry accounts for around 30 percent of the total, and manufacturing is responsible for around 80 percent of industrial use. In addition, the manufacturing industry designs and builds all of the equipment used in the other major energy use sectors.
""Manufacturing processes can be thought of as products with a huge energy appetite,"" he said. This contributes to global warming but is not as visible to the public as gas-guzzling SUVs or images of melting polar ice caps. ""Many people are not aware of the energy requirements for many manufacturing processes,"" said Gutowski, who, after extensive work in aerospace materials and composites, switched fields seven years ago to satisfy a need ""to contribute to society in a bigger way.""
The problem isn't that industry isn't interested in being environmentally friendly. In fact, in an MIT Laboratory for Manufacturing and Productivity working paper from earlier this year, Gutowski wrote that the World Business Council for Sustainable Development includes 180 international corporations, and the Global Environmental Management Initiative has members in 22 business sectors totaling $915 billion in annual sales. And, he added, many leading corporations have adopted sustainable development as a major corporate strategy.
But there are paradoxes.
For one, because of increased efficiency, energy use per kilogram of product produced by major industrial sectors has been declining. But, Gutowski pointed out, efficiency and increased production go hand in hand. And usually, increased production more than offsets any gains in efficiency. ""Hence, energy efficiency alone has not resulted in an absolute reduction in energy use,"" he said.
Further, the barriers to ""environmentally benign manufacturing"" differ from industry to industry and can be frustratingly complex. For instance, Gutowski said, automobiles, compared with other products, are already recycled very effectively, with only around 15 percent of the average car ending up in a landfill at the end of its life. So his suggested manufacturing alternative--using lightweight composites instead of steel--would solve one problem (making cars lighter and more fuel-efficient) while creating several others: Composite materials would increase waste because they are currently not as recyclable as metallic materials.
Meanwhile, microelectronics has different issues. Computers are used for approximately two to three years, compared with around 10 years for a car, and the recycling rate for all electronics is quite low. In addition, the manufacture of integrated circuits--the devices at the heart of all electronics products--requires the use of ultrapure materials and energy-intensive manufacturing processes.
Furthermore, new technologies such as those used to produce and process nanoscale materials and other advanced manufacturing processes exceed the energy use of older technologies by six to eight orders of magnitude on a per-unit-of-material-processed basis, Gutowski said.
Gutowski hopes these challenges can be overcome through the development of new technologies, the creation of new policies and, maybe most important, the public's willingness to foster change and absorb some of the costs. ""People will pay more in the short run for environmentally friendly products,"" he said. ""There will be a cost to this, but I don't think it will be something we can't manage.""
Gutowski added that one of the most important things we can do is ""educate our students and citizens about the high cost of our large-scale production and consumption on the ecosystems that presently support life as we know it.""
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