[Editors] MIT: ‘Alarming’ use of energy in modern manufacturing methods

[Elizabeth Thomson]

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MIT study sees ‘alarming’ use of energy, materials in newer  
manufacturing processes
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For Immediate Release
THURSDAY, MAR. 26, 2009

Contact: Elizabeth A. Thomson, MIT News Office
E: thomson at mit.edu, T: 617-258-5402


CAMBRIDGE, Mass.--Modern manufacturing methods are spectacularly  
inefficient in their use of energy and materials, according to a  
detailed MIT analysis of the energy use of 20 major manufacturing  
processes.

Overall, new manufacturing systems are anywhere from 1,000 to one  
million times bigger consumers of energy, per pound of output, than  
more traditional industries. In short, pound for pound, making  
microchips uses up orders of magnitude more energy than making manhole  
covers.

At first glance, it may seem strange to make comparisons between such  
widely disparate processes as metal casting and chip making. But  
Professor Timothy Gutowski of MIT’s Department of Mechanical  
Engineering, who led the analysis, explains that such a broad  
comparison of energy efficiency is an essential first step toward  
optimizing these newer manufacturing methods as they gear up for ever- 
larger production.

“The seemingly extravagant use of materials and energy resources by  
many newer manufacturing processes is alarming and needs to be  
addressed alongside claims of improved sustainability from products  
manufactured by these means,” Gutowksi and his colleagues say in their  
conclusion to the study, which was recently published in the journal  
Environmental Science and Technology (ES&T).

Gutowksi notes that manufacturers have traditionally been more  
concerned about factors like price, quality, or cycle time, and not as  
concerned over how much energy their manufacturing processes use. This  
latter issue will become more important, however, as the new  
industries scale up — especially if energy prices rise again or if a  
carbon tax is adopted, he says.

Solar panels are a good example. Their production, which uses the same  
manufacturing processes as microchips but on a large scale, is  
escalating dramatically. The inherent inefficiency of current solar  
panel manufacturing methods could drastically reduce the technology’s  
lifecycle energy balance — that is, the ratio of the energy the panel  
would produce over its useful lifetime to the energy required to  
manufacture it.

The new study is just “the first step in doing something about it,”  
Gutowski says — understanding which processes are most inefficient and  
need further research to develop less energy-intensive alternatives.  
For example, many of the newer processes involve vapor-phase  
processing (such as sputtering, in which a material is vaporized in a  
vacuum chamber so that it deposits a coating on an exposed surface in  
that chamber), which is usually much less efficient than liquid phase  
(such as depositing a coating from a liquid solution), but liquid  
processing alternatives might be developed.

The study covered everything “from soup to nuts” in terms of standard  
industrial methods, Gutowski says, “from heavy-duty old fashioned  
industries like a cast-iron foundry, all the way up to semiconductors  
and nanomaterials.” It includes injection molding, sputtering, carbon  
nanofiber production and dry etching, along with more traditional  
machining, milling, drilling and melting. There were some boundaries  
on the processes studied, however: The researchers did not analyze  
production of pharmaceuticals or petroleum, and they only looked  
primarily at processes where electricity was the primary energy source.

The figures the team derived are actually conservative, Gutowski says,  
because they did not include some significant energy costs such as the  
energy required to make the materials themselves or the energy  
required to maintain the environment of the plant (such as air  
conditioning and filtration for clean rooms used in semiconductor  
processing). “All these things would make [the energy costs] worse,”  
he says.

The bottom line is that “new processes are huge users of materials and  
energy,” he says. Because some of these processes are so new, “they  
will be optimized and improved over time,” he says. But as things  
stand now, over the last several decades as traditional processes such  
as machining and casting have increasingly given way to newer ones for  
the production of semiconductors, MEMS and nano-materials and devices,  
for a given quantity of output “we have increased our energy and  
materials consumption by three to six orders of magnitude.”

One message from the study is that “claims that these technologies are  
going to save us in some way need closer scrutiny. There’s a  
significant energy cost involved here,” he says. And another is that  
“each of these processes could be improved,” and using the analytical  
tools developed by the MIT team for this study would be a useful first  
step in such a detailed analysis.

In addition to Gutowski, the study was done by current and former MIT  
mechanical engineering students Matthew Branham, Jeffrey Dahmus,  
Alissa Jones and Alexandre Thiriez, and Dusan Sekulic, professor of  
mechanical engineering at the University of Kentucky.  It was funded  
by the National Science Foundation.


Written by David Chandler, MIT News Office
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