Assistant Professor Elsa Olivetti combines cost and environmental data to identify high-impact areas for reducing pollution and greenhouse gases.

By Denis Paiste | Materials Processing Center

Complex global manufacturing and shipping networks make it difficult for producers to choose materials and methods for cutting emissions and waste, whether for aluminum, paper, or plastic. Elsa Olivetti, the Thomas Lord Assistant Professor of Materials Science and Engineering at MIT, is developing models that combine cost and environmental data to guide choices for materials substitution and processing changes.

“We try to provide robust answers to questions of materials and technology choice by modeling and understanding the interdependencies within a market, including resource and energy use in supply chains,” says Olivetti. Underlying this work on the environmental and economic effectiveness of a material choice is a theme of reducing greenhouse emissions.

Choosing a particular material triggers a cascade of related events, including changes to the supply chain, the impact of recycled versus raw material, the processing technology for that material, the products it goes into, and its disposal or recovery at its end of life. “Often those are very complex decisions. What does that substitution imply for the resource effectiveness of the resulting cascade of activities?” Olivetti asks. To determine the environmental and economic impacts of materials choices and processes, Olivetti applies methods such as statistical simulation to rank the importance of data gaps and characterize uncertainty and maps the links between particular material or product attributes to resource and energy use.

Working with colleagues at MIT and elsewhere, Olivetti has tackled sustainability issues for biodiesel, aluminum, plastics, and computers from laptops to photonics integration. Her prior work on running shoes, with Randolph Kirchain, principal research scientist at the MIT Materials Systems Laboratory drew international attention. Their key finding was that more than two-thirds of the carbon impact can come from manufacturing processes for running shoes.

In her work with the Tata Center for Technology and Design, Olivetti advises the team behind the Eco-BLAC Brick, a form of alternative masonry being developed in Muzaffarnagar, India, and which has a far smaller environmental footprint than traditional clay bricks.

Systems approach

Although details vary from case to case, Olivetti’s approach simulates a cradle-to-grave system in a rough but comprehensive way. Gathering data across a wide spectrum of production and distribution activities requires building partnerships within the supply chain, so collaboration is key, Olivetti says.

Such a wide array of data also means uncertainty is inherent to the model. “What we’ve tried to do in the models we’ve developed is take on that uncertainty. In other words, be explicit about the fact that it’s there and find ways to deal with it,” she explains. “We find that developing methods of explicitly capturing that uncertainty in order to inform complex decisions benefits from a systems thinking approach. Uncertainty can be managed.”

Lessons learned

Developing a complete method for characterizing the carbon footprint of manufacturing processes, especially for information technology, is a work in progress. Olivetti and her team are evaluating ways to reduce the cost of this work by identifying the major drivers of impact, the relative success of reduction efforts, the best ways to manage uncertainty and how much primary data is actually needed. Information technology is a key market sector for measuring environmental impact because computing and communications device makers are large users of chemicals, water, and energy. But environmental analysis is complicated by the information technology industry’s complex and often changing production methods.

While the polluting effect of perfluoro-compounds was known, identifying the display manufacture step as a potentially top pollution activity in laptop manufacturing was possible because of the level of detail and explicit inclusion of uncertainty in Olivetti’s approach. “If we said, ‘Ah, we don’t know what the number is, we’ll just use the average,’ then you wouldn’t really get the fact that this is a very significant, high-leverage data point to get better understanding of what the true impact is,” she explains. “If we tried to get the specific information from the supply chain, we would never be finished with the analysis, but if instead we can take on the uncertainty that’s associated with having abatement or not, then we understand that’s a very high-leverage way to both reduce the impact and to understand what the specific impact is. If you can know which supply chain partners abate these gases, then you’ll have a better understanding of where that step ranks,” she adds. Besides laptops, Olivetti also studied tablet computers, monitors, desktops, servers, televisions, and several electrical equipment products including bulbs and motors.

Another example of high variability in this work is the carbon footprint from electricity usage, which varies widely from place to place, based on the sources of power, including coal, oil, gas, nuclear, wind, and solar. Since these sources are identifiable, the researchers were able to quantify the variation by treating electricity separately and accounting for geographic variation.

Teaching and family life

Olivetti’s teaching course load in the Department of Materials Science and Engineering at MIT is closely connected with her research. In the spring, she teaches 3.044 (Materials Processing), a core class for juniors covering topics such as heat transfer and fluid mechanics from an engineering perspective. In the fall, she teaches 3.081 (Industrial Ecology of Materials), which incorporates some of the tools she uses in her research. “Both of those are great complements to the research, so that’s fun. Everything is well-connected,” Olivetti says.

Olivetti, who grew up in Arlington, Virginia, and graduated from the University of Virginia, now lives in Arlington, Massachusetts. She received her PhD in materials science and engineering at MIT in 2007. She and her husband, Justin Reich, have two daughters, ages 4 and almost-2, and enjoy bike riding and rock climbing.

Photo by Denis Paiste.