Most coffee drinkers might guess that there is a difference in the environmental impact of different brewing methods. Andrea Hicks uses detailed observation and careful math to prove so.
Hicks, who joined the Department of Civil and Environmental Engineering in fall 2015 as an assistant professor, specializes in quantifying the environmental impact of products and processes, using tools such as life cycle assessment. One area she’s particularly interested in assessing is products of convenience, like those single-serve coffee pods.
“Where I start is getting samples of the products I want to compare,” says Hicks. “So let’s say I want to compare French press, drip filter and a single-serve coffee pod. First, I’d need to look at the materials that go into each. In a French press, it’s coffee and water and some amount of energy for heat. Whereas in a single-serve coffee pod you have the cup, the coffee, the filter, the foil and a little bit of nitrogen injected for freshness.”
After identifying and quantifying the materials that go into one single serve coffee pod, the process Hicks employs becomes a little trickier. She has to figure out how much energy, water and other resources the coffee pods use during both the manufacturing and brewing process.
“Then you also need to look at disposal — what do people do with it?” Hicks says. “Single-serve coffee pods aren’t terribly recyclable right now. You can disassemble them and have some recycling benefit, but will the average consumer do that? They’re a monstrous hybrid right now.”
The assessment is complete once Hicks is able to pinpoint the adoption rate of the product or process. That process includes data analysis from sales figures or consumer surveys, but Hicks also employs more theoretical approaches.
“I’m on the numbers side of everything,” Hicks says. “There’s a lot of math with this type of work.”
That math includes stochastic modeling.
“Stochastic means there’s a degree of randomness or uncertainty in the system,” Hicks says. “The work I do is usually agent-based modeling, where you can model individuals and their actions and understand their environmental impact as a function of their actions. Agents can be people, companies, wildlife, etc.”
Factoring in randomness is key to assessing the environmental impact of products, Hicks says, because consumers use the same products in vastly different ways.
Hicks studied an aspect of this difference as part of her PhD research at the University of Illinois at Chicago. She looked at the environmental impact of energy-efficient light bulbs and a phenomenon called Jevon’s Paradox, or the rebound effect.
“It’s the idea that as we as a society adopt more energy-efficient products or processes that we potentially use more of them,” Hicks says. “So if you buy a hybrid vehicle, you might drive it more. What is that environmental break-even point, and are we exceeding it?”
The consumer transition from incandescent light bulbs to more energy-efficient compact fluorescent light bulbs (CFLs) and LED lighting was a perfect case study for assessing the phenomenon.
“I looked at the potential to use more energy and erode the savings brought about by greater efficiency,” Hicks says.
She found that consumers would have to use vastly more electricity to erode the savings of the newer light bulbs. “It’s possible,” she says. “But there’s some heterogeneity within populations. Some consumers really use a lot more and erode the savings; some will use as much as they always have, and therefore they have the savings; and some will use less because it’s a new technology and they don’t want to break it or use it incorrectly.”
Enter the complex math of stochastic modeling, which is just one method of assessing a product’s societal level environmental impact throughout its whole lifecycle—from raw materials to use to the end of its life.
Lifecycle assessment is just one tool in Hicks’ field, called industrial ecology. Born at Yale, industrial ecology is grounded in looking to ecology to better understand and design industrial and human processes.
The principles of industrial ecology figure prominently in a new special topics course Hicks is offering in fall 2015, called Environmental Sustainability Engineering (CEE 629).
“It’s going to challenge students to think about how we make things, how we’ve treated the environment in the past and where we’re going in the future,” Hicks says.
Students in the class study historical environmental disasters and assess what lessons engineers can learn from them. They then apply those lessons to current engineering challenges.
“They’ll be challenged to think about, ‘Instead of making products less bad, what if we can make products all good,’” Hicks explains. “So, what if the idea was instead of trying to lessen the environmental impact, the waste of one product became feed stocks for another product.”
The course is not just conceptual, however:
“It’s a significantly quantitative course,” Hicks says. “We go through a lot of tools for designing for the environment, designing for disassembly, and lifecycle assessment, which are all very quantitative.”
Hicks will also continue her research into the environmental impacts of various consumer products. In addition to products of convenience, Hicks is most interested in the environmental impact of nanotechnology and energy efficiency with respect to the rebound effect.
“Most recently I’m looking at consumer products that use nano-silver,” Hicks says. Silver is inherently antimicrobial, so some t-shirt manufacturers have begun incorporating nano-silver into their fabrics. The idea, Hicks says, is that the t-shirts stay fresh longer, reducing the number of times they need laundering. Which is relevant as laundering has traditionally comprised a significant portion of the life cycle impact
“But adding silver involves the added environmental impact of mining silver, refining it and attaching it to the t-shirt,” Hicks says. “And then there’s the issue that the shirt loses the silver over its lifetime.” The lost silver is then released into the environment, where there is significant potential for impact in freshwater ecosystems.
After about 10 washes, nearly 90 percent of the silver in these new t-shirts is gone, Hicks says, which leads her to question whether there is a true environmental benefit to nano-silver, or if the environmental impact of the t-shirts has simply shifted.
Hicks comes to UW-Madison from a postdoctoral fellowship in Chicago.
“UW-Madison is one of the top 20 environmental engineering programs in the country, which was a definite draw,” Hicks says. “Researchers at UW are pursuing areas of research which I am really interested in, and I feel like I have a significant contribution to make. There is a great breadth of opportunities to be had within the scope of research, teaching and service.”
Before her PhD research in Chicago, Hicks received her master’s degree from Clemson University, where she looked at the carbon footprints of wastewater treatment plants.
“I’ve always been interested in environmental issues,” Hicks says. “That’s been the guiding path through all of this—understanding the impact that humans are having on the earth, and using my research to better understand and hopefully change it.”