Every time you use your phone, open your computer or listen to your favorite music on AirPods, you are relying on critical minerals.
These materials are the tiny building blocks powering modern life. From lithium, cobalt, nickel and graphite in batteries to gallium in telecommunication systems that enable constant connectivity, critical minerals act as the essential vitamins of modern technology: small in volume but vital to function.
Yet the U.S. depends heavily on imports for most critical materials. In 2024 the U.S. imported 80% of rare earth elements it used, 100% of gallium and natural graphite, and 48% to 76% of lithium, nickel and cobalt, to name a few.
In mid-April Georgia Tech’s Renewable Bioproducts Institute hosted a mini-symposium discussing the challenges and potential solutions to integration at different scales and levels of abstraction.
This workshop underscored the importance of collaborative efforts in advancing biomass integration, paving the way for a more sustainable and economically viable future in the refining industry.
To listen to the workshop:
We’d like to share our thanks with our speakers for their insights:
RBI would love to hear from you on future topics you would like to hear us cover. Share your feedback with Executive Director Carson Meredith.
Hedwig Oldendorff vessel at the start of its emission monitoring voyage
When the International Maritime Organization enacted a mandatory cap on the sulfur content of marine fuels in 2020, with an eye toward reducing harmful environmental and health impacts, it left shipping companies with three main options.
They could burn low-sulfur fossil fuels, like marine gas oil, or install cleaning systems to remove sulfur from the exhaust gas produced by burning heavy fuel oil. Biofuels with lower sulfur content offer another alternative, though their limited availability makes them less feasible.
While installing exhaust gas cleaning systems, known as scrubbers, is the most feasible and cost-effective option, there has been a great deal of uncertainty among firms, policymakers, and scientists as to how “green” these scrubbers are.
Through a novel lifecycle assessment, researchers from Georgia Tech, MIT, and elsewhere have now found that burning heavy fuel oil with scrubbers in the open ocean can match or surpass using low-sulfur fuels, when a wide variety of environmental factors is considered.
The scientists combined data on the production and operation of scrubbers and fuels with emissions measurements taken onboard an oceangoing cargo ship.
They found that, when the entire supply chain is considered, burning heavy fuel oil with scrubbers was the least harmful option in terms of nearly all 10 environmental impact factors they studied, such as greenhouse gas emissions, terrestrial acidification, and ozone formation.
“In our collaboration with Oldendorff Carriers to broadly explore reducing the environmental impact of shipping, this study of scrubbers turned out to be an unexpectedly deep and important transitional issue,” said Neil Gershenfeld, an MIT professor, director of the Center for Bits and Atoms (CBA), and senior author of the study.
“Claims about environmental hazards and policies to mitigate them should be backed by science. You need to see the data, be objective, and design studies that take into account the full picture to be able to compare different options from an apples-to-apples perspective,” added lead author Patricia Stathatou, an assistant professor at Georgia Tech, who began this study as a postdoc in the CBA.
Stathatou is joined on the paper by Michael Triantafyllou and others at Naias Laboratories, the National Technical University of Athens in Greece, and the maritime shipping firm Oldendorff Carriers. The research appeared recently in Environmental Science and Technology.
Slashing sulfur emissions
Heavy fuel oil, traditionally burned by bulk carriers that make up about 30 percent of the global maritime fleet, usually has a sulfur content around 2 to 3 percent. This is far higher than the International Maritime Organization’s 2020 cap of 0.5 percent in most areas of the ocean and 0.1 percent in areas near population centers or environmentally sensitive regions.
Sulfur oxide emissions contribute to air pollution and acid rain, and can damage the human respiratory system.
In 2018, fewer than 1,000 vessels employed scrubbers. After the cap went into place, higher prices of low-sulfur fossil fuels and limited availability of alternative fuels led many firms to install scrubbers so they could keep burning heavy fuel oil.
Today, more than 5,800 vessels utilize scrubbers, the majority of which are wet, open-loop scrubbers.
“Scrubbers are a very mature technology. They have traditionally been used for decades in land-based applications like power plants to remove pollutants,” Stathatou explained.
A wet, open-loop marine scrubber is a huge, metal, vertical tank installed in a ship’s exhaust stack, above the engines. Inside, seawater drawn from the ocean is sprayed through a series of nozzles downward to wash the hot exhaust gases as they exit the engines.
The seawater interacts with sulfur dioxide in the exhaust, converting it to sulfates — water-soluble, environmentally benign compounds that naturally occur in seawater. The washwater is released back into the ocean, while the cleaned exhaust escapes to the atmosphere with little to no sulfur dioxide emissions.
But the acidic washwater can contain other combustion byproducts like heavy metals, so scientists wondered if scrubbers were comparable, from a holistic environmental point of view, to burning low-sulfur fuels.
Several studies explored toxicity of washwater and fuel system pollution, but none painted a full picture.
The researchers set out to fill that scientific gap.
A “well-to-wake” analysis
The team conducted a lifecycle assessment using a global environmental database on production and transport of fossil fuels, such as heavy fuel oil, marine gas oil, and very-low sulfur fuel oil. Considering the entire lifecycle of each fuel is key, since producing low-sulfur fuel requires extra processing steps in the refinery, causing additional emissions of greenhouse gases and particulate matter.
“If we just look at everything that happens before the fuel is bunkered onboard the vessel, heavy fuel oil is significantly more low-impact, environmentally, than low-sulfur fuels,” Stathatou said.
The researchers also collaborated with a scrubber manufacturer to obtain detailed information on all materials, production processes, and transportation steps involved in marine scrubber fabrication and installation.
“If you consider that the scrubber has a lifetime of about 20 years, the environmental impacts of producing the scrubber over its lifetime are negligible compared to producing heavy fuel oil,” she noted.
For the final piece, Stathatou spent a week onboard a bulk carrier vessel in China to measure emissions and gather seawater and washwater samples. The ship burned heavy fuel oil with a scrubber and low-sulfur fuels under similar ocean conditions and engine settings.
Collecting these onboard data was the most challenging part of the study.
“All the safety gear, combined with the heat and the noise from the engines on a moving ship, was very overwhelming,” she said.
Their results showed that scrubbers reduce sulfur dioxide emissions by 97 percent, putting heavy fuel oil on par with low-sulfur fuels according to that measure. The researchers saw similar trends for emissions of other pollutants like carbon monoxide and nitrous oxide.
In addition, they tested washwater samples for more than 60 chemical parameters, including nitrogen, phosphorus, polycyclic aromatic hydrocarbons, and 23 metals.
The concentrations of chemicals regulated by the IMO were far below the organization’s requirements. For unregulated chemicals, the researchers compared the concentrations to the strictest limits for industrial effluents from the U.S. Environmental Protection Agency and European Union.
Most chemical concentrations were at least an order of magnitude below these requirements.
In addition, since washwater is diluted thousands of times as it is dispersed by a moving vessel, the concentrations of such chemicals would be even lower in the open ocean.
These findings suggest that the use of scrubbers with heavy fuel oil can be considered as equal to or more environmentally friendly than low-sulfur fuels across many of the impact categories the researchers studied.
“This study demonstrates the scientific complexity of the waste stream of scrubbers. Having finally conducted a multiyear, comprehensive, and peer-reviewed study, commonly held fears and assumptions are now put to rest,” said Scott Bergeron, managing director at Oldendorff Carriers and co-author of the study.
“This first-of-its-kind study on a well-to-wake basis provides very valuable input to ongoing discussion at the IMO,” said Thomas Klenum, executive vice president of innovation and regulatory affairs at the Liberian Registry, emphasizing the need “for regulatory decisions to be made based on scientific studies providing factual data and conclusions.”
Ultimately, this study shows the importance of incorporating lifecycle assessments into future environmental impact reduction policies, Stathatou said.
“There is all this discussion about switching to alternative fuels in the future, but how green are these fuels? We must do our due diligence to compare them equally with existing solutions to see the costs and benefits,” she concluded.
In addition to Georgia Tech and MIT, Mario Tsezos' team from Naias Labs in Greece contributed significantly to the research. This study was supported in part by Oldendorff Carriers.
- Written by Adam Zewe, MIT News Office
braddixon@gatech.edu
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The Strategic Energy Institute (SEI) and Stryten Energy are excited to announce the completion of the Lead Battery Energy Storage System (BESS) installation. The lead battery energy storage unit, situated directly behind the Carbon Neutral Energy Solutions building on the Georgia Tech campus, will serve as the first living lab battery pilot at Georgia Tech. As an essential component of the Distributed Energy Resources puzzle, this system will play a crucial role in advancing energy solutions research.
Following a nationwide search, Julia Kubanek, vice president for Interdisciplinary Research at Georgia Tech, has named Beril Toktay as the executive director of the Brook Byers Institute for Sustainable Systems (BBISS). Toktay has served as BBISS interim executive director since September 2022.
“As interim executive director, Beril has built the BBISS community, broadened its scope, and developed new programming to grow cross-disciplinary collaboration, community-engaged research, and entrepreneurship,” Kubanek said. “Faculty and students from the liberal arts, social sciences, design, business, computing, and fundamental science are engaging with BBISS in greater numbers, complementing our engineering community’s involvement. These are areas of strength at Georgia Tech that will help amplify the impact of BBISS.”
Toktay is professor of operations management, the Brady Family Chair, and Regents' Professor at the Scheller College of Business. She is an internationally recognized sustainable operations management scholar whose work has been recognized with multiple best paper awards. She is a Distinguished Fellow of the INFORMS Manufacturing & Service Operations Management (MSOM)Society. Through initiatives such as the Drawdown Georgia Business Compact, she has helped translate research insights into actionable business initiatives while fostering regional economic development.
Her academic leadership includes serving as department co-editor for “Health, Environment, and Society” for MSOM, area editor for “Environment, Energy, and Sustainability” at Operations Research, and special issue co-editor on “Business and Climate Change” for Management Science, as well as “Environment” for MSOM. She serves on the board of the Alliance for Research on Corporate Sustainability and the board of directors of the New York Climate Exchange.
Toktay has been instrumental in advancing sustainability at Georgia Tech, serving as founding faculty director of the Ray C. Anderson Center for Sustainable Business, co-architect of the Serve-Learn-Sustain initiative, and co-chair of the Sustainability Next Institute Strategic Plan Implementation Task Force. Her commitment to Ph.D. student success earned her the 2018 Georgia Tech Outstanding Doctoral Thesis Advisor Award. She also co-developed the Carbon Reduction Challenge, an award-winning interdisciplinary, co-curricular program that engages undergraduate students in climate intrapreneurship.
Toktay holds a Ph.D. in operations research from Massachusetts Institute of Technology, an M.S. in industrial engineering from Purdue University, and a B.S. in industrial engineering and mathematics from Boğaziçi University. She joined Georgia Tech in 2005 after serving as faculty at INSEAD business school in Fontainebleau, France.
Since assuming the interim role, Toktay has significantly strengthened BBISS by expanding the faculty leadership team, securing additional funding, establishing seed grant programs that have benefited over 100 researchers across all Colleges, and transforming the Center for Serve-Learn-Sustain into the Center for Sustainable Communities Research and Education.
"Energy and sustainability continue to be top Georgia Tech research priorities, for which we will need new funding strategies," said Tim Lieuwen, executive vice president for Research. "Philanthropy and business partnerships will grow in importance in the coming years. Beril has considerable experience and vision for maximizing these partnerships, which will serve BBISS and the Institute well into the future."
The Brook Byers Institute for Sustainable Systems is one of Georgia Tech’s interdisciplinary research institutes. The vision of BBISS is to grow and mobilize Georgia Tech’s knowledge assets — people and research — to create a sustainable future for all. BBISS is a key partner in the implementation of Georgia Tech’s Sustainability Next 2023-2030 Strategic Plan, a consensus road map to advance Georgia Tech’s vision to address the biggest local, national, and global challenges of our time. BBISS relentlessly serves the public good, catalyzes high-impact research, develops exceptional leaders, and cultivates partnerships that translate knowledge into practice.
"I'm honored to lead BBISS and build on the momentum we've created to date,” Toktay said. “Our vision is to maximize the collective impact of Georgia Tech's remarkable sustainability research community across all colleges and disciplines. By catalyzing collaborative research and connecting our faculty with key external partners and communities, we are positioning Georgia Tech to be a global thought leader in sustainability and to drive meaningful solutions to some of our most pressing environmental and social challenges."
The campus community is invited to a reception celebrating Toktay's appointment on Thursday, May 1, 2025, at 4:30 p.m. at the Collective Food Hall in the Coda building. Contact Susan Ryan for details.
Brent Verrill, Research Communications Program Manager, BBISS
Join us for an engaging discussion including the latest in dewatering technologies, electrochemical recovery, membranes for black liquor separations, and carbon accounting. We will also celebrate the grand opening of RBI's Multi-Phase Pilot Forming system.
Join us for an engaging discussion on De-watering Technologies, Poly Electrolyte Systems, Black Liquor Membranes and Carbon Accounting, as well as enjoying our student poster session. We will also celebrate the grand opening of the Multi-phase Former System.