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      in Energy

      At Climate Grand Challenges showcase event, an exploration of how to accelerate breakthrough solutions

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      On the eve of Earth Day, more than 300 faculty, researchers, students, government officials, and industry leaders gathered in the Samberg Conference Center, along with thousands more who tuned in online, to celebrate MIT’s first-ever Climate Grand Challenges and the five most promising concepts to emerge from the two-year competition.

      The event began with a climate policy conversation between MIT President L. Rafael Reif and Special Presidential Envoy for Climate John Kerry, followed by presentations from each of the winning flagship teams, and concluded with an expert panel that explored pathways for moving from ideas to impact at scale as quickly as possible.

      “In 2020, when we launched the Climate Grand Challenges, we wanted to focus the daring creativity and pioneering expertise of the MIT community on the urgent problem of climate change,” said President Reif in kicking off the event. “Together these flagship projects will define a transformative new research agenda at MIT, one that has the potential to make meaningful contributions to the global climate response.”

      Reif and Kerry discussed multiple aspects of the climate crisis, including mitigation, adaptation, and the policies and strategies that can help the world avert the worst consequences of climate change and make the United States a leader again in bringing technology into commercial use. Referring to the accelerated wartime research effort that helped turn the tide in World War II, which included work conducted at MIT, Kerry said, “We need about five Manhattan Projects, frankly.”

      “People are now sensing a much greater urgency to finding solutions — new technology — and taking to scale some of the old technologies,” Kerry said. “There are things that are happening that I think are exciting, but the problem is it’s not happening fast enough.”

      Strategies for taking technology from the lab to the marketplace were the basis for the final portion of the event. The panel was moderated by Alicia Barton, president and CEO of FirstLight Power, and included Manish Bapna, president and CEO of the Natural Resources Defense Council; Jack Little, CEO and co-founder of MathWorks; Arati Prabhakar, president of Actuate and former head of the Defense Advanced Research Projects Agency; and Katie Rae, president and managing director of The Engine. The discussion touched upon the importance of marshaling the necessary resources and building the cross-sector partnerships required to scale the technologies being developed by the flagship teams and to deliver them to the world in time to make a difference. 

      “MIT doesn’t sit on its hands ever, and innovation is central to its founding,” said Rae. “The students coming out of MIT at every level, along with the professors, have been committed to these challenges for a long time and therefore will have a big impact. These flagships have always been in process, but now we have an extraordinary moment to commercialize these projects.”

      The panelists weighed in on how to change the mindset around finance, policy, business, and community adoption to scale massive shifts in energy generation, transportation, and other major carbon-emitting industries. They stressed the importance of policies that address the economic, equity, and public health impacts of climate change and of reimagining supply chains and manufacturing to grow and distribute these technologies quickly and affordably. 

      “We are embarking on five adventures, but we do not know yet, cannot know yet, where these projects will take us,” said Maria Zuber, MIT’s vice president for research. “These are powerful and promising ideas. But each one will require focused effort, creative and interdisciplinary teamwork, and sustained commitment and support if they are to become part of the climate and energy revolution that the world urgently needs. This work begins now.” 

      Zuber called for investment from philanthropists and financiers, and urged companies, governments, and others to join this all-of-humanity effort. Associate Provost for International Activities Richard Lester echoed this message in closing the event. 

      “Every one of us needs to put our shoulder to the wheel at the points where our leverage is maximized — where we can do what we’re best at,” Lester said. “For MIT, Climate Grand Challenges is one of those maximum leverage points.” More

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      in Environment

      Using plant biology to address climate change

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      On April 11, MIT announced five multiyear flagship projects in the first-ever Climate Grand Challenges, a new initiative to tackle complex climate problems and deliver breakthrough solutions to the world as quickly as possible. This article is the fourth in a five-part series highlighting the most promising concepts to emerge from the competition and the interdisciplinary research teams behind them.

      The impact of our changing climate on agriculture and food security — and how contemporary agriculture contributes to climate change — is at the forefront of MIT’s multidisciplinary project “Revolutionizing agriculture with low-emissions, resilient crops.” The project The project is one of five flagship winners in the Climate Grand Challenges competition, and brings together researchers from the departments of Biology, Biological Engineering, Chemical Engineering, and Civil and Environmental Engineering.

      “Our team’s research seeks to address two connected challenges: first, the need to reduce the greenhouse gas emissions produced by agricultural fertilizer; second, the fact that the yields of many current agricultural crops will decrease, due to the effects of climate change on plant metabolism,” says the project’s faculty lead, Christopher Voigt, the Daniel I.C. Wang Professor in MIT’s Department of Biological Engineering. “We are pursuing six interdisciplinary projects that are each key to our overall goal of developing low-emissions methods for fertilizing plants that are bioengineered to be more resilient and productive in a changing climate.”

      Whitehead Institute members Mary Gehring and Jing-Ke Weng, plant biologists who are also associate professors in MIT’s Department of Biology, will lead two of those projects.

      Promoting crop resilience

      For most of human history, climate change occurred gradually, over hundreds or thousands of years. That pace allowed plants to adapt to variations in temperature, precipitation, and atmospheric composition. However, human-driven climate change has occurred much more quickly, and crop plants have suffered: Crop yields are down in many regions, as is seed protein content in cereal crops.

      “If we want to ensure an abundant supply of nutritious food for the world, we need to develop fundamental mechanisms for bioengineering a wide variety of crop plants that will be both hearty and nutritious in the face of our changing climate,” says Gehring. In her previous work, she has shown that many aspects of plant reproduction and seed development are controlled by epigenetics — that is, by information outside of the DNA sequence. She has been using that knowledge and the research methods she has developed to identify ways to create varieties of seed-producing plants that are more productive and resilient than current food crops.

      But plant biology is complex, and while it is possible to develop plants that integrate robustness-enhancing traits by combining dissimilar parental strains, scientists are still learning how to ensure that the new traits are carried forward from one generation to the next. “Plants that carry the robustness-enhancing traits have ‘hybrid vigor,’ and we believe that the perpetuation of those traits is controlled by epigenetics,” Gehring explains. “Right now, some food crops, like corn, can be engineered to benefit from hybrid vigor, but those traits are not inherited. That’s why farmers growing many of today’s most productive varieties of corn must purchase and plant new batches of seeds each year. Moreover, many important food crops have not yet realized the benefits of hybrid vigor.”

      The project Gehring leads, “Developing Clonal Seed Production to Fix Hybrid Vigor,” aims to enable food crop plants to create seeds that are both more robust and genetically identical to the parent — and thereby able to pass beneficial traits from generation to generation.

      The process of clonal (or asexual) production of seeds that are genetically identical to the maternal parent is called apomixis. Gehring says, “Because apomixis is present in 400 flowering plant species — about 1 percent of flowering plant species — it is probable that genes and signaling pathways necessary for apomixis are already present within crop plants. Our challenge is to tweak those genes and pathways so that the plant switches reproduction from sexual to asexual.”

      The project will leverage the fact that genes and pathways related to autonomous asexual development of the endosperm — a seed’s nutritive tissue — exist in the model plant Arabidopsis thaliana. In previous work on Arabidopsis, Gehring’s lab researched a specific gene that, when misregulated, drives development of an asexual endosperm-like material. “Normally, that seed would not be viable,” she notes. “But we believe that by epigenetic tuning of the expression of additional relevant genes, we will enable the plant to retain that material — and help achieve apomixis.”

      If Gehring and her colleagues succeed in creating a gene-expression “formula” for introducing endosperm apomixis into a wide range of crop plants, they will have made a fundamental and important achievement. Such a method could be applied throughout agriculture to create and perpetuate new crop breeds able to withstand their changing environments while requiring less fertilizer and fewer pesticides.

      Creating “self-fertilizing” crops

      Roughly a quarter of greenhouse gas (GHG) emissions in the United States are a product of agriculture. Fertilizer production and use accounts for one third of those emissions and includes nitrous oxide, which has heat-trapping capacity 298-fold stronger than carbon dioxide, according to a 2018 Frontiers in Plant Science study. Most artificial fertilizer production also consumes huge quantities of natural gas and uses minerals mined from nonrenewable resources. After all that, much of the nitrogen fertilizer becomes runoff that pollutes local waterways. For those reasons, this Climate Grand Challenges flagship project aims to greatly reduce use of human-made fertilizers.

      One tantalizing approach is to cultivate cereal crop plants — which account for about 75 percent of global food production — capable of drawing nitrogen from metabolic interactions with bacteria in the soil. Whitehead Institute’s Weng leads an effort to do just that: genetically bioengineer crops such as corn, rice, and wheat to, essentially, create their own fertilizer through a symbiotic relationship with nitrogen-fixing microbes.

      “Legumes such as bean and pea plants can form root nodules through which they receive nitrogen from rhizobia bacteria in exchange for carbon,” Weng explains. “This metabolic exchange means that legumes release far less greenhouse gas — and require far less investment of fossil energy — than do cereal crops, which use a huge portion of the artificially produced nitrogen fertilizers employed today.

      “Our goal is to develop methods for transferring legumes’ ‘self-fertilizing’ capacity to cereal crops,” Weng says. “If we can, we will revolutionize the sustainability of food production.”

      The project — formally entitled “Mimicking legume-rhizobia symbiosis for fertilizer production in cereals” — will be a multistage, five-year effort. It draws on Weng’s extensive studies of metabolic evolution in plants and his identification of molecules involved in formation of the root nodules that permit exchanges between legumes and nitrogen-fixing bacteria. It also leverages his expertise in reconstituting specific signaling and metabolic pathways in plants.

      Weng and his colleagues will begin by deciphering the full spectrum of small-molecule signaling processes that occur between legumes and rhizobium bacteria. Then they will genetically engineer an analogous system in nonlegume crop plants. Next, using state-of-the-art metabolomic methods, they will identify which small molecules excreted from legume roots prompt a nitrogen/carbon exchange from rhizobium bacteria. Finally, the researchers will genetically engineer the biosynthesis of those molecules in the roots of nonlegume plants and observe their effect on the rhizobium bacteria surrounding the roots.

      While the project is complex and technically challenging, its potential is staggering. “Focusing on corn alone, this could reduce the production and use of nitrogen fertilizer by 160,000 tons,” Weng notes. “And it could halve the related emissions of nitrous oxide gas.” More

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      in Energy

      Developing electricity-powered, low-emissions alternatives to carbon-intensive industrial processes

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      On April 11, 2022, MIT announced five multiyear flagship projects in the first-ever Climate Grand Challenges, a new initiative to tackle complex climate problems and deliver breakthrough solutions to the world as quickly as possible. This is the second article in a five-part series highlighting the most promising concepts to emerge from the competition, and the interdisciplinary research teams behind them.

      One of the biggest leaps that humankind could take to drastically lower greenhouse gas emissions globally would be the complete decarbonization of industry. But without finding low-cost, environmentally friendly substitutes for industrial materials, the traditional production of steel, cement, ammonia, and ethylene will continue pumping out billions of tons of carbon annually; these sectors alone are responsible for at least one third of society’s global greenhouse gas emissions. 

      A major problem is that industrial manufacturers, whose success depends on reliable, cost-efficient, and large-scale production methods, are too heavily invested in processes that have historically been powered by fossil fuels to quickly switch to new alternatives. It’s a machine that kicked on more than 100 years ago, and which MIT electrochemical engineer Yet-Ming Chiang says we can’t shut off without major disruptions to the world’s massive supply chain of these materials. What’s needed, Chiang says, is a broader, collaborative clean energy effort that takes “targeted fundamental research, all the way through to pilot demonstrations that greatly lowers the risk for adoption of new technology by industry.”

      This would be a new approach to decarbonization of industrial materials production that relies on largely unexplored but cleaner electrochemical processes. New production methods could be optimized and integrated into the industrial machine to make it run on low-cost, renewable electricity in place of fossil fuels. 

      Recognizing this, Chiang, the Kyocera Professor in the Department of Materials Science and Engineering, teamed with research collaborator Bilge Yildiz, the Breene M. Kerr Professor of Nuclear Science and Engineering and professor of materials science and engineering, with key input from Karthish Manthiram, visiting professor in the Department of Chemical Engineering, to submit a project proposal to the MIT Climate Grand Challenges. Their plan: to create an innovation hub on campus that would bring together MIT researchers individually investigating decarbonization of steel, cement, ammonia, and ethylene under one roof, combining research equipment and directly collaborating on new methods to produce these four key materials.

      Many researchers across MIT have already signed on to join the effort, including Antoine Allanore, associate professor of metallurgy, who specializes in the development of sustainable materials and manufacturing processes, and Elsa Olivetti, the Esther and Harold E. Edgerton Associate Professor in the Department of Materials Science and Engineering, who is an expert in materials economics and sustainability. Other MIT faculty currently involved include Fikile Brushett, Betar Gallant, Ahmed Ghoniem, William Green, Jeffrey Grossman, Ju Li, Yuriy Román-Leshkov, Yang Shao-Horn, Robert Stoner, Yogesh Surendranath, Timothy Swager, and Kripa Varanasi.

      “The team we brought together has the expertise needed to tackle these challenges, including electrochemistry — using electricity to decarbonize these chemical processes — and materials science and engineering, process design and scale-up technoeconomic analysis, and system integration, which is all needed for this to go out from our labs to the field,” says Yildiz.

      Selected from a field of more than 100 proposals, their Center for Electrification and Decarbonization of Industry (CEDI) will be the first such institute worldwide dedicated to testing and scaling the most innovative and promising technologies in sustainable chemicals and materials. CEDI will work to facilitate rapid translation of lab discoveries into affordable, scalable industry solutions, with potential to offset as much as 15 percent of greenhouse gas emissions. The team estimates that some CEDI projects already underway could be commercialized within three years.

      “The real timeline is as soon as possible,” says Chiang.

      To achieve CEDI’s ambitious goals, a physical location is key, staffed with permanent faculty, as well as undergraduates, graduate students, and postdocs. Yildiz says the center’s success will depend on engaging student researchers to carry forward with research addressing the biggest ongoing challenges to decarbonization of industry.

      “We are training young scientists, students, on the learned urgency of the problem,” says Yildiz. “We empower them with the skills needed, and even if an individual project does not find the implementation in the field right away, at least, we would have trained the next generation that will continue to go after them in the field.”

      Chiang’s background in electrochemistry showed him how the efficiency of cement production could benefit from adopting clean electricity sources, and Yildiz’s work on ethylene, the source of plastic and one of industry’s most valued chemicals, has revealed overlooked cost benefits to switching to electrochemical processes with less expensive starting materials. With industry partners, they hope to continue these lines of fundamental research along with Allanore, who is focused on electrifying steel production, and Manthiram, who is developing new processes for ammonia. Olivetti will focus on understanding risks and barriers to implementation. This multilateral approach aims to speed up the timeline to industry adoption of new technologies at the scale needed for global impact.

      “One of the points of emphasis in this whole center is going to be applying technoeconomic analysis of what it takes to be successful at a technical and economic level, as early in the process as possible,” says Chiang.

      The impact of large-scale industry adoption of clean energy sources in these four key areas that CEDI plans to target first would be profound, as these sectors are currently responsible for 7.5 billion tons of emissions annually. There is the potential for even greater impact on emissions as new knowledge is applied to other industrial products beyond the initial four targets of steel, cement, ammonia, and ethylene. Meanwhile, the center will stand as a hub to attract new industry, government stakeholders, and research partners to collaborate on urgently needed solutions, both newly arising and long overdue.

      When Chiang and Yildiz first met to discuss ideas for MIT Climate Grand Challenges, they decided they wanted to build a climate research center that functioned unlike any other to help pivot large industry toward decarbonization. Beyond considering how new solutions will impact industry’s bottom line, CEDI will also investigate unique synergies that could arise from the electrification of industry, like processes that would create new byproducts that could be the feedstock to other industry processes, reducing waste and increasing efficiencies in the larger system. And because industry is so good at scaling, those added benefits would be widespread, finally replacing century-old technologies with critical updates designed to improve production and markedly reduce industry’s carbon footprint sooner rather than later.

      “Everything we do, we’re going to try to do with urgency,” Chiang says. “The fundamental research will be done with urgency, and the transition to commercialization, we’re going to do with urgency.” More

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      in Energy

      MIT announces five flagship projects in first-ever Climate Grand Challenges competition

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      MIT today announced the five flagship projects selected in its first-ever Climate Grand Challenges competition. These multiyear projects will define a dynamic research agenda focused on unraveling some of the toughest unsolved climate problems and bringing high-impact, science-based solutions to the world on an accelerated basis.

      Representing the most promising concepts to emerge from the two-year competition, the five flagship projects will receive additional funding and resources from MIT and others to develop their ideas and swiftly transform them into practical solutions at scale.

      “Climate Grand Challenges represents a whole-of-MIT drive to develop game-changing advances to confront the escalating climate crisis, in time to make a difference,” says MIT President L. Rafael Reif. “We are inspired by the creativity and boldness of the flagship ideas and by their potential to make a significant contribution to the global climate response. But given the planet-wide scale of the challenge, success depends on partnership. We are eager to work with visionary leaders in every sector to accelerate this impact-oriented research, implement serious solutions at scale, and inspire others to join us in confronting this urgent challenge for humankind.”

      Brief descriptions of the five Climate Grand Challenges flagship projects are provided below.

      Bringing Computation to the Climate Challenge

      This project leverages advances in artificial intelligence, machine learning, and data sciences to improve the accuracy of climate models and make them more useful to a variety of stakeholders — from communities to industry. The team is developing a digital twin of the Earth that harnesses more data than ever before to reduce and quantify uncertainties in climate projections.

      Research leads: Raffaele Ferrari, the Cecil and Ida Green Professor of Oceanography in the Department of Earth, Atmospheric and Planetary Sciences, and director of the Program in Atmospheres, Oceans, and Climate; and Noelle Eckley Selin, director of the Technology and Policy Program and professor with a joint appointment in the Institute for Data, Systems, and Society and the Department of Earth, Atmospheric and Planetary Sciences

      Center for Electrification and Decarbonization of Industry

      This project seeks to reinvent and electrify the processes and materials behind hard-to-decarbonize industries like steel, cement, ammonia, and ethylene production. A new innovation hub will perform targeted fundamental research and engineering with urgency, pushing the technological envelope on electricity-driven chemical transformations.

      Research leads: Yet-Ming Chiang, the Kyocera Professor of Materials Science and Engineering, and Bilge Yıldız, the Breene M. Kerr Professor in the Department of Nuclear Science and Engineering and professor in the Department of Materials Science and Engineering

      Preparing for a new world of weather and climate extremes

      This project addresses key gaps in knowledge about intensifying extreme events such as floods, hurricanes, and heat waves, and quantifies their long-term risk in a changing climate. The team is developing a scalable climate-change adaptation toolkit to help vulnerable communities and low-carbon energy providers prepare for these extreme weather events.

      Research leads: Kerry Emanuel, the Cecil and Ida Green Professor of Atmospheric Science in the Department of Earth, Atmospheric and Planetary Sciences and co-director of the MIT Lorenz Center; Miho Mazereeuw, associate professor of architecture and urbanism in the Department of Architecture and director of the Urban Risk Lab; and Paul O’Gorman, professor in the Program in Atmospheres, Oceans, and Climate in the Department of Earth, Atmospheric and Planetary Sciences

      The Climate Resilience Early Warning System

      The CREWSnet project seeks to reinvent climate change adaptation with a novel forecasting system that empowers underserved communities to interpret local climate risk, proactively plan for their futures incorporating resilience strategies, and minimize losses. CREWSnet will initially be demonstrated in southwestern Bangladesh, serving as a model for similarly threatened regions around the world.

      Research leads: John Aldridge, assistant leader of the Humanitarian Assistance and Disaster Relief Systems Group at MIT Lincoln Laboratory, and Elfatih Eltahir, the H.M. King Bhumibol Professor of Hydrology and Climate in the Department of Civil and Environmental Engineering

      Revolutionizing agriculture with low-emissions, resilient crops

      This project works to revolutionize the agricultural sector with climate-resilient crops and fertilizers that have the ability to dramatically reduce greenhouse gas emissions from food production.

      Research lead: Christopher Voigt, the Daniel I.C. Wang Professor in the Department of Biological Engineering

      “As one of the world’s leading institutions of research and innovation, it is incumbent upon MIT to draw on our depth of knowledge, ingenuity, and ambition to tackle the hard climate problems now confronting the world,” says Richard Lester, MIT associate provost for international activities. “Together with collaborators across industry, finance, community, and government, the Climate Grand Challenges teams are looking to develop and implement high-impact, path-breaking climate solutions rapidly and at a grand scale.”

      The initial call for ideas in 2020 yielded nearly 100 letters of interest from almost 400 faculty members and senior researchers, representing 90 percent of MIT departments. After an extensive evaluation, 27 finalist teams received a total of $2.7 million to develop comprehensive research and innovation plans. The projects address four broad research themes:

      To select the winning projects, research plans were reviewed by panels of international experts representing relevant scientific and technical domains as well as experts in processes and policies for innovation and scalability.

      “In response to climate change, the world really needs to do two things quickly: deploy the solutions we already have much more widely, and develop new solutions that are urgently needed to tackle this intensifying threat,” says Maria Zuber, MIT vice president for research. “These five flagship projects exemplify MIT’s strong determination to bring its knowledge and expertise to bear in generating new ideas and solutions that will help solve the climate problem.”

      “The Climate Grand Challenges flagship projects set a new standard for inclusive climate solutions that can be adapted and implemented across the globe,” says MIT Chancellor Melissa Nobles. “This competition propels the entire MIT research community — faculty, students, postdocs, and staff — to act with urgency around a worsening climate crisis, and I look forward to seeing the difference these projects can make.”

      “MIT’s efforts on climate research amid the climate crisis was a primary reason that I chose to attend MIT, and remains a reason that I view the Institute favorably. MIT has a clear opportunity to be a thought leader in the climate space in our own MIT way, which is why CGC fits in so well,” says senior Megan Xu, who served on the Climate Grand Challenges student committee and is studying ways to make the food system more sustainable.

      The Climate Grand Challenges competition is a key initiative of “Fast Forward: MIT’s Climate Action Plan for the Decade,” which the Institute published in May 2021. Fast Forward outlines MIT’s comprehensive plan for helping the world address the climate crisis. It consists of five broad areas of action: sparking innovation, educating future generations, informing and leveraging government action, reducing MIT’s own climate impact, and uniting and coordinating all of MIT’s climate efforts. More

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      in Energy

      Leveraging science and technology against the world’s top problems

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      Looking back on nearly a half-century at MIT, Richard K. Lester, associate provost and Japan Steel Industry Professor, sees a “somewhat eccentric professional trajectory.”

      But while his path has been irregular, there has been a clearly defined through line, Lester says: the emergence of new science and new technologies, the potential of these developments to shake up the status quo and address some of society’s most consequential problems, and what the outcomes might mean for America’s place in the world.

      Perhaps no assignment in Lester’s portfolio better captures this theme than the new MIT Climate Grand Challenges competition. Spearheaded by Lester and Maria Zuber, MIT vice president for research, and launched at the height of the pandemic in summer 2020, this initiative is designed to mobilize the entire MIT research community around tackling “the really hard, challenging problems currently standing in the way of an effective global response to the climate emergency,” says Lester. “The focus is on those problems where progress requires developing and applying frontier knowledge in the natural and social sciences and cutting-edge technologies. This is the MIT community swinging for the fences in areas where we have a comparative advantage.”This is a passion project for him, not least because it has engaged colleagues from nearly all of MIT’s departments. After nearly 100 initial ideas were submitted by more than 300 faculty, 27 teams were named finalists and received funding to develop comprehensive research and innovation plans in such areas as decarbonizing complex industries; risk forecasting and adaptation; advancing climate equity; and carbon removal, management, and storage. In April, a small subset of this group will become multiyear flagship projects, augmenting the work of existing MIT units that are pursuing climate research. Lester is sunny in the face of these extraordinarily complex problems. “This is a bottom-up effort with exciting proposals, and where the Institute is collectively committed — it’s MIT at its best.”

      Nuclear to the core

      This initiative carries a particular resonance for Lester, who remains deeply engaged in nuclear engineering. “The role of nuclear energy is central and will need to become even more central if we’re to succeed in addressing the climate challenge,” he says. He also acknowledges that for nuclear energy technologies — both fission and fusion — to play a vital role in decarbonizing the economy, they must not just win “in the court of public opinion, but in the marketplace,” he says. “Over the years, my research has sought to elucidate what needs to be done to overcome these obstacles.”

      In fact, Lester has been campaigning for much of his career for a U.S. nuclear innovation agenda, a commitment that takes on increased urgency as the contours of the climate crisis sharpen. He argues for the rapid development and testing of nuclear technologies that can complement the renewable but intermittent energy sources of sun and wind. Whether powerful, large-scale, molten-salt-cooled reactors or small, modular, light water reactors, nuclear batteries or promising new fusion projects, U.S. energy policy must embrace nuclear innovation, says Lester, or risk losing the high-stakes race for a sustainable future.

      Chancing into a discipline

      Lester’s introduction to nuclear science was pure happenstance.

      Born in the English industrial city of Leeds, he grew up in a musical family and played piano, violin, and then viola. “It was a big part of my life,” he says, and for a time, music beckoned as a career. He tumbled into a chemical engineering concentration at Imperial College, London, after taking a job in a chemical factory following high school. “There’s a certain randomness to life, and in my case, it’s reflected in my choice of major, which had a very large impact on my ultimate career.”

      In his second year, Lester talked his way into running a small experiment in the university’s research reactor, on radiation effects in materials. “I got hooked, and began thinking of studying nuclear engineering.” But there were few graduate programs in British universities at the time. Then serendipity struck again. The instructor of Lester’s single humanities course at Imperial had previously taught at MIT, and suggested Lester take a look at the nuclear program there. “I will always be grateful to him (and, indirectly, to MIT’s Humanities program) for opening my eyes to the existence of this institution where I’ve spent my whole adult life,” says Lester.

      He arrived at MIT with the notion of mitigating the harms of nuclear weapons. It was a time when the nuclear arms race “was an existential threat in everyone’s life,” he recalls. He targeted his graduate studies on nuclear proliferation. But he also encountered an electrifying study by MIT meteorologist Jule Charney. “Professor Charney produced one of the first scientific assessments of the effects on climate of increasing CO2 concentrations in the atmosphere, with quantitative estimates that have not fundamentally changed in 40 years.”

      Lester shifted directions. “I came to MIT to work on nuclear security, but stayed in the nuclear field because of the contributions that it can and must make in addressing climate change,” he says.

      Research and policy

      His path forward, Lester believed, would involve applying his science and technology expertise to critical policy problems, grounded in immediate, real-world concerns, and aiming for broad policy impacts. Even as a member of NSE, he joined with colleagues from many MIT departments to study American industrial practices and what was required to make them globally competitive, and then founded MIT’s Industrial Performance Center (IPC). Working at the IPC with interdisciplinary teams of faculty and students on the sources of productivity and innovation, his research took him to many countries at different stages of industrialization, including China, Taiwan, Japan, and Brazil.

      Lester’s wide-ranging work yielded books (including the MIT Press bestseller “Made in America”), advisory positions with governments, corporations, and foundations, and unexpected collaborations. “My interests were always fairly broad, and being at MIT made it possible to team up with world-leading scholars and extraordinary students not just in nuclear engineering, but in many other fields such as political science, economics, and management,” he says.

      Forging cross-disciplinary ties and bringing creative people together around a common goal proved a valuable skill as Lester stepped into positions of ever-greater responsibility at the Institute. He didn’t exactly relish the prospect of a desk job, though. “I religiously avoided administrative roles until I felt I couldn’t keep avoiding them,” he says.

      Today, as associate provost, he tends to MIT’s international activities — a daunting task given increasing scrutiny of research universities’ globe-spanning research partnerships and education of foreign students. But even in the midst of these consuming chores, Lester remains devoted to his home department. “Being a nuclear engineer is a central part of my identity,” he says.

      To students entering the nuclear field nearly 50 years after he did, who are understandably “eager to fix everything that seems wrong immediately,” he has a message: “Be patient. The hard things, the ones that are really worth doing, will take a long time to do.” Putting the climate crisis behind us will take two generations, Lester believes. Current students will start the job, but it will also take the efforts of their children’s generation before it is done.  “So we need you to be energetic and creative, of course, but whatever you do we also need you to be patient and to have ‘stick-to-itiveness’ — and maybe also a moral compass that our generation has lacked.” More

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      MIT Energy Conference focuses on climate’s toughest challenges

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      This year’s MIT Energy Conference, the largest student-led event of its kind, included keynote talks and panels that tackled some of the thorniest remaining challenges in the global effort to cut back on climate-altering emissions. These include the production of construction materials such as steel and cement, and the role of transportation including aviation and shipping. While the challenges are formidable, approaches incorporating methods such as fusion, heat pumps, energy efficiency, and the use of hydrogen hold promise, participants said.

      The two-day conference, held on March 31 and April 1 for more than 900 participants, included keynote lectures, 14 panel discussions, a fireside chat, networking events, and more. The event this year included the final round of the annual MIT Climate and Energy Prize, whose winning team receives $100,000 and other support. The prize, awarded since 2007, has led to the creation of more than 220 companies and $1.1 billion in investments.

      This year’s winner is a project that hopes to provide an innovative, efficient waterless washing machine aimed at the vast majority of the world’s people, who still do laundry by hand.

      “A truly consequential moment in history”

      In his opening keynote address Fatih Birol, executive director of the International Energy Agency, noted that this year’s conference was taking place during the unprovoked invasion of Ukraine by Russia, a leading gas and oil exporter. As a result, “global oil markets are going through a major turmoil,” he said.

      He said that Russian oil exports are expected to drop by 3 million barrels a day, and that international efforts to release reserves and promote increased production elsewhere will help, but will not suffice. “We have to look to other measures” to make up the shortfall, he said, noting that his agency has produced a 10-point plan of measures to help reduce global demand for oil.

      Europe gets 45 percent of its natural gas from Russia, and the agency also has developed a 10-point plan to help alleviate expected shortages there, including measures to improve energy efficiency in homes and industries, promote renewable heating sources, and postpone retirement of some nuclear plants. But he emphasized that “our goals to reach our climate targets should not be yet another victim of Mr. Putin and his allies.”  Unfortunately, Birol said, “I see that addressing climate change is sliding down in the policy agenda of many governments.”

      But he sees reasons for optimism as well, in terms of the feasibility of achieving the global emissions reduction target, agreed to by countries representing 80 percent of the global economy, of reaching net zero carbon dioxide emissions by 2050. The IEA has developed a roadmap for the entire energy sector to get there, which is now used by many governments as a benchmark, according to Birol.

      In addition, the trend is already clear, he said. “More than 90 percent of all power plants installed in the world [last year] were renewable energy,” mainly solar and wind. And 10 percent of cars sold worldwide last year, and 20 percent in Europe, were electric cars. “Please remember that in 2019 it was only 2 percent!” he said. He also predicted that “nuclear is going to make a comeback in many countries,” both in terms of large plants and newer small modular reactors.

      Birol said that “I hope that the current crisis gives governments the impetus to address the energy security concerns, to reach our climate goals, and … [to] choose the right direction at this very important turning point.”

      The conference’s second day began with keynote talks by Gina McCarthy, national climate advisor at the White House Office of Domestic Climate Policy, and Maria Zuber, MIT’s vice president for research. In her address, Zuber said, “This conference comes at a truly consequential moment in history — a moment that puts into stark relief the enormous risks created by our current fossil-fuel based energy system — risks we cannot continue to accept.”

      She added that “time is not on our side.” To meet global commitments for limiting climate impacts, the world needs to reduce emissions by about half by 2030, and get to net zero by 2050. “In other words, we need to transform our entire global energy system in a few decades,” she said. She cited MIT’s “Fast Forward” climate action plan, issued last year, as presenting the two tracks that the world needs to pursue simultaneously: going as far as possible, as fast as possible, with the tools that exist now, while also innovating and investing in new ideas, technologies, practices, and institutions that may be needed to reach the net-zero goal.

      On the first track, she said, citing an IEA report, “from here until 2040, we can get most of the emissions reductions we need with technologies that are currently available or on the verge of becoming commercially available.” These include electrifying and boosting efficiency in buildings, industry, and transportation; increasing the portion of electricity coming from emissions-free sources; and investing in new infrastructure such as electric vehicle charging stations.

      But more than that is needed, she pointed out. For example, the amount of methane that leaks away into the atmosphere from fossil fuel operations is equivalent to all the natural gas used in Europe’s power sector, Zuber said. Recovering and selling that methane can dramatically reduce global methane emissions, often at little or no cost.

      For the longer run, “we need track-two solutions to decarbonize tough industries like aviation, shipping, chemicals, concrete, and steel,” and to remove carbon dioxide from the atmosphere. She described some of the promising technologies that are in the pipeline. Fusion, for example, has moved from being a scientific challenge to an engineering problem whose solution seems well underway, she said.

      Another important area is food-related systems, which currently account for a third of all global emissions. For example, fertilizer production uses a very energy-intensive process, but work on plants engineered to fix nitrogen directly could make a significant dent.

      These and several other advanced research areas may not all pan out, but some undoubtedly will, and will help curb climate change as well as create new jobs and reduce pollution.

      Though the problems we face are complex, they are not insurmountable, Zuber said. “We don’t need a miracle. What we need is to move along the two tracks I’ve outlined with determination, ingenuity, and fierce urgency.”

      The promise and challenges of hydrogen

      Other conference speakers took on some of the less-discussed but crucial areas that also need to be addressed in order to limit global warming to 1.5 degrees. Heavy transportation, and aviation in particular, have been considered especially challenging. In his keynote address, Glenn Llewellyn, vice president for zero-emission aircraft at Airbus, outlined several approaches his company is working on to develop competitive midrange alternative airliners by 2035 that use either batteries or fuel cells powered by hydrogen. The early-stage designs demonstrate that, contrary to some projections, there is a realistic pathway to weaning that industry from its present reliance on fossil fuel, chiefly kerosene.

      Hydrogen has real potential as an aviation fuel, he said, either directly for use in fuel cells for power or burned directly for propulsion, or indirectly as a feedstock for synthetic fuels. Both are being studied by the company, he said, including a hybrid model that uses both hydrogen fuel cells and hydrogen-fueled jet engines. The company projects a range of 2,000 nautical miles for a jet carrying 200 to 300 passengers, he said — all with no direct emissions and no contrails.

      But this vision will not be practical, Llewellyn said, unless economies of scale help to significantly lower the cost of hydrogen production. “Hydrogen is at the hub of aviation decarbonization,” he said. But that kind of price reduction seems quite feasible, he said, given that other major industries are also seriously looking at the use of hydrogen for their own decarbonization plans, including the production of steel and cement.

      Such uses were the subject of a panel discussion entitled “Deploying the Hydrogen Economy.” Hydrogen production technology exists, but not nearly at the scale that’s needed, which is about 500 million tons a year, pointed out moderator Dharik Mallapragada of the MIT Energy Initiative.

      Yet in some applications, the use of hydrogen both reduces emissions and is economically competitive. Preeti Pande of Plug Power said that her company, which produces hydrogen fuel cells, has found a significant market in an unexpected place: fork lifts, used in warehouses and factories worldwide. It turns out that replacing current battery-operated versions with fuel cell versions is a win-win for the companies that use them, saving money while helping to meet decarbonization goals.

      Lindsay Ashby of Avangrid Renewables said that the company has installed fuel-cell buses in Barcelona that run entirely on hydrogen generated by solar panels. The company is also building a 100-megawatt solar facility to produce hydrogen for the production of fertilizer, another major industry in need of decarbonization because of its large emissions footprint. And Brett Perleman of the Center for Houston’s Future said of his city that “we’re already a hydrogen hub today, just not green hydrogen” since the gas is currently mostly produced as a byproduct of fossil fuels. But that is changing rapidly, he said, and Houston, along with several other cities, aims to be a center of activity for hydrogen produced from renewable, non-carbon-emitting sources. They aim to be producing 1,000 tons a day by 2028, “and I think we’ll end up exceeding that,” he said.

      For industries that can switch to renewably generated electricity, that is typically the best choice, Perleman said. “But for those that can’t, hydrogen is a great option,” and that includes aviation, shipping, and rail. “The big oil companies all have plans in place” to develop clean hydrogen production, he said. “It’s not just a dream, but a reality.”

      For shipping, which tends to rely on bunker fuel, a particularly high-emissions fossil fuel, another potential option could be a new generation of small nuclear plants, said Jeff Navin of Terrapower, a company currently developing such units. “Finding replacements for coal, oil, or natural gas for industrial purposes is very hard,” he said, but often what these processes require is consistent high heat, which nuclear can deliver, as long as costs and regulatory issues can be resolved.  

      MIT professor of nuclear engineering Jacopo Buongiorno pointed out that the primary reasons for delays and cost overruns in nuclear plants have had to do with issues at the construction site, many of which could be alleviated by having smaller, factory-built modular plants, or by building multiple units at a time of a standardized design. If the government would take on the nuclear waste disposal, as some other countries have done, then nuclear power could play an important part in the decarbonization of many industries, he said.

      Student-led startups

      The two-day conference concluded with the final round of the annual MIT Climate and Energy Prize, consisting of the five finalist teams presenting brief pitches for their startup company ideas, followed by questions from the panel of judges. This year’s finalists included a team called Muket, dedicated to finding ways of reducing methane emissions from cattle and dairy farms. Feed additives or other measures could cut the emissions by 50 percent, the team estimates.

      A team called Ivu Biologics described a system for incorporating nitrogen-fixing microbes into the coatings of seeds, thereby reducing the need for added fertilizers, whose production is a major greenhouse gas source. The company is making use of seed-coating technology developed at MIT over the last few years. Another team, called Mesophase, also based on MIT-developed technology, aims to replace the condensers used in power plants and other industrial systems with much more efficient versions, thus increasing the energy output from a given amount of fuel or other heat source.

      A team called TerraTrade aims to facilitate the adoption of power purchase agreements by companies, institutions and governments, by acting as a kind of broker to create and administer such agreements, making it easier for even smaller entities to take part in these plans, which help to enable rapid development of renewable fossil-fuel-free energy production.

      The grand prize of $100,000 was awarded to a team called Ultropia, which is developing a combined clothes washer and drier that uses ultrasound instead of water for its cleaning. The system does use a small amount of water, but this can be recycled, making these usable even in areas where water availability is limited. The devices could have a great impact on the estimated 6 billion people in the world today who are still limited to washing clothes by hand, the team says, and because the machines would be so efficient, they would require very little energy to run — a significant improvement over the wider adoption of conventional washers and driers. More

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      in Environment

      Ocean vital signs

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      Without the ocean, the climate crisis would be even worse than it is. Each year, the ocean absorbs billions of tons of carbon from the atmosphere, preventing warming that greenhouse gas would otherwise cause. Scientists estimate about 25 to 30 percent of all carbon released into the atmosphere by both human and natural sources is absorbed by the ocean.

      “But there’s a lot of uncertainty in that number,” says Ryan Woosley, a marine chemist and a principal research scientist in the Department of Earth, Atmospheric and Planetary Sciences (EAPS) at MIT. Different parts of the ocean take in different amounts of carbon depending on many factors, such as the season and the amount of mixing from storms. Current models of the carbon cycle don’t adequately capture this variation.

      To close the gap, Woosley and a team of other MIT scientists developed a research proposal for the MIT Climate Grand Challenges competition — an Institute-wide campaign to catalyze and fund innovative research addressing the climate crisis. The team’s proposal, “Ocean Vital Signs,” involves sending a fleet of sailing drones to cruise the oceans taking detailed measurements of how much carbon the ocean is really absorbing. Those data would be used to improve the precision of global carbon cycle models and improve researchers’ ability to verify emissions reductions claimed by countries.

      “If we start to enact mitigation strategies—either through removing CO2 from the atmosphere or reducing emissions — we need to know where CO2 is going in order to know how effective they are,” says Woosley. Without more precise models there’s no way to confirm whether observed carbon reductions were thanks to policy and people, or thanks to the ocean.

      “So that’s the trillion-dollar question,” says Woosley. “If countries are spending all this money to reduce emissions, is it enough to matter?”

      In February, the team’s Climate Grand Challenges proposal was named one of 27 finalists out of the almost 100 entries submitted. From among this list of finalists, MIT will announce in April the selection of five flagship projects to receive further funding and support.

      Woosley is leading the team along with Christopher Hill, a principal research engineer in EAPS. The team includes physical and chemical oceanographers, marine microbiologists, biogeochemists, and experts in computational modeling from across the department, in addition to collaborators from the Media Lab and the departments of Mathematics, Aeronautics and Astronautics, and Electrical Engineering and Computer Science.

      Today, data on the flux of carbon dioxide between the air and the oceans are collected in a piecemeal way. Research ships intermittently cruise out to gather data. Some commercial ships are also fitted with sensors. But these present a limited view of the entire ocean, and include biases. For instance, commercial ships usually avoid storms, which can increase the turnover of water exposed to the atmosphere and cause a substantial increase in the amount of carbon absorbed by the ocean.

      “It’s very difficult for us to get to it and measure that,” says Woosley. “But these drones can.”

      If funded, the team’s project would begin by deploying a few drones in a small area to test the technology. The wind-powered drones — made by a California-based company called Saildrone — would autonomously navigate through an area, collecting data on air-sea carbon dioxide flux continuously with solar-powered sensors. This would then scale up to more than 5,000 drone-days’ worth of observations, spread over five years, and in all five ocean basins.

      Those data would be used to feed neural networks to create more precise maps of how much carbon is absorbed by the oceans, shrinking the uncertainties involved in the models. These models would continue to be verified and improved by new data. “The better the models are, the more we can rely on them,” says Woosley. “But we will always need measurements to verify the models.”

      Improved carbon cycle models are relevant beyond climate warming as well. “CO2 is involved in so much of how the world works,” says Woosley. “We’re made of carbon, and all the other organisms and ecosystems are as well. What does the perturbation to the carbon cycle do to these ecosystems?”

      One of the best understood impacts is ocean acidification. Carbon absorbed by the ocean reacts to form an acid. A more acidic ocean can have dire impacts on marine organisms like coral and oysters, whose calcium carbonate shells and skeletons can dissolve in the lower pH. Since the Industrial Revolution, the ocean has become about 30 percent more acidic on average.

      “So while it’s great for us that the oceans have been taking up the CO2, it’s not great for the oceans,” says Woosley. “Knowing how this uptake affects the health of the ocean is important as well.” More

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      in Energy

      Q&A: Climate Grand Challenges finalists on new pathways to decarbonizing industry

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      Note: This is the third article in a four-part interview series highlighting the work of the 27 MIT Climate Grand Challenges finalist teams, which received a total of $2.7 million in startup funding to advance their projects. In April, the Institute will name a subset of the finalists as multiyear flagship projects.

      The industrial sector is the backbone of today’s global economy, yet its activities are among the most energy-intensive and the toughest to decarbonize. Efforts to reach net-zero targets and avert runaway climate change will not succeed without new solutions for replacing sources of carbon emissions with low-carbon alternatives and developing scalable nonemitting applications of hydrocarbons.

      In conversations prepared for MIT News, faculty from three of the teams with projects in the competition’s “Decarbonizing complex industries and processes” category discuss strategies for achieving impact in hard-to-abate sectors, from long-distance transportation and building construction to textile manufacturing and chemical refining. The other Climate Grand Challenges research themes include using data and science to forecast climate-related risk, building equity and fairness into climate solutions, and removing, managing, and storing greenhouse gases. The following responses have been edited for length and clarity.

      Moving toward an all-carbon material approach to building

      Faced with the prospect of building stock doubling globally by 2050, there is a great need for sustainable alternatives to conventional mineral- and metal-based construction materials. Mark Goulthorpe, associate professor in the Department of Architecture, explains the methods behind Carbon >Building, an initiative to develop energy-efficient building materials by reorienting hydrocarbons from current use as fuels to environmentally benign products, creating an entirely new genre of lightweight, all-carbon buildings that could actually drive decarbonization.

      Q: What are all-carbon buildings and how can they help mitigate climate change?

      A: Instead of burning hydrocarbons as fuel, which releases carbon dioxide and other greenhouse gases that contribute to atmospheric pollution, we seek to pioneer a process that uses carbon materially to build at macro scale. New forms of carbon — carbon nanotube, carbon foam, etc. — offer salient properties for building that might effectively displace the current material paradigm. Only hydrocarbons offer sufficient scale to beat out the billion-ton mineral and metal markets, and their perilous impact. Carbon nanotube from methane pyrolysis is of special interest, as it offers hydrogen as a byproduct.

      Q: How will society benefit from the widespread use of all-carbon buildings?

      A: We anticipate reducing costs and timelines in carbon composite buildings, while increasing quality, longevity, and performance, and diminishing environmental impact. Affordability of buildings is a growing problem in all global markets as the cost of labor and logistics in multimaterial assemblies creates a burden that is very detrimental to economic growth and results in overcrowding and urban blight.

      Alleviating these challenges would have huge societal benefits, especially for those in lower income brackets who cannot afford housing, but the biggest benefit would be in drastically reducing the environmental footprint of typical buildings, which account for nearly 40 percent of global energy consumption.

      An all-carbon building sector will not only reduce hydrocarbon extraction, but can produce higher value materials for building. We are looking to rethink the building industry by greatly streamlining global production and learning from the low-labor methods pioneered by composite manufacturing such as wind turbine blades, which are quick and cheap to produce. This technology can improve the sustainability and affordability of buildings — and holds the promise of faster, cheaper, greener, and more resilient modes of dwelling.

      Emissions reduction through innovation in the textile industry

      Collectively, the textile industry is responsible for over 4 billion metric tons of carbon dioxide equivalent per year, or 5 to 10 percent of global greenhouse gas emissions — more than aviation and maritime shipping combined. And the problem is only getting worse with the industry’s rapid growth. Under the current trajectory, consumption is projected to increase 30 percent by 2030, reaching 102 million tons. A diverse group of faculty and researchers led by Gregory Rutledge, the Lammot du Pont Professor in the Department of Chemical Engineering, and Yuly Fuentes-Medel, project manager for fiber technologies and research advisor to the MIT Innovation Initiative, is developing groundbreaking innovations to reshape how textiles are selected, sourced, designed, manufactured, and used, and to create the structural changes required for sustained reductions in emissions by this industry.

      Q: Why has the textile industry been difficult to decarbonize?

      A: The industry currently operates under a linear model that relies heavily on virgin feedstock, at roughly 97 percent, yet recycles or downcycles less than 15 percent. Furthermore, recent trends in “fast fashion” have led to massive underutilization of apparel, such that products are discarded on average after only seven to 10 uses. In an industry with high volume and low margins, replacement technologies must achieve emissions reduction at scale while maintaining performance and economic efficiency.

      There are also technical barriers to adopting circular business models, from the challenge of dealing with products comprising fiber blends and chemical additives to the low maturity of recycling technologies. The environmental impacts of textiles and apparel have been estimated using life cycle analysis, and industry-standard indexes are under development to assess sustainability throughout the life cycle of a product, but information and tools are needed to model how new solutions will alter those impacts and include the consumer as an active player to keep our planet safe. This project seeks to deliver both the new solutions and the tools to evaluate their potential for impact.

      Q: Describe the five components of your program. What is the anticipated timeline for implementing these solutions?

      A: Our plan comprises five programmatic sections, which include (1) enabling a paradigm shift to sustainable materials using nontraditional, carbon-negative polymers derived from biomass and additives that facilitate recycling; (2) rethinking manufacturing with processes to structure fibers and fabrics for performance, waste reduction, and increased material efficiency; (3) designing textiles for value by developing products that are customized, adaptable, and multifunctional, and that interact with their environment to reduce energy consumption; (4) exploring consumer behavior change through human interventions that reduce emissions by encouraging the adoption of new technologies, increased utilization of products, and circularity; and (5) establishing carbon transparency with systems-level analyses that measure the impact of these strategies and guide decision making.

      We have proposed a five-year timeline with annual targets for each project. Conservatively, we estimate our program could reduce greenhouse gas emissions in the industry by 25 percent by 2030, with further significant reductions to follow.

      Tough-to-decarbonize transportation

      Airplanes, transoceanic ships, and freight trucks are critical to transporting people and delivering goods, and the cornerstone of global commerce, manufacturing, and tourism. But these vehicles also emit 3.7 billion tons of carbon dioxide annually and, left unchecked, they could take up a quarter of the remaining carbon budget by 2050. William Green, the Hoyt C. Hottel Professor in the Department Chemical Engineering, co-leads a multidisciplinary team with Steven Barrett, professor of aeronautics and astronautics and director of the MIT Laboratory for Aviation and the Environment, that is working to identify and advance economically viable technologies and policies for decarbonizing heavy duty trucking, shipping, and aviation. The Tough to Decarbonize Transportation research program aims to design and optimize fuel chemistry and production, vehicles, operations, and policies to chart the course to net-zero emissions by midcentury.

      Q: What are the highest priority focus areas of your research program?

      A: Hydrocarbon fuels made from biomass are the least expensive option, but it seems impractical, and probably damaging to the environment, to harvest the huge amount of biomass that would be needed to meet the massive and growing energy demands from these sectors using today’s biomass-to-fuel technology. We are exploring strategies to increase the amount of useful fuel made per ton of biomass harvested, other methods to make low-climate-impact hydrocarbon fuels, such as from carbon dioxide, and ways to make fuels that do not contain carbon at all, such as with hydrogen, ammonia, and other hydrogen carriers.

      These latter zero-carbon options free us from the need for biomass or to capture gigatons of carbon dioxide, so they could be a very good long-term solution, but they would require changing the vehicles significantly, and the construction of new refueling infrastructure, with high capital costs.

      Q: What are the scientific, technological, and regulatory barriers to scaling and implementing potential solutions?

      A: Reimagining an aviation, trucking, and shipping sector that connects the world and increases equity without creating more environmental damage is challenging because these vehicles must operate disconnected from the electrical grid and have energy requirements that cannot be met by batteries alone. Some of the concepts do not even exist in prototype yet, and none of the appealing options have been implemented at anywhere near the scale required.

      In most cases, we do not know the best way to make the fuel, and for new fuels the vehicles and refueling systems all need to be developed. Also, new fuels, or large-scale use of biomass, will introduce new environmental problems that need to be carefully considered, to ensure that decarbonization solutions do not introduce big new problems.

      Perhaps most difficult are the policy, economic, and equity issues. A new long-haul transportation system will be expensive, and everyone will be affected by the increased cost of shipping freight. To have the desired climate impact, the transport system must change in almost every country. During the transition period, we will need both the existing vehicle and fuel system to keep running smoothly, even as a new low-greenhouse system is introduced. We will also examine what policies could make that work and how we can get countries around the world to agree to implement them. More