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      3 Questions: Bridging anthropology and engineering for clean energy in Mongolia

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      In 2021, Michael Short, an associate professor of nuclear science and engineering, approached professor of anthropology Manduhai Buyandelger with an unusual pitch: collaborating on a project to prototype a molten salt heat bank in Mongolia, Buyandelger’s country of origin and place of her scholarship. It was also an invitation to forge a novel partnership between two disciplines that rarely overlap. Developed in collaboration with the National University of Mongolia (NUM), the device was built to provide heat for people in colder climates, and in places where clean energy is a challenge. Buyandelger and Short teamed up to launch Anthro-Engineering Decarbonization at the Million-Person Scale, an initiative intended to advance the heat bank idea in Mongolia, and ultimately demonstrate its potential as a scalable clean heat source in comparably challenging sites around the world. This project received funding from the inaugural MIT Climate and Sustainability Consortium Seed Awards program. In order to fund various components of the project, especially student involvement and additional staff, the project also received support from the MIT Global Seed Fund, New Engineering Education Transformation (NEET), Experiential Learning Office, Vice Provost for International Activities, and d’Arbeloff Fund for Excellence in Education.As part of this initiative, the partners developed a special topic course in anthropology to teach MIT undergraduates about Mongolia’s unique energy and climate challenges, as well as the historical, social, and economic context in which the heat bank would ideally find a place. The class 21A.S01 (Anthro-Engineering: Decarbonization at the Million-Person Scale) prepares MIT students for a January Independent Activities Period (IAP) trip to the Mongolian capital of Ulaanbaatar, where they embed with Mongolian families, conduct research, and collaborate with their peers. Mongolian students also engaged in the project. Anthropology research scientist and lecturer Lauren Bonilla, who has spent the past two decades working in Mongolia, joined to co-teach the class and lead the IAP trips to Mongolia. With the project now in its third year and yielding some promising solutions on the ground, Buyandelger and Bonilla reflect on the challenges for anthropologists of advancing a clean energy technology in a developing nation with a unique history, politics, and culture. Q: Your roles in the molten salt heat bank project mark departures from your typical academic routine. How did you first approach this venture?Buyandelger: As an anthropologist of contemporary religion, politics, and gender in Mongolia, I have had little contact with the hard sciences or building or prototyping technology. What I do best is listening to people and working with narratives. When I first learned about this device for off-the-grid heating, a host of issues came straight to mind right away that are based on socioeconomic and cultural context of the place. The salt brick, which is encased in steel, must be heated to 400 degrees Celsius in a central facility, then driven to people’s homes. Transportation is difficult in Ulaanbaatar, and I worried about road safety when driving the salt brick to gers [traditional Mongolian homes] where many residents live. The device seemed a bit utopian to me, but I realized that this was an amazing educational opportunity: We could use the heat bank as part of an ethnographic project, so students could learn about the everyday lives of people — crucially, in the dead of winter — and how they might respond to this new energy technology in the neighborhoods of Ulaanbaatar.Bonilla: When I first went to Mongolia in the early 2000s as an undergraduate student, the impacts of climate change were already being felt. There had been a massive migration to the capital after a series of terrible weather events that devastated the rural economy. Coal mining had emerged as a vital part of the economy, and I was interested in how people regarded this industry that both provided jobs and damaged the air they breathed. I am trained as a human geographer, which involves seeing how things happening in a local place correspond to things happening at a global scale. Thinking about climate or sustainability from this perspective means making linkages between social life and environmental life. In Mongolia, people associated coal with national progress. Based on historical experience, they had low expectations for interventions brought by outsiders to improve their lives. So my first take on the molten salt project was that this was no silver bullet solution. At the same time, I wanted to see how we could make this a great project-based learning experience for students, getting them to think about the kind of research necessary to see if some version of the molten salt would work.Q: After two years, what lessons have you and the students drawn from both the class and the Ulaanbaatar field trips?Buyandelger: We wanted to make sure MIT students would not go to Mongolia and act like consultants. We taught them anthropological methods so they could understand the experiences of real people and think about how to bring people and new technologies together. The students, from engineering and anthropological and social science backgrounds, became critical thinkers who could analyze how people live in ger districts. When they stay with families in Ulaanbaatar in January, they not only experience the cold and the pollution, but they observe what people do for work, how parents care for their children, how they cook, sleep, and get from one place to another. This enables them to better imagine and test out how these people might utilize the molten salt heat bank in their homes.Bonilla: In class, students learn that interventions like this often fail because the implementation process doesn’t work, or the technology doesn’t meet people’s real needs. This is where anthropology is so important, because it opens up the wider landscape in which you’re intervening. We had really difficult conversations about the professional socialization of engineers and social scientists. Engineers love to work within boxes, but don’t necessarily appreciate the context in which their invention will serve.As a group, we discussed the provocative notion that engineers construct and anthropologists deconstruct. This makes it seem as if engineers are creators, and anthropologists are brought in as add-ons to consult and critique engineers’ creations. Our group conversation concluded that a project such as ours benefits from an iterative back-and-forth between the techno-scientific and humanistic disciplines.Q: So where does the molten salt brick project stand?Bonilla: Our research in Mongolia helped us produce a prototype that can work: Our partners at NUM are developing a hybrid stove that incorporates the molten salt brick. Supervised by instructor Nathan Melenbrink of MIT’s NEET program, our engineering students have been involved in this prototyping as well.The concept is for a family to heat it up using a coal fire once a day and it warms their home overnight. Based on our anthropological research, we believe that this stove would work better than the device as originally conceived. It won’t eliminate coal use in residences, but it will reduce emissions enough to have a meaningful impact on ger districts in Ulaanbaatar. The challenge now is getting funding to NUM so they can test different salt combinations and stove models and employ local blacksmiths to work on the design.This integrated stove/heat bank will not be the ultimate solution to the heating and pollution crisis in Mongolia. But it will be something that can inspire even more ideas. We feel with this project we are planting all kinds of seeds that will germinate in ways we cannot anticipate. It has sparked new relationships between MIT and Mongolian students, and catalyzed engineers to integrate a more humanistic, anthropological perspective in their work.Buyandelger: Our work illustrates the importance of anthropology in responding to the unpredictable and diverse impacts of climate change. Without our ethnographic research — based on participant observation and interviews, led by Dr. Bonilla, — it would have been impossible to see how the prototyping and modifications could be done, and where the molten salt brick could work and what shape it needed to take. This project demonstrates how indispensable anthropology is in moving engineering out of labs and companies and directly into communities.Bonilla: This is where the real solutions for climate change are going to come from. Even though we need solutions quickly, it will also take time for new technologies like molten salt bricks to take root and grow. We don’t know where the outcomes of these experiments will take us. But there’s so much that’s emerging from this project that I feel very hopeful about. More

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      Aligning economic and regulatory frameworks for today’s nuclear reactor technology

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      Liam Hines ’22 didn’t move to Sarasota, Florida, until high school, but he’s a Floridian through and through. He jokes that he’s even got a floral shirt, what he calls a “Florida formal,” for every occasion.Which is why it broke his heart when toxic red algae used to devastate the Sunshine State’s coastline, including at his favorite beach, Caspersen. The outbreak made headline news during his high school years, with the blooms destroying marine wildlife and adversely impacting the state’s tourism-driven economy.In Florida, Hines says, environmental awareness is pretty high because everyday citizens are being directly impacted by climate change. After all, it’s hard not to worry when beautiful white sand beaches are covered in dead fish. Ongoing concerns about the climate cemented Hines’ resolve to pick a career that would have a strong “positive environmental impact.” He chose nuclear, as he saw it as “a green, low-carbon-emissions energy source with a pretty straightforward path to implementation.”

      Liam Hines: Ensuring that nuclear policy keeps up with nuclear technology.

      Undergraduate studies at MITKnowing he wanted a career in the sciences, Hines applied and got accepted to MIT for undergraduate studies in fall 2018. An orientation program hosted by the Department of Nuclear Science and Engineering (NSE) sold him on the idea of pursuing the field. “The department is just a really tight-knit community, and that really appealed to me,” Hines says.During his undergraduate years, Hines realized he needed a job to pay part of his bills. “Instead of answering calls at the dorm front desk or working in the dining halls, I decided I’m going to become a licensed nuclear operator onsite,” he says. “Reactor operations offer so much hands-on experience with real nuclear systems. It doesn’t hurt that it pays better.” Becoming a licensed nuclear reactor operator is hard work, however, involving a year-long training process studying maintenance, operations, and equipment oversight. A bonus: The job, supervising the MIT Nuclear Reactor Laboratory, taught him the fundamentals of nuclear physics and engineering.Always interested in research, Hines got an early start by exploring the regulatory challenges of advanced fusion systems. There have been questions related to licensing requirements and the safety consequences of the onsite radionuclide inventory. Hines’ undergraduate research work involved studying precedent for such fusion facilities and comparing them to experimental facilities such as the Tokamak Fusion Test Reactor at the Princeton Plasma Physics Laboratory.Doctoral focus on legal and regulatory frameworksWhen scientists want to make technologies as safe as possible, they have to do two things in concert: First they evaluate the safety of the technology, and then make sure legal and regulatory structures take into account the evolution of these advanced technologies. Hines is taking such a two-pronged approach to his doctoral work on nuclear fission systems.Under the guidance of Professor Koroush Shirvan, Hines is conducting systems modeling of various reactor cores that include graphite, and simulating operations under long time spans. He then studies radionuclide transport from low-level waste facilities — the consequences of offsite storage after 50 or 100 or even 10,000 years of storage. The work has to make sure to hit safety and engineering margins, but also tread a fine line. “You want to make sure you’re not over-engineering systems and adding undue cost, but also making sure to assess the unique hazards of these advanced technologies as accurately as possible,” Hines says.On a parallel track, under Professor Haruko Wainwright’s advisement, Hines is applying the current science on radionuclide geochemistry to track radionuclide wastes and map their profile for hazards. One of the challenges fission reactors face is that existing low-level waste regulations were fine-tuned to old reactors. Regulations have not kept up: “Now that we have new technologies with new wastes, some of the hazards of the new waste are completely missed by existing standards,” Hines says. He is working to seal these gaps.A philosophy-driven outlookHines is grateful for the dynamic learning environment at NSE. “A lot of the faculty have that go-getter attitude,” he points out, impressed by the entrepreneurial spirit on campus. “It’s made me confident to really tackle the things that I care about.”An ethics class as an undergraduate made Hines realize there were discussions in class he could apply to the nuclear realm, especially when it came to teasing apart the implications of the technology — where the devices would be built and who they would serve. He eventually went on to double-major in NSE and philosophy.The framework style of reading and reasoning involved in studying philosophy is particularly relevant in his current line of work, where he has to extract key points regarding nuclear regulatory issues. Much like philosophy discussions today that involve going over material that has been discussed for centuries and framing them through new perspectives, nuclear regulatory issues too need to take the long view.“In philosophy, we have to insert ourselves into very large conversations. Similarly, in nuclear engineering, you have to understand how to take apart the discourse that’s most relevant to your research and frame it,” Hines says. This technique is especially necessary because most of the time the nuclear regulatory issues might seem like wading in the weeds of nitty-gritty technical matters, but they can have a huge impact on the public and public perception, Hines adds.As for Florida, Hines visits every chance he can get. The red tide still surfaces but not as consistently as it once did. And since he started his job as a nuclear operator in his undergraduate days, Hines has progressed to senior reactor operator. This time around he gets to sign off on the checklists. “It’s much like when I was shift lead at Dunkin’ Donuts in high school,” Hines says, “everyone is kind of doing the same thing, but you get to be in charge for the afternoon.” More

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      Affordable high-tech windows for comfort and energy savings

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      Imagine if the windows of your home didn’t transmit heat. They’d keep the heat indoors in winter and outdoors on a hot summer’s day. Your heating and cooling bills would go down; your energy consumption and carbon emissions would drop; and you’d still be comfortable all year ’round.AeroShield, a startup spun out of MIT, is poised to start manufacturing such windows. Building operations make up 36 percent of global carbon dioxide emissions, and today’s windows are a major contributor to energy inefficiency in buildings. To improve building efficiency, AeroShield has developed a window technology that promises to reduce heat loss by up to 65 percent, significantly reducing energy use and carbon emissions in buildings, and the company just announced the opening of a new facility to manufacture its breakthrough energy-efficient windows.“Our mission is to decarbonize the built environment,” says Elise Strobach SM ’17, PhD ’20, co-founder and CEO of AeroShield. “The availability of affordable, thermally insulating windows will help us achieve that goal while also reducing homeowner’s heating and cooling bills.” According to the U.S. Department of Energy, for most homeowners, 30 percent of that bill results from window inefficiencies.Technology development at MITResearch on AeroShield’s window technology began a decade ago in the MIT lab of Evelyn Wang, Ford Professor of Engineering, now on leave to serve as director of the Advanced Research Projects Agency-Energy (ARPA-E). In late 2014, the MIT team received funding from ARPA-E, and other sponsors followed, including the MIT Energy Initiative through the MIT Tata Center for Technology and Design in 2016.The work focused on aerogels, remarkable materials that are ultra-porous, lighter than a marshmallow, strong enough to support a brick, and an unparalleled barrier to heat flow. Aerogels were invented in the 1930s and used by NASA and others as thermal insulation. The team at MIT saw the potential for incorporating aerogel sheets into windows to keep heat from escaping or entering buildings. But there was one problem: Nobody had been able to make aerogels transparent.An aerogel is made of transparent, loosely connected nanoscale silica particles and is 95 percent air. But an aerogel sheet isn’t transparent because light traveling through it gets scattered by the silica particles.After five years of theoretical and experimental work, the MIT team determined that the key to transparency was having the silica particles both small and uniform in size. This allows light to pass directly through, so the aerogel becomes transparent. Indeed, as long as the particle size is small and uniform, increasing the thickness of an aerogel sheet to achieve greater thermal insulation won’t make it less clear.Teams in the MIT lab looked at various applications for their super-insulating, transparent aerogels. Some focused on improving solar thermal collectors by making the systems more efficient and less expensive. But to Strobach, increasing the thermal efficiency of windows looked especially promising and potentially significant as a means of reducing climate change.The researchers determined that aerogel sheets could be inserted into the gap in double-pane windows, making them more than twice as insulating. The windows could then be manufactured on existing production lines with minor changes, and the resulting windows would be affordable and as wide-ranging in style as the window options available today. Best of all, once purchased and installed, the windows would reduce electricity bills, energy use, and carbon emissions.The impact on energy use in buildings could be considerable. “If we only consider winter, windows in the United States lose enough energy to power over 50 million homes,” says Strobach. “That wasted energy generates about 350 million tons of carbon dioxide — more than is emitted by 76 million cars.” Super-insulating windows could help home and building owners reduce carbon dioxide emissions by gigatons while saving billions in heating and cooling costs.The AeroShield storyIn 2019, Strobach and her MIT colleagues — Aaron Baskerville-Bridges MBA ’20, SM ’20 and Kyle Wilke PhD ’19 — co-founded AeroShield to further develop and commercialize their aerogel-based technology for windows and other applications. And in the subsequent five years, their hard work has attracted attention, recently leading to two major accomplishments.In spring 2024, the company announced the opening of its new pilot manufacturing facility in Waltham, Massachusetts, where the team will be producing, testing, and certifying their first full-size windows and patio doors for initial product launch. The 12,000 square foot facility will significantly expand the company’s capabilities, with cutting-edge aerogel R&D labs, manufacturing equipment, assembly lines, and testing equipment. Says Strobach, “Our pilot facility will supply window and door manufacturers as we launch our first products and will also serve as our R&D headquarters as we develop the next generation of energy-efficient products using transparent aerogels.”Also in spring 2024, AeroShield received a $14.5 million award from ARPA-E’s “Seeding Critical Advances for Leading Energy technologies with Untapped Potential” (SCALEUP) program, which provides new funding to previous ARPA-E awardees that have “demonstrated a viable path to market.” That funding will enable the company to expand its production capacity to tens of thousands, or even hundreds of thousands, of units per year.Strobach also cites two less-obvious benefits of the SCALEUP award.First, the funding is enabling the company to move more quickly on the scale-up phase of their technology development. “We know from our fundamental studies and lab experiments that we can make large-area aerogel sheets that could go in an entry or patio door,” says Elise. “The SCALEUP award allows us to go straight for that vision. We don’t have to do all the incremental sizes of aerogels to prove that we can make a big one. The award provides capital for us to buy the big equipment to make the big aerogel.”Second, the SCALEUP award confirms the viability of the company to other potential investors and collaborators. Indeed, AeroShield recently announced $5 million of additional funding from existing investors Massachusetts Clean Energy Center and MassVentures, as well as new investor MassMutual Ventures. Strobach notes that the company now has investor, engineering, and customer partners.She stresses the importance of partners in achieving AeroShield’s mission. “We know that what we’ve got from a fundamental perspective can change the industry,” she says. “Now we want to go out and do it. With the right partners and at the right pace, we may actually be able to increase the energy efficiency of our buildings early enough to help make a real dent in climate change.” More

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      MIT students combat climate anxiety through extracurricular teams

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      Climate anxiety affects nearly half of young people aged 16-25. Students like second-year Rachel Mohammed find hope and inspiration through her involvement in innovative climate solutions, working alongside peers who share her determination. “I’ve met so many people at MIT who are dedicated to finding climate solutions in ways that I had never imagined, dreamed of, or heard of. That is what keeps me going, and I’m doing my part,” she says.Hydrogen-fueled enginesHydrogen offers the potential for zero or near-zero emissions, with the ability to reduce greenhouse gases and pollution by 29 percent. However, the hydrogen industry faces many challenges related to storage solutions and costs.Mohammed leads the hydrogen team on MIT’s Electric Vehicle Team (EVT), which is dedicated to harnessing hydrogen power to build a cleaner, more sustainable future. EVT is one of several student-led build teams at the Edgerton Center focused on innovative climate solutions. Since its founding in 1992, the Edgerton Center has been a hub for MIT students to bring their ideas to life.Hydrogen is mostly used in large vehicles like trucks and planes because it requires a lot of storage space. EVT is building their second iteration of a motorcycle based on what Mohammed calls a “goofy hypothesis” that you can use hydrogen to power a small vehicle. The team employs a hydrogen fuel cell system, which generates electricity by combining hydrogen with oxygen. However, the technology faces challenges, particularly in storage, which EVT is tackling with innovative designs for smaller vehicles.Presenting at the 2024 World Hydrogen Summit reaffirmed Mohammed’s confidence in this project. “I often encounter skepticism, with people saying it’s not practical. Seeing others actively working on similar initiatives made me realize that we can do it too,” Mohammed says.The team’s first successful track test last October allowed them to evaluate the real-world performance of their hydrogen-powered motorcycle, marking a crucial step in proving the feasibility and efficiency of their design.MIT’s Sustainable Engine Team (SET), founded by junior Charles Yong, uses the combustion method to generate energy with hydrogen. This is a promising technology route for high-power-density applications, like aviation, but Yong believes it hasn’t received enough attention. Yong explains, “In the hydrogen power industry, startups choose fuel cell routes instead of combustion because gas turbine industry giants are 50 years ahead. However, these giants are moving very slowly toward hydrogen due to its not-yet-fully-developed infrastructure. Working under the Edgerton Center allows us to take risks and explore advanced tech directions to demonstrate that hydrogen combustion can be readily available.”Both EVT and SET are publishing their research and providing detailed instructions for anyone interested in replicating their results.Running on sunshineThe Solar Electric Vehicle Team powers a car built from scratch with 100 percent solar energy.The team’s single-occupancy car Nimbus won the American Solar Challenge two years in a row. This year, the team pushed boundaries further with Gemini, a multiple-occupancy vehicle that challenges conventional perceptions of solar-powered cars.Senior Andre Greene explains, “the challenge comes from minimizing how much energy you waste because you work with such little energy. It’s like the equivalent power of a toaster.”Gemini looks more like a regular car and less like a “spaceship,” as NBC’s 1st Look affectionately called Nimbus. “It more resembles what a fully solar-powered car could look like versus the single-seaters. You don’t see a lot of single-seater cars on the market, so it’s opening people’s minds,” says rising junior Tessa Uviedo, team captain.All-electric since 2013The MIT Motorsports team switched to an all-electric powertrain in 2013. Captain Eric Zhou takes inspiration from China, the world’s largest market for electric vehicles. “In China, there is a large government push towards electric, but there are also five or six big companies almost as large as Tesla size, building out these electric vehicles. The competition drives the majority of vehicles in China to become electric.”The team is also switching to four-wheel drive and regenerative braking next year, which reduces the amount of energy needed to run. “This is more efficient and better for power consumption because the torque from the motors is applied straight to the tires. It’s more efficient than having a rear motor that must transfer torque to both rear tires. Also, you’re taking advantage of all four tires in terms of producing grip, while you can only rely on the back tires in a rear-wheel-drive car,” Zhou says.Zhou adds that Motorsports wants to help prepare students for the electric vehicle industry. “A large majority of upperclassmen on the team have worked, or are working, at Tesla or Rivian.”Former Motorsports powertrain lead Levi Gershon ’23, SM ’24 recently founded CRABI Robotics — a fully autonomous marine robotic system designed to conduct in-transit cleaning of marine vessels by removing biofouling, increasing vessels’ fuel efficiency.An Indigenous approach to sustainable rocketsFirst Nations Launch, the all-Indigenous student rocket team, recently won the Grand Prize in the 2024 NASA First Nations Launch High-Power Rocket Competition. Using Indigenous methodologies, this team considers the environment in the materials and methods they employ.“The environmental impact is always something that we consider when we’re making design decisions and operational decisions. We’ve thought about things like biodegradable composites and parachutes,” says rising junior Hailey Polson, team captain. “Aerospace has been a very wasteful industry in the past. There are huge leaps and bounds being made with forward progress in regard to reusable rockets, which is definitely lowering the environmental impact.”Collecting climate change data with autonomous boatsArcturus, the recent first-place winner in design at the 16th Annual RoboBoat Competition, is developing autonomous surface vehicles that can greatly aid in marine research. “The ocean is one of our greatest resources to combat climate change; thus, the accessibility of data will help scientists understand climate patterns and predict future trends. This can help people learn how to prepare for potential disasters and how to reduce each of our carbon footprints,” says Arcturus captain and rising junior Amy Shi.“We are hoping to expand our outreach efforts to incorporate more sustainability-related programs. This can include more interactions with local students to introduce them to how engineering can make a positive impact in the climate space or other similar programs,” Shi says.Shi emphasizes that hope is a crucial force in the battle against climate change. “There are great steps being taken every day to combat this seemingly impending doom we call the climate crisis. It’s important to not give up hope, because this hope is what’s driving the leaps and bounds of innovation happening in the climate community. The mainstream media mostly reports on the negatives, but the truth is there is a lot of positive climate news every day. Being more intentional about where you seek your climate news can really help subside this feeling of doom about our planet.” More

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      Study: EV charging stations boost spending at nearby businesses

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      Charging stations for electric vehicles are essential for cleaning up the transportation sector. A new study by MIT researchers suggests they’re good for business, too.The study found that, in California, opening a charging station boosted annual spending at each nearby business by an average of about $1,500 in 2019 and about $400 between January 2021 and June 2023. The spending bump amounts to thousands of extra dollars annually for nearby businesses, with the increase particularly pronounced for businesses in underresourced areas.The study’s authors hope the research paints a more holistic picture of the benefits of EV charging stations, beyond environmental factors.“These increases are equal to a significant chunk of the cost of installing an EV charger, and I hope this study sheds light on these economic benefits,” says lead author Yunhan Zheng MCP ’21, SM ’21, PhD ’24, a postdoc at the Singapore-MIT Alliance for Research and Technology (SMART). “The findings could also diversify the income stream for charger providers and site hosts, and lead to more informed business models for EV charging stations.”Zheng’s co-authors on the paper, which was published today in Nature Communications, are David Keith, a senior lecturer at the MIT Sloan School of Management; Jinhua Zhao, an MIT professor of cities and transportation; and alumni Shenhao Wang MCP ’17, SM ’17, PhD ’20 and Mi Diao MCP ’06, PhD ’10.Understanding the EV effectIncreasing the number of electric vehicle charging stations is seen as a key prerequisite for the transition to a cleaner, electrified transportation sector. As such, the 2021 U.S. Infrastructure Investment and Jobs Act committed $7.5 billion to build a national network of public electric vehicle chargers across the U.S.But a large amount of private investment will also be needed to make charging stations ubiquitous.“The U.S. is investing a lot in EV chargers and really encouraging EV adoption, but many EV charging providers can’t make enough money at this stage, and getting to profitability is a major challenge,” Zheng says.EV advocates have long argued that the presence of charging stations brings economic benefits to surrounding communities, but Zheng says previous studies on their impact relied on surveys or were small-scale. Her team of collaborators wanted to make advocates’ claims more empirical.For their study, the researchers collected data from over 4,000 charging stations in California and 140,000 businesses, relying on anonymized credit and debit card transactions to measure changes in consumer spending. The researchers used data from 2019 through June of 2023, skipping the year 2020 to minimize the impact of the pandemic.To judge whether charging stations caused customer spending increases, the researchers compared data from businesses within 500 meters of new charging stations before and after their installation. They also analyzed transactions from similar businesses in the same time frame that weren’t near charging stations.Supercharging nearby businessesThe researchers found that installing a charging station boosted annual spending at nearby establishments by an average of 1.4 percent in 2019 and 0.8 percent from January 2021 to June 2023.While that might sound like a small amount per business, it amounts to thousands of dollars in overall consumer spending increases. Specifically, those percentages translate to almost $23,000 in cumulative spending increases in 2019 and about $3,400 per year from 2021 through June 2023.Zheng says the decline in spending increases over the two time periods might be due to a saturation of EV chargers, leading to lower utilization, as well as an overall decrease in spending per business after the Covid-19 pandemic and a reduced number of businesses served by each EV charging station in the second period. Despite this decline, the annual impact of a charging station on all its surrounding businesses would still cover approximately 11.2 percent of the average infrastructure and installation cost of a standard charging station.Through both time frames, the spending increases were highest for businesses within about a football field’s distance from the new stations. They were also significant for businesses in disadvantaged and low-income areas, as designated by California and the Justice40 Initiative.“The positive impacts of EV charging stations on businesses are not constrained solely to some high-income neighborhoods,” Wang says. “It highlights the importance for policymakers to develop EV charging stations in marginalized areas, because they not only foster a cleaner environment, but also serve as a catalyst for enhancing economic vitality.”Zheng believes the findings hold a lesson for charging station developers seeking to improve the profitability of their projects.“The joint gas station and convenience store business model could also be adopted to EV charging stations,” Zheng says. “Traditionally, many gas stations are affiliated with retail store chains, which enables owners to both sell fuel and attract customers to diversify their revenue stream. EV charging providers could consider a similar approach to internalize the positive impact of EV charging stations.”Zheng also says the findings could support the creation of new funding models for charging stations, such as multiple businesses sharing the costs of construction so they can all benefit from the added spending.Those changes could accelerate the creation of charging networks, but Zheng cautions that further research is needed to understand how much the study’s findings can be extrapolated to other areas. She encourages other researchers to study the economic effects of charging stations and hopes future research includes states beyond California and even other countries.“A huge number of studies have focused on retail sales effects from traditional transportation infrastructure, such as rail and subway stations, bus stops, and street configurations,” Zhao says. “This research provides evidence for an important, emerging piece of transportation infrastructure and shows a consistently positive effect on local businesses, paving the way for future research in this area.”The research was supported, in part, by the Singapore-MIT Alliance for Research and Technology (SMART) and the Singapore National Research Foundation. Diao was partially supported by the Natural Science Foundation of Shanghai and the Fundamental Research Funds for the Central Universities of China. More

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      Study of disordered rock salts leads to battery breakthrough

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      For the past decade, disordered rock salt has been studied as a potential breakthrough cathode material for use in lithium-ion batteries and a key to creating low-cost, high-energy storage for everything from cell phones to electric vehicles to renewable energy storage.A new MIT study is making sure the material fulfills that promise.Led by Ju Li, the Tokyo Electric Power Company Professor in Nuclear Engineering and professor of materials science and engineering, a team of researchers describe a new class of partially disordered rock salt cathode, integrated with polyanions — dubbed disordered rock salt-polyanionic spinel, or DRXPS — that delivers high energy density at high voltages with significantly improved cycling stability.“There is typically a trade-off in cathode materials between energy density and cycling stability … and with this work we aim to push the envelope by designing new cathode chemistries,” says Yimeng Huang, a postdoc in the Department of Nuclear Science and Engineering and first author of a paper describing the work published today in Nature Energy. “(This) material family has high energy density and good cycling stability because it integrates two major types of cathode materials, rock salt and polyanionic olivine, so it has the benefits of both.”Importantly, Li adds, the new material family is primarily composed of manganese, an earth-abundant element that is significantly less expensive than elements like nickel and cobalt, which are typically used in cathodes today.“Manganese is at least five times less expensive than nickel, and about 30 times less expensive than cobalt,” Li says. “Manganese is also the one of the keys to achieving higher energy densities, so having that material be much more earth-abundant is a tremendous advantage.”A possible path to renewable energy infrastructureThat advantage will be particularly critical, Li and his co-authors wrote, as the world looks to build the renewable energy infrastructure needed for a low- or no-carbon future.Batteries are a particularly important part of that picture, not only for their potential to decarbonize transportation with electric cars, buses, and trucks, but also because they will be essential to addressing the intermittency issues of wind and solar power by storing excess energy, then feeding it back into the grid at night or on calm days, when renewable generation drops.Given the high cost and relative rarity of materials like cobalt and nickel, they wrote, efforts to rapidly scale up electric storage capacity would likely lead to extreme cost spikes and potentially significant materials shortages.“If we want to have true electrification of energy generation, transportation, and more, we need earth-abundant batteries to store intermittent photovoltaic and wind power,” Li says. “I think this is one of the steps toward that dream.”That sentiment was shared by Gerbrand Ceder, the Samsung Distinguished Chair in Nanoscience and Nanotechnology Research and a professor of materials science and engineering at the University of California at Berkeley.“Lithium-ion batteries are a critical part of the clean energy transition,” Ceder says. “Their continued growth and price decrease depends on the development of inexpensive, high-performance cathode materials made from earth-abundant materials, as presented in this work.”Overcoming obstacles in existing materialsThe new study addresses one of the major challenges facing disordered rock salt cathodes — oxygen mobility.While the materials have long been recognized for offering very high capacity — as much as 350 milliampere-hour per gram — as compared to traditional cathode materials, which typically have capacities of between 190 and 200 milliampere-hour per gram, it is not very stable.The high capacity is contributed partially by oxygen redox, which is activated when the cathode is charged to high voltages. But when that happens, oxygen becomes mobile, leading to reactions with the electrolyte and degradation of the material, eventually leaving it effectively useless after prolonged cycling.To overcome those challenges, Huang added another element — phosphorus — that essentially acts like a glue, holding the oxygen in place to mitigate degradation.“The main innovation here, and the theory behind the design, is that Yimeng added just the right amount of phosphorus, formed so-called polyanions with its neighboring oxygen atoms, into a cation-deficient rock salt structure that can pin them down,” Li explains. “That allows us to basically stop the percolating oxygen transport due to strong covalent bonding between phosphorus and oxygen … meaning we can both utilize the oxygen-contributed capacity, but also have good stability as well.”That ability to charge batteries to higher voltages, Li says, is crucial because it allows for simpler systems to manage the energy they store.“You can say the quality of the energy is higher,” he says. “The higher the voltage per cell, then the less you need to connect them in series in the battery pack, and the simpler the battery management system.”Pointing the way to future studiesWhile the cathode material described in the study could have a transformative impact on lithium-ion battery technology, there are still several avenues for study going forward.Among the areas for future study, Huang says, are efforts to explore new ways to fabricate the material, particularly for morphology and scalability considerations.“Right now, we are using high-energy ball milling for mechanochemical synthesis, and … the resulting morphology is non-uniform and has small average particle size (about 150 nanometers). This method is also not quite scalable,” he says. “We are trying to achieve a more uniform morphology with larger particle sizes using some alternate synthesis methods, which would allow us to increase the volumetric energy density of the material and may allow us to explore some coating methods … which could further improve the battery performance. The future methods, of course, should be industrially scalable.”In addition, he says, the disordered rock salt material by itself is not a particularly good conductor, so significant amounts of carbon — as much as 20 weight percent of the cathode paste — were added to boost its conductivity. If the team can reduce the carbon content in the electrode without sacrificing performance, there will be higher active material content in a battery, leading to an increased practical energy density.“In this paper, we just used Super P, a typical conductive carbon consisting of nanospheres, but they’re not very efficient,” Huang says. “We are now exploring using carbon nanotubes, which could reduce the carbon content to just 1 or 2 weight percent, which could allow us to dramatically increase the amount of the active cathode material.”Aside from decreasing carbon content, making thick electrodes, he adds, is yet another way to increase the practical energy density of the battery. This is another area of research that the team is working on.“This is only the beginning of DRXPS research, since we only explored a few chemistries within its vast compositional space,” he continues. “We can play around with different ratios of lithium, manganese, phosphorus, and oxygen, and with various combinations of other polyanion-forming elements such as boron, silicon, and sulfur.”With optimized compositions, more scalable synthesis methods, better morphology that allows for uniform coatings, lower carbon content, and thicker electrodes, he says, the DRXPS cathode family is very promising in applications of electric vehicles and grid storage, and possibly even in consumer electronics, where the volumetric energy density is very important.This work was supported with funding from the Honda Research Institute USA Inc. and the Molecular Foundry at Lawrence Berkeley National Laboratory, and used resources of the National Synchrotron Light Source II at Brookhaven National Laboratory and the Advanced Photon Source at Argonne National Laboratory.  More

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      MIT engineers’ new theory could improve the design and operation of wind farms

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      The blades of propellers and wind turbines are designed based on aerodynamics principles that were first described mathematically more than a century ago. But engineers have long realized that these formulas don’t work in every situation. To compensate, they have added ad hoc “correction factors” based on empirical observations.Now, for the first time, engineers at MIT have developed a comprehensive, physics-based model that accurately represents the airflow around rotors even under extreme conditions, such as when the blades are operating at high forces and speeds, or are angled in certain directions. The model could improve the way rotors themselves are designed, but also the way wind farms are laid out and operated. The new findings are described today in the journal Nature Communications, in an open-access paper by MIT postdoc Jaime Liew, doctoral student Kirby Heck, and Michael Howland, the Esther and Harold E. Edgerton Assistant Professor of Civil and Environmental Engineering.“We’ve developed a new theory for the aerodynamics of rotors,” Howland says. This theory can be used to determine the forces, flow velocities, and power of a rotor, whether that rotor is extracting energy from the airflow, as in a wind turbine, or applying energy to the flow, as in a ship or airplane propeller. “The theory works in both directions,” he says.Because the new understanding is a fundamental mathematical model, some of its implications could potentially be applied right away. For example, operators of wind farms must constantly adjust a variety of parameters, including the orientation of each turbine as well as its rotation speed and the angle of its blades, in order to maximize power output while maintaining safety margins. The new model can provide a simple, speedy way of optimizing those factors in real time.“This is what we’re so excited about, is that it has immediate and direct potential for impact across the value chain of wind power,” Howland says.Modeling the momentumKnown as momentum theory, the previous model of how rotors interact with their fluid environment — air, water, or otherwise — was initially developed late in the 19th century. With this theory, engineers can start with a given rotor design and configuration, and determine the maximum amount of power that can be derived from that rotor — or, conversely, if it’s a propeller, how much power is needed to generate a given amount of propulsive force.Momentum theory equations “are the first thing you would read about in a wind energy textbook, and are the first thing that I talk about in my classes when I teach about wind power,” Howland says. From that theory, physicist Albert Betz calculated in 1920 the maximum amount of energy that could theoretically be extracted from wind. Known as the Betz limit, this amount is 59.3 percent of the kinetic energy of the incoming wind.But just a few years later, others found that the momentum theory broke down “in a pretty dramatic way” at higher forces that correspond to faster blade rotation speeds or different blade angles, Howland says. It fails to predict not only the amount, but even the direction of changes in thrust force at higher rotation speeds or different blade angles: Whereas the theory said the force should start going down above a certain rotation speed or blade angle, experiments show the opposite — that the force continues to increase. “So, it’s not just quantitatively wrong, it’s qualitatively wrong,” Howland says.The theory also breaks down when there is any misalignment between the rotor and the airflow, which Howland says is “ubiquitous” on wind farms, where turbines are constantly adjusting to changes in wind directions. In fact, in an earlier paper in 2022, Howland and his team found that deliberately misaligning some turbines slightly relative to the incoming airflow within a wind farm significantly improves the overall power output of the wind farm by reducing wake disturbances to the downstream turbines.In the past, when designing the profile of rotor blades, the layout of wind turbines in a farm, or the day-to-day operation of wind turbines, engineers have relied on ad hoc adjustments added to the original mathematical formulas, based on some wind tunnel tests and experience with operating wind farms, but with no theoretical underpinnings.Instead, to arrive at the new model, the team analyzed the interaction of airflow and turbines using detailed computational modeling of the aerodynamics. They found that, for example, the original model had assumed that a drop in air pressure immediately behind the rotor would rapidly return to normal ambient pressure just a short way downstream. But it turns out, Howland says, that as the thrust force keeps increasing, “that assumption is increasingly inaccurate.”And the inaccuracy occurs very close to the point of the Betz limit that theoretically predicts the maximum performance of a turbine — and therefore is just the desired operating regime for the turbines. “So, we have Betz’s prediction of where we should operate turbines, and within 10 percent of that operational set point that we think maximizes power, the theory completely deteriorates and doesn’t work,” Howland says.Through their modeling, the researchers also found a way to compensate for the original formula’s reliance on a one-dimensional modeling that assumed the rotor was always precisely aligned with the airflow. To do so, they used fundamental equations that were developed to predict the lift of three-dimensional wings for aerospace applications.The researchers derived their new model, which they call a unified momentum model, based on theoretical analysis, and then validated it using computational fluid dynamics modeling. In followup work not yet published, they are doing further validation using wind tunnel and field tests.Fundamental understandingOne interesting outcome of the new formula is that it changes the calculation of the Betz limit, showing that it’s possible to extract a bit more power than the original formula predicted. Although it’s not a significant change — on the order of a few percent — “it’s interesting that now we have a new theory, and the Betz limit that’s been the rule of thumb for a hundred years is actually modified because of the new theory,” Howland says. “And that’s immediately useful.” The new model shows how to maximize power from turbines that are misaligned with the airflow, which the Betz limit cannot account for.The aspects related to controlling both individual turbines and arrays of turbines can be implemented without requiring any modifications to existing hardware in place within wind farms. In fact, this has already happened, based on earlier work from Howland and his collaborators two years ago that dealt with the wake interactions between turbines in a wind farm, and was based on the existing, empirically based formulas.“This breakthrough is a natural extension of our previous work on optimizing utility-scale wind farms,” he says, because in doing that analysis, they saw the shortcomings of the existing methods for analyzing the forces at work and predicting power produced by wind turbines. “Existing modeling using empiricism just wasn’t getting the job done,” he says.In a wind farm, individual turbines will sap some of the energy available to neighboring turbines, because of wake effects. Accurate wake modeling is important both for designing the layout of turbines in a wind farm, and also for the operation of that farm, determining moment to moment how to set the angles and speeds of each turbine in the array.Until now, Howland says, even the operators of wind farms, the manufacturers, and the designers of the turbine blades had no way to predict how much the power output of a turbine would be affected by a given change such as its angle to the wind without using empirical corrections. “That’s because there was no theory for it. So, that’s what we worked on here. Our theory can directly tell you, without any empirical corrections, for the first time, how you should actually operate a wind turbine to maximize its power,” he says.Because the fluid flow regimes are similar, the model also applies to propellers, whether for aircraft or ships, and also for hydrokinetic turbines such as tidal or river turbines. Although they didn’t focus on that aspect in this research, “it’s in the theoretical modeling naturally,” he says.The new theory exists in the form of a set of mathematical formulas that a user could incorporate in their own software, or as an open-source software package that can be freely downloaded from GitHub. “It’s an engineering model developed for fast-running tools for rapid prototyping and control and optimization,” Howland says. “The goal of our modeling is to position the field of wind energy research to move more aggressively in the development of the wind capacity and reliability necessary to respond to climate change.”The work was supported by the National Science Foundation and Siemens Gamesa Renewable Energy. More

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      More durable metals for fusion power reactors

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      For many decades, nuclear fusion power has been viewed as the ultimate energy source. A fusion power plant could generate carbon-free energy at a scale needed to address climate change. And it could be fueled by deuterium recovered from an essentially endless source — seawater.Decades of work and billions of dollars in research funding have yielded many advances, but challenges remain. To Ju Li, the TEPCO Professor in Nuclear Science and Engineering and a professor of materials science and engineering at MIT, there are still two big challenges. The first is to build a fusion power plant that generates more energy than is put into it; in other words, it produces a net output of power. Researchers worldwide are making progress toward meeting that goal.The second challenge that Li cites sounds straightforward: “How do we get the heat out?” But understanding the problem and finding a solution are both far from obvious.Research in the MIT Energy Initiative (MITEI) includes development and testing of advanced materials that may help address those challenges, as well as many other challenges of the energy transition. MITEI has multiple corporate members that have been supporting MIT’s efforts to advance technologies required to harness fusion energy.The problem: An abundance of helium, a destructive forceKey to a fusion reactor is a superheated plasma — an ionized gas — that’s reacting inside a vacuum vessel. As light atoms in the plasma combine to form heavier ones, they release fast neutrons with high kinetic energy that shoot through the surrounding vacuum vessel into a coolant. During this process, those fast neutrons gradually lose their energy by causing radiation damage and generating heat. The heat that’s transferred to the coolant is eventually used to raise steam that drives an electricity-generating turbine.The problem is finding a material for the vacuum vessel that remains strong enough to keep the reacting plasma and the coolant apart, while allowing the fast neutrons to pass through to the coolant. If one considers only the damage due to neutrons knocking atoms out of position in the metal structure, the vacuum vessel should last a full decade. However, depending on what materials are used in the fabrication of the vacuum vessel, some projections indicate that the vacuum vessel will last only six to 12 months. Why is that? Today’s nuclear fission reactors also generate neutrons, and those reactors last far longer than a year.The difference is that fusion neutrons possess much higher kinetic energy than fission neutrons do, and as they penetrate the vacuum vessel walls, some of them interact with the nuclei of atoms in the structural material, giving off particles that rapidly turn into helium atoms. The result is hundreds of times more helium atoms than are present in a fission reactor. Those helium atoms look for somewhere to land — a place with low “embedding energy,” a measure that indicates how much energy it takes for a helium atom to be absorbed. As Li explains, “The helium atoms like to go to places with low helium embedding energy.” And in the metals used in fusion vacuum vessels, there are places with relatively low helium embedding energy — namely, naturally occurring openings called grain boundaries.Metals are made up of individual grains inside which atoms are lined up in an orderly fashion. Where the grains come together there are gaps where the atoms don’t line up as well. That open space has relatively low helium embedding energy, so the helium atoms congregate there. Worse still, helium atoms have a repellent interaction with other atoms, so the helium atoms basically push open the grain boundary. Over time, the opening grows into a continuous crack, and the vacuum vessel breaks.That congregation of helium atoms explains why the structure fails much sooner than expected based just on the number of helium atoms that are present. Li offers an analogy to illustrate. “Babylon is a city of a million people. But the claim is that 100 bad persons can destroy the whole city — if all those bad persons work at the city hall.” The solution? Give those bad persons other, more attractive places to go, ideally in their own villages.To Li, the problem and possible solution are the same in a fusion reactor. If many helium atoms go to the grain boundary at once, they can destroy the metal wall. The solution? Add a small amount of a material that has a helium embedding energy even lower than that of the grain boundary. And over the past two years, Li and his team have demonstrated — both theoretically and experimentally — that their diversionary tactic works. By adding nanoscale particles of a carefully selected second material to the metal wall, they’ve found they can keep the helium atoms that form from congregating in the structurally vulnerable grain boundaries in the metal.Looking for helium-absorbing compoundsTo test their idea, So Yeon Kim ScD ’23 of the Department of Materials Science and Engineering and Haowei Xu PhD ’23 of the Department of Nuclear Science and Engineering acquired a sample composed of two materials, or “phases,” one with a lower helium embedding energy than the other. They and their collaborators then implanted helium ions into the sample at a temperature similar to that in a fusion reactor and watched as bubbles of helium formed. Transmission electron microscope images confirmed that the helium bubbles occurred predominantly in the phase with the lower helium embedding energy. As Li notes, “All the damage is in that phase — evidence that it protected the phase with the higher embedding energy.”Having confirmed their approach, the researchers were ready to search for helium-absorbing compounds that would work well with iron, which is often the principal metal in vacuum vessel walls. “But calculating helium embedding energy for all sorts of different materials would be computationally demanding and expensive,” says Kim. “We wanted to find a metric that is easy to compute and a reliable indicator of helium embedding energy.”They found such a metric: the “atomic-scale free volume,” which is basically the maximum size of the internal vacant space available for helium atoms to potentially settle. “This is just the radius of the largest sphere that can fit into a given crystal structure,” explains Kim. “It is a simple calculation.” Examination of a series of possible helium-absorbing ceramic materials confirmed that atomic free volume correlates well with helium embedding energy. Moreover, many of the ceramics they investigated have higher free volume, thus lower embedding energy, than the grain boundaries do.However, in order to identify options for the nuclear fusion application, the screening needed to include some other factors. For example, in addition to the atomic free volume, a good second phase must be mechanically robust (able to sustain a load); it must not get very radioactive with neutron exposure; and it must be compatible — but not too cozy — with the surrounding metal, so it disperses well but does not dissolve into the metal. “We want to disperse the ceramic phase uniformly in the bulk metal to ensure that all grain boundary regions are close to the dispersed ceramic phase so it can provide protection to those regions,” says Li. “The two phases need to coexist, so the ceramic won’t either clump together or totally dissolve in the iron.”Using their analytical tools, Kim and Xu examined about 50,000 compounds and identified 750 potential candidates. Of those, a good option for inclusion in a vacuum vessel wall made mainly of iron was iron silicate.Experimental testingThe researchers were ready to examine samples in the lab. To make the composite material for proof-of-concept demonstrations, Kim and collaborators dispersed nanoscale particles of iron silicate into iron and implanted helium into that composite material. She took X-ray diffraction (XRD) images before and after implanting the helium and also computed the XRD patterns. The ratio between the implanted helium and the dispersed iron silicate was carefully controlled to allow a direct comparison between the experimental and computed XRD patterns. The measured XRD intensity changed with the helium implantation exactly as the calculations had predicted. “That agreement confirms that atomic helium is being stored within the bulk lattice of the iron silicate,” says Kim.To follow up, Kim directly counted the number of helium bubbles in the composite. In iron samples without the iron silicate added, grain boundaries were flanked by many helium bubbles. In contrast, in the iron samples with the iron silicate ceramic phase added, helium bubbles were spread throughout the material, with many fewer occurring along the grain boundaries. Thus, the iron silicate had provided sites with low helium-embedding energy that lured the helium atoms away from the grain boundaries, protecting those vulnerable openings and preventing cracks from opening up and causing the vacuum vessel to fail catastrophically.The researchers conclude that adding just 1 percent (by volume) of iron silicate to the iron walls of the vacuum vessel will cut the number of helium bubbles in half and also reduce their diameter by 20 percent — “and having a lot of small bubbles is OK if they’re not in the grain boundaries,” explains Li.Next stepsThus far, Li and his team have gone from computational studies of the problem and a possible solution to experimental demonstrations that confirm their approach. And they’re well on their way to commercial fabrication of components. “We’ve made powders that are compatible with existing commercial 3D printers and are preloaded with helium-absorbing ceramics,” says Li. The helium-absorbing nanoparticles are well dispersed and should provide sufficient helium uptake to protect the vulnerable grain boundaries in the structural metals of the vessel walls. While Li confirms that there’s more scientific and engineering work to be done, he, along with Alexander O’Brien PhD ’23 of the Department of Nuclear Science and Engineering and Kang Pyo So, a former postdoc in the same department, have already developed a startup company that’s ready to 3D print structural materials that can meet all the challenges faced by the vacuum vessel inside a fusion reactor.This research was supported by Eni S.p.A. through the MIT Energy Initiative. Additional support was provided by a Kwajeong Scholarship; the U.S. Department of Energy (DOE) Laboratory Directed Research and Development program at Idaho National Laboratory; U.S. DOE Lawrence Livermore National Laboratory; and Creative Materials Discovery Program through the National Research Foundation of Korea. More