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    Can US states afford to meet net-zero emissions targets by 2050?

    The Commonwealth of Massachusetts recently passed a climate bill that sets a target of net-zero emissions for the state by the year 2050. The bill is one of several successful legislative efforts in Northeastern states to reduce greenhouse gas emissions by as much as 80 to 100 percent by mid-century. To achieve these ambitious targets — which align with the Paris Agreement’s long-term goal of keeping global warming well below 2 degrees Celsius to avoid the worst impacts of climate change — will require a significant ramp-up of zero-carbon, intermittent, renewable energy technologies.

    Hydropower is a particularly appealing renewable energy option for policymakers in the region; substantial hydro resources available in nearby Quebec could be used to dispatch power to consumers in Northeastern states during periods of low wind and solar generation. But environmental and aesthetic concerns have mobilized communities along proposed hydro transmission line routes to nip that notion in the bud. To stand a chance of overcoming these concerns, policymakers in the U.S. Northeast and Quebec will need to demonstrate compelling benefits to consumers and transmission line abutters alike.

    To that end, researchers at the MIT Joint Program on the Science and Policy of Global Change and MIT Energy Initiative have conducted a study to assess the economic impacts of expanding hydropower transmission capacity from Quebec to the Northeast. Using a unique modeling framework that represents both regional economic behavior and hourly electricity operations, they project these impacts under three scenarios. In each scenario, transmission capacity is expanded by 10, 30, or 50 percent above existing capacity into New York and all New England states starting in 2026, and carbon emissions are capped in alignment with regional climate goals.

    Compared to a reference scenario in which current and projected state renewable energy technology policies are implemented with carbon emissions capped to achieve mid-century regional goals, the researchers estimate that by 2050, electricity imports enabled by these three transmission expansions save the New York state economy 38-40 cents per kilowatt hour (KWh) and the New England economy 30-33 cents per kWh. The results appear in the journal Energy Policy.

    “These economy-wide savings are significantly higher than the cost of the electricity itself,” says Joint Program research scientist Mei Yuan, the lead author of the study. “Moreover, the carbon limits that we impose in these scenarios raise fuel prices enough to make electricity cost-competitive in multiple economic sectors. This accelerates electrification in both New England and New York, particularly between 2030 and 2050.”

    The overall economic impact of the three transmission capacity expansion scenarios is a significantly lower cost of meeting the emissions reduction goals of all states in the region.

    The study is an outgrowth of an Energy Modeling Forum effort, EMF34, which aims to improve understanding of how energy markets affect one another throughout North America. The researchers were supported by sponsors of the MIT Joint Program sponsors and the MIT Energy Initiative Seed Fund Program. More

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    On course to create a fusion power plant

    “There is no lone genius who solves all the problems.”

    Dennis Whyte, director of the Plasma Science and Fusion Center (PSFC), is reflecting on a guiding belief behind his nuclear science and engineering class 22.63 (Principles of Fusion Engineering). He has recently watched his students, working in teams, make their final presentations on how to use fusion technology to create carbon-free fuel for shipping vessels. Since taking on the course over a decade ago, Whyte has moved away from standard lectures, prodding the class to work collectively on finding solutions to “real-world” issues. Over the past years the course, and its collaborative approach to design, has been instrumental in guiding the real future of fusion at the PSFC.

    For decades researchers have explored fusion, the reaction that powers the sun, as a potential source of virtually endless, carbon-free energy on Earth. MIT has studied the process with a series of “Alcator” tokamaks, compact machines that use high magnetic fields to keep the hot plasma inside and away from the walls of a donut-shaped vacuum vessel long enough for fusion to occur. But understanding how plasma affects tokamak materials, and making the plasma dense and hot enough to sustain fusion reactions, has been elusive.

    Incubating fusion machines and design teams

    The second time he taught the course, Whyte was ready for his students to attack problems related to net-energy tokamak operation, necessary to produce substantial and economical power. These problems could not be explored with the PSFC’s Alcator C-Mod tokamak, which maintained fusion in only brief pulses, but they could be studied by a class tasked with designing a fusion device that can operate around the clock.

    Around this time Whyte learned of high-temperature superconducting (HTS) tape, a newly available class of superconducting material that supported creating higher magnetic fields for effectively confining the plasma. It had the potential to surpass the performance of the previous generation of superconductors, like niobium-tin, which was being used in ITER, the burning plasma fusion experiment being built in France. Could the class design a machine that would answer questions about steady-state operation, while taking advantage of this revolutionary product? Furthermore, what if components of the machine could be easily taken out and replaced or altered, making the tokamak flexible for different experiments?

    What the class conceived was a tokamak called “Vulcan.” Whyte calls his students’ efforts “eye-opening,” original enough to produce five peer-reviewed articles for Fusion Engineering and Design. Although the tokamak design was never directly built, its exploration of demountable magnetic coils, made from the new HTS tape, suggested a path for a fusion future.

    Two years later, Whyte started his students down that path. He asked, “What would happen in a device where we try to make 500 megawatts of fusion power — identical to what ITER does — but we use this new HTS technology?”

    With student teams working on separate aspects of the project and coordinating with other groups to create an integrated design, Whyte decided to make the class environment even more collaborative. He invited PSFC fusion experts to contribute. In this “collective community teaching” environment the students expanded on the research from the previous class, creating the basis for HTS magnets and demountable coils.

    As before, the innovations explored resulted in a published paper. The lead author was then-graduate student Brandon Sorbom PhD ’17. He introduced the fusion community to ARC, describe in the article’s title as “a compact, high-field, fusion nuclear science facility and demonstration power plant with demountable magnets.” Because ARC was too large a project to consider building immediately, Whyte and some of his postdocs and students eventually began thinking about how they could study the most important elements of the ARC design in a smaller device.

    Their answer was SPARC, based on the experience gained from designing Vulcan and ARC. This compact, high-field, net fusion energy experiment has become a collaboration between MIT and Commonwealth Fusion Systems (CFS), a Cambridge, Massachusetts-based startup seeded with talent from 22.63. Bob Mumgaard and Dan Brunner, who helped design Vulcan, are in CFS leadership, as is Brandon Sorbom. MIT NSE Assistant Professor Zach Hartwig, who participated as a student in the Vulcan project, has also stayed involved in the SPARC project and developments. 

    The economic question

    The course had become an incubator for researchers interested in using the latest technology to re-imagine how quickly a fusion power plant would be possible. It helped redirect the focus of the PSFC from Alcator C-Mod, which ended operation in 2016, toward SPARC and ARC, and technology innovation. In the process the PSFC, whose fusion program had been largely funded by the U.S. Department of Energy, realized it would also need to expand its research sponsorship to private funding.

    The discussions with the private sector brought home the requirement not just for technical feasibility, but for making fusion an attractive product economically. This inspired Whyte to add an economic constraint to the 2020 22.63 class project, noting “it changes how you think about attacking the design.” Consequently, he expanded the teaching team to include Eric Ingersoll, founder and managing director at LucidCatalyst and TerraPraxis. Together they imagined a novel application and market that could use fusion as an intense carbon-free energy source — international shipping.

    The virtual nature of this year’s course offered the unique chance for a number of students, postdocs, and teachers from Princeton University to join the class as volunteers, with the intent of eventually creating a similarly structured course at Princeton. They integrated with MIT students and instructors into four teams working interdependently to design an onboard method of generating ammonia fuel for ship engines. The device was dubbed “ARCH,” the H standing for Hydrogen. By making innovations to the fusion design, mostly focused on improving materials and heat removal, the team showed they could meet economic targets.

    For MIT graduate student Rachel Bielajew, part of the Systems Integration Team, focusing on the economics of the project provided a very different experience from her other classes and everyday research.

    “It was definitely motivating to have an economic target driving design choices,” she says. “The class also reinforced for me that the pathway to successful fusion reactors is multidisciplinary and there is important research to be done in many fields.”

    Whyte’s teaching journey has been as transformative for him as for his students.

    “If you give young people the time, the tools, and the imaginative space to work together towards meaningful goals — it’s hard to imagine a more powerful force,” he says. “The class and the innovation provided by the collective student effort have changed my worldview, and, I believe, the prospects for fusion energy.” More

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    China’s transition to electric vehicles

    In recent decades, China’s rapid economic growth has enabled more and more consumers to buy their own cars. The result has been improved mobility and the largest automotive market in the world — but also serious urban air pollution, high greenhouse gas emissions, and growing dependence on oil imports.

    To counteract those troubling trends, the Chinese government has imposed policies to encourage the adoption of plug-in electric vehicles (EVs). Since buying an EV costs more than buying a conventional internal combustion engine (ICE) vehicle, in 2009 the government began to provide generous subsidies for EV purchases. But the price differential and the number of buyers were both large, so paying for the subsidies became extremely costly for the government.

    As a result, China’s policymakers planned to phase out the subsidies at the end of 2020 and instead impose a mandate on car manufacturers. Simply stated, the mandate requires that a certain percent of all vehicles sold by a manufacturer each year must be battery-powered. To avoid financial penalties, every year manufacturers must earn a stipulated number of points, which are awarded for each EV produced based on a complex formula that takes into account range, energy efficiency, performance, and more. The requirements get tougher over time, with a goal of having EVs make up 40 percent of all car sales by 2030.

    This move will have a huge impact on the worldwide manufacture of EVs, according to William H. Green, the Hoyt C. Hottel Professor in Chemical Engineering. “This is one of the strongest mandates for electric cars worldwide, and it’s being imposed on the largest car market in the world,” he says. “There will be a gigantic increase in the manufacture of EVs and in the production of batteries for them, driving down the cost of both globally.”

    But what will be the impact of the mandate within China? The transition to EVs will bring many environmental and other benefits. But how much will it cost the nation? In 2016, MIT chemical engineering colleagues Green and then-graduate student I-Yun Lisa Hsieh PhD ’20 decided to find out. Their goal was to examine the mixed impacts of the mandate on all affected factors: battery prices, manufacturing costs, vehicle prices and sales, and the cost to the consumer of owning and operating a car. Based on their results, they could estimate the total societal cost of complying with the mandate in the coming decade. (Note that the Chinese government recently extended subsidy support for EVs for two years due to the Covid-19 pandemic and that this analysis was performed before that change was announced.)

    Looking at battery prices

    “The main reason why EVs are costly is that their batteries are expensive,” says Green. In recent years, battery prices have dropped rapidly, largely due to the “learning effect”: As production volumes increase, manufacturers find ways to improve efficiency, and costs go down. It’s generally assumed that battery prices will continue to decrease as EVs take over more of the car market.

    Using a new modeling approach, Green and Hsieh determined that learning effects will lower costs appreciably for battery production, but not much for the mining and synthesis of critical battery materials. They concluded that the price of the most widely used EV battery technology — the lithium-ion nickel-manganese-cobalt battery — will indeed drop as more are manufactured. But the decline will slow as the price gets closer to the cost of the raw materials in it.

    Using the resulting estimates of battery price, the researchers calculated the extra cost of manufacturing an EV over time and — assuming a standard markup for profit — determined the likely selling price for those cars. In previous work, they had used a variety of data sources and analytical techniques to determine “affordability” for the Chinese population — in other words, the fraction of their income available to spend on buying a car. Based on those findings, they examined the expected impact on car sales in China between 2018 and 2030.

    As a baseline for comparison, the researchers first assumed a “counterfactual” (not true-to-life) scenario — car sales without significant adoption of EVs, so without the new mandate. Under that assumption, annual projected car sales climb to more than 34 million by 2030.

    When the subsidy on EV purchases is eliminated and the mandate is enacted in 2020, total car sales shrink. But thereafter, the growing economy and rising incomes increase consumer purchasing power and drive up the demand for private car ownership. Annual sales are on average 20 percent lower than in the counterfactual scenario, but they’re projected to reach about 30 million by 2030.

    The researchers also projected the breakdown in sales between ICE vehicles and battery EVs at three points in time. According to that analysis, in 2020, EVs make up just 7 percent of the total (1.6 million vehicles). By 2025, that share is up to 21 percent (5.4 million). And by 2030, it’s up to 37 percent (11.2 million) — close to the government’s 40 percent target. Altogether, 66 million EVs are sold between 2020 and 2030.

    Those results also track the split between two types of plug-in EVs: pure battery EVs and hybrid EVs (which are powered by both batteries and gasoline). About twice as many pure battery EVs are sold than hybrid EVs, even though the former are more expensive due to the higher cost of their batteries. “The mandate includes a special preference for cars with a longer range, which means cars with large batteries,” says Green. “So carmakers have a big incentive to manufacture the pure battery EVs and be awarded extra points under the mandate formula.”

    For the consumer, the added cost of owning an EV includes any difference in vehicle expenses over the whole lifetime of the car. To calculate that difference, the researchers quantified the “total cost of ownership,” or TCO, including the purchase cost, fuel cost, and operating and maintenance costs (including insurance) of their two plug-in EVs and an ICE vehicle out to 2030.

    Their results show that before 2020, owning either type of plug-in EV is less costly than owning an ICE vehicle due to the subsidy paid on EV purchases. After the subsidy is removed and the mandate imposed in 2020, owning a hybrid EV is comparable to owning an ICE vehicle. Owning a pure battery EV is more expensive due to its high-cost batteries. Dropping battery prices reduces total ownership cost for both types of EVs, but the pure battery EV remains more expensive out to 2030.

    Cost to society

    The next step for the researchers was to calculate the total cost to China of forcing the adoption of EVs. The basic approach is straightforward: They take the extra TCO for each EV sold in each year, discount that cost to its present value, and multiply the resulting figure by the number of cars sold in that year. (They exclude taxes embedded in the purchase prices of the vehicle, of electricity and gasoline, and so on, as the society will have to pay other taxes to replace that lost revenue.)

    Using that methodology, they calculated the incremental cost to society of each EV sold in each year as well as the extra cost per kilometer driven, assuming that the vehicle has a lifetime of 12 years and is driven 12,500 kilometers each year. The results show that the incremental cost of owning and driving an EV decreases from 2021 to 2030. The cost declines more for pure battery EVs than for hybrid EVs, but the former remain more costly.

    By combining the per-car cost to society with the number of cars sold, the researchers calculated the total extra cost incurred. In their results, the total number of EVs sold in a year more than offsets any decrease in per-vehicle cost, so the incremental cost to society grows. And that cost is sizeable. On average, the transition to EVs forced by the mandate will cost 100 billion yuan per year from 2021 to 2030, which is about 2 percent of the nationwide expenditure in the transport sector every year.

    During the 10 years from 2021-30, the annual societal cost of the transition to almost 40 percent EVs is equivalent to about 0.1 percent of China’s growing gross domestic product. “So the cost to society of forcing the sale of EVs in place of ICE vehicles is significant,” says Hsieh. “People will have far less money in their pockets to spend on other purchases.”

    Other considerations

    Green and Hsieh stress that the high societal cost of the forced EV adoption must be considered in light of the potential benefits to be gained. For example, switching from ICE vehicles to EVs will lower air pollution and associated health costs; reduce carbon dioxide emissions to help mitigate climate change; and reduce reliance on imported petroleum, enhancing the country’s national energy security and balance of payments.

    Hsieh is now working to quantify those benefits so that the team can perform a proper cost-benefit analysis of China’s transition to EVs. Her initial results suggest that the monetized benefits are — like the costs — substantial. “The benefits appear to be the same order of magnitude as the costs,” she says. “It’s so close that we need to be careful to get the numbers right.”

    The researchers cite two other factors that may impact the cost side of the equation. In early 2018, six Chinese megacities with high air pollution began restricting the number of license plates issued for ICE vehicles and charging high fees for them. With their lower-cost, more-abundant “green car plates,” EVs became cost-competitive, and sales soared. To protect Chinese carmakers, the national government recently announced that it plans to end those restrictions. The outcome and its impacts on EV sales remain uncertain. (Again, due to the pandemic, policies restricting car ownership have mostly been relaxed for now.)

    The second caveat concerns how carmakers price their vehicles. The results reported here assume that prices are calculated as they are today: the cost of manufacturing the vehicle plus a certain percentage markup for profit. With the new mandate in place, automakers will need to change their pricing strategy so as to persuade enough buyers to purchase EVs to reach the required fraction. “We don’t know what they’re going to do, but one possibility is that they’ll lower the price of their battery cars and raise the price of their gasoline cars,” says Green. “That way, they can still make their profits while operating within the law.” As an example, he cites how U.S. carmakers responded to Corporate Average Fuel Economy standards by adjusting the relative prices of their low- and high-efficiency vehicles.

    While such a change in Chinese automakers’ pricing strategy would lower the price of EVs, it would also push up average car prices overall, because the total car sales mix is dominated by ICE vehicles. “Some people in China who would otherwise be able to afford a cheap gasoline car now won’t be able to afford it,” says Hsieh. “They’ll be priced out of the market.”

    Green emphasizes the impact of the mandate on all carmakers worldwide. “I can’t overstate how hugely important this is,” he says. “As soon as the mandate came out, carmakers realized that electric vehicles had become a major market rather than a niche market on the side.” And he believes that even without subsidies, the added expense of buying an EV won’t be prohibitive for many car buyers — especially in light of the benefits they offer.

    However, he does have a final concern. As more and more EVs are manufactured, global supplies of critical battery materials will become increasingly limited. At the same time, however, the supply of spent batteries will increase, creating an opportunity to recycle critical materials for use in new batteries and simultaneously prevent environmental threats from their disposal. The researchers recommend that policymakers “help to integrate the entire industry chain among automakers, battery producers, used-car dealers, and scrap companies in battery recycling systems to achieve a more sustainable society.”

    This research was supported through the MIT Energy Initiative’s Mobility of the Future study.

    This article appears in the Autumn 2020 issue of Energy Futures, the magazine of the MIT Energy Initiative. More

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    Q&A: Vivienne Sze on crossing the hardware-software divide for efficient artificial intelligence

    Not so long ago, watching a movie on a smartphone seemed impossible. Vivienne Sze was a graduate student at MIT at the time, in the mid 2000s, and she was drawn to the challenge of compressing video to keep image quality high without draining the phone’s battery. The solution she hit upon called for co-designing energy-efficient circuits with energy-efficient algorithms.

    Sze would go on to be part of the team that won an Engineering Emmy Award for developing the video compression standards still in use today. Now an associate professor in MIT’s Department of Electrical Engineering and Computer Science, Sze has set her sights on a new milestone: bringing artificial intelligence applications to smartphones and tiny robots.

    Her research focuses on designing more-efficient deep neural networks to process video, and more-efficient hardware to run those applications. She recently co-published a book on the topic, and will teach a professional education course on how to design efficient deep learning systems in June.

    On April 29, Sze will join Assistant Professor Song Han for an MIT Quest AI Roundtable on the co-design of efficient hardware and software moderated by Aude Oliva, director of MIT Quest Corporate and the MIT director of the MIT-IBM Watson AI Lab. Here, Sze discusses her recent work.

    Q: Why do we need low-power AI now?

    A: AI applications are moving to smartphones, tiny robots, and internet-connected appliances and other devices with limited power and processing capabilities. The challenge is that AI has high computing requirements. Analyzing sensor and camera data from a self-driving car consumes about 2,500 watts, but the computing budget of a smartphone is just about a single watt. Closing this gap requires rethinking the entire stack, a trend that will define the next decade of AI.

    Q: What’s the big deal about running AI on a smartphone?

    A: It means that the data processing no longer has to take place in the “cloud,” on racks of warehouse servers. Untethering compute from the cloud allows us to broaden AI’s reach. It gives people in developing countries with limited communication infrastructure access to AI. It also speeds up response time by reducing the lag caused by communicating with distant servers. This is crucial for interactive applications like autonomous navigation and augmented reality, which need to respond instantaneously to changing conditions. Processing data on the device can also protect medical and other sensitive records. Data can be processed right where they’re collected.

    Q: What makes modern AI so inefficient?

    A: The cornerstone of modern AI — deep neural networks — can require hundreds of millions to billions of calculations — orders of magnitude greater than compressing video on a smartphone. But it’s not just number crunching that makes deep networks energy-intensive — it’s the cost of shuffling data to and from memory to perform these computations. The farther the data have to travel, and the more data there are, the greater the bottleneck.

    Q: How are you redesigning AI hardware for greater energy efficiency?

    A: We focus on reducing data movement and the amount of data needed for computation. In some deep networks, the same data are used multiple times for different computations. We design specialized hardware to reuse data locally rather than send them off-chip. Storing reused data on-chip makes the process extremely energy-efficient.  

    We also optimize the order in which data are processed to maximize their reuse. That’s the key property of the Eyeriss chip that I co-designed with Joel Emer. In our followup work, Eyeriss v2, we made the chip flexible enough to reuse data across a wider range of deep networks. The Eyeriss chip also uses compression to reduce data movement, a common tactic among AI chips. The low-power Navion chip that I co-designed with Sertac Karaman for mapping and navigation applications in robotics uses two to three orders of magnitude less energy than a CPU, in part by using optimizations that reduce the amount of data processed and stored on-chip. 

    Q: What changes have you made on the software side to boost efficiency?

    A: The more that software aligns with hardware-related performance metrics like energy efficiency, the better we can do. Pruning, for example, is a popular way to remove weights from a deep network to reduce computation costs. But rather than remove weights based on their magnitude, our work on energy-aware pruning suggests you can remove the more energy-intensive weights to improve overall energy consumption. Another method we’ve developed, NetAdapt, automates the process of adapting and optimizing a deep network for a smartphone or other hardware platforms. Our recent followup work, NetAdaptv2, accelerates the optimization process to further boost efficiency.

    Q: What low-power AI applications are you working on?

    A: I’m exploring autonomous navigation for low-energy robots with Sertac Karaman. I’m also working with Thomas Heldt to develop a low-cost and potentially more effective way of diagnosing and monitoring people with neurodegenerative disorders like Alzheimer’s and Parkinson’s by tracking their eye movements. Eye-movement properties like reaction time could potentially serve as biomarkers for brain function. In the past, eye-movement tracking took place in clinics because of the expensive equipment required. We’ve shown that an ordinary smartphone camera can take measurements from a patient’s home, making data collection easier and less costly. This could help to monitor disease progression and track improvements in clinical drug trials.

    Q: Where is low-power AI headed next?

    A: Reducing AI’s energy requirements will extend AI to a wider range of embedded devices, extending its reach into tiny robots, smart homes, and medical devices. A key challenge is that efficiency often requires a tradeoff in performance. For wide adoption, it will be important to dig deeper into these different applications to establish the right balance between efficiency and accuracy. More

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    How to get salt out of water: Make it self-eject

    About a quarter of a percent of the entire gross domestic product of industrialized countries is estimated to be lost through a single technical issue: the fouling of heat exchanger surfaces by salts and other dissolved minerals. This fouling lowers the efficiency of multiple industrial processes and often requires expensive countermeasures such as water pretreatment. Now, findings from MIT could lead to a new way of reducing such fouling, and potentially even enable turning that deleterious process into a productive one that can yield saleable products.

    The findings are the result of years of work by recent MIT graduates Samantha McBride PhD ’20 and Henri-Louis Girard PhD ’20 with professor of mechanical engineering Kripa Varanasi. The work, reported today in the journal Science Advances, shows that due to a combination of hydrophobic (water repelling) surfaces and heat, dissolved salts can crystallize in a way that makes it easy to remove them from the surface, in some cases by gravity alone.

    Play video

    When the researchers began studying the way salts crystallize on such surfaces, they found that the precipitating salt would initially form a partial spherical shell around a droplet. Unexpectedly, this shell would then suddenly rise on a set of spindly leg-like extensions grown during evaporation. The process repeatedly produced  multilegged shapes, resembling elephants and other animals, and even sci-fi droids. The researchers dubbed these formations “crystal critters” in the title of their paper.

    After many experiments and detailed analysis, the team determined the mechanism that was producing these leg-like protrusions. They also showed how the protrusions varied depending on temperature and the nature of the hydrophobic surface, which was produced by creating a nanoscale pattern of low ridges. They found that the narrow legs holding up these critter-like forms continue to grow upward from the bottom, as the salty water flows downward through the straw-like legs and precipitates out at the bottom, somewhat like a growing icicle, only balanced on its tip. Eventually the legs become so long they are unable to support the critter’s weight, and the blob of salt crystal breaks off and falls or is swept away.

    The work was motivated by the desire to limit or prevent the formation of scaling on surfaces, including inside pipes where such scaling can lead to blockages, Varanasi says. “Samantha’s experiment showed this interesting effect where the scale pretty much just pops off by itself,” he says.

    “These legs are hollow tubes, and the liquid is funneled down through these tubes. Once it hits the bottom and evaporates, it forms new crystals that continuously increase the length of the tube,” McBride says. “In the end, you have very, very limited contact between the substrate and the crystal, to the point where these are going to just roll away on their own.”

    McBride recalls that in doing the initial experiments as part of her doctoral thesis work, “we definitely suspected that this particular surface would work well for eliminating sodium chloride adhesion, but we didn’t know that a consequence of preventing that adhesion would be the ejection of the entire thing” from the surface.

    One key, she found, was the exact scale of the patterns on the surface. While many different length scales of patterning can yield hydrophobic surfaces, only patterns at the nanometer scale achieve this self-ejecting effect. “When you evaporate a drop of salt water on a superhydrophobic surface, usually what happens is those crystals start getting inside of the texture and just form a globe, and they don’t end up lifting off,” McBride says. “So it’s something very specific about the texture and the length scale that we’re looking at here that allows this effect to occur.”

    This self-ejecting process, based simply on evaporation from a surface whose texture can be easily produced by etching, abrasion, or coating, could be a boon for a wide variety of processes. All kinds of metal structures in a marine environment or exposed to seawater suffer from scaling and corrosion. The findings may also enable new methods for investigating the mechanisms of scaling and corrosion, the researchers say.

    By varying the amount of heat along the surface, it’s even possible to get the crystal formations to roll along in a specific direction, the researchers found. The higher the temperature, the faster the growth and liftoff of these forms takes place, minimizing the amount of time the crystals block the surface.

    Heat exchangers are used in a wide variety of different processes, and their efficiency is strongly affected by any surface fouling. Those losses alone, Varanasi says, equal a quarter of a percent of the GDP of the U.S. and other industrialized nations. But fouling is also a major factor in many other areas. It affects pipes in water distribution systems, geothermal wells, agricultural settings, desalination plants, and a variety of renewable energy systems and carbon dioxide conversion methods.

    This method, Varanasi says, might even enable the use of untreated salty water in some processes where that would not be practical otherwise, such as in some industrial cooling systems. Further, in some situations the recovered salts and other minerals could be salable products.

    While the initial experiments were done with ordinary sodium chloride, other kinds of salts or minerals are expected to produce similar effects, and the researchers are continuing to explore the extension of this process to other kinds of solutions.

    Because the methods for making the textures to produce a hydrophobic surface are already well-developed, Varanasi says, implementing this process at large industrial scale should be relatively rapid, and could enable the use of salty or brackish water for cooling systems that would otherwise require the use of valuable and often limited fresh water. For example, in the U.S. alone, a trillion gallons of fresh water are used per year for cooling. A typical 600-megawatt power plant consumes about a billion gallons of water per year, which could be enough to serve 100,000 people. That means that using sea water for cooling where possible could help to alleviate a fresh-water scarcity problem.

    “This work shows a remarkable and interesting phenomenon,” says Neelesh Patankar, a professor of mechanical engineering at Northwestern University, who was not associated with this research. The findings, he says, “may lead to an entirely new approach to mitigate mineral fouling in industrial processes. Not only is this work interesting from a fundamental science perspective, in my opinion it is also of practical importance.”

    The work was supported by Equinor through MIT Energy Initiative, the MIT Martin Fellowship Program, and the National Science Foundation. More

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    Seeking enhanced materials for nuclear reactors

    One of India’s largest commercial and research nuclear reactor facilities lies just south of Arunkumar Seshadri’s hometown of Chennai, India. It was there, during a high school field trip, that the seeds of his interest in nuclear power were planted.

    “We learned the basic outline of how a reactor functions,” recalls Seshadri, a fifth-year doctoral student in nuclear science and engineering. “I was fascinated by how such a little bit of uranium or other fuel could produce such an enormous amount of energy.”

    This fascination quickly found a formal outlet during Seshadri’s undergraduate years, and continues to propel him now at MIT.

    Working closely with his advisor Koroush Shirvan, John Clark Hardwick (1986) Career Development Professor, Seshadri has forged a singular path identifying and testing a new generation of radiation-, corrosion-, and heat-resistant materials and fuels that can better withstand the extreme conditions in nuclear reactors.

    His investigations have yielded advances in both basic science and practical technologies, as evidenced by a flurry of journal publications and patents. “I really enjoy answering engineering problems faced by the nuclear industry, and moving toward a more fundamental understanding of the structural and chemical changes” that affect materials in reactors, says Seshadri.

    Focused on heat transfer

    The son of a Sanskrit language teacher and a stay-at-home mother, Seshadri was dismantling and reassembling his home’s appliances and acquiring programming skills during his elementary years, and competing in science tournaments in high school. At SASTRA University, where he majored in mechanical engineering and controls systems, Seshadri was recruited to a research project funded by the nuclear industry. It proved a decisive experience.

    “The goal was to develop sensors for two-phase flow — water and steam — as happens in a boiling water reactor,” he says. “We wanted to extract information about these two different phases so we could learn exactly what was happening inside.” The challenge of designing technology for monitoring and better predicting how heat moves inside a reactor, and the associated prospect of improving operations in commercial nuclear facilities, proved irresistible.  

    Inspired by the Indian government’s call for a skilled workforce to help expand its nuclear industry, Seshadri decided to tackle an advanced degree in nuclear science and engineering. “MIT had a rich tradition of experts in two-phase heat transfer; they are torchbearers in the field,” he says. “I thought this could be a place to enrich my interests.”

    He found immediate direction for his research pursuits with Shirvan, who was running a series of experiments for the Department of Energy to formulate nuclear reactor fuels with greater accident tolerance. For his master’s thesis, Seshadri examined how different kinds of coating on the metal cladding of nuclear fuels behaved as they were heated up and cooled down. He was particularly interested in wettability, the property that determines whether a material attracts or repels fluids such as the coolants in nuclear reactors.When materials demonstrate higher wettability, coolants can more efficiently carry away heat. But with lower wettability, materials repel fluid, causing steam vapor to form on surfaces, trapping heat and leading to potentially perilous temperature increases within the reactor.

    In 2004, Japanese researchers discovered that gamma radiation, a byproduct of the nuclear reactions taking place, enhances wettability. Using high-resolution microscopy, Seshadri helped demonstrate the precise mechanism by which this happens: gamma radiation generated nanosized oxide pores over the surfaces of metal components, creating a highly wettable surface.

    “It was the first time anyone showed that gamma radiation created such an impact, and this enabled us to test different coated claddings to improve their heat transfer behaviors,” he says. Seshadri carried out high-resolution microscopic measurements that revealed precisely how gamma radiation affected these coatings.

    “I was thrilled,” he says. “To industry, radiation was an evil, damaging surfaces, but we saw that it helped heat transfer.” Some of these enhanced fuel claddings have moved on to industry evaluations. In a twist to their research, Seshadri and Shirvan have patented a technique based on gamma irradiation to make water-repellent coatings, which could be used on windshields or in desalination plants.

    Passion for research and teaching

    For his doctoral research, Seshadri has shifted to a related area: investigating a silicon carbide composite of great interest to industry as a replacement for a zirconium alloy fuel cladding that is highly susceptible to corrosion. “Silicon carbide composite can withstand very high temperatures and is strong without being brittle,” he says, “but the challenge is that in extreme hydrothermal environments and in the presence of radiation, small quantities of silica dissolve into the coolant, potentially damaging components.”

    Seshadri’s job is to determine how different types of reactor radiation contribute to the loss of silicon, and whether that circulating silica is within industry limits. “If silica deposits in reactor components, industry will need to develop a process for removing it,” he says. Seshadri is developing models for predicting the rate of silica dissolution.  His experiments are vital in the search for fuel cladding that can better tolerate temperature fluctuations in the world’s operating light-water reactors. His work will also help in the development of advanced reactors that operate at much higher temperatures, and that use silicon carbide components and molten salt as a coolant.

    Seshadri credits Shirvan as integral to his accomplishments and his growth as a researcher. “I came to MIT with no background in nuclear science, and wasn’t doing well,” he recalls. “Shirvan spent countless hours teaching me the essentials I needed, and then giving me the freedom to pursue problems and the time to get results, without pressure.” 

    This mode of mentorship powers Seshadri’s own teaching. In his free time, Seshadri supervises undergraduates in India working on energy projects, encouraging them to pursue ambitious goals. On a remote basis, he instructs them in computational modeling, helps them write up research for publication, and apply to graduate schools. “My passions, and all my hobbies, are related to research, and interacting with these students is a step toward the career I want in academia: leading a research team at a university, and getting solutions to deep problems.” More

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    Collaborators in climate action

    MIT is committed to driving the transition to a low-carbon world, throwing the full weight of its research forces into transformative technologies for reducing greenhouse gas emissions. But “MIT can’t solve climate change alone,” said Maria T. Zuber, MIT’s vice president for research and the E. A. Griswold Professor of Geophysics, speaking at a virtual symposium in late March.

    When MIT initiated its first Climate Action Plan in 2015, a key tenet, said Zuber, was “engagement with actors and entities outside of MIT.” As the Institute prepares to issue an updated version of the plan later this spring, this engagement forum, “Research collaborations to decarbonize the energy system,” was conceived as an opportunity for the MIT community to learn about and comment upon some of the low-carbon research projects between MIT and key outside collaborators. It was co-hosted by the Office of the Vice President for Research and the MIT Energy Initiative (MITEI).

    “With vignettes of current or recent engagement activities, we seek to share a small handful of examples of how working with industry has catalyzed progress in the electric power sector, life-cycle analysis to inform decarbonization efforts, and fusion energy, to name a few,” said MITEI Director Robert C. Armstrong, the Chevron Professor of Chemical Engineering, in his introductory remarks.

    Symposium speakers, who included MIT faculty and scientists, industry liaisons, and venture capital leaders, made clear that joining forces yields concrete benefits — not simply in specific technologies or sectors, but in the kind of large-scale, market-based solutions required to meet the climate crisis.

    Wind, electric vehicles, and nuclear

    Take, for instance, the case of Iberdrola, a Spanish-based multinational electric utility with a large renewables portfolio, which is launching a vast fleet of offshore wind farms around the world. As a senior asset performance analysis engineer for the company, Sofia Koukoura found help in modeling the operation of these turbines from Kalyan Veeramachaneni, a principal research scientist with the MIT Laboratory for Information and Decision Systems.

    Veeramachaneni harnessed machine learning to predict component failures and likely repairs affecting the longevity of these turbines, providing Koukoura with “flexible, reproducible, and scalable solutions,” she says. “Bridging the gap between development and deployment of a project is a big leap, and the team at MIT is helping us do that.”

    Other panels in this session, also moderated by Angela Belcher, the James Mason Crafts Professor of Biological Engineering and Materials Science and Engineering and head of the Department of Biological Engineering, demonstrated the reciprocal nature of MIT’s research with industry associates.

    One such case: MITEI research scientist Emre Gençer has developed a life-cycle assessment tool called SESAME (Sustainable Energy Systems Analysis Modeling Environment) to enable a systems-level understanding of the environmental impact and fuel emissions reduction potential of a spectrum of interrelated energy technologies.

    ExxonMobil’s Research and Engineering Company — a sponsor of MITEI’s Mobility of the Future Study  — engaged with Gençer to use SESAME for modeling the emissions impacts of switching from internal combustion engine vehicles to hybrid, battery electric, and hydrogen fuel cell vehicles in different regions of the United States. Jennifer Morris, a research scientist with both MITEI and the MIT Joint Program on the Science and Policy of Global Change, provided the various policy scenario projections for the Mobility of the Future Study.

    The resulting studies proved useful not just to ExxonMobil, but to the MIT scientists as well.

    “In academia, we can come up with solutions, but if they’re not implementable, they’re not as valuable, especially during a climate crisis,” said Gençer. “These connections with industrial sponsors are valuable, because they provide reality checks on our technological and economic assumptions,” said Morris. “These are real-world challenges that make our applications relevant and have real-world impact.” The goal is to make these tools widely available to policymakers, industry, and other stakeholders to inform decision-making that can drive decarbonization.

    An example from another research domain: Michael Short the Class of ’42 Associate Professor of Nuclear Science and Engineering (NSE), had been searching for a solution to a vexing, decades-old issue for light water nuclear reactors — the deposition of corrosive deposits on nuclear fuel, which can lead to reactor downtime. 

    When Short’s lab cracked this problem of fuel rod fouling, a major U.S. clean energy provider recognized it might be valuable for reducing costs on its nuclear fleet. With support from this company, Short’s lab is now busy developing materials with better resistance to these deposits, which could help keep existing reactors producing clean energy for decades to come.

    Beyond such technological advances, Short notes there are less-tangible yet significant rewards to the joint enterprise with industry. When “students have frequent, primary contact with an industry sponsor, they learn they are not just first authors on papers but on patents as well, giving them a sense of what problems they want to work on and what to do with their lives,” he said. If a student solves a problem in science, they will see “someone is ready to snap it up and make an impact on the carbon issue.”

    Solar and fusion breakthroughs

    In recent years, alliances formed between MIT researchers and outside companies have not merely sparked novel carbon-cutting technologies, but laid the groundwork for path-breaking spinoffs, and even potential new industries. Two panels moderated by Anne White, head of the Department of Nuclear Science and Engineering and the MIT School of Engineering Distinguished Professor of Engineering, featured instructive cases.

    When Italian energy company Eni first paired up with MIT in 2008, founding the Solar Frontiers Center (SFC), the initial goal was to “explore everything beyond silicon,” said Massimiliano Pieri, Eni’s cleantech director at Eni Next, Eni’s corporate venture capital organization. After dozens of SFC projects, which have involved a small army of graduate students, generated many patent filings, and produced hundreds of research papers, it is readily apparent that MIT “has dramatically benefited,” said Vladimir Bulović, a professor of electrical engineering and the Fariborz Maseeh Chair in Emerging Technology. Among the results of this mutual venture: a new class of super thin, flexible, and lightweight materials that could vastly expand the use of solar energy.

    This long-lived collaboration has also served as the launchpad for such startups as Swift Solar, co-founded by Joel Jean SM ’13, PhD ’17, and Ubiquitous Energy, co-founded by Miles Barr SM ’08, PhD ’12, both of whom earned a Forbes “30 under 30 in Energy” for innovations in the solar industry. Work with Eni at SFC “inspired me to start a career commercializing new solar technology,” said Barr.

    In 2016, when researchers in MIT’s Plasma Science and Fusion Center (PSFC) saw a path to making commercial fusion energy a reality, they went big, searching for collaborators who could help “launch a new energy industry,” said Dennis G. Whyte, PSFC director and Hitachi America Professor of Engineering. “It was high risk, but the idea resonated with us,” said Pieri, whose Eni Next firm invested in the MIT spinoff, Commonwealth Fusion Systems (CFS).

    With additional investment from Bill Gates’ Breakthrough Energy Ventures and other leading investors in breakthrough energy technologies, said CFS CEO Bob Mumgaard SM ’15, PhD ’15, “We were able to attract talent from all sorts of disciplines much earlier than normally possible, start the company, and scale up quickly.” CFS is now on a fast track to build the world’s first net energy fusion machine, and from there, the first commercially viable fusion power plant, opening a window to limitless clean energy.

    By symposium’s end, participants had reached consensus: To achieve the urgent goals of the climate fight, whether by catalyzing new energy industries or deploying cost-effective, carbon-reducing applications, industry and academia must work cooperatively. “We truly need to step up our game — we simply don’t yet have all the technologies we need to decarbonize our energy systems and our economy,” said Zuber. “You’ve heard the phrase, ‘Go big, or go home.’ When it comes to climate change, going big is imperative, because Earth is our home.”   

    On April 1, the Office of the Vice President for Research co-hosted another forum, “Viewpoints from the MIT community engaging on climate change: An all-of-MIT approach,” this one in conjunction with the Environmental Solutions Initiative. More

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    Keeping humanity central to solving climate change

    As a small child, Manduhai Buyandelger lived with her grandparents in a house unconnected to the heating grid on the outskirts of Ulaanbaatar, Mongolia. There, in the world’s coldest capital city, temperatures can drop as low as minus 40 degrees Fahrenheit in the winter months.

    “Once I moved further into the city with my parents, I had nightmares about my grandparents,” recalls Buyandelger, now a professor of anthropology at MIT. “I felt so vulnerable for them. In the ger district where they lived, most people do not have central heating, and they warm their homes by making fire in their stoves. My grandparents didn’t have heat. I was always worried about them getting up in this icy cold house, carrying buckets of coal from their little shed back into the house, and then using a small shovel putting the coal in the stove. It has been more than 40 years since then, and life there is still very much like that.”

    With temperatures this harsh, having access to safe and affordable heat sources is critical for the citizens of Ulaanbaatar, especially for the 60 percent of the population living in the ger district. This suburban area of the city, composed mainly of off-grid nomadic tents, houses some of the city’s poorest and most vulnerable citizens.

    Traditionally, the households occupying the ger district kept their homes warm as Buyandelger’s grandparents did, by using individual coal-burning stoves — contributing to Ulaanbaatar’s other “claim to fame” as the world’s most-polluted capital city. In recent years, as air pollution reached levels twice as high as what the World Health Organization defined as “acutely hazardous,” the Mongolian government took measures to combat this pollution. They banned the use of coal in ger district homes and enforced the use of cleaner-burning charcoal briquettes, which in turn created a new set of problems.  

    “A lot of people died,” says Buyandelger. “The briquettes are toxic in a different way. Their instructions for burning are nuanced and require more oxygen in the house, which means people have to open their windows and doors, defeating their purpose.” When burned incorrectly, these briquettes generate large amounts of carbon monoxide — an odorless, colorless, and toxic gas.

    Establishing interdisciplinary collaborations

    Enter Michael Short, the Class of ’42 Associate Professor of Nuclear Science and Engineering (NSE) at MIT. He recognized the need for a safer, cleaner heat source and connected with Buyandelger, whose work in Mongolian anthropology was uniquely suited to aid these efforts. According to Buyandelger, “Oftentimes in history, people adjusted their behaviors so they can use technology. But we can do better and change the technology so that we don’t necessarily jeopardize the people or culture.”

    With this goal in mind, Buyandelger, Short, and a team of students from NSE and the Department of Anthropology have begun a collaboration to study the particularities of the local culture, environment, political climate, and economy in Ulaanbaatar to inform their work designing a sustainable, flameless thermal heat source made from molten nitrate salts. Once Covid-19 restrictions have lifted, they plan to travel to Mongolia, where they will live in the ger district with those they aim to help, conducting ethnographic participant observations and extensive interviews to prototype a useful heat bank, observe its functionality in person, and make adaptations and improvements as needed.

    For the students, the goal is twofold: They will be trained in “anthropologically informed engineering” and see firsthand the benefits of developing a product with the end-user in mind from the outset; and they will see how targeted, well-informed engineering can empower citizens and in turn preserve democracy.

    “Our core hypothesis is that clean fuel independence from the government will foster democratization and prevent setbacks to authoritarianism,” says Buyandelger. She explains that the people in the ger district are heavily dependent on the government: They must agree to use these dangerous fuels or else they will not qualify for other vital government subsidies and food programs. “We want to see if implementing the heat banks would help generate a more open and free society.”

    Understanding human complexities

    When thinking about climate change and energy challenges across the globe, a lot of emphasis is put on how technology and policy can enact change. But, as illustrated in the Ulaanbaatar project, there is an important, undeniable element that is central: people. 

    “For scholars doing this research, if they don’t include the political, social, and cultural dimensions, it is an incomplete project,” says Melissa Nobles. She is the Kenan Sahin Dean of MIT’s School of Humanities, Arts, and Social Sciences (MIT SHASS), as well as a professor of political science.

    MIT SHASS is home to 13 academic fields, including anthropology, history, international studies, economics, and music and theater arts — all contributing to understanding the world’s many human complexities. Part of the school’s mission is to generate research and ideas that can change the world for the better, and it helps do this by informing public policy, educating leading science communicators, and shedding light on the cultural barriers that prevent people, organizations, and governments from supporting effective environmental policies and practices.

    “Human motivation is hugely complicated,” says Nobles. “The science has been clear on climate change, and it has been clear for a while; but as we see, the facts don’t change people’s behavior. You have to actually get people to ingest it intellectually and emotionally, because part of the resistance is rooted in fears of uncertainty: How am I going to have to change my life? What does it mean for my day-to-day? What does it mean for future generations?”

    This question of the day-to-day was something that stuck out to Buyandelger when thinking about the cultural and social challenges their heat bank might face: “How do we distribute this? How heavy is it; will people be able to carry it? Who in the household will receive it? Can the temperature be altered for cooking?”

    Integrating climate into curriculum

    In MIT’s SHASS classrooms, students learn to think critically about these big sociopolitical questions through some 30 courses that tackle climate and energy topics. Presented through rigorous humanities and social science lenses, the subjects range from history to literature to economics to political science to philosophy.Courses include 24.07 (The Ethics of Climate Change), a moral philosophy class in which students explore the ethical implications of a rapidly warming world; CMS.375 (Reading Climate through Media), in which students learn how contemporary media shapes public perceptions about climate issues, as well as how to craft effective climate stories and messages themselves; and 21H.421 (Introduction to Environmental History), which explores the influence of planetary life and conditions on human history, and the reciprocal influence of people on the Earth.

    Clare Balboni, the 3M Career Development Assistant Professor of Environmental Economics, teaches graduate- and undergraduate-level courses on environmental policy and economics. The undergraduate-level course, which will be taught this semester for the first time in several years, fulfills an elective requirement for MIT’s energy studies minor. Balboni joined the Department of Economics in 2019 and has been working toward making environmental economics a core topic in the department.

    “It’s a really exciting time in environmental economics, and there is a tremendous amount of interest from the student body,” Balboni says. “There is a longstanding tradition of theoretical work in this area, but more recently there has also been an upsurge in related empirical work. This reflects in part increased awareness and political and policy focus on environmental issues, but also enormous opportunities presented by new data sources, which make it possible to study environmental phenomena in ways that we weren’t previously able to do.” 

    She explains that economic studies can be key to informing effective climate solutions. “Understanding economic incentives and human behavior and responses is crucial. For instance, pollutants and climate damages can affect a wide range of human outcomes, such as mortality and health, labor productivity, education, conflict, and crime, which it is critical to understand and quantify when thinking about environmental policy design and implementation.”

    A growing area of interest for MIT’s School of Humanities, Arts, and Social Sciences is how to continue incorporating climate into its curriculum across all of its varied academic disciplines. As climate change issues become an even more important topic in national legislation and policymaking — especially with the new Biden-Harris administration in office — Nobles expects research and teaching to follow suit.

    She explains that “what literature does, what music does, what art can do, what studying philosophy, culture, politics, and economics can do, is help students understand why it’s so complicated for climate change efforts to move forward, and then, what they can do to help.” More