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      Meeting the clean energy needs of tomorrow

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      Yuri Sebregts, chief technology officer at Shell, succinctly laid out the energy dilemma facing the world over the rest of this century. On one hand, demand for energy is quickly growing as countries in the developing world modernize and the global population grows, with 100 gigajoules of energy per person needed annually to enable quality-of-life benefits and industrialization around the globe. On the other, traditional energy sources are quickly warming the planet, with the world already seeing the devastating effects of increasingly frequent extreme weather events. 

      While the goals of energy security and energy sustainability are seemingly at odds with one another, the two must be pursued in tandem, Sebregts said during his address at the MIT Energy Initiative Fall Colloquium.

      “An environmentally sustainable energy system that isn’t also a secure energy system is not sustainable,” Sebregts said. “And conversely, a secure energy system that is not environmentally sustainable will do little to ensure long-term energy access and affordability. Therefore, security and sustainability must go hand-in-hand. You can’t trade off one for the other.”

      Sebregts noted that there are several potential pathways to help strike this balance, including investments in renewable energy sources, the use of carbon offsets, and the creation of more efficient tools, products, and processes. However, he acknowledged that meeting growing energy demands while minimizing environmental impacts is a global challenge requiring an unprecedented level of cooperation among countries and corporations across the world. 

      “At Shell, we recognize that this will require a lot of collaboration between governments, businesses, and civil society,” Sebregts said. “That’s not always easy.”

      Global conflict and global warming

      In 2021, Sebregts noted, world leaders gathered in Glasgow, Scotland and collectively promised to deliver on the “stretch goal” of the 2015 Paris Agreement, which would limit global warming to 1.5 degrees Celsius — a level that scientists believe will help avoid the worst potential impacts of climate change. But, just a few months later, Russia invaded Ukraine, resulting in chaos in global energy markets and illustrating the massive impact that geopolitical friction can have on efforts to reduce carbon emissions.

      “Even though global volatility has been a near constant of this century, the situation in Ukraine is proving to be a turning point,” Sebregts said. “The stress it placed on the global supply of energy, food, and other critical materials was enormous.”

      In Europe, Sebregts noted, countries affected by the loss of Russia’s natural gas supply began importing from the Middle East and the United States. This, in turn, drove up prices. While this did result in some efforts to limit energy use, such as Europeans lowering their thermostats in the winter, it also caused some energy buyers to turn to coal. For instance, the German government approved additional coal mining to boost its energy security — temporarily reversing a decades-long transition away from the fuel. To put this into wider perspective, in a single quarter, China increased its coal generation capacity by as much as Germany had reduced its own over the previous 20 years.

      The promise of electrification

      Sebregts noted the strides being made toward electrification, which is expected to have a significant impact on global carbon emissions. To meet net-zero emissions (the point at which humans are adding no more carbon to the atmosphere than they are removing) by 2050, the share of electricity as a portion of total worldwide energy consumption must reach 37 percent by 2030, up from 20 percent in 2020, Sebregts said.

      He pointed out that Shell has become one of the world’s largest electric vehicle charging companies, with more than 30,000 public charge points. By 2025, that number will increase to 70,000, and it is expected to soar to 200,000 by 2030. While demand and infrastructure for electric vehicles are growing, Sebregts said that the “real needle-mover” will be industrial electrification, especially in so-called “hard-to-abate” sectors.

      This progress will depend heavily on global cooperation — Sebregts pointed out that China dominates the international market for many rare elements that are key components of electrification infrastructure. “It shouldn’t be a surprise that the political instability, shifting geopolitical tensions, and environmental and social governance issues are significant risks for the energy transition,” he said. “It is imperative that we reduce, control, and mitigate these risks as much as possible.”

      Two possible paths

      For decades, Sebregts said, Shell has created scenarios to help senior managers think through the long-term challenges facing the company. While Sebregts stressed that these scenarios are not predictions, they do take into account real-world conditions, and they are meant to give leaders the opportunity to grapple with plausible situations.

      With this in mind, Sebregts outlined Shell’s most recent Energy Security Scenarios, describing the potential future consequences of attempts to balance growing energy demand with sustainability — scenarios that envision vastly different levels of global cooperation, with huge differences in projected results. 

      The first scenario, dubbed “Archipelagos,” imagines countries pursuing energy security through self-interest — a fragmented, competitive process that would result in a global temperature increase of 2.2 degrees Celsius by the end of this century. The second scenario, “Sky 2050,” envisions countries around the world collaborating to change the energy system for their mutual benefit. This more optimistic scenario would see a much lower global temperature increase of 1.2 C by 2100.

      “The good news is that in both scenarios, the world is heading for net-zero emissions at some point,” Sebregts said. “The difference is a question of when it gets there. In Sky 2050, it is the middle of the century. In Archipelagos, it is early in the next century.”

      On the other hand, Sebregts added, the average global temperature will increase by more than 1.5 C for some period of time in either scenario. But, in the Archipelagos scenario, this overshoot will be much larger, and will take much longer to come down. “So, two very different futures,” Sebregts said. “Two very different worlds.”

      The work ahead

      Questioned about the costs of transitioning to a net-zero energy ecosystem, Sebregts said that it is “very hard” to provide an accurate answer. “If you impose an additional constraint … you’re going to have to add some level of cost,” he said. “But then, of course, there’s 30 years of technology development pathway that might counteract some of that.”

      In some cases, such as air travel, Sebregts said, it will likely remain impractical to either rely on electrification or sequester carbon at the source of emission. Direct air capture (DAC) methods, which mechanically pull carbon directly from the atmosphere, will have a role to play in offsetting these emissions, he said. Sebregts predicted that the price of DAC could come down significantly by the middle of this century. “I would venture that a price of $200 to $250 a ton of CO2 by 2050 is something that the world would be willing to spend, at least in developed economies, to offset those very hard-to-abate instances.”

      Sebregts noted that Shell is working on demonstrating DAC technologies in Houston, Texas, constructing what will become Europe’s largest hydrogen plant in the Netherlands, and taking other steps to profitably transition to a net-zero emissions energy company by 2050. “We need to understand what can help our customers transition quicker and how we can continue to satisfy their needs,” he said. “We must ensure that energy is affordable, accessible, and sustainable, as soon as possible.” More

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      Soaring high, in the Army and the lab

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      Starting off as a junior helicopter pilot, Lt. Col. Jill Rahon deployed to Afghanistan three times. During the last one, she was an air mission commander, the  pilot who is designated to interface with the ground troops throughout the mission.

      Today, Rahon is a fourth-year doctoral student studying applied physics at the Department of Nuclear Science and Engineering (NSE). Under the supervision of Areg Danagoulian, she is working on engineering solutions for enforcement of nuclear nonproliferation treaties. Rahon and her husband have 2-year-old twins: “They have the same warm relationship with my advisor that I had with my dad’s (PhD) advisor,” she says.

      Jill Rahon: Engineering solutions for enforcement of nuclear nonproliferation treaties

      A path to the armed forces

      The daughter of a health physicist father and a food chemist mother, Rahon grew up in the Hudson Valley, very close to New York City. Nine-eleven was a life-altering event: “Many of my friends’ fathers and uncles were policemen and firefighters [who] died responding to the attacks,” Rahon says. A hurt and angry teenager, Rahon was determined to do her part to help: She joined the Army and decided to pursue science, becoming part of the first class to enter West Point after 9/11.

      Rahon started by studying strategic history, a field that covers treaties and geopolitical relationships. It would prove useful later. Inspired by her father, who works in the nuclear field, Rahon added on a nuclear science and engineering track.

      After graduating from West Point, Rahon wanted to join active combat and chose aviation. At flight school in Fort Novosel, Alabama, she discovered that she loved flying. It was there that Rahon learned to fly the legendary Chinook helicopter. In short order, Rahon was assigned to the 101st Airborne Division and deployed to Afghanistan quickly thereafter.

      As expected, flying in Afghanistan, especially on night missions, was adrenaline-charged. “You’re thinking on the fly, you’re talking on five different radios, you’re making decisions for all the helicopters that are part of the mission,” Rahon remembers. Very often Rahon and her cohorts did not have the luxury of time. “We would get information that would need to be acted on quickly,” she says. During the planning meetings, she would be delighted to see a classmate from West Point function as the ground forces commander. “It would be surprising to see somebody you knew from a different setting halfway around the world, working toward common goals,” Rahon says.

      Also awesome: helping launch the first training program for female pilots to be recruited in the Afghan National Air Force. “I got to meet [and mentor] these strong young women who maybe didn’t have the same encouragement that I had growing up and they were out there hanging tough,” Rahon says.

      Exploring physics and nuclear engineering

      After serving in the combat forces, Rahon decided she wanted to teach physics at West Point. She applied to become a part of the Functional Area (FA52) as a nuclear and countering weapons of mass destruction officer.

      FA52 officers provide nuclear technical advice to maneuver commanders about nuclear weapons, effects, and operating in a nuclear environment or battlefield. Rahon’s specialty is radiation detection and operations in a nuclear environment, which poses unique threats and challenges to forces.

      Knowing she wanted to teach at West Point, she “brushed up extensively on math and physics” and applied to MIT NSE to pursue a master’s degree. “My fellow students were such an inspiration. They might not have had the same life experiences that I had but were still so mature and driven and knowledgeable not only about nuclear engineering but how that fits in the energy sector and in politics,” Rahon says.

      Resonance analysis to verify treaties

      Rahon returned to NSE to pursue her doctorate, where she does a “lot of detection and treaty verification work.”

      When looking at nuclear fuels to verify safeguards for treaties, experts search for the presence and quantities of heavy elements such as uranium, plutonium, thorium, and any of their decay products. To do so nondestructively is of high importance so they don’t destroy a piece of the material or fuel to identify it.

      Rahon’s research is built on resonance analysis, the fact that most midrange to heavy isotopes have unique resonance signatures that are accessed by neutrons of epithermal energy, which is relatively low on the scale of possible neutron energies. This means they travel slowly — crossing a distance of 2 meters in tens of microseconds, permitting their detection time to be used to calculate their energy.

      Studying how neutrons of a particular energy interact with a sample to identify worrisome nuclear materials is much like studying fingerprints to solve crimes. Isotopes that have a spike in likelihood of interaction occurring over a small neutron energy are said to have resonances, and these resonance patterns are isotopically unique. Experts can use this technique to nondestructively assess an item, identifying the constituent isotopes and their concentrations.

      Resonance analysis can be used to verify that the fuels are what the nuclear plant owner says they are. “There are a lot of safeguards activities and verification protocols that are managed by the International Atomic Energy Agency (IAEA) to ensure that a state is not misusing nuclear power for ulterior motives,” Rahon points out. And her method helps.

      “Our technique that leverages resonance analysis is nothing new,” Rahon says, “It’s been applied practically since the ’70s at very large beam facilities, hundreds of meters long with a very large accelerator that pulses neutrons, and then you’re able to correlate a neutron time of flight with a resonance profile. What we’ve done that is novel is we’ve shrunk it down to a 3-meter system with a portable neutron residence generator and a 2-meter beam path,” she says.

      Mobility confers many significant advantages: “This is something that could be conceivably put on the back of a truck and moved to a fuel facility, then driven to the next one for inspections or put at a treaty verification site. It could be taken out to a silo field where they are dismantling nuclear weapons,” Rahon says. However, the miniaturization does come with significant challenges, such as the neutron generator’s impacts on the signal to noise ratio.

      Rahon is delighted her research can ensure that a necessary fuel source will not be misused. “We need nuclear power. We need low-carbon solutions for energy and we need safe ones. We need to ensure that this powerful technology is not being misused. And that’s why these engineering solutions are needed for these safeguards,” she says.

      Rahon sees parallels between her time in active duty and her doctoral research. Teamwork and communication are key in both, she says. Her dad is her role model and Rahon is a firm believer in mentorship, something she nurtured both in the armed forces and at MIT. “My advisor is genuinely a wonderful person who has always given me so much support from not only being a student, but also being a parent,” Rahon adds.

      In turn, Danagoulian has been impressed by Rahon’s remarkable abilities: “Raising twins, doing research in applied nuclear physics, and flying coalition forces into Taliban territory while evading ground fire … [Jill] developed her own research project with minimal help from me and defended it brilliantly during the first part of the exam,” he says. 

      It seems that Rahon flies high no matter which mission she takes on. More

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      Study reveals a reaction at the heart of many renewable energy technologies

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      A key chemical reaction — in which the movement of protons between the surface of an electrode and an electrolyte drives an electric current — is a critical step in many energy technologies, including fuel cells and the electrolyzers used to produce hydrogen gas.

      For the first time, MIT chemists have mapped out in detail how these proton-coupled electron transfers happen at an electrode surface. Their results could help researchers design more efficient fuel cells, batteries, or other energy technologies.

      “Our advance in this paper was studying and understanding the nature of how these electrons and protons couple at a surface site, which is relevant for catalytic reactions that are important in the context of energy conversion devices or catalytic reactions,” says Yogesh Surendranath, a professor of chemistry and chemical engineering at MIT and the senior author of the study.

      Among their findings, the researchers were able to trace exactly how changes in the pH of the electrolyte solution surrounding an electrode affect the rate of proton motion and electron flow within the electrode.

      MIT graduate student Noah Lewis is the lead author of the paper, which appears today in Nature Chemistry. Ryan Bisbey, a former MIT postdoc; Karl Westendorff, an MIT graduate student; and Alexander Soudackov, a research scientist at Yale University, are also authors of the paper.

      Passing protons

      Proton-coupled electron transfer occurs when a molecule, often water or an acid, transfers a proton to another molecule or to an electrode surface, which stimulates the proton acceptor to also take up an electron. This kind of reaction has been harnessed for many energy applications.

      “These proton-coupled electron transfer reactions are ubiquitous. They are often key steps in catalytic mechanisms, and are particularly important for energy conversion processes such as hydrogen generation or fuel cell catalysis,” Surendranath says.

      In a hydrogen-generating electrolyzer, this approach is used to remove protons from water and add electrons to the protons to form hydrogen gas. In a fuel cell, electricity is generated when protons and electrons are removed from hydrogen gas and added to oxygen to form water.

      Proton-coupled electron transfer is common in many other types of chemical reactions, for example, carbon dioxide reduction (the conversion of carbon dioxide into chemical fuels by adding electrons and protons). Scientists have learned a great deal about how these reactions occur when the proton acceptors are molecules, because they can precisely control the structure of each molecule and observe how electrons and protons pass between them. However, when proton-coupled electron transfer occurs at the surface of an electrode, the process is much more difficult to study because electrode surfaces are usually very heterogenous, with many different sites that a proton could potentially bind to.

      To overcome that obstacle, the MIT team developed a way to design electrode surfaces that gives them much more precise control over the composition of the electrode surface. Their electrodes consist of sheets of graphene with organic, ring-containing compounds attached to the surface. At the end of each of these organic molecules is a negatively charged oxygen ion that can accept protons from the surrounding solution, which causes an electron to flow from the circuit into the graphitic surface.

      “We can create an electrode that doesn’t consist of a wide diversity of sites but is a uniform array of a single type of very well-defined sites that can each bind a proton with the same affinity,” Surendranath says. “Since we have these very well-defined sites, what this allowed us to do was really unravel the kinetics of these processes.”

      Using this system, the researchers were able to measure the flow of electrical current to the electrodes, which allowed them to calculate the rate of proton transfer to the oxygen ion at the surface at equilibrium — the state when the rates of proton donation to the surface and proton transfer back to solution from the surface are equal. They found that the pH of the surrounding solution has a significant effect on this rate: The highest rates occurred at the extreme ends of the pH scale — pH 0, the most acidic, and pH 14, the most basic.

      To explain these results, researchers developed a model based on two possible reactions that can occur at the electrode. In the first, hydronium ions (H3O+), which are in high concentration in strongly acidic solutions, deliver protons to the surface oxygen ions, generating water. In the second, water delivers protons to the surface oxygen ions, generating hydroxide ions (OH-), which are in high concentration in strongly basic solutions.

      However, the rate at pH 0 is about four times faster than the rate at pH 14, in part because hydronium gives up protons at a faster rate than water.

      A reaction to reconsider

      The researchers also discovered, to their surprise, that the two reactions have equal rates not at neutral pH 7, where hydronium and hydroxide concentrations are equal, but at pH 10, where the concentration of hydroxide ions is 1 million times that of hydronium. The model suggests this is because the forward reaction involving proton donation from hydronium or water contributes more to the overall rate than the backward reaction involving proton removal by water or hydroxide.

      Existing models of how these reactions occur at electrode surfaces assume that the forward and backward reactions contribute equally to the overall rate, so the new findings suggest that those models may need to be reconsidered, the researchers say.

      “That’s the default assumption, that the forward and reverse reactions contribute equally to the reaction rate,” Surendranath says. “Our finding is really eye-opening because it means that the assumption that people are using to analyze everything from fuel cell catalysis to hydrogen evolution may be something we need to revisit.”

      The researchers are now using their experimental setup to study how adding different types of ions to the electrolyte solution surrounding the electrode may speed up or slow down the rate of proton-coupled electron flow.

      “With our system, we know that our sites are constant and not affecting each other, so we can read out what the change in the solution is doing to the reaction at the surface,” Lewis says.

      The research was funded by the U.S. Department of Energy Office of Basic Energy Sciences. More

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      The future of motorcycles could be hydrogen

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      MIT’s Electric Vehicle Team, which has a long record of building and racing innovative electric vehicles, including cars and motorcycles, in international professional-level competitions, is trying something very different this year: The team is building a hydrogen-powered electric motorcycle, using a fuel cell system, as a testbed for new hydrogen-based transportation.

      The motorcycle successfully underwent its first full test-track demonstration in October. It is designed as an open-source platform that should make it possible to swap out and test a variety of different components, and for others to try their own versions based on plans the team is making freely available online.

      Aditya Mehrotra, who is spearheading the project, is a graduate student working with mechanical engineering professor Alex Slocum, the Walter M. May  and A. Hazel May Chair in Emerging Technologies. Mehrotra was studying energy systems and happened to also really like motorcycles, he says, “so we came up with the idea of a hydrogen-powered bike. We did an evaluation study, and we thought that this could actually work. We [decided to] try to build it.”

      Team members say that while battery-powered cars are a boon for the environment, they still face limitations in range and have issues associated with the mining of lithium and resulting emissions. So, the team was interested in exploring hydrogen-powered vehicles as a clean alternative, allowing for vehicles that could be quickly refilled just like gasoline-powered vehicles.

      Unlike past projects by the team, which has been part of MIT since 2005, this vehicle will not be entering races or competitions but will be presented at a variety of conferences. The team, consisting of about a dozen students, has been working on building the prototype since January 2023. In October they presented the bike at the Hydrogen Americas Summit, and in May they will travel to the Netherlands to present it at the World Hydrogen Summit. In addition to the two hydrogen summits, the team plans to show its bike at the Consumer Electronics Show in Las Vegas this month.

      “We’re hoping to use this project as a chance to start conversations around ‘small hydrogen’ systems that could increase demand, which could lead to the development of more infrastructure,” Mehrotra says. “We hope the project can help find new and creative applications for hydrogen.” In addition to these demonstrations and the online information the team will provide, he adds, they are also working toward publishing papers in academic journals describing their project and lessons learned from it, in hopes of making “an impact on the energy industry.”

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      For the love of speed: Building a hydrogen-powered motorcycle

      The motorcycle took shape over the course of the year piece by piece. “We got a couple of industry sponsors to donate components like the fuel cell and a lot of the major components of the system,” he says. They also received support from the MIT Energy Initiative, the departments of Mechanical Engineering and Electrical Engineering and Computer Science, and the MIT Edgerton Center.

      Initial tests were conducted on a dynamometer, a kind of instrumented treadmill Mehrotra describes as “basically a mock road.” The vehicle used battery power during its development, until the fuel cell, provided by South Korean company Doosan, could be delivered and installed. The space the group has used to design and build the prototype, the home of the Electric Vehicle Team, is in MIT’s Building N51 and is well set up to do detailed testing of each of the bike’s components as it is developed and integrated.

      Elizabeth Brennan, a senior in mechanical engineering, says she joined the team in January 2023 because she wanted to gain more electrical engineering experience, “and I really fell in love with it.” She says group members “really care and are very excited to be here and work on this bike and believe in the project.”

      Brennan, who is the team’s safety lead, has been learning about the safe handling methods required for the bike’s hydrogen fuel, including the special tanks and connectors needed. The team initially used a commercially available electric motor for the prototype but is now working on an improved version, designed from scratch, she says, “which gives us a lot more flexibility.”

      As part of the project, team members are developing a kind of textbook describing what they did and how they carried out each step in the process of designing and fabricating this hydrogen electric fuel-cell bike. No such motorcycle yet exists as a commercial product, though a few prototypes have been built.

      That kind of guidebook to the process “just doesn’t exist,” Brennan says. She adds that “a lot of the technology development for hydrogen is either done in simulation or is still in the prototype stages, because developing it is expensive, and it’s difficult to test these kinds of systems.” One of the team’s goals for the project is to make everything available as an open-source design, and “we want to provide this bike as a platform for researchers and for education, where researchers can test ideas in both space- and funding-constrained environments.”

      Unlike a design built as a commercial product, Mehrotra says, “our vehicle is fully designed for research, so you can swap components in and out, and get real hardware data on how good your designs are.” That can help people work on implementing their new design ideas and help push the industry forward, he says.

      The few prototypes developed previously by some companies were inefficient and expensive, he says. “So far as we know, we are the first fully open-source, rigorously documented, tested and released-as-a-platform, [fuel cell] motorcycle in the world. No one else has made a motorcycle and tested it to the level that we have, and documented to the point that someone might actually be able to take this and scale it in the future, or use it in research.”

      He adds that “at the moment, this vehicle is affordable for research, but it’s not affordable yet for commercial production because the fuel cell is a very big, expensive component.” Doosan Fuel Cell, which provided the fuel cell for the prototype bike, produces relatively small and lightweight fuel cells mostly for use in drones. The company also produces hydrogen storage and delivery systems.

      The project will continue to evolve, says team member Annika Marschner, a sophomore in mechanical engineering. “It’s sort of an ongoing thing, and as we develop it and make changes, make it a stronger, better bike, it will just continue to grow over the years, hopefully,” she says.

      While the Electric Vehicle Team has until now focused on battery-powered vehicles, Marschner says, “Right now we’re looking at hydrogen because it seems like something that’s been less explored than other technologies for making sustainable transportation. So, it seemed like an exciting thing for us to offer our time and effort to.”

      Making it all work has been a long process. The team is using a frame from a 1999 motorcycle, with many custom-made parts added to support the electric motor, the hydrogen tank, the fuel cell, and the drive train. “Making everything fit in the frame of the bike is definitely something we’ve had to think about a lot because there’s such limited space there. So, it required trying to figure out how to mount things in clever ways so that there are not conflicts,” she says.

      Marschner says, “A lot of people don’t really imagine hydrogen energy being something that’s out there being used on the roads, but the technology does exist.” She points out that Toyota and Hyundai have hydrogen-fueled vehicles on the market, and that some hydrogen fuel stations exist, mostly in California, Japan, and some European countries. But getting access to hydrogen, “for your average consumer on the East Coast, is a huge, huge challenge. Infrastructure is definitely the biggest challenge right now to hydrogen vehicles,” she says.

      She sees a bright future for hydrogen as a clean fuel to replace fossil fuels over time. “I think it has a huge amount of potential,” she says. “I think one of the biggest challenges with moving hydrogen energy forward is getting these demonstration projects actually developed and showing that these things can work and that they can work well. So, we’re really excited to bring it along further.” More

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      MIT researchers outline a path for scaling clean hydrogen production

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      Hydrogen is an integral component for the manufacture of steel, fertilizer, and a number of chemicals. Producing hydrogen using renewable electricity offers a way to clean up these and many other hard-to-decarbonize industries.

      But supporting the nascent clean hydrogen industry while ensuring it grows into a true force for decarbonization is complicated, in large part because of the challenges of sourcing clean electricity. To assist regulators and to clarify disagreements in the field, MIT researchers published a paper today in Nature Energy that outlines a path to scale the clean hydrogen industry while limiting emissions.

      Right now, U.S. electric grids are mainly powered by fossil fuels, so if scaling hydrogen production translates to greater electricity use, it could result in a major emissions increase. There is also the risk that “low-carbon” hydrogen projects could end up siphoning renewable energy that would have been built anyway for the grid. It is therefore critical to ensure that low-carbon hydrogen procures electricity from “additional” renewables, especially when hydrogen production is supported by public subsidies. The challenge is allowing hydrogen producers to procure renewable electricity in a cost-effective way that helps the industry grow, while minimizing the risk of high emissions.

      U.S. regulators have been tasked with sorting out this complexity. The Inflation Reduction Act (IRA) is offering generous production tax credits for low-carbon hydrogen. But the law didn’t specify exactly how hydrogen’s carbon footprint should be judged.

      To this end, the paper proposes a phased approach to qualify for the tax credits. In the first phase, hydrogen created from grid electricity can receive the credits under looser standards as the industry gets its footing. Once electricity demand for hydrogen production grows, the industry should be required to adhere to stricter standards for ensuring the electricity is coming from renewable sources. Finally, many years from now when the grid is mainly powered by renewable energy, the standards can loosen again.

      The researchers say the nuanced approach ensures the law supports the growth of clean hydrogen without coming at the expense of emissions.

      “If we can scale low-carbon hydrogen production, we can cut some significant sources of existing emissions and enable decarbonization of other critical industries,” says paper co-author Michael Giovanniello, a graduate student in MIT’s Technology and Policy Program. “At the same time, there’s a real risk of implementing the wrong requirements and wasting lots of money to subsidize carbon-intensive hydrogen production. So, you have to balance scaling the industry with reducing the risk of emissions. I hope there’s clarity and foresight in how this policy is implemented, and I hope our paper makes the argument clear for policymakers.”

      Giovanniello’s co-authors on the paper are MIT Energy Initiative (MITEI) Principal Research Scientist Dharik Mallapragada, MITEI Research Assistant Anna Cybulsky, and MIT Sloan School of Management Senior Lecturer Tim Schittekatte.

      On definitions and disagreements

      When renewable electricity from a wind farm or solar array flows through the grid, it’s mixed with electricity from fossil fuels. The situation raises a question worth billions of dollars in federal tax credits: What are the carbon dioxide emissions of grid users who are also signing agreements to procure electricity from renewables?

      One way to answer this question is via energy system models that can simulate various scenarios related to technology configurations and qualifying requirements for receiving the credit.

      To date, many studies using such models have come up with very different emissions estimates for electrolytic hydrogen production. One source of disagreement is over “time matching,” which refers to how strictly to align the timing of electric hydrogen production with the generation of clean electricity. One proposed approach, known as hourly time matching, would require that electricity consumption to produce hydrogen is accounted for by procured clean electricity at every hour.

      A less stringent approach, called annual time matching, would offer more flexibility in hourly electricity consumption for hydrogen production, so long as the annual consumption matches the annual generation from the procured clean electricity generation. The added flexibility could reduce the cost of hydrogen production, which is critical for scaling its use, but could lead to greater emissions per unit of hydrogen produced.

      Another point of disagreement stems from how hydrogen producers purchase renewable electricity. If an electricity user procures energy from an existing solar farm, it’s simply increasing overall electricity demand and taking clean energy away from other users. But if the tax credits only go to electric hydrogen producers that sign power purchase agreements with new renewable suppliers, they’re supporting clean electricity that wouldn’t have otherwise been contributing to the grid. This concept is known as “additionality.”

      The researchers analyzed previous studies that reached conflicting conclusions, and identified different interpretations of additionality underlying their methodologies. One interpretation of additionality is that new electrolytic hydrogen projects do not compete with nonhydrogen demand for renewable energy resources. The other assumes that they do compete for all newly deployed renewables — and, because of low-carbon hydrogen subsidies, the electrolyzers take priority.

      Using DOLPHYN, an open-source energy systems model, the researchers tested how these two interpretations of additionality (the “compete” and “noncompete” scenarios) impact the cost and emissions of the alternative time-matching requirements (hourly and annual) associated with grid-interconnected hydrogen production. They modeled two regional U.S. grids — in Texas and Florida — which represent the high and low end of renewables deployment. They further tested the interaction of four critical policy factors with the hydrogen tax credits, including renewable portfolio standards, constraints of renewables and energy storage deployment, limits on hydrogen electrolyzer capacity factors, and competition with natural gas-based hydrogen with carbon capture.

      They show that the different modeling interpretations of additionality are the primary factor explaining the vastly different estimates of emissions from electrolyzer hydrogen under annual time-matching.

      Getting policy right

      The paper concludes that the right way to implement the production tax credit qualifying requirements depends on whether you believe we live in a “compete” or “noncompete” world. But reality is not so binary.

      “What framework is more appropriate is going to change with time as we deploy more hydrogen and the grid decarbonizes, so therefore the policy has to be adaptive to those changes,” Mallapragada says. “It’s an evolving story that’s tied to what’s happening in the rest of the energy system, and in particular the electric grid, both from the technological as policy perspective.”

      Today, renewables deployment is driven, in part, by binding factors, such as state renewable portfolio standards and corporate clean-energy commitments, as well as by purely market forces. Since the electrolyzer is so nascent, and today resembles a “noncompete” world, the researchers argue for starting with the less strict annual requirement. But as hydrogen demand for renewable electricity grows, and market competition drives an increasing quantity of renewables deployment, transitioning to hourly matching will be necessary to avoid high emissions.

      This phased approach necessitates deliberate, long-term planning from regulators. “If regulators make a decision and don’t outline when they’ll reassess that decision, they might never reassess that decision, so we might get locked into a bad policy,” Giovanniello explains. In particular, the paper highlights the risk of locking in an annual time-matching requirement that leads to significant emissions in future.

      The researchers hope their findings will contribute to upcoming policy decisions around the Inflation Reduction Act’s tax credits. They started looking into this question around a year ago, making it a quick turnaround by academic standards.

      “There was definitely a sense to be timely in our analysis so as to be responsive to the needs of policy,” Mallapragada says.

      The researchers say the paper can also help policymakers understand the emissions impacts of companies procuring renewable energy credits to meet net-zero targets and electricity suppliers attempting to sell “green” electricity.

      “This question is relevant in a lot of different domains,” Schittekatte says. “Other popular examples are the emission impacts of data centers that procure green power, or even the emission impacts of your own electric car sourcing power from your rooftop solar and the grid. There are obviously differences based on the technology in question, but the underlying research question we’ve answered is the same. This is an extremely important topic for the energy transition.” More

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      Making nuclear energy facilities easier to build and transport

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      For the United States to meet its net zero goals, nuclear energy needs to be on the smorgasbord of options. The problem: Its production still suffers from a lack of scale. To increase access rapidly, we need to stand up reactors quickly, says Isabel Naranjo De Candido, a third-year doctoral student advised by Professor Koroush Shirvan.

      One option is to work with microreactors, transportable units that can be wheeled to areas that need clean electricity. Naranjo De Candido’s master’s thesis at MIT, supervised by Professor Jacopo Buongiorno, focused on such reactors.

      Another way to improve access to nuclear energy is to develop reactors that are modular so their component units can be manufactured quickly while still maintaining quality. “The idea is that you apply the industrialization techniques of manufacturing so companies produce more [nuclear] vessels, with a more predictable supply chain,” she says. The assumption is that working with standardized recipes to manufacture just a few designed components over and over again improves speed and reliability and decreases cost.

      As part of her doctoral studies, Naranjo De Candido is working on optimizing the operations and management of these small, modular reactors so they can be efficient in all stages of their lifecycle: building; operations and maintenance; and decommissioning. The motivation for her research is simple: “We need nuclear for climate change because we need a reliable and stable source of energy to fight climate change,” she says.

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      A childhood in Italy

      Despite her passion for nuclear energy and engineering today, Naranjo De Candido was unsure what she wanted to pursue after high school in Padua, Italy. The daughter of a physician Italian mother and an architect Spanish father, she enrolled in a science-based high school shortly after middle school, as she knew that was the track she enjoyed best.

      Having earned very high marks in school, she won a full scholarship to study in Pisa, at the special Sant’Anna School of Advanced Studies. Housed in a centuries-old convent, the school granted only masters and doctoral degrees. “I had to select what to study but I was unsure. I knew I was interested in engineering,” she recalls, “so I selected mechanical engineering because it’s more generic.”

      It turns out Sant’Anna was a perfect fit for Naranjo De Candido to explore her passions. An inspirational nuclear engineering course during her studies set her on the path toward studying the field as part of her master’s studies in Pisa. During her time there, she traveled around the world — to China as part of a student exchange program and to Switzerland and the United States for internships. “I formed a good background and curriculum and that allowed me to [gain admission] to MIT,” she says.

      At an internship at NASA’s Jet Propulsion Lab, she met an MIT mechanical engineering student who encouraged her to apply to the school for doctoral studies. Yet another mentor in the Italian nuclear sector had also suggested she apply to MIT to pursue nuclear engineering, so she decided to take the leap.

      And she is glad she did.

      Improving access to nuclear energy

      At MIT, Naranjo De Candido is working on improving access to nuclear energy by scaling down reactor size and, in the case of microreactors, making them mobile enough to travel to places where they’re needed. “The idea with a microreactor is that when the fuel is exhausted, you replace the entire microreactor onsite with a freshly fueled unit and take the old one back to a central facility where it’s going to be refueled,” she says. One of the early use cases for such microreactors has been remote mining sites which need reliable power 24/7.

      Modular reactors, about 10 times the size of microreactors, ensure access differently: The components can be manufactured and installed at scale. These reactors don’t just deliver electricity but also cater to the market for industrial heat, she says. “You can locate them close to industrial facilities and use the heat directly to power ammonia or hydrogen production or water desalinization for example,” she adds.

      As more of these modular reactors are installed, the industry is expected to expand to include enterprises that choose to simply build them and hand off operations to other companies. Whereas traditional nuclear energy reactors might have a full suite of staff on board, smaller-scale reactors such as modular ones cannot afford to staff in large numbers, so talent needs to be optimized and staff shared among many units. “Many of these companies are very interested in knowing exactly how many people and how much money to allocate, and how to organize resources to serve more than one reactor at the same time,” she says.

      Naranjo De Candido is working on a complex software program that factors in a large range of variables — from raw materials cost and worker training, reactor size, megawatt output and more — and leans on historical data to predict what resources newer plants might need. The program also informs operators about the tradeoffs they need to accept. For example, she explains, “if you reduce people below the typical level assigned, how does that impact the reliability of the plant, that is, the number of hours that it is able to operate without malfunctions and failures?”

      And managing and operating a nuclear reactor is particularly complex because safety standards limit how much time workers can work in certain areas and how safe zones need to be handled.

      “There’s a shortage of [qualified talent] in the industry so this is not just about reducing costs but also about making it possible to have plants out there,” Naranjo De Candido says. Different types of talent are needed, from professionals who specialize in mechanical components to electronic controls. The model that she is working on considers the need for such specialized skillsets as well as making room for cross-training talent in multiple fields as needed.

      In keeping with her goal of making nuclear energy more accessible, the optimization software will be open-source, available for all to use. “We want this to be a common ground for utilities and vendors and other players to be able to communicate better,” Naranjo De Candido says, Doing so will accelerate the operation of nuclear energy plants at scale, she hopes — an achievement that will come not a moment too soon. More

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      Accelerated climate action needed to sharply reduce current risks to life and life-support systems

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      Hottest day on record. Hottest month on record. Extreme marine heatwaves. Record-low Antarctic sea-ice.

      While El Niño is a short-term factor in this year’s record-breaking heat, human-caused climate change is the long-term driver. And as global warming edges closer to 1.5 degrees Celsius — the aspirational upper limit set in the Paris Agreement in 2015 — ushering in more intense and frequent heatwaves, floods, wildfires, and other climate extremes much sooner than many expected, current greenhouse gas emissions-reduction policies are far too weak to keep the planet from exceeding that threshold. In fact, on roughly one-third of days in 2023, the average global temperature was at least 1.5 C higher than pre-industrial levels. Faster and bolder action will be needed — from the in-progress United Nations Climate Change Conference (COP28) and beyond — to stabilize the climate and minimize risks to human (and nonhuman) lives and the life-support systems (e.g., food, water, shelter, and more) upon which they depend.

      Quantifying the risks posed by simply maintaining existing climate policies — and the benefits (i.e., avoided damages and costs) of accelerated climate action aligned with the 1.5 C goal — is the central task of the 2023 Global Change Outlook, recently released by the MIT Joint Program on the Science and Policy of Global Change.

      Based on a rigorous, integrated analysis of population and economic growth, technological change, Paris Agreement emissions-reduction pledges (Nationally Determined Contributions, or NDCs), geopolitical tensions, and other factors, the report presents the MIT Joint Program’s latest projections for the future of the earth’s energy, food, water, and climate systems, as well as prospects for achieving the Paris Agreement’s short- and long-term climate goals.

      The 2023 Global Change Outlook performs its risk-benefit analysis by focusing on two scenarios. The first, Current Trends, assumes that Paris Agreement NDCs are implemented through the year 2030, and maintained thereafter. While this scenario represents an unprecedented global commitment to limit greenhouse gas emissions, it neither stabilizes climate nor limits climate change. The second scenario, Accelerated Actions, extends from the Paris Agreement’s initial NDCs and aligns with its long-term goals. This scenario aims to limit and stabilize human-induced global climate warming to 1.5 C by the end of this century with at least a 50 percent probability. Uncertainty is quantified using 400-member ensembles of projections for each scenario.

      This year’s report also includes a visualization tool that enables a higher-resolution exploration of both scenarios.

      Energy

      Between 2020 and 2050, population and economic growth are projected to drive continued increases in energy needs and electrification. Successful achievement of current Paris Agreement pledges will reinforce a shift away from fossil fuels, but additional actions will be required to accelerate the energy transition needed to cap global warming at 1.5 C by 2100.

      During this 30-year period under the Current Trends scenario, the share of fossil fuels in the global energy mix drops from 80 percent to 70 percent. Variable renewable energy (wind and solar) is the fastest growing energy source with more than an 8.6-fold increase. In the Accelerated Actions scenario, the share of low-carbon energy sources grows from 20 percent to slightly more than 60 percent, a much faster growth rate than in the Current Trends scenario; wind and solar energy undergo more than a 13.3-fold increase.

      While the electric power sector is expected to successfully scale up (with electricity production increasing by 73 percent under Current Trends, and 87 percent under Accelerated Actions) to accommodate increased demand (particularly for variable renewables), other sectors face stiffer challenges in their efforts to decarbonize.

      “Due to a sizeable need for hydrocarbons in the form of liquid and gaseous fuels for sectors such as heavy-duty long-distance transport, high-temperature industrial heat, agriculture, and chemical production, hydrogen-based fuels and renewable natural gas remain attractive options, but the challenges related to their scaling opportunities and costs must be resolved,” says MIT Joint Program Deputy Director Sergey Paltsev, a lead author of the 2023 Global Change Outlook.

      Water, food, and land

      With a global population projected to reach 9.9 billion by 2050, the Current Trends scenario indicates that more than half of the world’s population will experience pressures to its water supply, and that three of every 10 people will live in water basins where compounding societal and environmental pressures on water resources will be experienced. Population projections under combined water stress in all scenarios reveal that the Accelerated Actions scenario can reduce approximately 40 million of the additional 570 million people living in water-stressed basins at mid-century.

      Under the Current Trends scenario, agriculture and food production will keep growing. This will increase pressure for land-use change, water use, and use of energy-intensive inputs, which will also lead to higher greenhouse gas emissions. Under the Accelerated Actions scenario, less agricultural and food output is observed by 2050 compared to the Current Trends scenario, since this scenario affects economic growth and increases production costs. Livestock production is more greenhouse gas emissions-intensive than crop and food production, which, under carbon-pricing policies, drives demand downward and increases costs and prices. Such impacts are transmitted to the food sector and imply lower consumption of livestock-based products.

      Land-use changes in the Accelerated Actions scenario are similar to those in the Current Trends scenario by 2050, except for land dedicated to bioenergy production. At the world level, the Accelerated Actions scenario requires cropland area to increase by 1 percent and pastureland to decrease by 4.2 percent, but land use for bioenergy must increase by 44 percent.

      Climate trends

      Under the Current Trends scenario, the world is likely (more than 50 percent probability) to exceed 2 C global climate warming by 2060, 2.8 C by 2100, and 3.8 C by 2150. Our latest climate-model information indicates that maximum temperatures will likely outpace mean temperature trends over much of North and South America, Europe, northern and southeast Asia, and southern parts of Africa and Australasia. So as human-forced climate warming intensifies, these regions are expected to experience more pronounced record-breaking extreme heat events.

      Under the Accelerated Actions scenario, global temperature will continue to rise through the next two decades. But by 2050, global temperature will stabilize, and then slightly decline through the latter half of the century.

      “By 2100, the Accelerated Actions scenario indicates that the world can be virtually assured of remaining below 2 C of global warming,” says MIT Joint Program Deputy Director C. Adam Schlosser, a lead author of the report. “Nevertheless, additional policy mechanisms must be designed with more comprehensive targets that also support a cleaner environment, sustainable resources, as well as improved and equitable human health.”

      The Accelerated Actions scenario not only stabilizes global precipitation increase (by 2060), but substantially reduces the magnitude and potential range of increases to almost one-third of Current Trends global precipitation changes. Any global increase in precipitation heightens flood risk worldwide, so policies aligned with the Accelerated Actions scenario would considerably reduce that risk.

      Prospects for meeting Paris Agreement climate goals

      Numerous countries and regions are progressing in fulfilling their Paris Agreement pledges. Many have declared more ambitious greenhouse gas emissions-mitigation goals, while financing to assist the least-developed countries in sustainable development is not forthcoming at the levels needed. In this year’s Global Stocktake Synthesis Report, the U.N. Framework Convention on Climate Change evaluated emissions reductions communicated by the parties of the Paris Agreement and concluded that global emissions are not on track to fulfill the most ambitious long-term global temperature goals of the Paris Agreement (to keep warming well below 2 C — and, ideally, 1.5 C — above pre-industrial levels), and there is a rapidly narrowing window to raise ambition and implement existing commitments in order to achieve those targets. The Current Trends scenario arrives at the same conclusion.

      The 2023 Global Change Outlook finds that both global temperature targets remain achievable, but require much deeper near-term emissions reductions than those embodied in current NDCs.

      Reducing climate risk

      This report explores two well-known sets of risks posed by climate change. Research highlighted indicates that elevated climate-related physical risks will continue to evolve by mid-century, along with heightened transition risks that arise from shifts in the political, technological, social, and economic landscapes that are likely to occur during the transition to a low-carbon economy.

      “Our Outlook shows that without aggressive actions the world will surpass critical greenhouse gas concentration thresholds and climate targets in the coming decades,” says MIT Joint Program Director Ronald Prinn. “While the costs of inaction are getting higher, the costs of action are more manageable.” More

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      New study shows how universities are critical to emerging fusion industry

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      A new study suggests that universities have an essential role to fulfill in the continued growth and success of any modern high-tech industry, and especially the nascent fusion industry; however, the importance of that role is not reflected in the number of fusion-oriented faculty and educational channels currently available. Academia’s responsiveness to the birth of other modern scientific fields, such as aeronautics and nuclear fission, provides a template for the steps universities can take to enable a robust fusion industry.

      Authored by Dennis Whyte, the Hitachi America Professor of Engineering and director of the Plasma Science and Fusion Center at MIT; Carlos Paz-Soldan, associate professor of applied physics and applied mathematics at Columbia University; and Brian D. Wirth, the Governor’s Chair Professor of Computational Nuclear Engineering at the University of Tennessee, the paper was recently published in the journal Physics of Plasmas as part of a special collection titled “Private Fusion Research: Opportunities and Challenges in Plasma Science.”

      With contributions from authors in academia, government, and private industry, the collection outlines a framework for public-private partnerships that will be essential for the success of the fusion industry.

      Now being seen as a potential source of unlimited green energy, fusion is the same process that powers the sun — hydrogen atoms combine to form helium, releasing vast amounts of clean energy in the form of light and heat.

      The excitement surrounding fusion’s arrival has resulted in the proliferation of dozens of for-profit companies positioning themselves at the forefront of the commercial fusion energy industry. In the near future, those companies will require a significant network of fusion-fluent workers to take on varied tasks requiring a range of skills.

      While the authors acknowledge the role of private industry, especially as an increasingly dominant source of research funding, they also show that academia is and will continue to be critical to industry’s development, and it cannot be decoupled from private industry’s growth. Despite the evidence of this burgeoning interest, the size and scale of the field’s academic network at U.S.-based universities is sparse.

      According to Whyte, “Diversifying the [fusion] field by adding more tracks for master’s students and undergraduates who can transition into industry more quickly is an important step.”

      An analysis found that while there are 57 universities in the United States active in plasma and fusion research, the average number of tenured or tenure-track plasma/fusion faculty at each institution is only two. By comparison, a sampling of US News and World Report’s top 10 programs for nuclear fission and aeronautics/astronautics found an average of nearly 20 faculty devoted to fission and 32 to aero/astro.

      “University programs in fusion and their sponsors need to up their game and hire additional faculty if they want to provide the necessary workforce to support a growing U.S. fusion industry,” adds Paz-Soldan.

      The growth and proliferation of those fields and others, such as computing and biotechnology, were historically in lockstep with the creation of academic programs that helped drive the fields’ progress and widespread acceptance. Creating a similar path for fusion is essential to ensuring its sustainable growth, and as Wirth notes, “that this growth should be pursued in a way that is interdisciplinary across numerous engineering and science disciplines.”

      At MIT, an example of that path is seen at the Plasma Science and Fusion Center.

      The center has deep historical ties to government research programs, and the largest fusion company in the world, Commonwealth Fusion Systems (CFS), was spun out of the PSFC by Whyte’s former students and an MIT postdoc. Whyte also serves as the primary investigator in collaborative research with CFS on SPARC, a proof-of-concept fusion platform for advancing tokamak science that is scheduled for completion in 2025.

      “Public and private roles in the fusion community are rapidly evolving in response to the growth of privately funded commercial product development,” says Michael Segal, head of open innovation at CFS. “The fusion industry will increasingly rely on its university partners to train students, work across diverse disciplines, and execute small and midsize programs at speed.”

      According to the authors, another key reason academia will remain essential to the continued growth and development of fusion is because it is unconflicted. Whyte comments, “Our mandate is sharing information and education, which means we have no competitive conflict and innovation can flow freely.” Furthermore, fusion science is inherently multidisciplinary: “[It] requires physicists, computer scientists, engineers, chemists, etc. and it’s easy to tap into all those disciplines in an academic environment where they’re all naturally rubbing elbows and collaborating.”

      Creating a new energy industry, however, will also require a workforce skilled in disciplines other than STEM, say the authors. As fusion companies continue to grow, they will need expertise in finance, safety, licensing, and market analysis. Any successful fusion enterprise will also have major geopolitical, societal, and economic impacts, all of which must be managed.

      Ultimately, there are several steps the authors identify to help build the connections between academia and industry that will be important going forward: The first is for universities to acknowledge the rapidly changing fusion landscape and begin to adapt. “Universities need to embrace the growth of the private sector in fusion, recognize the opportunities it provides, and seek out mutually beneficial partnerships,” says Paz-Soldan.

      The second step is to reconcile the mission of educational institutions — unconflicted open access — with condensed timelines and proprietary outputs that come with private partnerships. At the same time, the authors note that private fusion companies should embrace the transparency of academia by publishing and sharing the findings they can through peer-reviewed journals, which will be a necessary part of building the industry’s credibility.

      The last step, the authors say, is for universities to become more flexible and creative in their technology licensing strategies to ensure ideas and innovations find their way from the lab into industry.

      “As an industry, we’re in a unique position because everything is brand new,” Whyte says. “But we’re enough students of history that we can see what’s needed to succeed; quantifying the status of the private and academic landscape is an important strategic touchstone. By drawing attention to the current trajectory, hopefully we’ll be in a better position to work with our colleagues in the public and private sector and make better-informed choices about how to proceed.” More