Evelyn Reynolds

Arnav Patel is a self-described sustainability enthusiast. Working on solutions related to climate change has been a central thread woven throughout his time at MIT.  As a first-year student, he was initially drawn to mechanical engineering because he wanted to keep his options open.

“I felt like mechanical engineering is that perfect niche where there’s so much exposure to so many different fields. It has taught me more than just how to build things, it has changed how I think. It was honestly the best decision I ever made,” says Patel, now a senior studying mechanical engineering.

Class 2.00C (Design for Complex Environmental Issues), which is offered through the departments of Mechanical Engineering, Civil and Environmental Engineering, and MIT D-Lab, was the first class to expose him to how engineers are developing solutions to promote sustainability. Part of the Terrascope program for first-year students, the class focused on the theme “climate resiliency” the year Patel took it. Patel and his classmates traveled to the Netherlands for the class to see the infrastructure that has been built to mitigate damage from climate change-related flooding. 

The class and trip were a turning point for Patel.

“From then on, I have approached sustainability in pretty much every direction I could at MIT,” he says.

Advocating for fossil fuel divestment

The summer after his sophomore year, Patel became a founding member of a group called MIT Divest. The student-led group advocates for MIT to divest or remove investments in any companies that “develop fossil fuel resources beyond the 2 degrees Celsius carbon emissions limit, spread climate disinformation, and engage in anti-climate lobbying.”

The group also asks that any money divested from the fossil fuel industry be reinvested into carbon-free energy enterprises. For Patel, who is now co-chair of MIT Divest along with physics major Jessica Cohen, the group was his first foray into activism.

“Our work at MIT Divest is really exploring the climate activism side of things,” says Patel. “As a young person, I don’t have a lot of power on a government scale besides how I vote, but with MIT Divest I felt empowered to fight for change within the MIT community.”

Since launching, the group engaged in a number of activities to encourage fellow students and faculty to consider divestiture, including surveys, articles in MIT’s student newspaper The Tech, and meetings with members of MIT’s administration.

Patel is also the MIT Divest representative on MIT’s Climate Action Advisory Committee. He and the MIT Divest team hope to make divestments a central talking point as MIT shapes its Climate Action Plan, to be released this spring.

While MIT Divest has afforded Patel the opportunity to explore climate activism, his academic work has helped him develop sustainable solutions both on MIT’s campus and places further afield, like the Himalaya.

Reusable utensils on campusAs with most seniors this year, the fall 2020 semester looked different than Patel had envisioned. He was able to live on campus with his classmates, following various Covid-19 protocols put in place to keep the campus community safe.  

In class 2.S885 (Exploring Sustainability at Different Scales), Patel and his classmate Sheila Kennedy-Moore examined how to make on-campus dining during the pandemic more sustainable. For their final project in the class, Patel and Kennedy-Moore compared the energy use and carbon emissions associated with a variety of disposable utensils, containers, and cups.

They did a quantitative analysis of the materials used in the disposables provided to students eating in their dorm rooms by MIT Dining and made recommendations based on which materials had the smallest carbon footprint.

The pair also examined the effectiveness of the Reusable Utensil Pilot, launched by the Student Sustainability Coalition during the fall semester. They took into account the energy used to wash reusable utensils in warm water after each use.“What we found was that shifting from fully disposable utensils to reusable utensils could halve carbon emissions for the utensils during the semester,” says Patel.

Their work was referenced in a recommendation made by Waste Watchers, UA Sustain, and MIT SSC for MIT to provide reusable utensils to students. This spring, MIT Dining decided to include reusable utensils in students’ “back-to-campus” tote bag to promote the use of reusable utensils.

Sustainable Homes in the HimalayaFor his senior thesis, Patel is working with a team at MIT D-Lab in collaboration with Institute of Chemical Technology (ICT)-Mumbai and University of Petroleum and Energy Studies (UPES) on developing home energy solutions for communities in the Himalayan region. During the cold winter months, many Himalayan communities rely on inefficient and ineffective home heating methods. Some of these methods, in addition to open fires used to cook meals, are hazardous to people’s health.

“People often walk long distances to collect wood, suffer from fine particulate pollution from indoor fires and heating and cooking devices, and lack the ability to adequately provide heat during cold months and cook safely throughout the year,” says Patel.

The research team has conducted surveys to better understand the difficulties these communities face. Patel will conduct an analysis of this data and analyze user needs and preferences. His analysis will help to guide the team on which solutions may be suitable for problems associated with household energy in the region.

“Arnav has used his engineering intuition and user research skills that he learned in D-Lab courses to design and analyze a household needs assessment for our project on Livable Himalayan Homes,” says Daniel Sweeney, a research scientist at MIT D-Lab. “This project will result in affordable home energy solutions that meet the unique needs of these families and can be scaled across communities in the Himalayan region.”

According to Sweeney, Patel has become an integral part of MIT D-Lab over the years. “Arnav has a unique mix of MIT-nerdiness along with great care, dedication, and respect for the many collaborators he has worked with around the world. He has been a valuable member of the D-Lab family,” Sweeney adds.

In addition to working on his thesis, this semester Patel is participating in an MIT Experiential Learning Opportunity (ELO) with Beth Israel Deaconess Medical Center to help assess how their real estate decisions affect their carbon emissions. 

Sustainability in consultingAfter graduation in June, Patel will join management consulting firm Bain and Company as an associate consultant. While the move to management consulting may seem like a divergence from his passion for sustainability, Patel sees an opportunity to approach problems associated with climate change from a different angle.

“I landed in the management consulting realm because I wanted to understand the business world a little bit better,” he says. “That’s another area where I feel like I could play my part in pushing sustainability.” More

“The overall question for me is how to decarbonize society in the most affordable way,” says Nestor Sepulveda SM ’16, PhD ’20. As a postdoc at MIT and a researcher with the MIT Energy Initiative (MITEI), he worked with a team over several years to investigate what mix of energy sources might best accomplish this goal. The group’s initial studies suggested the “need to develop energy storage technologies that can be cost-effectively deployed for much longer durations than lithium-ion batteries,” says Dharik Mallapragada, a research scientist with MITEI.  

In a new paper published in Nature Energy, Sepulveda, Mallapragada, and colleagues from MIT and Princeton University offer a comprehensive cost and performance evaluation of the role of long-duration energy storage (LDES) technologies in transforming energy systems. LDES, a term that covers a class of diverse, emerging technologies, can respond to the variable output of renewables, discharging electrons for days and even weeks, providing resilience to an electric grid poised to deploy solar and wind power on a large scale.

“If we want to rely overwhelmingly on wind and solar power for electricity — increasingly the most affordable way to decrease carbon emissions — we have to deal with their intermittency,” says Jesse Jenkins SM ’14, PhD ’18, an assistant professor of mechanical and aerospace engineering and the Andlinger Center for Energy and the Environment at Princeton University and former researcher at MITEI.

In their paper, the researchers analyzed whether LDES paired with renewable energy sources and short-duration energy storage options like lithium-ion batteries could indeed power a massive and cost-effective transition to a decarbonized grid. They also investigated whether LDES might even eliminate the need for available-on-demand, or firm, low-carbon energy sources such as nuclear power and natural gas with carbon capture and sequestration.

“The message here is that innovative and low-cost LDES technologies could potentially have a big impact, making a deeply decarbonized electricity system more affordable and reliable,” says lead author Sepulveda, who now works as a consultant with McKinsey and Company.  But, he notes, “We will still be better off retaining firm low-carbon energy sources among our options.”

In addition to Jenkins and Mallapragada, the paper’s coauthors include Aurora Edington SM ’19, a MITEI research assistant at the time of this research and now a consultant at The Cadmus Group; and Richard K. Lester, the Japan Steel Industry Professor and associate provost at MIT, and former head of the Department of Nuclear Science and Engineering.

“As the world begins to focus more seriously on how to achieve deep decarbonization goals in the coming decades, the insights from these system-level studies are essential,” says Lester. “Researchers, innovators, investors, and policymakers will all benefit from knowledge of the cost and technical performance targets that are suggested by this work.” 

Performance and cost

The team set out to assess the impacts of LDES solutions in hypothetical electric systems that reflect real-world conditions, where technologies are scrutinized not merely by their standalone attributes, but by their relative value when matched against other energy sources.

“We need to decarbonize at an affordable cost to society, and we wanted to know if LDES can increase our probability of success while also reducing overall system cost, given the other technologies competing in the space,” says Sepulveda.

In pursuit of this goal, the team deployed an electricity system capacity expansion model, GenX, earlier developed by Jenkins and Sepulveda while at MIT. This simulation tool made it possible to evaluate the potential system impact of utilizing LDES technologies, including technologies currently being developed and others that could potentially be developed, for different future low-carbon electric grid scenarios characterized by cost and performance attributes of renewable generation, different types of firm generation, as well as alternative electricity demand projections. The study, says Jenkins, was “the first extensive use of this sort of experimental method of applying wide-scale parametric uncertainty and long-term systems-level analysis to evaluate and identify target goals regarding cost and performance for emerging long-duration energy storage technologies.”

For their study, the researchers surveyed a range of long-duration technologies — some backed by the U.S. Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E) program — to define the plausible cost and performance attributes of future LDES systems based on five key parameters that encompass a range of mechanical, chemical, electrochemical, and thermal approaches. These include pumped hydropower storage, vanadium redox flow batteries, aqueous sulfur flow batteries, and firebrick resistance-heated thermal storage, among others.

“Think of a bathtub, where the parameter of energy storage capacity is analogous to the volume of the tub,” explains Jenkins. Continuing the analogy, another important parameter, charge power capacity, is the size of the faucet filling the tub, and discharge power capacity, the size of the drain. In the most generalized version of an LDES technology, each attribute of the system can be independently sized. In optimizing an energy system where LDES technology functions as “an economically attractive contributor to a lower-cost, carbon-free grid,” says Jenkins, the researchers found that the parameter that matters the most is energy storage capacity cost.

“For a comprehensive assessment of LDES technology design and its economic value to decarbonized grids, we evaluated nearly 18,000 distinctive cases,” Edington explains, “spanning variations in load and renewable resource availability, northern and southern latitude climates, different combinations of LDES technologies and LDES design parameters, and choice of competing firm low-carbon generation resources.”

Some of the key takeaways from the researchers’ rigorous analysis:

LDES technologies can offer more than a 10 percent reduction in the costs of deeply decarbonized electricity systems if the storage energy capacity cost (the cost to increase the size of the bathtub) remains under the threshold of $20/kilowatt-hour. This value could increase to 40 percent if energy capacity cost of future technologies is reduced to $1/kWh and to as much as 50 percent for the best combinations of parameters modeled in the space. For purposes of comparison, the current storage energy capacity cost of batteries is around $200/kWh.
Given today’s prevailing electricity demand patterns, the LDES energy capacity cost must fall below $10/kWh to replace nuclear power; for LDES to replace all firm power options entirely, the cost must fall below $1/kWh.
In scenarios with extensive electrification of transportation and other end-uses to meet economy-wide deep decarbonization goals, it will be more challenging in northern latitudes to displace firm generation under any likely future combination of costs and efficiency performance range for known LDES technologies. This is primarily due to greater peak electricity demand resulting from heating needs in colder climates.

Actionable insights

While breakthroughs in fusion energy, next-generation nuclear power, or carbon capture could well shake up their models, the researchers believe that insights from their study can make an impact right now.

“People working with LDES can see where their technology fits in to the future electricity mix and ask: ‘Does it make economic sense from a system perspective?’” says Mallapragada. “And it’s a call for action in policy and investment in innovation, because we show where the technology gaps lie and where we see the greatest value for research breakthroughs in LDES technology development.”

Not all LDES technologies can clear the bar in this design space, nor can there be reliance on LDES as the exclusive means to expand wind and solar swiftly in the near term, or to enable a complete transition to a zero-carbon economy by 2050.

“We show how promising LDES technologies could be,” says Sepulveda. “But we also show that these technologies are not the one solution, and that we are still better off with them complementing firm resources.”

Jenkins spies niche market opportunities for LDES immediately, such as places with a lot of wind and solar deployed and limits on transmission to export that power. In such locations, storage could fill up when transmission is at its limit, and export power later while maximizing use of the power line capacity. But LDES technologies must be ready to make a major impact by the late 2030s and 2040s, he believes, by which time economies might need to be weaned completely off of natural gas dependency if decarbonization is to succeed.

“We must develop and deploy LDES and improve other low-carbon technologies this decade, so we can present real alternatives to policymakers and power system operators,” he says.

In light of this urgent need, Jenkins at Princeton and Mallapragada at MIT are now working to evaluate and advance technologies with the greatest potential in the storage and energy fields to hasten the zero-carbon goal. With help from ARPA-E and MITEI, they are making the state-of-the-art GenX electricity system planning model an open-source tool for public use as well. If their research and modeling approach can show developers and policymakers what kind of designs are most impactful, says Sepulveda, “We could have a decarbonized system that’s less expensive than today’s system if we do things right.”

This research was supported by a grant from the National Science Foundation, and by MITEI’s Low-Carbon Energy Center for Electric Power Systems. More

As incomes in developing countries continue to rise, demand for air conditioners is expected to triple by 2050. The surge will multiply what is already a major source of greenhouse gas emissions: Air conditioning is currently responsible for almost 20 percent of electricity use in buildings around the world.

Now the startup Transaera is working to curb those energy demands with a more efficient air conditioner that uses safer refrigerants to cool homes. The company believes its machine could have one-fifth the impact on the climate when compared to traditional ACs.

“The thing about air conditioning is the basic technology hasn’t changed much since it was invented 100 years ago,” says Transaera chief engineer Ross Bonner SM ’20.

That will change rapidly if Transaera’s small team is successful. The company is currently a finalist in a global competition to redesign the air conditioner. The winner of the competition, named the Global Cooling Prize, will get $1 million to commercialize their machines.

At the heart of Transaera’s design is a class of highly porous materials called metal organic frameworks, or MOFs, that passively pull moisture from the air as the machine works. Co-founder Mircea Dincă, the W.M. Keck Professor of Energy in MIT’s Department of Chemistry, has done pioneering research on MOFs, and the company’s team members see the materials’ commercial advancement as an important part of their mission.

“MOFs have a lot of potential applications, but the thing that’s held them back is unit economics and the inability to make them in a cost-effective way at scale,” says Bonner. “What Transaera aims to do is be the first to commercialize MOFs at scale and lead the breakthrough that brings MOFs into the public domain.”

Dincă’s co-founders are Transaera CEO Sorin Grama SM ’07, who is also a lecturer at MIT D-Lab, and CTO Matt Dorson, a mechanical engineer who worked with Grama on a previous startup.

“I’m just incentivized by this idea of creating something revolutionary,” says Grama. “We’ve designed these new devices, but we’re also bringing this material knowledge, with Mircea and our collaborators, and blending the two to create something really new and different.”

A material of opportunity

Grama and Dorson previously collaborated at Promethean Power Systems, which develops off-grid refrigeration solutions for farmers in India. To date, the company has installed 1,800 refrigeration systems that serve roughly 60,000 farmers each day. After stepping down as CEO in 2015, Grama returned to the Institute to teach at MIT D-Lab and serve as an entrepreneur-in-residence at the Martin Trust Center for MIT Entrepreneurship.

During that time Grama was introduced to MOFs by Rob Stoner, the MIT Energy Initiative’s deputy director for science and technology and a founding director of the MIT Tata Center.

Stoner introduced Grama to Dincă, who had been studying MOFs since he joined MIT’s faculty in 2010 and grew up 10 miles from Grama’s hometown in Romania.

MOF’s intriguing properties come from their large internal surface area and the ability to finely tune the size of the tiny chambers that run through them. Dincă previously developed MOFs with chambers just big enough to trap water molecules from the air. He described them as “sponges on steroids.”

Grama began thinking about using the material for refrigeration, but another application soon presented itself. Most people think air conditioners only cool the air in a space, but they also dry the air they’re cooling. Traditional machines use something called an evaporator, a cold coil to pull water out of the air through condensation. The cold coil must be made much colder than the desired temperature in the room in order to collect moisture. Dorson says pulling moisture out of the air takes up about half of the electricity used by traditional air conditioners.

Transaera’s MOFs passively collect moisture as air enters the system. The machine’s waste heat is then used to dry the MOF material for continuous reuse.

Transaera was formally founded in the beginning of 2018, and the Global Cooling Prize was announced later that year. Hundreds of teams expressed interest, and Transaera was ultimately selected as one of eight finalists and given $200,000 to deliver prototypes to competition organizers.

Bonner joined the company in 2019 after exploring paths to carbon neutral ACs as part of a mechanical engineering class at MIT.

When Covid-19 began sweeping through countries around the world, it was decided the Cooling Prize’s trials in India would be run remotely. Adding to the challenge, the co-founders didn’t have access to their lab in Somerville due to restrictions and were using their own tools and garages to complete the prototypes. After shipping off their prototypes, Transaera had to help Prize organizers install them through a live video feed for field trials in multiple locations in India. The team says the results validated Transaera’s approach and showed the system had a significantly lower climate impact than baseline units.

Transaera’s system also used a refrigerant known as R-32 with zero ozone depleting potential (ODP) and a global warming potential about three times lower than another commonly used refrigerant.

The milestone further convinced Transaera’s small team they were onto something.

“This air conditioning problem can have a real, material impact on people’s quality of life,” Dorson says.

Pushing a field forward

The Global Cooling Prize will announce its winner next month. Regardless of what happens, Transaera will be growing the team this year and running additional trials in Boston. The company has been working with large manufacturers that have supplied equipment for prototypes and shown the founders how they might integrate their devices with existing technologies.

The company’s foundational work with MOFs has continued even as Transaera’s air conditioner gets closer to commercialization. In fact, Transaera recently received a grant from the National Science Foundation to explore more efficient paths to MOF production with a lab at MIT.

“MOFs open up so many possibilities for all kinds of revolutionary devices, not just in air conditioning, but in water harvesting, energy storage, and super capacitors,” Grama says. “This knowledge we’re developing can apply to so many other applications down the road, and I feel like we’re pioneering this field and pushing the edge of the technology.”

Still, Transaera’s founders remain focused on bringing their AC to market first, acknowledging the problem they’re trying to tackle is big enough to keep them busy for a while.

“It’s clear when you look at the swath of the world that’s in the hot, humid tropics, there’s a growing middle class, and one of the first thing they’ll want to buy is an air conditioner,” Dorson says. “Developing more efficient air conditioning systems is critical for the health of people and of our planet’s environment.” More

Lithium-ion batteries have made possible the lightweight electronic devices whose portability we now take for granted, as well as the rapid expansion of electric vehicle production. But researchers around the world are continuing to push limits to achieve ever-greater energy densities — the amount of energy that can be stored in a given mass of material — in order to improve the performance of existing devices and potentially enable new applications such as long-range drones and robots.

One promising approach is the use of metal electrodes in place of the conventional graphite, with a higher charging voltage in the cathode. Those efforts have been hampered, however, by a variety of unwanted chemical reactions that take place with the electrolyte that separates the electrodes. Now, a team of researchers at MIT and elsewhere has found a novel electrolyte that overcomes these problems and could enable a significant leap in the power-per-weight of next-generation batteries, without sacrificing the cycle life.

The research is reported today in the journal Nature Energy in a paper by MIT professors Ju Li, Yang Shao-Horn, and Jeremiah Johnson; postdoc Weijiang Xue; and 19 others at MIT, two national laboratories, and elsewhere. The researchers say the finding could make it possible for lithium-ion batteries, which now typically can store about 260 watt-hours per kilogram, to store about 420 watt-hours per kilogram. That would translate into longer ranges for electric cars and longer-lasting changes on portable devices.

The basic raw materials for this electrolyte are inexpensive (though one of the intermediate compounds is still costly because it’s in limited use), and the process to make it is simple. So, this advance could be implemented relatively quickly, the researchers say.

The electrolyte itself is not new, explains Johnson, a professor of chemistry. It was developed a few years ago by some members of this research team, but for a different application. It was part of an effort to develop lithium-air batteries, which are seen as the ultimate long-term solution for maximizing battery energy density. But there are many obstacles still facing the development of such batteries, and that technology may still be years away. In the meantime, applying that electrolyte to lithium-ion batteries with metal electrodes turns out to be something that can be achieved much more quickly.

The new application of this electrode material was found “somewhat serendipitously,” after it had initially been developed a few years ago by Shao-Horn, Johnson, and others, in a collaborative venture aimed at lithium-air battery development.

“There’s still really nothing that allows a good rechargeable lithium-air battery,” Johnson says. However, “we designed these organic molecules that we hoped might confer stability, compared to the existing liquid electrolytes that are used.” They developed three different sulfonamide-based formulations, which they found were quite resistant to oxidation and other degradation effects. Then, working with Li’s group, postdoc Xue decided to try this material with more standard cathodes instead.

The type of battery electrode they have now used with this electrolyte, a nickel oxide containing some cobalt and manganese, “is the workhorse of today’s electric vehicle industry,” says Li, who is a professor of nuclear science and engineering and materials science and engineering.  

Because the electrode material expands and contracts anisotropically as it gets charged and discharged, this can lead to cracking and a breakdown in performance when used with conventional electrolytes. But in experiments in collaboration with Brookhaven National Laboratory, the researchers found that using the new electrolyte drastically reduced these stress-corrosion cracking degradations.

The problem was that the metal atoms in the alloy tended to dissolve into the liquid electrolyte, losing mass and leading to cracking of the metal. By contrast, the new electrolyte is extremely resistant to such dissolution. Looking at the data from the Brookhaven tests, Li says, it was “sort of shocking to see that, if you just change the electrolyte, then all these cracks are gone.” They found that the morphology of the electrolyte material is much more robust, and the transition metals “just don’t have as much solubility” in these new electrolytes.

That was a surprising combination, he says, because the material still readily allows lithium ions to pass through — the essential mechanism by which batteries get charged and discharged — while blocking the other cations, known as transition metals, from entering. The accumulation of unwanted compounds on the electrode surface after many charging-discharging cycles was reduced more than tenfold compared to the standard electrolyte.

“The electrolyte is chemically resistant against oxidation of high-energy nickel-rich materials, preventing particle fracture and stabilizing the positive electrode during cycling,” says Shao-Horn, a professor of mechanical engineering and materials science and engineering. “The electrolyte also enables stable and reversible stripping and plating of lithium metal, an important step toward enabling rechargeable lithium-metal batteries with energy two times that of the state-the-art lithium-ion batteries. This finding will catalyze further electrolyte search and designs of liquid electrolytes for lithium-metal batteries rivaling those with solid state electrolytes.”

The next step is to scale the production to make it affordable. “We make it in one very easy reaction from readily available commercial starting materials,” Johnson says. Right now, the precursor compound used to synthesize the electrolyte is expensive, but he says,  “I think if we can show the world that this is a great electrolyte for consumer electronics, the motivation to further scale up will help to drive the price down.”

Because this is essentially a “drop in” replacement for an existing electrolyte and doesn’t require redesign of the entire battery system, Li says, it could be implemented quickly and could be commercialized within a couple of years. “There’s no expensive elements, it’s just carbon and fluorine. So it’s not limited by resources, it’s just the process,” he says.

The research was supported by the U.S. Department of Energy and the National Science Foundation, and made use of facilities at Brookhaven National Laboratory and Argonne National Laboratory. More

Global power generation from renewables like solar and wind continues to rise, and innovation in fields like clean hydrogen production and nuclear fusion is thriving. But translating all that progress into lower global emissions will require major changes to legacy energy systems around the world. That was the most discussed challenge among speakers at this year’s MIT Energy Conference, hosted virtually last week by the MIT Energy Club.

In some cases, energy systems can be adapted to integrate new power sources. In others, entirely new systems will have to be constructed to get power to people when they need it.

“There’s an equilibrium between technology, policy, and infrastructure, and they all depend on each other,” explained panelist Vijay Swarup, the vice president of research and development at ExxonMobil.

Many presenters began by acknowledging the huge strides solar and wind energy have made in terms of price and deployments over the last decade. In the event’s first keynote, George Bilicic of the global financial services firm Lazard presented his firm’s analysis on the cost of various energy sources, showing large-scale deployments of renewables are cost competitive with coal and gas in many circumstances.

But incorporating variable energy sources like solar and wind into the grid can be difficult, both economically and technically. New systems are needed to better integrate such energy sources into existing infrastructure, speakers said.

“I see digital services as a critical enabler of [clean energy] technologies, because there’s a lot more real-time management required when you’re dealing with a proliferation of energy solutions,” said Shell Energy Americas Senior Vice President Carolyn Comer, adding that Shell is developing new businesses models to harness more wind and solar energy. “The ability to switch [energy streams] on and off in a way that keeps the grid stable is critically important.”

Grid stability was top of mind for many participants in the wake of the February storms in Texas, which resulted in an energy crisis that left 4.5 million homes and businesses without power. Although the causes of the system failures are still being investigated, multiple speakers voiced frustration that renewables were quickly blamed for a disaster in which energy from natural gas was also disrupted and the grid experienced broad failures.

Speaking from San Antonio, Anthony Dorazio of Avangrid Renewables noted that in a future where extreme weather events are more common, grid resiliency needs to be a top priority.

“It’s not how we design a perfect system, because we’ll never design a perfect system,” Dorazio said. “It’s how we react to the changing environment. We need to look at digitization, we need information to move much quicker, we need to use forecasting tools to manage these changes as they approach. When you look at what happened in Texas, in the end we’ll all learn from it. We’ll be better and stronger, and figure out better systems as a result.”

The March 10-12 event, which featured talks by energy industry executives, startup founders, investors, and current and former government officials, is the largest, student-run clean energy conference in the world, according to conference co-organizer Trevor Thompson, an MBA candidate at the MIT Sloan School of Management.

The 16th annual conference was also the first to include a panel on climate justice, where attendees heard from members of communities that have been disproportionately affected by fossil fuel emissions and pollution.

As part of that panel, Jacqueline Patterson, the senior director of the NAACP Environmental and Climate Justice Program, talked about observing higher rates of asthma among children in her hometown neighborhood in the South Side of Chicago.

“We have a broken energy system because instead of having a core purpose of providing energy and access to all, it has as a core purpose of providing wealth and power to a small few,” Patterson said.

The panelists stressed the importance of an inclusive approach to crafting climate solutions that includes low-income, minority communities, which have historically been left out of discussions on energy.

“Climate change is an all-hands-on-deck problem. Every one of us has to be part of the solution,” said Steph Speirs, founder and CEO of Solstice, a startup that works with low-income communities to build community solar projects.

Speakers at the conference also discussed a number of policy proposals, including carbon taxes and clean energy subsidies.

In a second keynote address, former U.S. secretary of energy Ernest Moniz discussed what he sees as key energy priorities for the administration of President Joe Biden, including the increased electrification of sectors like transportation and materials production, and the decarbonization of the U.S. electricity sector by 2035.

Moniz, who is the Cecil and Ida Green Professor of Physics and Engineering Systems emeritus and special advisor to MIT President L. Rafael Reif, also cited areas like innovation and infrastructure where he sees bipartisan support for changes that could help lower greenhouse gas emissions. On the technology front, Moniz said so-called negative carbon solutions like carbon dioxide removal may be needed to help the world get to carbon neutrality in the near term. But, he added, “We’d better innovate like hell if we’re going to have something like carbon dioxide removal available in any appreciable way.”

In an interactive session, Jason Jay, a senior lecturer at MIT and the director of the MIT Sloan Sustainability Initiative, gave a demonstration of the En-ROADS Climate Solutions Simulator, a model that lets users explore the impact of different climate policies on global temperatures.

Jay entered an ambitious scenario into the simulator in which all developed countries dramatically reduce emissions beginning this year, and showed that global temperatures would still warm above 3 degrees Celsius by 2100 — a level scientists have warned would lead to catastrophic climate changes — demonstrating the importance of getting participation from China and other developing countries.

“If we want solutions to the climate crisis, they have to be global solutions,” Jay said.

A total of 15 student-led teams also pitched their startup ideas as part of the ClimateTech and Energy Prize, which concluded the conference. Finalist innovations included a biodegradable, mushroom-based packaging material, a water-treatment solution that uses no electricity or moving parts, and a company attempting to decarbonize hydrogen production.

The winning team, Osmoses, is developing membrane technologies to improve chemical separation processes. The students said their solution could dramatically reduce industrial energy consumption.

The pitch competition was a fitting end to a conference in which many speakers expressed optimism about the prospects of scaling innovations to avert the worst-case scenarios of global warming projected by experts.

Still, many speakers said, it will take a lot of work and a renewed sense of urgency from the world’s leaders.

“We can’t just wait until 2040 to meet the 2050 targets,” said Judy Chang, the Massachusetts undersecretary of energy. “Because 2050 sounds so far away, we might think can wait for the next generation, but we really only have several opportunities to take things on, and action is necessary in this decade.” More

More extreme weather, heat waves, and inland flooding are some of the impacts that the state of Pennsylvania expects to see with a changing climate. And scientists and economists agree that, if we don’t quickly reduce the greenhouse gas pollution from fossil fuels like coal and gas that contribute to warming the planet, these impacts will only grow more costly and dangerous.

Yet parts of western Pennsylvania, like many regions of the United States, rely on coal and gas production to support the local economy. Through its Here and Real project, the MIT Environmental Solutions Initiative (ESI) is investigating solutions that reduce carbon pollution and are economically just for communities that are reliant on fossil fuel production.

In a new ESI white paper, the authors highlight the case of Greene County, Pennsylvania, and how equitable solutions need to be about more than creating jobs; they also need to protect schools.

A frontline community for changing energy markets

A roughly 36,000-person county in the southwestern corner of the state bounded on two sides by West Virginia, Greene County sits atop a vast coal bed that stretches from Alabama to northern Pennsylvania. Since 1986, it has been the number one coal mining county in one of the biggest coal-producing states in the country. But, as coal struggles to compete with methane gas prices, Greene County coal production has decreased in recent years.

When most people hear about the decline of coal in the U.S., they picture out-of-work miners. What’s perhaps less obvious is that, in parts of the country where governments count on mines as major taxpayers, like Greene County, this reliance on coal also has affected critical social services, from public schools to senior programs.

In the new white paper, authors at ESI show that the county’s reliance on tax revenues from coal production creates substantial financial risk. They also found that differences in how taxes are collected on coal production versus methane gas (also called natural gas) call into question claims that the shale gas boom could make up for the tax revenue shortfall.

As coal mining wanes, Greene County contemplates its future

While waiting tables after moving back home to Greene County in the wake of the Great Recession, Veronica Coptis heard from customers who felt captive to the coal industry. Coal provided good-paying jobs, but mining also wreaked havoc on the environment — something Coptis, who grew up fishing on a lake that was drained after a mining company ruptured a dam on it, has seen firsthand.

Coptis soon started working at the Center for Coalfield Justice (CCJ), the nonprofit she now heads, to make sure that state regulators enforced environmental regulations on the mining industry. “There was definitely the need to advocate for the environment,” she recalls. “But being from the community, I couldn’t continue just doing environmental advocacy if I wasn’t doing economic justice advocacy as well.”

In 2017, ESI Director John Fernández read a New Yorker profile of Coptis and reached out to explore a collaboration between CCJ and MIT. That year, CCJ had started a community outreach campaign to hear what residents thought about the decline of coal, the rise of methane gas, and the future of Greene County. “People were widely concerned about the jobs,” Coptis says. “But people were also widely aware of how much tax revenue and support comes back to the community from the coal operations that are here.”

Greene County became the first engagement for ESI’s Here and Real project. “Our approach is not for MIT to come in and tell communities, ‘Here’s what we know and here’s what you should do,’” says Laur Hesse Fisher, ESI program director who heads Here and Real. Rather, “we work closely with local partners to conduct research that’s deeply relevant to the community, keeping front of mind the issues that matter most to them.”

The following summer, Fernández and MIT student intern Ben Delhees, a finance and mathematical economics double major, visited western Pennsylvania to learn more about how the decline of the coal industry was affecting the county.

School districts’ heavy reliance on coal taxes proves risky

In the summer of 2018, Delhees worked with data from the Greene County Budget Office to study the local economic and environmental consequences of coal’s departure. Over winter and spring of 2018-2019, MIT students Mimi Wahid and Caroline Boone built upon his research by looking into how declining tax revenues from coal companies impacted school funding. Their internships with CCJ were supported by ESI and the PKG Center.

They uncovered a concerning trend. Some school districts receive over half of their funding from a tax on the value of coal mined, which has declined almost 13% county-wide from 2010 to 2019. One district, Central Greene, saw mineral values decrease by 44% from 2010 to 2018. Even with tax raises, the district still saw mineral revenues go down 32% — a loss of $888,724.

Wahid and Boone worked with the Center for Coalfield Justice to include these findings in the group’s door-to-door canvassing in the county, as well as a series of workshops that CCJ ran over the summer to educate residents on their local tax structure and how it was changing as coal companies leave and petrochemical companies move in. ESI also worked with students at Emerson College’s EnGAgeMEnt Lab to design a hands-on educational game to illustrate this research, that CCJ ran at three summer county fairs.

“Part of what made this project successful was the diverse disciplines of the students,” said Hesse Fisher. Wahid majors in writing and urban planning and studies, while Boone majors in mechanical engineering, adding to Delhees’ focus on finance and mathematical economics and White-Nockleby’s anthropology studies. “Their different perspectives strengthened both the research and how we engaged with the community.”

Authors find methane gas “can’t replace coal”

Caroline White-Nockleby, a graduate student in MIT’s Doctoral Program in History, Anthropology, and Science, Technology, and Society, expanded upon their work by looking into how coal’s decline was impacting real estate tax revenues, and the extent to which the shale gas boom could offset those losses. Her research culminated in a white paper synthesizing all this information into a complete picture of Greene County’s tax structure, public services, and vulnerabilities as the coal industry declines.

Hydraulic fracking — the process used to extract methane gas from shale — has soared in the past decade with 870 active wells in the county. To help make up for lost coal revenue, school districts have been using funds from a fee charged on these wells. But this is not a long-term solution, according to the white paper, because those revenues are so much lower than what was coming in from the coal mines.

“There’s a narrative that money from fracking would be able to replace some of the money from coal extraction,” says White-Nockleby. “But actually, if you look at the numbers, that’s really not what’s happening. … You can project that within three years, they’re not going to be able to fill the budget gaps.”

Greene County’s real estate tax revenue has also taken a hit. While coal companies remain the largest property taxpayers in the county, White-Nockleby found that property taxes paid by the largest coal companies fell from $5.2 million in 2015 to $3.1 million in 2019. And while there was some hope that increased methane gas production would offset this decline, methane gas companies pay much less in real estate taxes. “Gas basically can’t replace coal, and it has its own huge suite of environmental impacts,” White-Nockleby says.  

The consolidation of Greene County’s revenue base among a small number of actors in which coal companies figure heavily, combined with the past and projected decline of the industry, poses a distinct financial risk — one that has been noted by the Global Credit Portal, the organization that rates the financial stability of the county’s municipal bonds. 

Coptis, from the Center for Coalfield Justice, says the MIT tax analyses armed her group and other community members with the data needed to convince school board members and local officials to anticipate, rather than react to, mine closures.

“Let’s start making the plan now to figure out [what] alternative revenue sources to build,” she says. “Because what these communities can’t withstand … is an increase in tax rates to cover the cost of an industry that bails on the community.”

Next, ESI and CCJ are bringing these findings to county and state officials, as well as other communities going through similar transitions.

“It is imperative to slow climate change, and we need to take care of people as we lower emissions,” says Hesse Fisher. “This paper has shown that we also need to look at the broader fiscal impacts of the energy transition. We hope this work can support states and communities as they plan for a resilient future.” More

As researchers push the boundaries of battery design, seeking to pack ever greater amounts of power and energy into a given amount of space or weight, one of the more promising technologies being studied is lithium-ion batteries that use a solid electrolyte material between the two electrodes, rather than the typical liquid.

But such batteries have been plagued by a tendency for branch-like projections of metal called dendrites to form on one of the electrodes, eventually bridging the electrolyte and shorting out the battery cell. Now, researchers at MIT and elsewhere have found a way to prevent such dendrite formation, potentially unleashing the potential of this new type of high-powered battery.

The findings are described in the journal Nature Energy, in a paper by MIT graduate student Richard Park, professors Yet-Ming Chiang and Craig Carter, and seven others at MIT, Texas A&M University, Brown University, and Carnegie Mellon University.

Solid-state batteries, Chiang explains, have been a long-sought technology for two reasons: safety and energy density. But, he says, “the only way you can reach the energy densities that are interesting is if you use a metal electrode.” And while it’s possible to couple that metal electrode with a liquid electrolyte and still get good energy density, that does not provide the same safety advantage as a solid electrolyte does, he says.

Solid state batteries only make sense with metal electrodes, he says, but attempts to develop such batteries have been hampered by the growth of dendrites, which eventually bridge the gap between the two electrode plates and short out the circuit, weakening or inactivating that cell in a battery.

It’s been known that dendrites form more rapidly when the current flow is higher — which is generally desirable in order to allow rapid charging. So far, the current densities that have been achieved in experimental solid-state batteries have been far short of what would be needed for a practical commercial rechargeable battery. But the promise is worth pursuing, Chiang says, because the amount of energy that can be stored in experimental versions of such cells, is already nearly double that of conventional lithium-ion batteries.

The team solved the dendrite problem by adopting a compromise between solid and liquid states. They made a semisolid electrode, in contact with a solid electrolyte material. The semisolid electrode provided a kind of self-healing surface at the interface, rather than the brittle surface of a solid that could lead to tiny cracks that provide the initial seeds for dendrite formation.

The idea was inspired by experimental high-temperature batteries, in which one or both electrodes consist of molten metal. According to Park, the first author of the paper, the hundreds-of-degrees temperatures of molten-metal batteries would never be practical for a portable device, but the work did demonstrate that a liquid interface can enable high current densities with no dendrite formation. “The motivation here was to develop electrodes that are based on carefully selected alloys in order to introduce a liquid phase that can serve as a self-healing component of the metal electrode,” Park says.

The material is more solid than liquid, he explains, but resembles the amalgam dentists use to fill a cavity — solid metal, but still able to flow and be shaped. At the ordinary temperatures that the battery operates in, “it stays in a regime where you have both a solid phase and a liquid phase,” in this case made of a mixture of sodium and potassium. The team demonstrated that it was possible to run the system at 20 times greater current than using solid lithium, without forming any dendrites, Chiang says. The next step was to replicate that performance with an actual lithium-containing electrode.

In a second version of their solid battery, the team introduced a very thin layer of liquid sodium potassium alloy in between a solid lithium electrode and a solid electrolyte. They showed that this approach could also overcome the dendrite problem, providing an alternative approach for further research.

The new approaches, Chiang says, could easily be adapted to many different versions of solid-state lithium batteries that are being investigated by researchers around the world. He says the team’s next step will be to demonstrate this system’s applicability to a variety of battery architectures. Co-author Viswanathan, professor of mechanical engineering at Carnegie Mellon University, says, “We think we can translate this approach to really any solid-state lithium-ion battery. We think it could be used immediately in cell development for a wide range of applications, from handheld devices to electric vehicles to electric aviation.”

“Metal penetration through solid electrolyte separators is a key challenge facing high energy-density batteries, and to date much attention has been directed toward the properties of the separator material through which the metal penetrates,” says Paul Albertus, an associate professor of chemical and biomolecular engineering at the University of Maryland, who was not associated with this research. Noting that the new work focuses instead on the properties of the metal electrode itself, he says the research “is important for both setting scientific priorities for understanding metal penetration, as well as developing innovations to help mitigate this important failure mode.”

The team also included Christopher Eschler, Cole Fincher, and Andres Badel at MIT; Pinwen Guan at Carnegie Mellon University; and Brian Sheldon at Brown University. The work was supported by the U.S. Department of Energy, the National Science Foundation, and the MIT-Skoltech Next Generation Program. More

“I had always expected I’d stay at MIT for the four years, get my undergraduate degree at the end and probably return to the UK.”

Richard Ibekwe recalls his early assumptions about his academic path at MIT. Now he is a nuclear science and engineering (NSE) PhD candidate working at the Plasma Science and Fusion Center (PSFC), dedicated to long-term fusion research at MIT, focusing on magnet technology. Recipient of multiple undergraduate awards, Ibekwe has earned graduate-level support from the MIT Energy Initiative, which has enlisted him as an MIT Energy Fellow, sponsored by Commonwealth Fusion Systems. He is also the current president of the MIT student chapter of the American Nuclear Society (ANS).                                                              

“Three things that have always fascinated me,” he says, “have been learning how things work, finding how to fix them, and using that knowledge to serve and care for those around me. Growing up, that manifested in building and tinkering with things — first toys, and then DIY around the house. Now I see fusion fitting into that interest: There are few problems as hard to solve or that might have as profound a potential positive impact on our planet and the whole of humanity.”

Fusion, the reaction that fuels the sun and other stars, is a potentially endless source of carbon-free energy on Earth, if it can only be harnessed. Much research has favored heating hydrogen fuel inside a donut-shaped device called a tokamak, creating plasma that is hot and dense enough for fusion to occur. Because plasma will follow magnetic field lines, these devices are wrapped with magnets to keep the hot fuel from damaging the chamber walls.

Ibekwe’s interest in fusion developed only in his senior year, after taking an introductory design class from NSE Assistant Professor Zachary Hartwig.

“As an undergrad, from a distance, fusion seemed a very esoteric, very physics-heavy endeavor. My background was much more engineering-focused,” he says. “I was inspired by Zach’s teaching, and by the way he fused the science and engineering of fusion research.”

When Ibekwe applied to join Hartwig’s team as a PhD student he was not aware of the future that was taking shape at the PSFC. A tokamak called SPARC was being designed using a new high-temperature superconductor (HTS), a tape allowing larger electric currents and higher magnetic fields than traditional superconducting coils: It suggested a path to a smaller, less-expensive fusion power plant that could be built more quickly than currently funded international projects.

“I just thought that fusion would be a cool subject to get involved with,” says Ibekwe. “It was a happy surprise to discover SPARC was in the works.”

Because so much of SPARC’s success depends on the new superconducting technology, it is not surprising that Ibekwe and his colleagues are researching it. Because high-temperature superconductors can handle greater magnetic fields than regular superconductors, they are ideal for tokamaks. 

“It turns out that almost everything about the fusion process gets much better and more favorable when you increase the magnetic field,” Ibekwe says. But he wonders what might negatively impact this process. How might flaws in the HTS tapes affect tokamak performance?

As they fabricate magnets with these thin HTS tapes, Ibekwe and his colleagues ask one key question: What is the critical current? What is the maximum current the tapes can carry before they cease to be superconducting, losing the features that make them central to a tokamak’s success, like their ability to conduct large electric currents with no electrical resistance?

“When producing these tapes — these thin, ribbon-shaped wires — the goal is to make them as high-quality as possible so that the maximum current is high and uniform throughout the wire’s length. It turns out that when manufacturing these tapes, because perhaps it gets dented, or a speck of dust falls on the tape when growing the crystal, it results in regions where the critical current is much lower. We call those dropouts.”

The critical current drops out at those locations, and the superconductor experiences electrical resistance. The area heats up, producing a situation where the heat expands, causing the entire cable to lose conductivity. To make the best of this situation, engineers can try to cut out any defects in the tape and use a shorter length, or they can produce a new length of tape to get what they want. But this corrective process can be expensive and time-consuming.

Ibekwe is embracing the imperfections, doing a deep dive into HTS tape flaws in an attempt to offer pragmatic solutions. 

“First,” he says, “let’s measure and understand the effect of these defects on the performance of the superconducting tapes, which hasn’t really been done before in detail. Second, we need to figure out quantitatively how bad a defect we can withstand. Thirdly, how can we create magnets that contain defects in such a way that we can still make usable, efficient magnets?”

Ibekwe believes he may have inherited his pragmatic approach from his parents, who had moved from Nigeria to study in London before Richard was born. His mother completed her PhD in child nutrition while he was growing up. 

“I think I got the academic influence from her,” he says. “My father is a building contractor. There’s the element of the practical aspect in me from him.”

Ibekwe’s preliminary research suggests the HTS tape magnets he’s been working on are intrinsically more tolerant to the presence of defects than low-temperature superconductors.

“The challenge,” he says, “is to come up with a design guide that will show engineers building these magnets what’s acceptable and what’s not.”

Ibekwe wants to continue working on the challenging problems in fusion and related fields, taking a holistic approach that is inspired in part by his leadership in ANS, which this year provided opportunities to address issues related to health, isolation, diversity, equity, and inclusion. He foresees an academic career as a good way to achieve this goal.

“I want to wrestle not only with the scientific and engineering questions, but also with the societal and political, the philosophical and ethical questions,” he says. “I think the university is the best place to do that.” More