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    Using liquid air for grid-scale energy storage

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    As the world moves to reduce carbon emissions, solar and wind power will play an increasing role on electricity grids. But those renewable sources only generate electricity when it’s sunny or windy. So to ensure a reliable power grid — one that can deliver electricity 24/7 — it’s crucial to have a means of storing electricity when supplies are abundant and delivering it later, when they’re not. And sometimes large amounts of electricity will need to be stored not just for hours, but for days, or even longer.Some methods of achieving “long-duration energy storage” are promising. For example, with pumped hydro energy storage, water is pumped from a lake to another, higher lake when there’s extra electricity and released back down through power-generating turbines when more electricity is needed. But that approach is limited by geography, and most potential sites in the United States have already been used. Lithium-ion batteries could provide grid-scale storage, but only for about four hours. Longer than that and battery systems get prohibitively expensive.A team of researchers from MIT and the Norwegian University of Science and Technology (NTNU) has been investigating a less-familiar option based on an unlikely-sounding concept: liquid air, or air that is drawn in from the surroundings, cleaned and dried, and then cooled to the point that it liquefies. “Liquid air energy storage” (LAES) systems have been built, so the technology is technically feasible. Moreover, LAES systems are totally clean and can be sited nearly anywhere, storing vast amounts of electricity for days or longer and delivering it when it’s needed. But there haven’t been conclusive studies of its economic viability. Would the income over time warrant the initial investment and ongoing costs? With funding from the MIT Energy Initiative’s Future Energy Systems Center, the researchers developed a model that takes detailed information on LAES systems and calculates when and where those systems would be economically viable, assuming future scenarios in line with selected decarbonization targets as well as other conditions that may prevail on future energy grids.They found that under some of the scenarios they modeled, LAES could be economically viable in certain locations. Sensitivity analyses showed that policies providing a subsidy on capital expenses could make LAES systems economically viable in many locations. Further calculations showed that the cost of storing a given amount of electricity with LAES would be lower than with more familiar systems such as pumped hydro and lithium-ion batteries. They conclude that LAES holds promise as a means of providing critically needed long-duration storage when future power grids are decarbonized and dominated by intermittent renewable sources of electricity.The researchers — Shaylin A. Cetegen, a PhD candidate in the MIT Department of Chemical Engineering (ChemE); Professor Emeritus Truls Gundersen of the NTNU Department of Energy and Process Engineering; and MIT Professor Emeritus Paul I. Barton of ChemE — describe their model and their findings in a new paper published in the journal Energy.The LAES technology and its benefitsLAES systems consists of three steps: charging, storing, and discharging. When supply on the grid exceeds demand and prices are low, the LAES system is charged. Air is then drawn in and liquefied. A large amount of electricity is consumed to cool and liquefy the air in the LAES process. The liquid air is then sent to highly insulated storage tanks, where it’s held at a very low temperature and atmospheric pressure. When the power grid needs added electricity to meet demand, the liquid air is first pumped to a higher pressure and then heated, and it turns back into a gas. This high-pressure, high-temperature, vapor-phase air expands in a turbine that generates electricity to be sent back to the grid.According to Cetegen, a primary advantage of LAES is that it’s clean. “There are no contaminants involved,” she says. “It takes in and releases only ambient air and electricity, so it’s as clean as the electricity that’s used to run it.” In addition, a LAES system can be built largely from commercially available components and does not rely on expensive or rare materials. And the system can be sited almost anywhere, including near other industrial processes that produce waste heat or cold that can be used by the LAES system to increase its energy efficiency.Economic viabilityIn considering the potential role of LAES on future power grids, the first question is: Will LAES systems be attractive to investors? Answering that question requires calculating the technology’s net present value (NPV), which represents the sum of all discounted cash flows — including revenues, capital expenditures, operating costs, and other financial factors — over the project’s lifetime. (The study assumed a cash flow discount rate of 7 percent.)To calculate the NPV, the researchers needed to determine how LAES systems will perform in future energy markets. In those markets, various sources of electricity are brought online to meet the current demand, typically following a process called “economic dispatch:” The lowest-cost source that’s available is always deployed next. Determining the NPV of liquid air storage therefore requires predicting how that technology will fare in future markets competing with other sources of electricity when demand exceeds supply — and also accounting for prices when supply exceeds demand, so excess electricity is available to recharge the LAES systems.For their study, the MIT and NTNU researchers designed a model that starts with a description of an LAES system, including details such as the sizes of the units where the air is liquefied and the power is recovered, and also capital expenses based on estimates reported in the literature. The model then draws on state-of-the-art pricing data that’s released every year by the National Renewable Energy Laboratory (NREL) and is widely used by energy modelers worldwide. The NREL dataset forecasts prices, construction and retirement of specific types of electricity generation and storage facilities, and more, assuming eight decarbonization scenarios for 18 regions of the United States out to 2050.The new model then tracks buying and selling in energy markets for every hour of every day in a year, repeating the same schedule for five-year intervals. Based on the NREL dataset and details of the LAES system — plus constraints such as the system’s physical storage capacity and how often it can switch between charging and discharging — the model calculates how much money LAES operators would make selling power to the grid when it’s needed and how much they would spend buying electricity when it’s available to recharge their LAES system. In line with the NREL dataset, the model generates results for 18 U.S. regions and eight decarbonization scenarios, including 100 percent decarbonization by 2035 and 95 percent decarbonization by 2050, and other assumptions about future energy grids, including high-demand growth plus high and low costs for renewable energy and for natural gas.Cetegen describes some of their results: “Assuming a 100-megawatt (MW) system — a standard sort of size — we saw economic viability pop up under the decarbonization scenario calling for 100 percent decarbonization by 2035.” So, positive NPVs (indicating economic viability) occurred only under the most aggressive — therefore the least realistic — scenario, and they occurred in only a few southern states, including Texas and Florida, likely because of how those energy markets are structured and operate.The researchers also tested the sensitivity of NPVs to different storage capacities, that is, how long the system could continuously deliver power to the grid. They calculated the NPVs of a 100 MW system that could provide electricity supply for one day, one week, and one month. “That analysis showed that under aggressive decarbonization, weekly storage is more economically viable than monthly storage, because [in the latter case] we’re paying for more storage capacity than we need,” explains Cetegen.Improving the NPV of the LAES systemThe researchers next analyzed two possible ways to improve the NPV of liquid air storage: by increasing the system’s energy efficiency and by providing financial incentives. Their analyses showed that increasing the energy efficiency, even up to the theoretical limit of the process, would not change the economic viability of LAES under the most realistic decarbonization scenarios. On the other hand, a major improvement resulted when they assumed policies providing subsidies on capital expenditures on new installations. Indeed, assuming subsidies of between 40 percent and 60 percent made the NPVs for a 100 MW system become positive under all the realistic scenarios.Thus, their analysis showed that financial incentives could be far more effective than technical improvements in making LAES economically viable. While engineers may find that outcome disappointing, Cetegen notes that from a broader perspective, it’s good news. “You could spend your whole life trying to optimize the efficiency of this process, and it wouldn’t translate to securing the investment needed to scale the technology,” she says. “Policies can take a long time to implement as well. But theoretically you could do it overnight. So if storage is needed [on a future decarbonized grid], then this is one way to encourage adoption of LAES right away.”Cost comparison with other energy storage technologiesCalculating the economic viability of a storage technology is highly dependent on the assumptions used. As a result, a different measure — the “levelized cost of storage” (LCOS) — is typically used to compare the costs of different storage technologies. In simple terms, the LCOS is the cost of storing each unit of energy over the lifetime of a project, not accounting for any income that results.On that measure, the LAES technology excels. The researchers’ model yielded an LCOS for liquid air storage of about $60 per megawatt-hour, regardless of the decarbonization scenario. That LCOS is about a third that of lithium-ion battery storage and half that of pumped hydro. Cetegen cites another interesting finding: the LCOS of their assumed LAES system varied depending on where it’s being used. The standard practice of reporting a single LCOS for a given energy storage technology may not provide the full picture.Cetegen has adapted the model and is now calculating the NPV and LCOS for energy storage using lithium-ion batteries. But she’s already encouraged by the LCOS of liquid air storage. “While LAES systems may not be economically viable from an investment perspective today, that doesn’t mean they won’t be implemented in the future,” she concludes. “With limited options for grid-scale storage expansion and the growing need for storage technologies to ensure energy security, if we can’t find economically viable alternatives, we’ll likely have to turn to least-cost solutions to meet storage needs. This is why the story of liquid air storage is far from over. We believe our findings justify the continued exploration of LAES as a key energy storage solution for the future.” More

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      Making solar projects cheaper and faster with portable factories

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      As the price of solar panels has plummeted in recent decades, installation costs have taken up a greater share of the technology’s overall price tag. The long installation process for solar farms is also emerging as a key bottleneck in the deployment of solar energy.Now the startup Charge Robotics is developing solar installation factories to speed up the process of building large-scale solar farms. The company’s factories are shipped to the site of utility solar projects, where equipment including tracks, mounting brackets, and panels are fed into the system and automatically assembled. A robotic vehicle autonomously puts the finished product — which amounts to a completed section of solar farm — in its final place.“We think of this as the Henry Ford moment for solar,” says CEO Banks Hunter ’15, who founded Charge Robotics with fellow MIT alumnus Max Justicz ’17. “We’re going from a very bespoke, hands on, manual installation process to something much more streamlined and set up for mass manufacturing. There are all kinds of benefits that come along with that, including consistency, quality, speed, cost, and safety.”Last year, solar energy accounted for 81 percent of new electric capacity in the U.S., and Hunter and Justicz see their factories as necessary for continued acceleration in the industry.The founders say they were met with skepticism when they first unveiled their plans. But in the beginning of last year, they deployed a prototype system that successfully built a solar farm with SOLV Energy, one of the largest solar installers in the U.S. Now, Charge has raised $22 million for its first commercial deployments later this year.From surgical robots to solar robotsWhile majoring in mechanical engineering at MIT, Hunter found plenty of excuses to build things. One such excuse was Course 2.009 (Product Engineering Processes), where he and his classmates built a smart watch for communication in remote areas.After graduation, Hunter worked for the MIT alumni-founded startups Shaper Tools and Vicarious Surgical. Vicarious Surgical is a medical robotics company that has raised more than $450 million to date. Hunter was the second employee and worked there for five years.“A lot of really hands on, project-based classes at MIT translated directly into my first roles coming out of school and set me up to be very independent and run large engineering projects,” Hunter says, “Course 2.009, in particular, was a big launch point for me. The founders of Vicarious Surgical got in touch with me through the 2.009 network.”As early as 2017, Hunter and Justicz, who majored in mechanical engineering and computer science, had discussed starting a company together. But they had to decide where to apply their broad engineering and product skillsets.“Both of us care a lot about climate change. We see climate change as the biggest problem impacting the greatest number of people on the planet,” Hunter says. “Our mentality was if we can build anything, we might as well build something that really matters.”In the process of cold calling hundreds of people in the energy industry, the founders decided solar was the future of energy production because its price was decreasing so quickly.“It’s becoming cheaper faster than any other form of energy production in human history,” Hunter says.When the founders began visiting construction sites for the large, utility-scale solar farms that make up the bulk of energy generation, it wasn’t hard to find the bottlenecks. The first site they traveled to was in the Mojave Desert in California. Hunter describes it as a massive dust bowl where thousands of workers spent months repeating tasks like moving material and assembling the same parts, over and over again.“The site had something like 2 million panels on it, and every single one was assembled and fastened the same way by hand,” Hunter says. “Max and I thought it was insane. There’s no way that can scale to transform the energy grid in a short window of time.”Hunter says he heard from each of the largest solar companies in the U.S. that their biggest limitation for scaling was labor shortages. The problem was slowing growth and killing projects.Hunter and Justicz founded Charge Robotics in 2021 to break through that bottleneck. Their first step was to order utility solar parts and assemble them by hand in their backyards.“From there, we came up with this portable assembly line that we could ship out to construction sites and then feed in the entire solar system, including the steel tracks, mounting brackets, fasteners, and the solar panels,” Hunter explains. “The assembly line robotically assembles all those pieces to produce completed solar bays, which are chunks of a solar farm.”

      Charge Robotics’ machine transports an autonomously assembled portion of solar farm to its final place in a solar farm.

      Credit: Courtesy of Charge Robotics

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      Each bay represents a 40-foot piece of the solar farm and weighs about 800 pounds. A robotic vehicle brings it to its final location in the field. Hunter says Charge’s system automates all mechanical installation except for the process of pile driving the first metal stakes into the ground.Charge’s assembly lines also have machine-vision systems that scan each part to ensure quality, and the systems work with the most common solar parts and panel sizes.From pilot to productWhen the founders started pitching their plans to investors and construction companies, people didn’t believe it was possible.“The initial feedback was basically, ‘This will never work,’” Hunter says. “But as soon as we took our first system out into the field and people saw it operating, they got much more excited and started believing it was real.”Since that first deployment, Charge’s team has been making its system faster and easier to operate. The company plans to set up its factories at project sites and run them in partnership with solar construction companies. The factories could even run alongside human workers.“With our system, people are operating robotic equipment remotely rather than putting in the screws themselves,” Hunter explains. “We can essentially deliver the assembled solar to customers. Their only responsibility is to deliver the materials and parts on big pallets that we feed into our system.”Hunter says multiple factories could be deployed at the same site and could also operate 24/7 to dramatically speed up projects.“We are hitting the limits of solar growth because these companies don’t have enough people,” Hunter says. “We can build much bigger sites much faster with the same number of people by just shipping out more of our factories. It’s a fundamentally new way of scaling solar energy.” More

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      How hard is it to prevent recurring blackouts in Puerto Rico?

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      Researchers at MIT’s Laboratory for Information and Decision Systems (LIDS) have shown that using decision-making software and dynamic monitoring of weather and energy use can significantly improve resiliency in the face of weather-related outages, and can also help to efficiently integrate renewable energy sources into the grid.The researchers point out that the system they suggest might have prevented or at least lessened the kind of widespread power outage that Puerto Rico experienced last week by providing analysis to guide rerouting of power through different lines and thus limit the spread of the outage.The computer platform, which the researchers describe as DyMonDS, for Dynamic Monitoring and Decision Systems, can be used to enhance the existing operating and planning practices used in the electric industry. The platform supports interactive information exchange and decision-making between the grid operators and grid-edge users — all the distributed power sources, storage systems and software that contribute to the grid. It also supports optimization of available resources and controllable grid equipment as system conditions vary. It further lends itself to implementing cooperative decision-making by different utility- and non-utility-owned electric power grid users, including portfolios of mixed resources, users, and storage. Operating and planning the interactions of the end-to-end high-voltage transmission grid with local distribution grids and microgrids represents another major potential use of this platform.This general approach was illustrated using a set of publicly-available data on both meteorology and details of electricity production and distribution in Puerto Rico. An extended AC Optimal Power Flow software developed by SmartGridz Inc. is used for system-level optimization of controllable equipment. This provides real-time guidance for deciding how much power, and through which transmission lines, should be channeled by adjusting plant dispatch and voltage-related set points, and in extreme cases, where to reduce or cut power in order to maintain physically-implementable service for as many customers as possible. The team found that the use of such a system can help to ensure that the greatest number of critical services maintain power even during a hurricane, and at the same time can lead to a substantial decrease in the need for construction of new power plants thanks to more efficient use of existing resources.The findings are described in a paper in the journal Foundations and Trends in Electric Energy Systems, by MIT LIDS researchers Marija Ilic and Laurentiu Anton, along with recent alumna Ramapathi Jaddivada.“Using this software,” Ilic says, they show that “even during bad weather, if you predict equipment failures, and by using that information exchange, you can localize the effect of equipment failures and still serve a lot of customers, 50 percent of customers, when otherwise things would black out.”Anton says that “the way many grids today are operated is sub-optimal.” As a result, “we showed how much better they could do even under normal conditions, without any failures, by utilizing this software.” The savings resulting from this optimization, under everyday conditions, could be in the tens of percents, they say.The way utility systems plan currently, Ilic says, “usually the standard is that they have to build enough capacity and operate in real time so that if one large piece of equipment fails, like a large generator or transmission line, you still serve customers in an uninterrupted way. That’s what’s called N-minus-1.” Under this policy, if one major component of the system fails, they should be able to maintain service for at least 30 minutes. That system allows utilities to plan for how much reserve generating capacity they need to have on hand. That’s expensive, Ilic points out, because it means maintaining this reserve capacity all the time, even under normal operating conditions when it’s not needed.In addition, “right now there are no criteria for what I call N-minus-K,” she says. If bad weather causes five pieces of equipment to fail at once, “there is no software to help utilities decide what to schedule” in terms of keeping the most customers, and the most important services such as hospitals and emergency services, provided with power. They showed that even with 50 percent of the infrastructure out of commission, it would still be possible to keep power flowing to a large proportion of customers.Their work on analyzing the power situation in Puerto Rico started after the island had been devastated by hurricanes Irma and Maria. Most of the electric generation capacity is in the south, yet the largest loads are in San Juan, in the north, and Mayaguez in the west. When transmission lines get knocked down, a lot of rerouting of power needs to happen quickly.With the new systems, “the software finds the optimal adjustments for set points,” for example, changing voltages can allow for power to be redirected through less-congested lines, or can be increased to lessen power losses, Anton says.The software also helps in the long-term planning for the grid. As many fossil-fuel power plants are scheduled to be decommissioned soon in Puerto Rico, as they are in many other places, planning for how to replace that power without having to resort to greenhouse gas-emitting sources is a key to achieving carbon-reduction goals. And by analyzing usage patterns, the software can guide the placement of new renewable power sources where they can most efficiently provide power where and when it’s needed.As plants are retired or as components are affected by weather, “We wanted to ensure the dispatchability of power when the load changes,” Anton says, “but also when crucial components are lost, to ensure the robustness at each step of the retirement schedule.”One thing they found was that “if you look at how much generating capacity exists, it’s more than the peak load, even after you retire a few fossil plants,” Ilic says. “But it’s hard to deliver.” Strategic planning of new distribution lines could make a big difference.Jaddivada, director of innovation at SmartGridz, says that “we evaluated different possible architectures in Puerto Rico, and we showed the ability of this software to ensure uninterrupted electricity service. This is the most important challenge utilities have today. They have to go through a computationally tedious process to make sure the grid functions for any possible outage in the system. And that can be done in a much more efficient way through the software that the company  developed.”The project was a collaborative effort between the MIT LIDS researchers and others at MIT Lincoln Laboratory, the Pacific Northwest National Laboratory, with overall help of SmartGridz software.  More

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      So you want to build a solar or wind farm? Here’s how to decide where.

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      Deciding where to build new solar or wind installations is often left up to individual developers or utilities, with limited overall coordination. But a new study shows that regional-level planning using fine-grained weather data, information about energy use, and energy system modeling can make a big difference in the design of such renewable power installations. This also leads to more efficient and economically viable operations.The findings show the benefits of coordinating the siting of solar farms, wind farms, and storage systems, taking into account local and temporal variations in wind, sunlight, and energy demand to maximize the utilization of renewable resources. This approach can reduce the need for sizable investments in storage, and thus the total system cost, while maximizing availability of clean power when it’s needed, the researchers found.The study, appearing today in the journal Cell Reports Sustainability, was co-authored by Liying Qiu and Rahman Khorramfar, postdocs in MIT’s Department of Civil and Environmental Engineering, and professors Saurabh Amin and Michael Howland.Qiu, the lead author, says that with the team’s new approach, “we can harness the resource complementarity, which means that renewable resources of different types, such as wind and solar, or different locations can compensate for each other in time and space. This potential for spatial complementarity to improve system design has not been emphasized and quantified in existing large-scale planning.”Such complementarity will become ever more important as variable renewable energy sources account for a greater proportion of power entering the grid, she says. By coordinating the peaks and valleys of production and demand more smoothly, she says, “we are actually trying to use the natural variability itself to address the variability.”Typically, in planning large-scale renewable energy installations, Qiu says, “some work on a country level, for example saying that 30 percent of energy should be wind and 20 percent solar. That’s very general.” For this study, the team looked at both weather data and energy system planning modeling on a scale of less than 10-kilometer (about 6-mile) resolution. “It’s a way of determining where should we, exactly, build each renewable energy plant, rather than just saying this city should have this many wind or solar farms,” she explains.To compile their data and enable high-resolution planning, the researchers relied on a variety of sources that had not previously been integrated. They used high-resolution meteorological data from the National Renewable Energy Laboratory, which is publicly available at 2-kilometer resolution but rarely used in a planning model at such a fine scale. These data were combined with an energy system model they developed to optimize siting at a sub-10-kilometer resolution. To get a sense of how the fine-scale data and model made a difference in different regions, they focused on three U.S. regions — New England, Texas, and California — analyzing up to 138,271 possible siting locations simultaneously for a single region.By comparing the results of siting based on a typical method vs. their high-resolution approach, the team showed that “resource complementarity really helps us reduce the system cost by aligning renewable power generation with demand,” which should translate directly to real-world decision-making, Qiu says. “If an individual developer wants to build a wind or solar farm and just goes to where there is the most wind or solar resource on average, it may not necessarily guarantee the best fit into a decarbonized energy system.”That’s because of the complex interactions between production and demand for electricity, as both vary hour by hour, and month by month as seasons change. “What we are trying to do is minimize the difference between the energy supply and demand rather than simply supplying as much renewable energy as possible,” Qiu says. “Sometimes your generation cannot be utilized by the system, while at other times, you don’t have enough to match the demand.”In New England, for example, the new analysis shows there should be more wind farms in locations where there is a strong wind resource during the night, when solar energy is unavailable. Some locations tend to be windier at night, while others tend to have more wind during the day.These insights were revealed through the integration of high-resolution weather data and energy system optimization used by the researchers. When planning with lower resolution weather data, which was generated at a 30-kilometer resolution globally and is more commonly used in energy system planning, there was much less complementarity among renewable power plants. Consequently, the total system cost was much higher. The complementarity between wind and solar farms was enhanced by the high-resolution modeling due to improved representation of renewable resource variability.The researchers say their framework is very flexible and can be easily adapted to any region to account for the local geophysical and other conditions. In Texas, for example, peak winds in the west occur in the morning, while along the south coast they occur in the afternoon, so the two naturally complement each other.Khorramfar says that this work “highlights the importance of data-driven decision making in energy planning.” The work shows that using such high-resolution data coupled with carefully formulated energy planning model “can drive the system cost down, and ultimately offer more cost-effective pathways for energy transition.”One thing that was surprising about the findings, says Amin, who is a principal investigator in the MIT Laboratory of Information and Data Systems, is how significant the gains were from analyzing relatively short-term variations in inputs and outputs that take place in a 24-hour period. “The kind of cost-saving potential by trying to harness complementarity within a day was not something that one would have expected before this study,” he says.In addition, Amin says, it was also surprising how much this kind of modeling could reduce the need for storage as part of these energy systems. “This study shows that there is actually a hidden cost-saving potential in exploiting local patterns in weather, that can result in a monetary reduction in storage cost.”The system-level analysis and planning suggested by this study, Howland says, “changes how we think about where we site renewable power plants and how we design those renewable plants, so that they maximally serve the energy grid. It has to go beyond just driving down the cost of energy of individual wind or solar farms. And these new insights can only be realized if we continue collaborating across traditional research boundaries, by integrating expertise in fluid dynamics, atmospheric science, and energy engineering.”The research was supported by the MIT Climate and Sustainability Consortium and MIT Climate Grand Challenges. More

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      Is there enough land on Earth to fight climate change and feed the world?

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      Capping global warming at 1.5 degrees Celsius is a tall order. Achieving that goal will not only require a massive reduction in greenhouse gas emissions from human activities, but also a substantial reallocation of land to support that effort and sustain the biosphere, including humans. More land will be needed to accommodate a growing demand for bioenergy and nature-based carbon sequestration while ensuring sufficient acreage for food production and ecological sustainability.The expanding role of land in a 1.5 C world will be twofold — to remove carbon dioxide from the atmosphere and to produce clean energy. Land-based carbon dioxide removal strategies include bioenergy with carbon capture and storage; direct air capture; and afforestation/reforestation and other nature-based solutions. Land-based clean energy production includes wind and solar farms and sustainable bioenergy cropland. Any decision to allocate more land for climate mitigation must also address competing needs for long-term food security and ecosystem health.Land-based climate mitigation choices vary in terms of costs — amount of land required, implications for food security, impact on biodiversity and other ecosystem services — and benefits — potential for sequestering greenhouse gases and producing clean energy.Now a study in the journal Frontiers in Environmental Science provides the most comprehensive analysis to date of competing land-use and technology options to limit global warming to 1.5 C. Led by researchers at the MIT Center for Sustainability Science and Strategy (CS3), the study applies the MIT Integrated Global System Modeling (IGSM) framework to evaluate costs and benefits of different land-based climate mitigation options in Sky2050, a 1.5 C climate-stabilization scenario developed by Shell.Under this scenario, demand for bioenergy and natural carbon sinks increase along with the need for sustainable farming and food production. To determine if there’s enough land to meet all these growing demands, the research team uses the global hectare (gha) — an area of 10,000 square meters, or 2.471 acres — as the standard unit of measurement, and current estimates of the Earth’s total habitable land area (about 10 gha) and land area used for food production and bioenergy (5 gha).The team finds that with transformative changes in policy, land management practices, and consumption patterns, global land is sufficient to provide a sustainable supply of food and ecosystem services throughout this century while also reducing greenhouse gas emissions in alignment with the 1.5 C goal. These transformative changes include policies to protect natural ecosystems; stop deforestation and accelerate reforestation and afforestation; promote advances in sustainable agriculture technology and practice; reduce agricultural and food waste; and incentivize consumers to purchase sustainably produced goods.If such changes are implemented, 2.5–3.5 gha of land would be used for NBS practices to sequester 3–6 gigatonnes (Gt) of CO2 per year, and 0.4–0.6 gha of land would be allocated for energy production — 0.2–0.3 gha for bioenergy and 0.2–0.35 gha for wind and solar power generation.“Our scenario shows that there is enough land to support a 1.5 degree C future as long as effective policies at national and global levels are in place,” says CS3 Principal Research Scientist Angelo Gurgel, the study’s lead author. “These policies must not only promote efficient use of land for food, energy, and nature, but also be supported by long-term commitments from government and industry decision-makers.” More

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      New solar projects will grow renewable energy generation for four major campus buildings

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      In the latest step to implement commitments made in MIT’s Fast Forward climate action plan, staff from the Department of Facilities; Office of Sustainability; and Environment, Health and Safety Office are advancing new solar panel installations this fall and winter on four major campus buildings: The Stratton Student Center (W20), the Dewey Library building (E53), and two newer buildings, New Vassar (W46) and the Theater Arts building (W97).These four new installations, in addition to existing rooftop solar installations on campus, are “just one part of our broader strategy to reduce MIT’s carbon footprint and transition to clean energy,” says Joe Higgins, vice president for campus services and stewardship.The installations will not only meet but exceed the target set for total solar energy production on campus in the Fast Forward climate action plan that was issued in 2021. With an initial target of 500 kilowatts of installed solar capacity on campus, the new installations, along with those already in place, will bring the total output to roughly 650 kW, exceeding the goal. The solar installations are an important facet of MIT’s approach to eliminating all direct campus emissions by 2050.The process of advancing to the stage of placing solar panels on campus rooftops is much more complex than just getting them installed on an ordinary house. The process began with a detailed assessment of the potential for reducing the campus greenhouse gas footprint. A first cut eliminated rooftops that were too shaded by trees or other buildings. Then, the schedule for regular replacement of roofs had to be taken into account — it’s better to put new solar panels on top of a roof that will not need replacement in a few years. Other roofs, especially lab buildings, simply had too much existing equipment on them to allow a large area of space for solar panels.Randa Ghattas, senior sustainability project manager, and Taya Dixon, assistant director for capital budgets and contracts within the Department of Facilities, spearheaded the project. Their initial assessment showed that there were many buildings identified with significant solar potential, and it took the impetus of the Fast Forward plan to kick things into action. Even after winnowing down the list of campus buildings based on shading and the life cycle of roof replacements, there were still many other factors to consider. Some buildings that had ample roof space were of older construction that couldn’t bear the loads of a full solar installation without significant reconstruction. “That actually has proved trickier than we thought,” Ghattas says. For example, one building that seemed a good candidate, and already had some solar panels on it, proved unable to sustain the greater weight and wind loads of a full solar installation. Structural capacity, she says, turned out to be “probably the most important” factor in this case.The roofs on the Student Center and on the Dewey Library building were replaced in the last few years with the intention of the later addition of solar panels. And the two newer buildings were designed from the beginning with solar in mind, even though the solar panels were not part of the initial construction. “The designs were built into them to accommodate solar,” Dixon says, “so those were easy options for us because we knew the buildings were solar-ready and could support solar being integrated into their systems, both the electrical system and the structural system of the roof.”But there were also other considerations. The Student Center is considered a historically significant building, so the installation had to be designed so that it was invisible from street level, even including a safety railing that had to be built around the solar array. But that was not a problem. “It was fine for this building,” Ghattas says, because it turned out that the geometry of the building and the roofs hid the safety railing from view below.Each installation will connect directly to the building’s electrical system, and thus into the campus grid. The power they produce will be used in the buildings they are on, though none will be sufficient to fully power its building. Overall, the new installations, in addition to the existing ones on the MIT Sloan School of Management building (E62) and the Alumni Pool (57) and the planned array on the new Graduate Junction dorm (W87-W88), will be enough to power 5 to 10 percent of the buildings’ electric needs, and offset about 190 metric tons of carbon dioxide emissions each year, Ghattas says. This is equivalent to the electricity use of 35 homes annually.Each building installation is expected to take just a couple of weeks. “We’re hopeful that we’re going to have everything installed and operational by the end of this calendar year,” she says.Other buildings could be added in coming years, as their roof replacement cycles come around. With the lessons learned along the way in getting to this point, Ghattas says, “now that we have a system in place, hopefully it’s going to be much easier in the future.”Higgins adds that “in parallel with the solar projects, we’re working on expanding electric vehicle charging stations and the electric vehicle fleet and reducing energy consumption in campus buildings.”Besides the on-campus improvements, he says, “MIT is focused on both the local and the global.” In addition to solar installations on campus buildings, which can only mitigate a small portion of campus emissions, “large-scale aggregation partnerships are key to moving the actual market landscape for adding cleaner energy generation to power grids,” which must ultimately lead to zero emissions, he says. “We are spurring the development of new utility-grade renewable energy facilities in regions with high carbon-intensive electrical grids. These projects have an immediate and significant impact in the urgently needed decarbonization of regional power grids.”MIT is also making more advances to accelerate renewable energy generation and electricity grid decarbonization at the local and state level. The Institute has recently concluded an agreement through the Solar Massachusetts Renewable Target program that supports the Commonwealth of Massachusetts’ state solar power development goals by enabling the construction of a new 5-megawatt solar energy facility on Cape Cod. The new solar energy system is integral to supporting a new net-zero emissions development that includes affordable housing, while also providing additional resiliency to the local grid.Higgins says that other technologies, strategies, and practices are being evaluated for heating, cooling, and power for the campus, “with zero carbon emissions by 2050, utilizing cleaner energy sources.” He adds that these campus initiatives “are part of MIT’s larger Climate Project, aiming to drive progress both on campus and beyond, advancing broader partnerships, new market models, and informing approaches to climate policy.”  More

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      in Environment

      New solar projects will grow renewable energy generation for four major campus buildings

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      In the latest step to implement commitments made in MIT’s Fast Forward climate action plan, staff from the Department of Facilities; Office of Sustainability; and Environment, Health and Safety Office are advancing new solar panel installations this fall and winter on four major campus buildings: The Stratton Student Center (W20), the Dewey Library building (E53), and two newer buildings, New Vassar (W46) and the Theater Arts building (W97).These four new installations, in addition to existing rooftop solar installations on campus, are “just one part of our broader strategy to reduce MIT’s carbon footprint and transition to clean energy,” says Joe Higgins, vice president for campus services and stewardship.The installations will not only meet but exceed the target set for total solar energy production on campus in the Fast Forward climate action plan that was issued in 2021. With an initial target of 500 kilowatts of installed solar capacity on campus, the new installations, along with those already in place, will bring the total output to roughly 650 kW, exceeding the goal. The solar installations are an important facet of MIT’s approach to eliminating all direct campus emissions by 2050.The process of advancing to the stage of placing solar panels on campus rooftops is much more complex than just getting them installed on an ordinary house. The process began with a detailed assessment of the potential for reducing the campus greenhouse gas footprint. A first cut eliminated rooftops that were too shaded by trees or other buildings. Then, the schedule for regular replacement of roofs had to be taken into account — it’s better to put new solar panels on top of a roof that will not need replacement in a few years. Other roofs, especially lab buildings, simply had too much existing equipment on them to allow a large area of space for solar panels.Randa Ghattas, senior sustainability project manager, and Taya Dixon, assistant director for capital budgets and contracts within the Department of Facilities, spearheaded the project. Their initial assessment showed that there were many buildings identified with significant solar potential, and it took the impetus of the Fast Forward plan to kick things into action. Even after winnowing down the list of campus buildings based on shading and the life cycle of roof replacements, there were still many other factors to consider. Some buildings that had ample roof space were of older construction that couldn’t bear the loads of a full solar installation without significant reconstruction. “That actually has proved trickier than we thought,” Ghattas says. For example, one building that seemed a good candidate, and already had some solar panels on it, proved unable to sustain the greater weight and wind loads of a full solar installation. Structural capacity, she says, turned out to be “probably the most important” factor in this case.The roofs on the Student Center and on the Dewey Library building were replaced in the last few years with the intention of the later addition of solar panels. And the two newer buildings were designed from the beginning with solar in mind, even though the solar panels were not part of the initial construction. “The designs were built into them to accommodate solar,” Dixon says, “so those were easy options for us because we knew the buildings were solar-ready and could support solar being integrated into their systems, both the electrical system and the structural system of the roof.”But there were also other considerations. The Student Center is considered a historically significant building, so the installation had to be designed so that it was invisible from street level, even including a safety railing that had to be built around the solar array. But that was not a problem. “It was fine for this building,” Ghattas says, because it turned out that the geometry of the building and the roofs hid the safety railing from view below.Each installation will connect directly to the building’s electrical system, and thus into the campus grid. The power they produce will be used in the buildings they are on, though none will be sufficient to fully power its building. Overall, the new installations, in addition to the existing ones on the MIT Sloan School of Management building (E62) and the Alumni Pool (57) and the planned array on the new Graduate Junction dorm (W87-W88), will be enough to power 5 to 10 percent of the buildings’ electric needs, and offset about 190 metric tons of carbon dioxide emissions each year, Ghattas says. This is equivalent to the electricity use of 35 homes annually.Each building installation is expected to take just a couple of weeks. “We’re hopeful that we’re going to have everything installed and operational by the end of this calendar year,” she says.Other buildings could be added in coming years, as their roof replacement cycles come around. With the lessons learned along the way in getting to this point, Ghattas says, “now that we have a system in place, hopefully it’s going to be much easier in the future.”Higgins adds that “in parallel with the solar projects, we’re working on expanding electric vehicle charging stations and the electric vehicle fleet and reducing energy consumption in campus buildings.”Besides the on-campus improvements, he says, “MIT is focused on both the local and the global.” In addition to solar installations on campus buildings, which can only mitigate a small portion of campus emissions, “large-scale aggregation partnerships are key to moving the actual market landscape for adding cleaner energy generation to power grids,” which must ultimately lead to zero emissions, he says. “We are spurring the development of new utility-grade renewable energy facilities in regions with high carbon-intensive electrical grids. These projects have an immediate and significant impact in the urgently needed decarbonization of regional power grids.”MIT is also making more advances to accelerate renewable energy generation and electricity grid decarbonization at the local and state level. The Institute has recently concluded an agreement through the Solar Massachusetts Renewable Target program that supports the Commonwealth of Massachusetts’ state solar power development goals by enabling the construction of a new 5-megawatt solar energy facility on Cape Cod. The new solar energy system is integral to supporting a new net-zero emissions development that includes affordable housing, while also providing additional resiliency to the local grid.Higgins says that other technologies, strategies, and practices are being evaluated for heating, cooling, and power for the campus, “with zero carbon emissions by 2050, utilizing cleaner energy sources.” He adds that these campus initiatives “are part of MIT’s larger Climate Project, aiming to drive progress both on campus and beyond, advancing broader partnerships, new market models, and informing approaches to climate policy.”  More

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      in Energy

      Consortium led by MIT, Harvard University, and Mass General Brigham spurs development of 408 MW of renewable energy

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      MIT is co-leading an effort to enable the development of two new large-scale renewable energy projects in regions with carbon-intensive electrical grids: Big Elm Solar in Bell County, Texas, came online this year, and the Bowman Wind Project in Bowman County, North Dakota, is expected to be operational in 2026. Together, they will add a combined 408 megawatts (MW) of new renewable energy capacity to the power grid. This work is a critical part of MIT’s strategy to achieve its goal of net-zero carbon emissions by 2026.The Consortium for Climate Solutions, which includes MIT and 10 other Massachusetts organizations, seeks to eliminate close to 1 million metric tons of greenhouse gases each year — more than five times the annual direct emissions from MIT’s campus — by committing to purchase an estimated 1.3-million-megawatt hours of new solar and wind electricity generation annually.“MIT has mobilized on multiple fronts to expedite solutions to climate change,” says Glen Shor, executive vice president and treasurer. “Catalyzing these large-scale renewable projects is an important part of our comprehensive efforts to reduce carbon emissions from generating energy. We are pleased to work in partnership with other local enterprises and organizations to amplify the impact we could achieve individually.”The two new projects complement MIT’s existing 25-year power purchase agreement established with Summit Farms in 2016, which enabled the construction of a roughly 650-acre, 60 MW solar farm on farmland in North Carolina, leading to the early retirement of a coal-fired plant nearby. Its success has inspired other institutions to implement similar aggregation models.A collective approach to enable global impactMIT, Harvard University, and Mass General Brigham formed the consortium in 2020 to provide a structure to accelerate global emissions reductions through the development of large-scale renewable energy projects — accelerating and expanding the impact of each institution’s greenhouse gas reduction initiatives. As the project’s anchors, they collectively procured the largest volume of energy through the aggregation.  The consortium engaged with PowerOptions, a nonprofit energy-buying consortium, which offered its members the opportunity to participate in the projects. The City of Cambridge, Beth Israel Lahey, Boston Children’s Hospital, Dana-Farber Cancer Institute, Tufts University, the Mass Convention Center Authority, the Museum of Fine Arts, and GBH later joined the consortium through PowerOptions.  The consortium vetted over 125 potential projects against its rigorous project evaluation criteria. With faculty and MIT stakeholder input on a short list of the highest-ranking projects, it ultimately chose Bowman Wind and Big Elm Solar. Collectively, these two projects will achieve large greenhouse gas emissions reductions in two of the most carbon-intensive electrical grid regions in the United States and create clean energy generation sources to reduce negative health impacts.“Enabling these projects in regions where the grids are most carbon-intensive allows them to have the greatest impact. We anticipate these projects will prevent two times more emissions per unit of generated electricity than would a similar-scale project in New England,” explains Vice President for Campus Services and Stewardship Joe Higgins.By all consortium institutions making significant 15-to-20-year financial commitments to buy electricity, the developer was able to obtain critical external project financing to build the projects. Owned and operated by Apex Clean Energy, the projects will add new renewable electricity to the grid equivalent to powering 130,000 households annually, displacing over 950,000 metric tons of greenhouse gas emissions each year from highly carbon-intensive power plants in the region. Complementary decarbonization work underway In addition to investing in offsite renewable energy projects, many consortium members have developed strategies to reduce and eliminate their own direct emissions. At MIT, accomplishing this requires transformative change in how energy is generated, distributed, and used on campus. Efforts underway include the installation of solar panels on campus rooftops that will increase renewable energy generation four-fold by 2026; continuing to transition our heat distribution infrastructure from steam-based to hot water-based; utilizing design and construction that minimizes emissions and increases energy efficiency; employing AI-enabled sensors to optimize temperature set points and reduce energy use in buildings; and converting MIT’s vehicle fleet to all-electric vehicles while adding more electric car charging stations.The Institute has also upgraded the Central Utilities Plant, which uses advanced co-generation technology to produce power that is up to 20 percent less carbon-intensive than that from the regional power grid. MIT is charting the course toward a next-generation district energy system, with a comprehensive planning initiative to revolutionize its campus energy infrastructure. The effort is exploring leading-edge technology, including industrial-scale heat pumps, geothermal exchange, micro-reactors, bio-based fuels, and green hydrogen derived from renewable sources as solutions to achieve full decarbonization of campus operations by 2050.“At MIT, we are focused on decarbonizing our own campus as well as the role we can play in solving climate at the largest of scales, including supporting a cleaner grid in line with the call to triple renewables globally by 2030. By enabling these large-scale renewable projects, we can have an immediate and significant impact of reducing emissions through the urgently needed decarbonization of regional power grids,” says Julie Newman, MIT’s director of sustainability.   More

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      in Environment

      Startup turns mining waste into critical metals for the U.S.

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      At the heart of the energy transition is a metal transition. Wind farms, solar panels, and electric cars require many times more copper, zinc, and nickel than their gas-powered alternatives. They also require more exotic metals with unique properties, known as rare earth elements, which are essential for the magnets that go into things like wind turbines and EV motors.Today, China dominates the processing of rare earth elements, refining around 60 percent of those materials for the world. With demand for such materials forecasted to skyrocket, the Biden administration has said the situation poses national and economic security threats.Substantial quantities of rare earth metals are sitting unused in the United States and many other parts of the world today. The catch is they’re mixed with vast quantities of toxic mining waste.Phoenix Tailings is scaling up a process for harvesting materials, including rare earth metals and nickel, from mining waste. The company uses water and recyclable solvents to collect oxidized metal, then puts the metal into a heated molten salt mixture and applies electricity.The company, co-founded by MIT alumni, says its pilot production facility in Woburn, Massachusetts, is the only site in the world producing rare earth metals without toxic byproducts or carbon emissions. The process does use electricity, but Phoenix Tailings currently offsets that with renewable energy contracts.The company expects to produce more than 3,000 tons of the metals by 2026, which would have represented about 7 percent of total U.S. production last year.Now, with support from the Department of Energy, Phoenix Tailings is expanding the list of metals it can produce and accelerating plans to build a second production facility.For the founding team, including MIT graduates Tomás Villalón ’14 and Michelle Chao ’14 along with Nick Myers and Anthony Balladon, the work has implications for geopolitics and the planet.“Being able to make your own materials domestically means that you’re not at the behest of a foreign monopoly,” Villalón says. “We’re focused on creating critical materials for the next generation of technologies. More broadly, we want to get these materials in ways that are sustainable in the long term.”Tackling a global problemVillalón got interested in chemistry and materials science after taking Course 3.091 (Introduction to Solid-State Chemistry) during his first year at MIT. In his senior year, he got a chance to work at Boston Metal, another MIT spinoff that uses an electrochemical process to decarbonize steelmaking at scale. The experience got Villalón, who majored in materials science and engineering, thinking about creating more sustainable metallurgical processes.But it took a chance meeting with Myers at a 2018 Bible study for Villalón to act on the idea.“We were discussing some of the major problems in the world when we came to the topic of electrification,” Villalón recalls. “It became a discussion about how the U.S. gets its materials and how we should think about electrifying their production. I was finally like, ‘I’ve been working in the space for a decade, let’s go do something about it.’ Nick agreed, but I thought he just wanted to feel good about himself. Then in July, he randomly called me and said, ‘I’ve got [$7,000]. When do we start?’”Villalón brought in Chao, his former MIT classmate and fellow materials science and engineering major, and Myers brought Balladon, a former co-worker, and the founders started experimenting with new processes for producing rare earth metals.“We went back to the base principles, the thermodynamics I learned with MIT professors Antoine Allanore and Donald Sadoway, and understanding the kinetics of reactions,” Villalón says. “Classes like Course 3.022 (Microstructural Evolution in Materials) and 3.07 (Introduction to Ceramics) were also really useful. I touched on every aspect I studied at MIT.”The founders also received guidance from MIT’s Venture Mentoring Service (VMS) and went through the U.S. National Science Foundation’s I-Corps program. Sadoway served as an advisor for the company.After drafting one version of their system design, the founders bought an experimental quantity of mining waste, known as red sludge, and set up a prototype reactor in Villalón’s backyard. The founders ended up with a small amount of product, but they had to scramble to borrow the scientific equipment needed to determine what exactly it was. It turned out to be a small amount of rare earth concentrate along with pure iron.Today, at the company’s refinery in Woburn, Phoenix Tailings puts mining waste rich in rare earth metals into its mixture and heats it to around 1,300 degrees Fahrenheit. When it applies an electric current to the mixture, pure metal collects on an electrode. The process leaves minimal waste behind.“The key for all of this isn’t just the chemistry, but how everything is linked together, because with rare earths, you have to hit really high purities compared to a conventionally produced metal,” Villalón explains. “As a result, you have to be thinking about the purity of your material the entire way through.”From rare earths to nickel, magnesium, and moreVillalón says the process is economical compared to conventional production methods, produces no toxic byproducts, and is completely carbon free when renewable energy sources are used for electricity.The Woburn facility is currently producing several rare earth elements for customers, including neodymium and dysprosium, which are important in magnets. Customers are using the materials for things likewind turbines, electric cars, and defense applications.The company has also received two grants with the U.S. Department of Energy’s ARPA-E program totaling more than $2 million. Its 2023 grant supports the development of a system to extract nickel and magnesium from mining waste through a process that uses carbonization and recycled carbon dioxide. Both nickel and magnesium are critical materials for clean energy applications like batteries.The most recent grant will help the company adapt its process to produce iron from mining waste without emissions or toxic byproducts. Phoenix Tailings says its process is compatible with a wide array of ore types and waste materials, and the company has plenty of material to work with: Mining and processing mineral ores generates about 1.8 billion tons of waste in the U.S. each year.“We want to take our knowledge from processing the rare earth metals and slowly move it into other segments,” Villalón explains. “We simply have to refine some of these materials here. There’s no way we can’t. So, what does that look like from a regulatory perspective? How do we create approaches that are economical and environmentally compliant not just now, but 30 years from now?” More