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    Bringing sustainable and affordable electricity to all

    When MIT electrical engineer Reja Amatya PhD ’12 arrived in Rwanda in 2015, she was whisked off to a village. She saw that diesel generators provided power to the local health center, bank, and shops, but like most of rural Rwanda, Karambi’s 200 homes did not have electricity. Amatya knew the hilly terrain would make it challenging to connect the village to high-voltage lines from the capital, Kigali, 50 kilometers away.

    While many consider electricity a basic human right, there are places where people have never flipped a light switch. Among the United Nations’ Sustainable Development Goals is global access to affordable, reliable, and sustainable energy by 2030. Recently, the U.N. reported that progress in global electrification had slowed due to the challenge of reaching those hardest to reach.

    Researchers from the MIT Energy Initiative (MITEI) and Comillas Pontifical University in Madrid created Waya Energy Inc., a Cambridge, Massachusetts-based startup commercializing MIT-developed planning and analysis software, to help governments determine the most cost-effective ways to provide electricity to all their citizens.

    The researchers’ 2015 trip to Rwanda marked the beginning of four years of phone calls, Zoom meetings, and international travel to help the east African country — still reeling from the 1994 genocide that killed more than a million people — develop a national electrification strategy and extend its power infrastructure.

    Amatya, Waya president and one of five Waya co-founders, knew that electrifying Karambi and the rest of the country would provide new opportunities for work, education, and connections — and the ability to charge cellphones, often an expensive and inconvenient undertaking.

    To date, Waya — with funding from the Asian Development Bank, the African Development Bank, the Inter-American Development Bank for Latin America, and the World Bank — has helped governments develop electrification plans in 22 countries on almost every continent, including in refugee camps in sub-Saharan Africa’s Sahel and Chad regions, where violence has led to 3 million internally displaced people.

    “With a modeling and visualization tool like ours, we are able to look at the entire spectrum of need and demand and say, ‘OK, what might be the most optimized solution?’” Amatya says.

    More than 15 graduate students and researchers from MIT and Comillas contributed to the development of Waya’s software under the supervision of Robert Stoner, the interim director at MITEI, and Ignacio Pérez-Arriaga, a visiting professor at the MIT Sloan School of Management from Comillas. Pérez-Arriaga looks at how changing electricity use patterns have forced utilities worldwide to rethink antiquated business models.

    The team’s Reference Electrification Model (REM) software pulls information from population density maps, satellite images, infrastructure data, and geospatial points of interest to determine where extending the grid will be most cost-effective and where other solutions would be more practical.

    “I always say we are agnostic to the technology,” Amatya says. “Traditionally, the only way to provide long-term reliable access was through the grid, but that’s changing. In many developing countries, there are many more challenges for utilities to provide reliable service.”

    Off-grid solutions

    Waya co-founder Stoner, who is also the founding director of the MIT Tata Center for Technology and Design, recognized early on that connecting homes to existing infrastructure was not always economically feasible. What’s more, billions of people with grid connections had unreliable access due to uneven regulation and challenging terrain.

    With Waya co-founders Andres Gonzalez-Garcia, a MITEI affiliate researcher, and Professor Fernando de Cuadra Garcia of Comillas, Pérez-Arriaga and Stoner led a team that developed a set of principles to guide universal regional electrification. Their approach — which they dubbed the Integrated Distribution Framework — incorporates elements of optimal planning as well as novel business models and regulation. Getting all three right is “necessary,” Stoner says, “if you want a viable long-term outcome.”

    Amatya says, “Initially, we designed REM to understand what the level of demand is in these countries with very rural and poor populations, and what the system should look like to serve it. We took a lot of that input into developing the model.” In 2019, Waya was created to commercialize the software and add consulting to the package of services the team provides.

    Now, in addition to advising governments and regulators on how to expand existing grids, Waya proposes options such as a mini-grid, powered by renewables like wind, hydropower, or solar, to serve single villages or large-scale mini-grid solutions for larger areas. In some cases, an even more localized, scalable solution is a mesh grid, which might consist of a single solar panel for a few houses that, over time, can be expanded and ultimately connected to the main grid.

    The REM software has been used to design off-grid systems for remote and mountainous regions in Uganda, Peru, Nigeria, Cambodia, Indonesia, India, and elsewhere. When Tata Power, India’s largest integrated power company, saw how well mini-grids would serve parts of east India, the company created a mini-grid division called Tata Renewables.

    Amatya notes that the REM software enables her to come up with an entire national electrification plan from her workspace in Cambridge. But site visits and on-the-ground partners are critical in helping the Waya team understand existing systems, engage with clients to assess demand, and identify stakeholders. In Haiti, an energy consultant reported that the existing grid had typically been operational only six out of every 24 hours. In Karambi, University of Rwanda students surveyed the village’s 200 families and helped lead a community-wide meeting.

    Waya connects with on-the-ground experts and agencies “who can engage directly with the government and other stakeholders, because many times those are the doors that we knock on,” Amatya says. “Local energy ministries, utilities, and regulators have to be open to regulatory change. They have to be open to working with financial institutions and new technology.”

    The goals of regulators, energy providers, funding agencies, and government officials must align in real time “to provide reliable access to energy for a billion people,” she says.

    Moving past challenges

    Growing up in Kathmandu, Amatya used to travel to remote villages with her father, an electrical engineer who designed cable systems for landlines for Nepal Telecom. She remembers being fascinated by the high-voltage lines crisscrossing Nepal on these trips. Now, she points out utility poles to her children and explains how the distribution lines carry power from local substations to customers.

    After majoring in engineering science and physics at Smith College, Amatya completed her PhD in electrical engineering at MIT in 2012. Within two years, she was traveling to off-grid communities in India as a research scientist exploring potential technologies for providing access. There were unexpected challenges: At the time, digitized geospatial data didn’t exist for many regions. In India in 2013, the team used phones to take pictures of paper maps spread out on tables. Team members now scour digital data available through Facebook, Google, Microsoft, and other sources for useful geographical information. 

    It’s one thing to create a plan, Amatya says, but how it gets utilized and implemented becomes a big question. With all the players involved — funding agencies, elected officials, utilities, private companies, and regulators within the countries themselves — it’s sometimes hard to know who’s responsible for next steps.

    “Besides providing technical expertise, our team engages with governments to, let’s say, develop a financial plan or an implementation plan,” she says. Ideally, Waya hopes to stay involved with each project long enough to ensure that its proposal becomes the national electrification strategy of the country. That’s no small feat, given the multiple players, the opaque nature of government, and the need to enact a regulatory framework where none may have existed.

    For Rwanda, Waya identified areas without service, estimated future demand, and proposed the most cost-effective ways to meet that demand with a mix of grid and off-grid solutions. Based on the electrification plan developed by the Waya team, officials have said they hope to have the entire country electrified by 2024.

    In 2017, by the time the team submitted its master plan, which included an off-grid solution for Karambi, Amatya was surprised to learn that electrification in the village had already occurred — an example, she says, of the challenging nature of local planning.

    Perhaps because of Waya’s focus and outreach efforts, Karambi had become a priority. However it happened, Amatya is happy that Karambi’s 200 families finally have access to electricity. More

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    Processing waste biomass to reduce airborne emissions

    To prepare fields for planting, farmers the world over often burn corn stalks, rice husks, hay, straw, and other waste left behind from the previous harvest. In many places, the practice creates huge seasonal clouds of smog, contributing to air pollution that kills 7 million people globally a year, according to the World Health Organization.

    Annually, $120 billion worth of crop and forest residues are burned in the open worldwide — a major waste of resources in an energy-starved world, says Kevin Kung SM ’13, PhD ’17. Kung is working to transform this waste biomass into marketable products — and capitalize on a billion-dollar global market — through his MIT spinoff company, Takachar.

    Founded in 2015, Takachar develops small-scale, low-cost, portable equipment to convert waste biomass into solid fuel using a variety of thermochemical treatments, including one known as oxygen-lean torrefaction. The technology emerged from Kung’s PhD project in the lab of Ahmed Ghoniem, the Ronald C. Crane (1972) Professor of Mechanical Engineering at MIT.

    Biomass fuels, including wood, peat, and animal dung, are a major source of carbon emissions — but billions of people rely on such fuels for cooking, heating, and other household needs. “Currently, burning biomass generates 10 percent of the primary energy used worldwide, and the process is used largely in rural, energy-poor communities. We’re not going to change that overnight. There are places with no other sources of energy,” Ghoniem says.

    What Takachar’s technology provides is a way to use biomass more cleanly and efficiently by concentrating the fuel and eliminating contaminants such as moisture and dirt, thus creating a “clean-burning” fuel — one that generates less smoke. “In rural communities where biomass is used extensively as a primary energy source, torrefaction will address air pollution head-on,” Ghoniem says.

    Thermochemical treatment densifies biomass at elevated temperatures, converting plant materials that are typically loose, wet, and bulky into compact charcoal. Centralized processing plants exist, but collection and transportation present major barriers to utilization, Kung says. Takachar’s solution moves processing into the field: To date, Takachar has worked with about 5,500 farmers to process 9,000 metric tons of crops.

    Takachar estimates its technology has the potential to reduce carbon dioxide equivalent emissions by gigatons per year at scale. (“Carbon dioxide equivalent” is a measure used to gauge global warming potential.) In recognition, in 2021 Takachar won the first-ever Earthshot Prize in the clean air category, a £1 million prize funded by Prince William and Princess Kate’s Royal Foundation.

    Roots in Kenya

    As Kung tells the story, Takachar emerged from a class project that took him to Kenya — which explains the company’s name, a combination of takataka, which mean “trash” in Swahili, and char, for the charcoal end product.

    It was 2011, and Kung was at MIT as a biological engineering grad student focused on cancer research. But “MIT gives students big latitude for exploration, and I took courses outside my department,” he says. In spring 2011, he signed up for a class known as 15.966 (Global Health Delivery Lab) in the MIT Sloan School of Management. The class brought Kung to Kenya to work with a nongovernmental organization in Nairobi’s Kibera, the largest urban slum in Africa.

    “We interviewed slum households for their views on health, and that’s when I noticed the charcoal problem,” Kung says. The problem, as Kung describes it, was that charcoal was everywhere in Kibera — piled up outside, traded by the road, and used as the primary fuel, even indoors. Its creation contributed to deforestation, and its smoke presented a serious health hazard.

    Eager to address this challenge, Kung secured fellowship support from the MIT International Development Initiative and the Priscilla King Gray Public Service Center to conduct more research in Kenya. In 2012, he formed Takachar as a team and received seed money from the MIT IDEAS Global Challenge, MIT Legatum Center for Development and Entrepreneurship, and D-Lab to produce charcoal from household organic waste. (This work also led to a fertilizer company, Safi Organics, that Kung founded in 2016 with the help of MIT IDEAS. But that is another story.)

    Meanwhile, Kung had another top priority: finding a topic for his PhD dissertation. Back at MIT, he met Alexander Slocum, the Walter M. May and A. Hazel May Professor of Mechanical Engineering, who on a long walk-and-talk along the Charles River suggested he turn his Kenya work into a thesis. Slocum connected him with Robert Stoner, deputy director for science and technology at the MIT Energy Initiative (MITEI) and founding director of MITEI’s Tata Center for Technology and Design. Stoner in turn introduced Kung to Ghoniem, who became his PhD advisor, while Slocum and Stoner joined his doctoral committee.

    Roots in MIT lab

    Ghoniem’s telling of the Takachar story begins, not surprisingly, in the lab. Back in 2010, he had a master’s student interested in renewable energy, and he suggested the student investigate biomass. That student, Richard Bates ’10, SM ’12, PhD ’16, began exploring the science of converting biomass to more clean-burning charcoal through torrefaction.

    Most torrefaction (also known as low-temperature pyrolysis) systems use external heating sources, but the lab’s goal, Ghoniem explains, was to develop an efficient, self-sustained reactor that would generate fewer emissions. “We needed to understand the chemistry and physics of the process, and develop fundamental scaling models, before going to the lab to build the device,” he says.

    By the time Kung joined the lab in 2013, Ghoniem was working with the Tata Center to identify technology suitable for developing countries and largely based on renewable energy. Kung was able to secure a Tata Fellowship and — building on Bates’ research — develop the small-scale, practical device for biomass thermochemical conversion in the field that launched Takachar.

    This device, which was patented by MIT with inventors Kung, Ghoniem, Stoner, MIT research scientist Santosh Shanbhogue, and Slocum, is self-contained and scalable. It burns a little of the biomass to generate heat; this heat bakes the rest of the biomass, releasing gases; the system then introduces air to enable these gases to combust, which burns off the volatiles and generates more heat, keeping the thermochemical reaction going.

    “The trick is how to introduce the right amount of air at the right location to sustain the process,” Ghoniem explains. “If you put in more air, that will burn the biomass. If you put in less, there won’t be enough heat to produce the charcoal. That will stop the reaction.”

    About 10 percent of the biomass is used as fuel to support the reaction, Kung says, adding that “90 percent is densified into a form that’s easier to handle and utilize.” He notes that the research received financial support from the Abdul Latif Jameel Water and Food Systems Lab and the Deshpande Center for Technological Innovation, both at MIT. Sonal Thengane, another postdoc in Ghoniem’s lab, participated in the effort to scale up the technology at the MIT Bates Lab (no relation to Richard Bates).

    The charcoal produced is more valuable per ton and easier to transport and sell than biomass, reducing transportation costs by two-thirds and giving farmers an additional income opportunity — and an incentive not to burn agricultural waste, Kung says. “There’s more income for farmers, and you get better air quality.”

    Roots in India

    When Kung became a Tata Fellow, he joined a program founded to take on the biggest challenges of the developing world, with a focus on India. According to Stoner, Tata Fellows, including Kung, typically visit India twice a year and spend six to eight weeks meeting stakeholders in industry, the government, and in communities to gain perspective on their areas of study.

    “A unique part of Tata is that you’re considering the ecosystem as a whole,” says Kung, who interviewed hundreds of smallholder farmers, met with truck drivers, and visited existing biomass processing plants during his Tata trips to India. (Along the way, he also connected with Indian engineer Vidyut Mohan, who became Takachar’s co-founder.)

    “It was very important for Kevin to be there walking about, experimenting, and interviewing farmers,” Stoner says. “He learned about the lives of farmers.”

    These experiences helped instill in Kung an appreciation for small farmers that still drives him today as Takachar rolls out its first pilot programs, tinkers with the technology, grows its team (now up to 10), and endeavors to build a revenue stream. So, while Takachar has gotten a lot of attention and accolades — from the IDEAS award to the Earthshot Prize — Kung says what motivates him is the prospect of improving people’s lives.

    The dream, he says, is to empower communities to help both the planet and themselves. “We’re excited about the environmental justice perspective,” he says. “Our work brings production and carbon removal or avoidance to rural communities — providing them with a way to convert waste, make money, and reduce air pollution.”

    This article appears in the Spring 2022 issue of Energy Futures, the magazine of the MIT Energy Initiative. More

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    Vapor-collection technology saves water while clearing the air

    About two-fifths of all the water that gets withdrawn from lakes, rivers, and wells in the U.S. is used not for agriculture, drinking, or sanitation, but to cool the power plants that provide electricity from fossil fuels or nuclear power. Over 65 percent of these plants use evaporative cooling, leading to huge white plumes that billow from their cooling towers, which can be a nuisance and, in some cases, even contribute to dangerous driving conditions.

    Now, a small company based on technology recently developed at MIT by the Varanasi Research Group is hoping to reduce both the water needs at these plants and the resultant plumes — and to potentially help alleviate water shortages in areas where power plants put pressure on local water systems.

    The technology is surprisingly simple in principle, but developing it to the point where it can now be tested at full scale on industrial plants was a more complex proposition. That required the real-world experience that the company’s founders gained from installing prototype systems, first on MIT’s natural-gas-powered cogeneration plant and then on MIT’s nuclear research reactor.

    In these demanding tests, which involved exposure to not only the heat and vibrations of a working industrial plant but also the rigors of New England winters, the system proved its effectiveness at both eliminating the vapor plume and recapturing water. And, it purified the water in the process, so that it was 100 times cleaner than the incoming cooling water. The system is now being prepared for full-scale tests in a commercial power plant and in a chemical processing plant.

    “Campus as a living laboratory”

    The technology was originally envisioned by professor of mechanical engineering Kripa Varanasi to develop efficient water-recovery systems by capturing water droplets from both natural fog and plumes from power plant cooling towers. The project began as part of doctoral thesis research of Maher Damak PhD ’18, with funding from the MIT Tata Center for Technology and Design, to improve the efficiency of fog-harvesting systems like the ones used in some arid coastal regions as a source of potable water. Those systems, which generally consist of plastic or metal mesh hung vertically in the path of fogbanks, are extremely inefficient, capturing only about 1 to 3 percent of the water droplets that pass through them.

    Varanasi and Damak found that vapor collection could be made much more efficient by first zapping the tiny droplets of water with a beam of electrically charged particles, or ions, to give each droplet a slight electric charge. Then, the stream of droplets passes through a wire mesh, like a window screen, that has an opposite electrical charge. This causes the droplets to be strongly attracted to the mesh, where they fall away due to gravity and can be collected in trays placed below the mesh.

    Lab tests showed the concept worked, and the researchers, joined by Karim Khalil PhD ’18, won the MIT $100K Entrepreneurship Competition in 2018 for the basic concept. The nascent company, which they called Infinite Cooling, with Damak as CEO, Khalil as CTO, and Varanasi as chairperson, immediately went to work setting up a test installation on one of the cooling towers of MIT’s natural-gas-powered Central Utility Plant, with funding from the MIT Office of Sustainability. After experimenting with various configurations, they were able to show that the system could indeed eliminate the plume and produce water of high purity.

    Professor Jacopo Buongiorno in the Department of Nuclear Science and Engineering immediately spotted a good opportunity for collaboration, offering the use of MIT’s Nuclear Reactor Laboratory research facility for further testing of the system with the help of NRL engineer Ed Block. With its 24/7 operation and its higher-temperature vapor emissions, the plant would provide a more stringent real-world test of the system, as well as proving its effectiveness in an actual operating reactor licensed by the Nuclear Regulatory Commission, an important step in “de-risking” the technology so that electric utilities could feel confident in adopting the system.

    After the system was installed above one of the plant’s four cooling towers, testing showed that the water being collected was more than 100 times cleaner than the feedwater coming into the cooling system. It also proved that the installation — which, unlike the earlier version, had its mesh screens mounted vertically, parallel to the vapor stream — had no effect at all on the operation of the plant. Video of the tests dramatically illustrates how as soon as the power is switched on to the collecting mesh, the white plume of vapor immediately disappears completely.

    The high temperature and volume of the vapor plume from the reactor’s cooling towers represented “kind of a worst-case scenario in terms of plumes,” Damak says, “so if we can capture that, we can basically capture anything.”

    Working with MIT’s Nuclear Reactor Laboratory, Varanasi says, “has been quite an important step because it helped us to test it at scale. … It really both validated the water quality and the performance of the system.” The process, he says, “shows the importance of using the campus as a living laboratory. It allows us to do these kinds of experiments at scale, and also showed the ability to sustainably reduce the water footprint of the campus.”

    Far-reaching benefits

    Power plant plumes are often considered an eyesore and can lead to local opposition to new power plants because of the potential for obscured views, and even potential traffic hazards when the obscuring plumes blow across roadways. “The ability to eliminate the plumes could be an important benefit, allowing plants to be sited in locations that might otherwise be restricted,” Buongiorno says. At the same time, the system could eliminate a significant amount of water used by the plants and then lost to the sky, potentially alleviating pressure on local water systems, which could be especially helpful in arid regions.

    The system is essentially a distillation process, and the pure water it produces could go into power plant boilers — which are separate from the cooling system — that require high-purity water. That might reduce the need for both fresh water and purification systems for the boilers.

    What’s more, in many arid coastal areas power plants are cooled directly with seawater. This system would essentially add a water desalination capability to the plant, at a fraction of the cost of building a new standalone desalination plant, and at an even smaller fraction of its operating costs since the heat would essentially be provided for free.

    Contamination of water is typically measured by testing its electrical conductivity, which increases with the amount of salts and other contaminants it contains. Water used in power plant cooling systems typically measures 3,000 microsiemens per centimeter, Khalil explains, while the water supply in the City of Cambridge is typically around 500 or 600 microsiemens per centimeter. The water captured by this system, he says, typically measures below 50 microsiemens per centimeter.

    Thanks to the validation provided by the testing on MIT’s plants, the company has now been able to secure arrangements for its first two installations on operating commercial plants, which should begin later this year. One is a 900-megawatt power plant where the system’s clean water production will be a major advantage, and the other is at a chemical manufacturing plant in the Midwest.

    In many locations power plants have to pay for the water they use for cooling, Varanasi says, and the new system is expected to reduce the need for water by up to 20 percent. For a typical power plant, that alone could account for about a million dollars saved in water costs per year, he says.

    “Innovation has been a hallmark of the U.S. commercial industry for more than six decades,” says Maria G. Korsnick, president and CEO of the Nuclear Energy Institute, who was not involved in the research. “As the changing climate impacts every aspect of life, including global water supplies, companies across the supply chain are innovating for solutions. The testing of this innovative technology at MIT provides a valuable basis for its consideration in commercial applications.” More