Stanford Energy Student Lectures 2022
Stanford students, postdocs, faculty, and staff were invited to our 12th annual summer series to learn about cutting-edge science and clean-energy breakthroughs from 17 students doing the research. A tutor from the School of Engineering's Technical Communication Program provided live feedback to each of the speakers on how to improve their presentations.
(2023 details to be confirmed. Stay tuned.)
2022 Speaker Schedule, Abstracts and Biographies
Title: Characterization of energy consumption in a portfolio of commercial buildings
Abstract: Buildings represent one-third of global emissions and energy consumption, but building lifetimes are long and stock turnover slow. Identifying operational energy efficiency and flexibility opportunities in existing buildings is crucial but remains a challenge for urban planners. This work aims to propose simple, interpretable, data-driven solutions to help stakeholders ask 'the right questions' to extract actionable insights from available data. We validate the proposed framework on the Stanford campus buildings. Using measurements from 2019, we were able to characterize the cooling consumption in at least 65% of buildings with mean absolute percentage error of 20%. We identify underperforming buildings that need to undergo energy retrofits for making them more resilient to weather variations. Our findings also exhibit potential implications for demand response, fault diagnosis, and building portfolio management.
Bio: Aqsa Naeem is working as a Postdoctoral Research Fellow in the Department of Energy Resources Engineering at Stanford University. Her current research focuses on the use of data analytics to characterize the energy consumption in buildings and to assist the urban building planners in making these buildings energy efficient and resilient. Naeem obtained her PhD in Electrical Engineering from Lahore University of Management Sciences (LUMS) Pakistan, where she worked on the design of resilient and cost-effective microgrids, to further the adoption of renewable energy systems in power sector. Her work highlights the significance of using complementary energy sources to mitigate the inherent intermittency of renewable energy sources.
Title: Quantifying indoor air pollution from natural gas stoves
Abstract: Natural gas stoves are ubiquitous in the United States and across much of the world, but a growing body of work is raising concerns about their impacts on human health and the climate. Recent studies have quantified gas stove emission rates of methane, NO2, NO, and formaldehyde, as well as the resulting indoor concentrations of these pollutants. We expand our understanding of gas stove pollution by measuring emissions of volatile organic compounds (VOCs) which have not been previously studied in the context of gas stoves. We also contextualize gas stove health impacts by comparing gas stove emissions with emissions from electric coils, induction stoves, and certain cooking scenarios. We find that emissions of our target VOC from gas stoves are significantly higher than emissions from cooking as well as from coil and induction stoves. In line with previous studies on methane emissions, we find that target VOC emissions from gas stoves follow a long-tail distribution.
Bio: Yannai grew up across the bay in Oakland, CA, where he homeschooled though high school and spent much of his time in a tent or on a hike. His passion for climate action and solutions brought him to Stanford’s Earth System Science program, where he is currently working on documenting and communicating the climate and health impacts of gas appliances.
Title: Towards grid-scale aging models for lithium-ion batteries
Abstract: Energy storage is an integral part of the renewable energy infrastructure of the future. In particular, lithium-ion batteries (LIBs) will be a primary grid energy storage technology, which degrade over time according to their dispatch (charge and discharge) under grid applications. This talk presents an algorithm for the synthesis of duty cycles for grid LIB dispatch for laboratory aging experiments towards developing a physics-based grid LIB model, which can then be used for degradation-aware optimal control of the LIB. In addition, we demonstrate the applicability of this algorithm to other LIB use cases, such as electric vehicles.
Bio: Kevin Moy is a third year Ph.D. candidate in the Stanford Energy Control Lab in the Energy Resources Engineering department at Stanford University, under the direction of Prof. Simona Onori. Previously, he received the bachelor’s degree in Engineering Physics with a concentration in Renewable Energy and a coterminal master’s degree in Civil and Environmental Engineering (Atmosphere and Energy), both from Stanford University.
Title: Redesigning the current collector for energy-dense and fast-charging lithium batteries
Abstract: Independent to the active material’s design, the “dead weight” component plays a significant role in functioning battery yet doesn’t contribute to cell capacity. One of the most typical examples is the current collector. As electron carriers in batteries, the current collector is generally made of dense metal foils and occupies >15% of the total battery weight. We demonstrated that redesigning the current collector is an effective way to reduce the appreciable parasitic weight and improve battery-specific energy. This ultralight current collector consists of a robust and ultrathin polymeric backbone on which a conducting thin film can be deposited. Thanks to the new design, high-energy-density batteries become more versatile, efficient, reliable, and flexible. I am going to talk about how current collector can enable batteries with high safety, cold starting, and fast charging while not sacrificing their performance.
Bio: Yusheng Ye received his Ph.D in Materials Science and Engineering from Beijing Institute of Technology in 2018. He is currently a postdoc researcher working with Professor Yi Cui in Materials Science and Engineering at Stanford University. His work focuses broadly on understanding the limitation of and redesigning energy-dense and fast-charging lithium batteries.
Title: Nighttime power generation using radiative cooling of a solar cell
Abstract: A large fraction of the world’s population lacks access to the electric grid. Standard solar cells can provide a renewable off-grid source of electricity, but only produce power from daytime solar irradiance and do not produce power at night. Here we construct a device which incorporates a thermoelectric generator that harvests electricity from the temperature difference between a solar cell and the ambient surrounding. We achieve 50 mW/m2 nighttime power generation with a clear night sky. During the daytime, the thermoelectric generator also provides additional power on top of the electric power generated directly from the solar cell. Our system can be used as a continuous renewable power source for both day and night time in off-grid locations.
Bio: Sid is a postdoctoral scholar in Professor Shanhui Fan’s group at Stanford. He does research in energy-related areas such as wireless power transfer and radiative cooling.
Koosha Nassiri Nazif
Title: Power everything: high-specific-power flexible TMD solar cells
Abstract: A flexible solar cell with a high specific power (power-per-weight) opens unprecedented opportunities in a wide range of industries from wearable electronics to electric vehicles. Ultrathin transition metal dichalcogenides (TMDs) are promising candidates due to their excellent optical and electrical properties. However, engineering challenges have prevented most TMD solar cells from exceeding 2% power conversion efficiency (PCE). In this talk, I explain how we addressed these issues and as a result achieved record PCE of 5.1% and record specific power of 4.4 W g−1 in flexible TMD (WSe2) solar cells, the latter on par with established thin-film solar cell technologies. Further design optimization could achieve an additional 10x increase in specific power, providing unprecedented capabilities for wearable electronics and autonomous drones among many others.
Bio: Koosha is a postdoctoral scholar at Stanford developing novel flexible sensors and solar cells for use in a wide range of applications, from wearable electronics to autonomous drones. He received his Ph.D. (2021) in Electrical Engineering and M.S. (2016) in Mechanical Engineering from Stanford, and B.S. (2014) in Mechanical Engineering from Sharif University of Technology.
Title: Reprocessable and recyclable polymer network electrolytes
Abstract: Polymer network electrolytes are ideal separator and conductor materials for all-solid-state batteries, but they suffer from reprocessability due to the permanently crosslinked network structure. Here, we demonstrate a reprocessability and recyclability polymer network electrolyte through the incorporation of dynamic covalent bonds, and this property is achieved without detrimentally affecting the electrolyte’s mechanical and ionic conducting properties.
Bio: Yangju Lin obtained his B.S. in chemistry and M.S. in polymer chemistry and physics from Xiamen University. He later earned his Ph.D. degree under the guidance of Prof. Stephen Craig at Duke University, where he focused on the molecular-level engineering of stress-responsive materials. Yangju Lin is currently a postdoc in Zhenan Bao’s group at Stanford University, with an interest in the molecular design of advanced polymer materials for batteries.
Title: Quantification of solid-electrolyte interphase composition during nonaqueous electrochemical nitrogen reduction
Abstract: To accommodate the growing population and decarbonize synthetic ammonia (NH3) production, electrified alternatives to Haber-Bosch must be developed. However, electrified methods are often hindered by poor selectivity to NH3, which is underpinned by a poorly formed solid-electrolyte interphase (SEI) layer on the cathode surface. In this work, our novel quantitative SEI composition measurements reveal that SEI growth coincides with improved Faradaic efficiency to NH3, suggesting that the SEI acts as a membrane which selectively hinders transport of ethanol while still allowing N2 transport to the cathode surface. Our findings provide important insights for the rational design of electrolytes to impart beneficial SEI properties which can improve selectivity in emerging electrochemical NH3 synthesis systems.
Bio: Eric received his BS in Chemical and Biomolecular Engineering from Cornell University in 2016, where he worked as an undergraduate researcher studying scalable synthesis methods for Si and Ge nanowires in the lab of Tobias Hanrath as part of the Rawling Cornell Presidential Research Scholars Program. He then earned the NSF Graduate Research Fellowship before beginning his graduate studies at UC Berkeley in the fall of 2016, joining Bryan McCloskey’s lab to study the kinetic, transport, and degradation phenomena underpinning lithium-ion battery operation during fast charge. After graduating in September 2021, he began his postdoctoral position at Stanford University in the Cargnello lab, where he now studies electrolyte engineering methods to improve the Faradaic efficiency of the Li-mediated electrochemical ammonia synthesis process.
Title: Criteria and workflow for selecting depleted hydrocarbon reservoirs for carbon storage
Abstract: Carbon capture and sequestration (CCS) is playing a role in mitigating carbon emissions and that role is expected to grow dramatically with time. Clustering CO2 sources and sinks through hubs is one way to achieve large-scale deployment of CCS and widespread decarbonization of the energy sector. A key element to the success of hub projects is finding a suitable sequestration site to store these combined emissions. Our study develops a quantitative, criteria-driven methodology to assess the potential suitability of depleted oil and gas reservoirs for carbon storage. The methodology utilizes a three-stage process that screens, ranks, and characterizes potential sites based on three categories: (1) capacity and injectivity optimization, (2) retention and geomechanical risk minimization, and (3) siting and economic constraints. The framework is designed to provide insights into the suitability of depleted reservoirs in a variety of different geological environments as well as to be adaptable to a project’s specifications.
Bio: Catherine Callas is a PhD candidate in Energy Resources Engineering working with Professor Sally Benson and Professor Tony Kovscek on carbon capture and sequestration. Catherine obtained a MS in Civil and Environmental Engineering at Stanford University in 2020 and a BS in Chemical Engineering from Brown University in 2015.
Title: High Efficiency Power Conversion Using Piezoelectric Materials
Abstract: All electronic devices require a power supply to function. These power supplies use magnetic components, inductors and transformers, to convert the voltage from the AC line or battery to the voltage required by the electronics of the device. Consumer demand drives the miniaturization of these power supplies but the volumetric scaling laws for magnetic components are unfavorable, leading to reduced efficiency if the magnetic components are merely scaled down. In this research we sidestep the scaling issues of magnetic components entirely by replacing them with acoustic resonators made from piezoelectric materials. These resonators store energy with low loss in the mechanical domain and are electrically coupled to the circuit via the piezoelectric effect. While not a direct circuit substitute, different circuit topologies allow for piezoelectric resonators to completely replace the need for inductors or transformers. In comparison to inductors and transformers, piezoelectric resonators maintain favorable performance at small sizes and can have a planar fabrication process. This enables miniaturized power supplies that maintain a high efficiency.
Bio: Weston Braun is a 5th year PhD student in electrical engineering in the Stanford University Power Electronics Research (SUPER) Lab under the supervision of Professor Juan Rivas. He received his B.S and M.Eng. in electrical engineering and computer science at the Massachusetts Institute of Technology. His current research focuses on using piezoelectric materials to enable high power density power conversion.
Title: Temperature sensitivity of electricity demand in the small and medium business sector
Abstract: As global temperatures rise, the need to cool buildings will increase throughout the world, and with it, electricity demand related to thermal comfort. One area in particular – the small and medium business (SMB)– is a critical yet often understudied aspect of climate impacts research, with implications for both individual business establishments and the overall electrical grid. In this research we focus on how business establishments’ electricity demand changes in response to temperature and demonstrate on a unique dataset containing more than 60,000 SMBs with one year of hourly electricity demand data and information about business operations. Our findings suggest that impacts of climate change on individual business establishments and the electrical grid could be substantial in the future, especially for areas that will be differentially impacted by more frequent high temperature days.
Bio: Tao Sun is a PhD candidate in Civil and Environmental Engineering advised by Prof. Ram Rajagopal. He received his B.S. and M.S. from Shanghai Jiao Tong University, both in electrical engineering. His main interests are in data-driven methods (machine learning and econometrics), optimization and control, with special applications in energy systems.
Title: Pathways to carbon neutrality in California: the bioenergy opportunity
Abstract: California has an abundance of biomass-based resources derived from the state’s diverse agricultural, urban waste and forest streams. These biomass resource types can be converted to bioenergy products that have many potential applications across California's energy system. However, today, most of the carbon from this biomass returns to the atmosphere as carbon dioxide or methane as the biomass naturally decays or gets burned, representing an opportunity lost for bioenergy production. We analyze the types, quantities, and the emission reduction potential of biomass resources available for bioenergy production currently, in 2025 and in 2045 as a result of existing practices and policies in California. We find that landfill gas holds the greatest energy potential currently while MSW and agricultural residues hold the most significant potential in 2045. We also find that if the total gross waste biomass potential were utilized for energy production, California’s total emissions could be reduced by 1-8%, depending on the conversion process and the end-product. This study is one of the eight studies published as a part of the Stanford Center for Carbon Storage effort to inform the discussion on pathways to carbon neutrality in California. Its results will be used in an integrated assessment model in the upcoming year to create decarbonization scenarios for the state.
Bio: Anela Arifi is an E-IPER Ph.D. student and a Knight-Hennessy scholar co-advised by Chris Field and Ines Azavedo. Her research focuses on the role of biomass energy in energy system decarbonization. At the last year’s Energy Student Lectures, Anela presented her work on designing biomass conversion processes that would aid in sustainably setting biofuels in a circular economy paradigm. While in her home country, Bosnia and Herzegovina, Anela developed biomass energy systems for rural communities using waste chicken feathers and municipal waste as feedstock. To raise awareness about energy poverty, she spoke at TEDWomen and addressed the UN.
Title: Coordination of distributed energy resources for distribution grid reliability
Abstract: We use a data-driven simulation methodology to quantify the impacts of future increases in electrification and DER penetration on transformer overloading and voltage variations in distribution grids and the role of DER coordination in mitigating these impacts. We apply this methodology to 11 3-phase distribution grid models representing various urban, suburban and rural areas, different climates, and varying mixes of residential and commercial consumers, with load profiles and forecasts of PV, EV, stationary storage, and electrification up to the year 2050 from recent NREL studies. To quantify the potential benefits of DER coordination on grid reliability, we compare the results for a perfect foresight fully centralized DER control scheme to a baseline local control scheme that only minimizes local electricity bills. We find that across all networks, coordinating DERs can provide a significant reduction in overloaded transformers and voltage variations over local only control without the need for additional equipment.
Bio: Thomas Navidi is a PhD student in electrical engineering at Stanford University. His research interests involve the design of smart grid systems to enable increased penetration of renewable energy resources.
Title: Carbonate-catalyzed CO2 hydrogenation for sustainable liquid fuel production
Abstract: Despite increasing electrification, generating carbon-neutral liquid fuels remains critical for decarbonizing sectors that cannot readily electrify. Recently commercialized gas fermentation, a technology that makes alcohols from CO and H2, has created a new opportunity for sustainable liquid fuel production provided that CO and H2 can be sourced renewably. While H2 can be made from water electrolysis, the renewable production of CO remains a challenge. Here, we demonstrate a scalable, selective, and stable thermochemical catalyst that upgrades H2 and CO2 into a CO-containing feedstock appropriate for gas fermentation to ethanol. The combination of water electrolysis, our process, and gas fermentation could convert electricity into ethanol fuel with nearly 50% overall energy efficiency, highlighting a unique opportunity to generate renewable liquid fuels at scale.
Bio: Chastity Li received her B.A. in Chemistry and Physics from Harvard University in 2018. She is a fourth-year Chemistry Ph.D. candidate supported by the Chevron Fellowship in Energy and Stanford's Sustainability Accelerator. Her research with Professor Matthew Kanan explores methods for sustainable liquid fuel generation that circumvent the efficiency limitations and land-use requirements of current biofuel production.
Title: Engineering the electrochemical reaction microenvironment to valorize nitrate-polluted wastewaters
Abstract: The nitrogen cycle is in urgent need of reinvention: Haber-Bosch fertilizer production has outpaced removal of N from wastewater, leading to continuous losses from the nitrogen economy and exerting great burden on the environment. As the most prevalent waterborne N pollutant, nitrate jeopardizes the health of ecosystems and human beings. By selectively producing ammonia, electrochemical nitrate reduction reaction (NO3RR) can directly transform nitrate pollutants into widely used commodity chemicals and fertilizers, thus balancing the nitrogen cycle while reducing energy consumption from the traditional Haber-Bosch process. The reaction microenvironment that is located at the interfacial region between the electrode and the electrolyte has been found to significantly impact the activity and selectivity of electrocatalytic reactions. Using a combination of electrochemical testing, advanced characterization and computation, we investigated both the electrocatalyst evolution and electrolyte properties in the NO3RR reaction microenvironment and provided engineering strategies to optimize ammonia production.
Bio: Jinyu Guo is a 3rd year PhD student in Chemical Engineering and works in the Tarpeh Group. Her research focuses on understanding the molecular mechanisms in electrochemical processes of valorizing waterborne nitrogen pollutants. She received her B.S. in Chemical Engineering from Tianjin University in 2019.
Title: Hydrogen direct iron reduction for decarbonizing steelmaking
Abstract: Hydrogen-based direct reduction (HyDR) is a melt-free and carbon-neutral approach to reducing iron ores for steelmaking, far below the melting point of iron. Many studies have developed mathematical models to describe the kinetics of HyDR reactions for iron oxides; however, the kinetics are highly sensitive to differences in reaction conditions and are not generalizable across length scales. We seek to identify the fundamental mechanisms involved in HyDR reactions and subsequently build more robust kinetics models for industrial-scale HyDR. We performed in-situ XRD analysis of iron oxide nanoparticles under various reaction conditions and are building kinetics models to describe the results.
Bio: Lauren is a PhD student within the Department of Materials Science and Engineering at Stanford University. In Professor Dresselhaus-Marais’ group, she is interested in studying the energetics of “hydrogen direct reduction” of iron oxides, which is an alternative approach to iron extraction that aims to reduce carbon emissions from the steelmaking industry. She completed a B.S. in Materials Science and Engineering with highest honors from the University of Arizona, where she researched solution-processed chalcogenide glasses for infrared-transparent optical applications.
Title: Design considerations for a novel three-phase multilevel inverter
Abstract: A power electronic inverter is a core component for many renewable technologies such as solar photovoltaic (PV) and electric vehicles. Recently, multilevel inverters (MLIs) have emerged as a promising technology for utility-scale PV power plants due to their higher output voltage and lower filtering requirements. Existing three-phase MLIs are built from single-phase inverter modules or three-phase inverter modules. Single-phase inverter modules require large DC-link capacitors that increase the system cost. Three-phase inverter modules require a complex circuit topology that results in poor efficiency. In this talk, I will propose a novel two-phase inverter module-based MLI, that eliminates the need for bulky input capacitance, while also operating at a high efficiency. This design is enabled by a novel power sharing scheme among the inverter modules in the MLI system. I will demonstrate the control and hardware design in simulation and experiment. Lastly, I will present a formal way of optimizing power sharing schemes for general multi-converter systems.
Bio: Tuofei (Francis) Chen is a Ph.D. Candidate in the Electrical Engineering Department at Stanford. He is advised by Prof. Bill Dally and his research interest lies in the design, modeling, and control of multilevel power electronics converters for renewable energy systems. He also has prior industry experience with battery modeling and power system controls.