This article is part of a series featuring Q&As with Ralph O’Connor Sustainable Energy Institute (ROSEI)-affiliated researchers. Next up is Sijia Geng, an assistant professor in the Department of Electrical and Computer Engineering and a ROSEI core faculty member. She joined Hopkins in January 2023.

How did you first get involved with or learn about sustainability?

Sijia Geng (SG): My connection to sustainability dates back to a very young age, fueled by a profound interest in appreciating the natural world and its wild inhabitants. As a child, I was fascinated with geographic documentaries and encyclopedias on natural history and evolution. Even now I still enjoy spending weekend afternoons wondering in natural history museums. This intrinsic curiosity extended to a desire to preserve our planet and create a positive impact on the world – a drive that paved the way for my academic journey.

During my undergraduate years studying automation and astronautics, I enrolled in innovation workshops centered on renewable energy and carbon reduction starting my freshman year (even though that meant I had to travel to another campus every Saturday night). These workshops fostered an environment where students came together to discuss, educate one another, and make progress on independent research project. That experience sharpened my critical thinking and nurtured my attitude towards doing fundamental research.

I didn’t get serious about sustainability as a career until I began planning for graduate studies, though. At that point, I truly spent time to introspect on my aspirations. It became clear that sustainability and energy challenges were areas where my passion aligned seamlessly with my engineering and mathematical background, while addressing grand societal challenges. I undertook a research project on control of wind turbines, for which my knowledge on aircraft aerodynamics became useful because they share the same physics.

These experiences shape my trajectory towards a PhD study with Ian Hiskens, a truly exceptional mentor whose influence has been transformative in my growth into a scholar and an expert in energy systems. Now that I think back, I’m amazed by how seemingly disparate experiences can weave into one’s future in unexpected ways.

Why are you passionate about sustainability/renewable energy?

SG: I believe that we all share a responsibility to take care of our planet. Sustainability and renewable energy offer a way to reduce pollution, minimize our ecological footprint, and mitigate the impacts of climate change. Through my work in this field, I find purpose in striving for a more harmonious relationship between humanity and nature, and I love working on something that can uplift the well-being of the general population and improve quality of life. This intrinsic interest helps drive me to work hard on deriving innovative solutions.

How does your commitment to sustainability play out in your everyday life?

SG: One thing that I am very careful about is food waste. Reducing wasted food does a great thing for the environment: Saves resources. When food is wasted, it also wastes the resources – such as the land, water, energy, and labor – that are invested throughout the entire lifecycle of food, from cultivation, distribution, to preparation. Moreover, in my daily life, I make intentional efforts to reduce my use of plastics and I am conscious of buying products that would last longer over disposable ones.

Tell us about your research, and what aspects currently or in the future tie into sustainable energy efforts?

SG: My research integrates methodologies from system and control theory, mathematical analysis, and optimization to address pressing and fundamental challenges in complex networked energy systems. I develop theory and computational tools to enable the renewable energy transition and achieve an autonomous, resilient, and sustainable next-generation energy system.

The first direction of my research focuses on developing a modeling, analysis, and control framework to ensure the stability of large-scale power systems that are dominated by inverter-based resources (IBRs). Power systems are expected to host hundreds of millions of distributed and renewable-sourced IBRs soon. Novel methods are needed that meet the challenges that arise in IBR-dominated power grids, such as significant fluctuations in operating conditions, a lack of transparency in control implementations, and unprecedented complexity in dynamic behavior.

The second direction of my research develops rigorous theory and scalable algorithms for analyzing the stability and performance of nonlinear and hybrid dynamical systems. Many critical infrastructure systems that support modern societies, such as energy systems and transportation systems, can be modeled as large-scale networked dynamical systems. However, nonlinearities and hybrid dynamics, heterogeneity, model uncertainty, and large scale, when combined render existing tools over conservative or infeasible. I adopt methodologies rooted in system theory to address the analysis and control of such systems.

The third direction of my research develops computationally efficient optimization tools and algorithms geared towards achieving optimal design and operation of integrated multi-energy systems, with a focus on managing uncertainties. Next-generation energy systems will couple multiple energy carriers, including electricity, natural gas, hydrogen, together with their corresponding energy transformation process and storage. Moreover, electric vehicles lead to a tighter integration between transportation and energy systems. I leverage real geospatial data for transportation schedules, renewable generation, load, and meteorological information, to provide valuable insights into decarbonization across sectors.

In essence, these research directions all share a concerted effort in improving energy system reliability and efficiency and enable greater use of renewable energy. Such enhancements will play a key role in moving toward a more sustainable energy system of the future.

Is there an article, book, or podcast that you recommend to help people better understand your work and your field in general?

SG: The Global Power System Transformation Consortium (G-PST) and the Energy Systems Integration Group (ESIG) host a very nice webinar series that is related to what I am doing. G-PST also posts online graduate-level courses that I think are useful resources.

What advice or suggestions do you have for students who want to pursue careers in sustainable energy?

SG: I would encourage them to think outside of the box, to always be curious and to think independently. Focus on addressing the fundamental challenges. Don’t simply buy into what others tell you about the world and how things work. Instead, think creatively about what a sustainable future for society looks like and what it truly entails. Then, devise innovative ways to catalyze the transformation and help the world get there.

You joined Hopkins recently. How have you found the sustainable energy community here to be thus far?

SG: There is a strong and convergent interest in sustainable energy at Hopkins that is integrated through ROSEI. My engagement with ROSEI has been enriching. The institute tries to help faculty push their research to achieve greater impact, as well as promote collaborations. I’ve already participated in a couple of the institute’s workshops in my short time here. I remember clearly about the ROSEI Summit that took place in January, only a few days after my arrival, that demonstrated the remarkable breadth and depth of energy research being done at Hopkins. We have a variety of expertise. Just looking at the Grid pillar, Ben Hobbs, Yury Dvorkin, Dennice Gayme, Enrique Mallada, and myself, each bring unique expertise to the group. This positions us as a strong player in the energy field, ready to make a transformative change on a global scale. Plus, it is fantastic that everyone is very friendly and collegial and takes genuine interest in helping each other achieve their goal.