Sustainable and Resilient Systems Lab

Category: NC State

  • New paper on (extended) access impacts of electric vehicles

    By lead author Yamil Essus (yaessus@ncsu.edu)
    We are very excited to share the publication of our most recent paper in the IEEE Access Journal!

     

    Paper Summary:

    Electric vehicles link mobility to the availability of electric power, posing a risk of rendering transportation unavailable during blackouts. Building on our previous work on modeling how vehicle electrification affects access to essential services, this study extends the framework with elements that increase its practical relevance, including commuting-related energy burdens and correlations between vehicle price and battery capacity. We apply the methodology across the entire state of North Carolina, capturing major urban centers as well as a broad range of communities that vary in density, service availability, and access conditions.

     

    • What did this research initially set out to find?
    The main goal of this project was to extend our methodology to incorporate commuting in our estimate of access risk. This was motivated both by an intuition that it represented a significant expense (in kWh) for most people, and also by comments of reviewers and other researchers in the Risk Analysis community.

     

    • What’s something you learned (a fact or crazy figure) doing this work?
    Learning to think about access beyond accessibility is what stands out the most to me. We don’t really use it too much in this paper but it was context that was very meaningful in my perspective of this and future research. Not really a fun fact, but still I think most people would resonate with the importance of the other A’s in access.

     

    • What was one software package/tool you used in this project that you hadn’t used before?
    A central part of our methodology to estimate energy consumption on commuting was isochrones. An isochrone represents the boundary of the region that you can reach from a given starting point and given a time limit. Importantly, these regions need not to be convex, in fact, a non-convex isochrone tends to be much more informative than a convex one. However, this meant that to estimate an isochrone from a set of points, we needed to come up with an algorithm for a concave hull. Luckily, shapely has a function to do this. Unfortunately, this is not a repeatable process in the sense that it involves using an arbitrary parameter and it really needs to be selected on a case-by-case basis.

     

    • What’s been your go-to procrastination activity when working on this paper?
    Civilization VI. It’s always just one more turn.

     

    • Where do you think you did most of this work (home, desk, coffee shops?)
    Most of it was at home. However, I spent a lot of time writing the manuscript while camping for a 3D printer outside of the Makerspace in the D.H. Hill library. This was during the time I was iterating on my design of a split keyboard.

  • New paper on the American Housing Survey

    Article by Ben.
    Paper Summary:
    We are very excited to share the publication of our most recent paper in Risk Analysis exploring how the American Housing Survey (AHS) might be used to study community resilience. While the AHS is usually designed for tracking housing trends, we wanted to see if it could also reveal insights about how households think about and experience risk. The cool part is that the AHS is longitudinal — it goes back to the same houses year after year, and surveys the same people rather than just the same neighborhoods. That’s really unique compared to something like the census, which only gives a snapshot. Even better, the AHS asks a handful of questions about risk perception. These aren’t perfect, but they give us a baseline sense of how people are thinking about hazards and housing.

    Our original idea was that this dataset could let us track population-level changes in housing and risk perception before and after disasters. In the end, the paper became more of an exploratory piece: instead of developing new metrics, we tested how useful this survey could be for resilience research.

    • What did this research initially set out to find?

    Originally, Kendrick and I wanted to evaluate how housing stock changes after major disasters. This idea had been floating around for a while, but we kept running into what I call “paralysis of plenty” where so many possible questions meant we kept stalling out. We were both super excited when Kelsea joined as a co-author to shift the focus into a broader, big-picture perspective. Instead of chasing a single takeaway, we stepped back and explored the value of the dataset itself.

    • What’s something you learned (a fact or crazy figure) doing this work?

    One of our biggest takeaways was around risk perception. For example, between 2017 and 2019, the number of people in Houston who said they perceived risk increased dramatically — about ten times higher than the change we saw in Phoenix. That’s almost certainly tied to the impact hurricanes.We also saw differences in how people compared their current homes to previous ones. Some thought their new homes were more at risk, others less. These perceptions varied by age, by whether people rented or owned, and was highest among people who self-reported as “illegally occuping” homes (i.e. squatters). Goes to show the power of census data, they can capture opinions of people only temporariliy in homes.

    • What was one software package/tool you used in this project that you hadn’t used before?

    I got really into an R package called cowplot, built by Claus Wilke. It’s amazing for aligning figures, adding annotations, and putting everything together without having to jump into Illustrator. Before this, I would export figures to PDFs, open them in Illustrator, and manually rearrange everything. Now I can just do it all in R. Huge time saver — thanks, Claus!

    • What’s been your go-to procrastination activity when working on this paper?

    There were many, because this paper was in the works for a long time. But the big one was learning piano. I bought one and started playing for the first time since I was a kid. Turns out  Hot Cross Buns and Three Blind Mice are the same song and Pink Pony Club is really hard. It was a good break from staring at data.

     

    • Where do you think you did most of this work (home, desk, coffee shops?)
      Mostly in my office at NC State (I recently added a treadmill desk, which makes it easier to keep moving while writing.) The runner-up location is SUNdays in Wilmington, NC (which also happens to be where I wrote much of my dissertation and is across the street from where I took the “coming back but better” picture on this website’s homepage!)

     

  • New paper on access impacts of electric vehicles

    By lead author Yamil Essus (yaessus@ncsu.edu)
    We are very excited to share the publication of our most recent paper!

     

    Paper Summary:

    Electric vehicles link mobility to the availability of electric power, posing a risk of rendering transportation unavailable during blackouts. We developed a computational framework to quantify the impact of this change on access. We found that solutions like larger batteries and vehicle-to-grid technologies offer benefits, but their effectiveness depends heavily on the geographic distribution of services. This highlights the importance of considering unintended consequences of public policies and city planning. Equitable access to essential services—such as supermarkets, schools, and parks—is the most important aspect of community resilience, making it crucial that vehicle electrification is thoughtfully integrated into sustainable transportation policies.

     

    • What did this research initially set out to find?
    We started this research project aiming to explore the impacts of Vehicle-to-grid (V2G) technologies on mobility. The key insight was that under vehicle electrification, distance traveled by car [km] could be expressed in terms of electricity consumption [kWh]. Because electricity could serve multiple needs (groceries vs. hair dryers), there was a trade-off between essential services and quality-of-life. We found this trade-off to be interesting and insightful but ended up unveiling a larger problem in the disparities in access across the country.

     

    • What’s something you learned (a fact or crazy figure) doing this work?
    I still can’t get over the fact that there are dozens of “Orange Counties”. As an international student, I was really not expecting to find this kind of duplicate. I started retrieving the location of services based on county names, which quickly became a problem. At least now I understand why people in movies talk about “City, State” like the city is not enough.

     

    • What was one software package/tool you used in this project that you hadn’t used before?
    During this project, I took the courage to learn how to use Docker, and I’m very happy about it. It really is a wonderful tool and it used to sound very intimidating but now I try to squeeze it on everything I do. The routing engine we used to compute shortest paths between households and services could be compiled and run directly but it was strongly suggested to use the provided Docker image so that’s what I did.

     

    • What’s been your go-to procrastination activity when working on this paper?
     I got really into baking when we started the project. I tried all sorts of sourdough breads and pizzas. It was pretty fun but consumed a lot of energy.
    Sourdough

     

    • Where do you think you did most of this work (home, desk, coffee shops?)
    Probably at home with two honorable mentions. First, Hunt library. What a great place to get some work done. Second, a good part of the production happened overseas while I was stuck in Chile after a clerk mistake at the consulate.

  • The universe is always expanding (and so is our research group)

    There’s finally stuff to write about! The spring semester is in full swing, we have a bunch of projects all fully underway and we are finally updating the website. The lab is now fully stocked, with Ph.D. students, master’s students, and undergrads. Check out the People page to get acquainted, and stay tuned, we should be expanding more in Fall of 2024.

  • New Paper on Drought Impacts

    New Paper on Drought Impacts

    Excited to share a new paper in Nature Water on the impact of droughts on low-income household water affordability! Also check out the companion piece by Dr. Casey Wichman!