Georgia Tech faculty and researchers are involved in five university-led projects and two new Energy Earthshot Research Centers that are part of a $264 million grant from the U.S. Department of Energy (DOE). The funding includes establishing 11 new Energy Earthshot Research Centers (EERC) led by DOE’s national labs and 18 university research teams addressing one or more of DOE’s Energy Earthshots initiatives focused on industrial decarbonization, carbon storage and removal, offshore wind, and more.

The DOE national lab EERCs will bring together multi-institutional, multidisciplinary teams to perform energy-relevant research with a scope and complexity beyond what is possible in standard single-investigator or small-group awards. Addressing key research challenges relevant to the Energy Earthshots, the 11 new centers will be housed at eight DOE national laboratories and will receive a combined $195 million over four years.

The Department of Energy launched the Energy Earthshots Initiative to spur decarbonization efforts that will help the United States meet climate and clean energy goals. The initiative connects DOE’s basic science and energy technology offices to accelerate innovations toward more abundant, affordable, and reliable clean energy solutions; seeks to revolutionize many sectors across the United States; and will rely on fundamental science and innovative technology to be successful.

Writer and Media Contact:
Priya Devarajan | priya.devarajan@research.gatech.edu        

While the U.S. federal government has clean energy targets, they are not binding. Most economically developed countries have mandatory policies designed to bolster renewable electricity production. Because the U.S. lacks an enforceable federal mandate for renewable electricity, individual states are left to develop their own regulations. 

Marilyn Brown, Regents’ and Brook Byers Professor of Sustainable Systems in Georgia Tech’s School of Public Policy; Shan Zhou, an assistant professor at Purdue University and Georgia Tech Ph.D. alumna; and Barry Solomon, a professor emeritus of environmental policy at Michigan Technological University, investigated how clean electricity policies affect not only the states that adopt them, but neighboring states as well. Using data-driven comparisons, the researchers found that the impact of these subnational clean energy policies is far greater — and more nuanced — than previously known. 

Their research was recently published in the journal Proceedings of the National Academy of Sciences. 

“Analysts are asking if the U.S. should have a federal renewable mandate to put the whole country on the same page, or if individual state policies are sufficient,” Brown said. “To answer that question, it is useful to know if states with renewable energy policies are influencing those without them.”

Brown, Solomon, and Zhou examined a common clean energy policy tool: the Renewable Portfolio Standard (RPS). Adopted by more than half of U.S. states, RPSs are regulations requiring a state’s utility providers to generate a certain percentage of their electricity from renewable resources, such as wind or solar. Many of these standards are mandatory, with utility companies facing fines if they fail to reach targets within a given time.

To investigate the influence of these policies across state lines, the researchers first created a dataset that included 31 years (1991-2021) of annual renewable electricity generation data for 48 U.S. states and the District of Columbia. They then used the dataset to generate pairs of states linking each state to its geographic neighbors or electricity trading partners, allowing them to examine the influence of the RPS policy adopted by one of the pair on the renewable energy generation of the other — a total of 1,519 paired comparisons. 

“By only looking at the pairs, we can see if an RPS in one state directly affects renewable electricity generation in another state, and, if that’s the case, whether it is because they are geographic neighbors or if it’s because they are participating in the same wholesale electricity market,” Zhou said. 

Looking into the electricity market is important, because states often purchase electricity from other states through wholesale markets rather than exclusively producing their own power, and the purchased power can be generated from renewables. Utilities in some states may be allowed to meet their own RPS requirements by purchasing renewable energy credits based on the renewable electricity generated in other states. 

In their analyses, the team also considered the concept of “policy stringency.” A stringency measure evaluates a state’s renewable electricity targets relative to the amount currently produced in the state. For example, if a state requires electric utilities to generate 30% of their electricity from renewable sources by 2030 and the state already has 25%, it isn’t a very stringent policy. On the other hand, if a state has a 30% target and only uses 10% renewables currently, it has a more ambitious and stringent RPS.

Though policy experts have used the metric in related work for over a decade, the research team improved the design. 

“Our stringency variable includes interim targets as well as the existing share of renewable energy generation,” Solomon said.

The team found that the amount of renewable electricity generation in a state is not only influenced by whether that state has its own RPS, but also by the RPS policies of neighboring states. 

“We also learned that the stronger a neighboring state’s RPS policy is, the more likely a given state is to generate more renewable electricity,” Brown said. “It’s all a very interactive web with many co-benefits.”

The authors were surprised to find that a given state’s electricity trading partners did not hold the most influence over renewable generation, but rather the geographical proximity to RPS states. They suggest that past RPS policy research focusing on within-state impacts likely underestimated an RPS’s full impact. While the researchers have not yet identified all factors that can cause spillover effects, they plan to investigate this further. 

“The spillover effect is very significant and should not be overlooked by future research, especially for states without RPSs,” Zhou said. “For states without policies, their renewable electricity generation is very heavily influenced by their neighbors.”

Citation: Shan Zhou, Barry D. Solomon, and Marilyn A. Brown, “The spillover effect of mandatory renewable portfolio standards.” PNAS (June 2024). 
DOI: https://doi.org/10.1073/pnas.2313193121
 

- Written by Benjamin Wright -

Yuanzhi Tang knows firsthand how much of an impact BBISS can make through its programs. The associate professor in the School of Earth and Atmospheric Sciences answered a BBISS call for faculty fellowships, and later seed funding for a project related to sustainable resources. That project grew into a collaboration with Georgia Tech’s Strategic Energy Institute; the Center for Critical Mineral Solutions (CCMS), supported by the College of Sciences and co-sponsored by BBISS; SEI; the Institute for Electronics and Nanotechnology (IEN); and the Institute for Materials (IMat and IEN are now combined into the Institute for Matter and Systems). The goal of the center is to develop sustainable solutions for the grand challenges associated with critical metals and materials essential for the clean energy transition.

During her time as a faculty fellow within BBISS, Yuanzhi became familiar with the people in the organization and had the opportunity to evaluate student and faculty fellow applications. When the opportunity arose to take on the role of associate co-director of interdisciplinary research for BBISS, she was happy to accept so she could help others access resources that had shaped her growth as a researcher at Georgia Tech.

“Being part of a community of people who value interdisciplinary research on sustainability-related topics, I benefited from the interactions and engagement with BBISS and I hope to carry that forward, particularly for young faculty. They are often eager to connect but might not know where to begin. BBISS can be a starting point for them.”

With a background in geochemistry and degrees from Peking University, Stony Brook University, and a postdoc at Harvard, Yuanzhi has gained a breadth of experience that has earned her a variety of awards and recognition. As she joins BBISS in a formal role, she has some advice for early-career colleagues.

“Go to seminars, events, and organized activities, as the best ideas often come through communicating and networking with others, and that’s how you discover that your expertise is needed in other fields. Be confident in who you are as a scholar, but also go out and find ways to collaborate. Georgia Tech places value on interdisciplinary research, and this is a unique strength that you should leverage.”

Away from the office, classroom, and lab, Yuanzhi is a wife and mother of two young children. She enjoys cuddle time with the kids and navigating parenthood in an academically driven household. Her husband is also a Georgia Tech professor and together they juggle the challenges of their careers with spending quality time with the children. “We try to keep work minimal on weekends and get out of the house and enjoy what Atlanta has to offer. We love nature and appreciate that we can be close to campus, close to the city, and still have so many green places to be outside.”

As she embarks on her new role with BBISS, Yuanzhi sees parallels between being a parent, professor, and now an administrator.

“The world is changing rapidly with the explosion of information and technology. It’s a struggle to know what to teach my kids and my students. How do we prepare them for five, 10, or even 20 years from now? This feeling of responsibility connects my work and personal life. It’s challenging, but also very exciting to see how we can help them embrace changes.”