Mariana Alifa (Crippa Group)

A spatio-temporal model for vertical extrapolation of wind speed and wind energy assessment

March 17, 2021

Mariana Alifa

Mariana Alifa is a third-year graduate student co-advised by Paola Crippa, assistant professor, and Diogo Bolster, Professor and Notre Dame Collegiate Chair in Hydrology and director of graduate studies, in the Department of Civil and Environmental Engineering and Earth Sciences. Alifa presented her research titled, "A spatio-temporal model for vertical extrapolation of wind speed and wind energy assessment" during the ND Energy PD&GS Seminar in March 2021.

Although her main thesis direction studies the impact of air pollution, Alifa had the opportunity to develop a secondary research focus in the field of wind energy. Her project seeks to find a reliable way to predict the wind speeds at the height of a wind turbine’s rotor, based on the wind speed measured near the ground.

“When exploring a site’s suitability for deployment of wind turbines, data scarcity is a common obstacle to the accurate assessment of the wind power potential of the site,” Alifa said, noting the difficulty of measuring wind speed at heights of more than 400 feet.

Using models to extrapolate the wind speed from the surface to the rotor height has become an essential part of the assessments for wind energy potential. However, traditional models do not always account for the variability in wind conditions that can happen seasonally or even within different hours of the day, leading to significant estimation errors.

“The new statistical model we are introducing takes into account the temporal variation of wind speed, providing better results than traditional models without adding too much complexity to the extrapolation method,” Alifa said.

This research project is part of a larger grant to investigate the wind energy potential of Saudi Arabia in collaboration with the King Abdullah University of Science and Technology (KAUST). Additionally, she collaborates on campus with Stefano Castruccio, assistant professor in the Department of Applied and Computational Mathematics and Statistics.

The group has made extensive use of the resources at the Center for Research Computing (CRC) for running and analyzing atmospheric model simulations for this project.

“This project is one of the many examples of the ongoing revision of established assumptions,” Alifa said. “This is good news, because it allows us to gain better knowledge of the potential of wind energy and, therefore, achieve more efficient real-world implementation.”

However, Alifa acknowledges that updating old hypotheses can create a challenge in the communication of these results to the general public, who may perceive these changes as indicators of uncertainty or lack of knowledge in the field.

“This applies not only to wind energy, but to all environmental research,” she said. “It is up to us as researchers to frame our new understanding of the processes we study as a continuation of previous work, such that the new knowledge is received as an update to our previous notions instead of as a contradiction.”

Alifa completed her undergraduate studies at Loyola Marymount University in Los Angeles, California. Originally a physics major, she switched her focus to civil engineering upon realizing she was interested in the applied problem-solving component of engineering.

“My mixed interests for research and applied problem-solving are what led me to seek opportunities in environmental and energy research for graduate school, since I wanted to continue doing research that could inform real-life decisions and applications,” Alifa said.

Alifa felt right at home at Notre Dame from the time she interviewed. She was confident that she would be able to build a stable community of peers and mentors in her department. In addition to her home department, Alifa credits The Graduate School for providing useful resources for personal and professional development.

“Knowing I have people to fall back on if things don’t go to plan has allowed me to take more risks and be more creative with my research ideas,” Alifa said.

You can learn more about Alifa and her research here.