Help Dams Survive the “Surges”

By Wenxi Zhao '21
Hometown: Beijing, China
Major: Environmental Systems Engineering
Intern, California Department of Water Resources

My summer internship at the California Department of Water Resources is super intriguing and has inspired me to delve into a hydropower-related field in the future. Before starting my project, I took hydropower to be one of the major sources of renewable energy and never thought it could fall into a disadvantage in the future greener energy market. 

As I started to dive into the background stories of the dam that my project focuses on, I came to realize the complexities behind the operation of a hydropower plant--how do ownership issues, administrative concerns, reservoirs’ water rights, and downstream habitat conservation intertwine and, all together, tow down the upgrading speed of a hydro plant adapting to the new normal in the electricity market? As solar and wind power take major roles in the daytime electricity market, the net demand curve for hydro has shifted drastically--demand plunges during solar hours and peaks during shoulder hours, and so does the price curve. To survive in such a market, other power suppliers made changes accordingly--generating less or none during daytime and more during nighttime. However, the adaptation of hydro often takes much longer. A dam is usually obliged to maintain a stable flow pattern in the river, so the power generation schedule cannot simply be adjusted to pursue economic interest. Especially when the ownership of the dam and upstream/downstream water rights involves multiple stakeholders, the situation becomes even more complicated and the authorization process may take years.

My work at DWR is basically trying to facilitate this process. My colleagues and I have built models to simulate dam operations in wet, medium, and dry years and optimize its generation plan to gain the best profit. We also looked into scenarios where reshaping the generation plan would not be accepted by the stakeholders, and that is when the battery system comes into play. Attaching a battery system to the power plant enables the plant to maintain its original generation schedule while having an unsynchronized output schedule. By charging the battery during low-price hours with hydro and discharging the energy to the grid during high-price hours, the plant can gain more profit. 

The study of finding the future path for a dam is really sophisticated work that basically tries to find an optimum solution against a full-set of metrics. Hard as it is, the study is extremely valuable, since the dam has to adapt to survive, and nothing is green if it is not sustainable. Working in this project, I dipped my toes into various aspects surrounding the problem and found them fascinating. To help dams keep up with the coming surges in the energy market, we need to do more work, and I’m ready. 

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