Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Mechanical Engineering

First Advisor

Michael Twedt


cycling, emissions, fossil fuels, power plant, renewable energy, wind energy


One of the most significant shifts in the mix of U.S. electricity generation over the past few years has been the rapid expansion of renewable energy resources, especially solar and wind. However, fossil fuels are still necessary to fulfill the world’s energy requirements. Despite efforts to increase the use of renewable energy sources, these sources can be at times unreliable, causing countries around the world to continue to rely on base load units such as coal and natural gas. This decrease in fossil fuels and increase in renewable energy sources presents many complex issues in terms of power system planning, meeting system demands, source reliability, and unit flexibility. The penetration of wind generation has resulted in base load units having to change their operational norms. Cycling is defined as frequently varying the load on power units to respond to changes in demand. Base load units are forced to conduct cyclic operations in order to stay competitive with other sources and contribute to the reliability of the region – giving rise to serious concerns about increased maintenance costs, increased forced outage rates, thermal shock, decreased unit efficiency, and increased emissions due to this cycling. Historical plant data was collected from a base load unit in South Dakota from 2018 – 2023 with the goals of quantifying the increase of unit cycling and analyzing the effect cycling has on emissions and unit efficiency. Overall, from 2018 through 2023, cycling saw a decrease of 1.75% - all cycle types decreased except for half cycles which had an increase of 133.33%.

Library of Congress Subject Headings

Wind power -- Middle West.
Wind power plants -- Middle West.
Electric power production.
Renewable energy sources.


South Dakota State University



Rights Statement

In Copyright