Integrating thermoelectric power generation operations with aquatic ecosystem sustainability

Open-loop thermoelectric power plants, representing 30% of the electricity generation in the United States, withdraw and discharge large quantities of water for cooling purposes. This process can cause thermal pollution in waterways, adversely affecting aquatic ecosystems. Incorporating biology into the energy-water nexus can aid decision-makers in identifying tradeoffs and more effectively assessing and managing aquatic ecosystems. The central research question in this work is as follows: How can thermoelectric power plant thermal pollution be quantified with applications to biology, and how are the various forms of quantification useful in policy- and decision-making frameworks? This work fills a gap in the literature, as integration of biology into the energy-water nexus has been sparse, and largely qualitative to date. To quantify thermal pollution and the risk posed to aquatic species, a novel methodology was developed that utilizes plume mixing and probability distribution analyses with temperature and flow data for both a power plant's discharge and the adjoining river. 2D probability risk spaces were created that quantify the probability of exceeding a given temperature. The Shawnee Fossil Plant on the Ohio River was used to demonstrate the methodology on three fish species endemic to the power plant location. Using the novel risk assessment method as a baseline, a scenario analysis of three differently-sized power plants on two differently-sized rivers demonstrated the creation and comparison of temperature duration curves for thermoelectric power plant thermal pollution as a means to visually and mathematically quantify thermal pollution. Following the concept of thermal performance curves, biological data at the Shawnee Fossil Plant were used to demonstrate the relationship between temperature and population. Using those biological data and the newly defined temperature duration curves, population habitat duration curves were generated, which can be used in decision-making frameworks and for economic analyses. The tradeoff in loss of electricity generation and gain of ecosystem system value (via fish populations) is presented for a 1.1 °C change in ΔT (thermal pollution). The probability risk space results highlight that both the lateral and longitudinal location within the river affects the probability of risk, and that a high degree of risk within a plume can reduce to a smaller total risk within the context of a large river cross-section. Temperature duration curves demonstrate the usefulness of such tools in policy-setting, such as for regulatory mixing zones. Population habitat duration curves demonstrate the quantification of temperature as a resource, and that economic tradeoffs between thermoelectric power plants and aquatic ecosystem sustainability are quantifiable. Overall, the results emphasize the need for individualized risk assessment for Clean Water Act §316(a) requirements for power plant effluent temperature limits and National Pollutant Discharge Elimination System permits, with applicability in policy-making, environmental mitigation, and power plant operations management