Cheatham County Generation Site EIS Scoping Report
• Recovery: Ability to recover to normal operating levels quickly and efficiently. The combination of quick response and recovery addresses the concept of resiliency, as opposed to reliability, which reflects the need for ongoing and continuous operations. Natural gas-fueled electricity generation is an important source of energy for the U.S. power sector in general, as well as for TVA. The natural gas fuel supply and delivery system proposed to serve the Action Alternative would be robust, interconnected, redundant, and geographically diversified. The approximately 8-mile pipeline lateral would be buried underground, offering protection against storms, natural events, and physical attack. The redundancy of natural gas networks, as well as access to the diverse sources of natural gas supply for the generation facilities they will or already serve, provides a highly reliable and highly resilient fuel source for power generation. Petroleum fuels also play an important role in TVA’s generation mix in both combined cycle combustion turbine (CC) and CT facilities as a back-up/alternative option in dual-fuel units. The petroleum delivery system is robust, complex, redundant, diversified, and resilient, providing a multi-modal network that utilizes pipelines, trucks, and storage tanks. When combining the network benefits of natural gas with the network benefits of petroleum delivery, dual-fuel generation plants using ULSD fuel as a back-up fuel further strengthens TVA’s resiliency and provides one of the most robust forms of generation on the system. Natural gas units with dual-fuel capability can switch to an alternative fuel if the gas supply is TVA would construct a 161-kV switchyard for the proposed CT plant. TVA would install a 161-kV switch house (potentially including water and septic systems) and station service. TVA would also install fiber, relaying, digital fault recorders, and redundant metering for the proposed plant. All unit substation transformers would be oil-filled; therefore, concrete foundations and an oil containment system would be included. 3.2.6.1 Transmission Lines and Stations Upgrades TVA would construct two to four double-circuit transmission lines (TL), totaling approximately 35 to 45 miles of new 100-foot ROW, to connect the new generation to the transmission system. Additional upgrades may include uprating, reconductoring, or rebuilding transmission lines as well as replacing breakers, terminal equipment, bus work, or jumpers at substations. Upgrades are typically performed to increase the electrical capacity of the existing TL and would include the following: • Moving Features that Interfere with Clearance. As more electricity is transmitted through the TL, the conductor (the cable that carries the current) temperature rises and the TL may sag. Features such as sheds or storage buildings located within the ROW may interfere with the ability to operate the TL safety and would be moved. • Replacement or Modification of Existing TL Structures or Installation of Intermediate TL Structures. Typical TL structure replacement, extensions, or installation of intermediate TL structures would be performed with standard TL equipment such as bulldozers, bucket trucks, disrupted and then recover rapidly after the trigger event has subsided. 3.2.6 Transmission and Electrical System Components
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