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Figure 3.16-1. Potential Noise Receptors in the Project Vicinity
Final License Application – Exhibit E Seminoe Pumped Storage Project
Figure 3.16-1. Potential Noise Receptors in the Project Vicinity
January 2023 | 391
3.16.2 Direct and Indirect Environmental Effects - Noise
Construction and operation of the Project will result in short-term increases in ambient noise.
3.16.2.1 Construction
The highest levels of noise associated with the Project will primarily consist of short-term construction noise produced during heavy earthwork. During construction of the upper reservoir and powerhouse, blasting has the potential to be an intermittent annoyance to residents. To minimize the effects of project construction and operation-related noise within proposed project lands, the applicant would utilize several strategies to manage noise associated with construction, including sequencing of the use of noise-producing machinery and siting laydown areas and other construction activities to take advantage of natural buffering of noise from vegetation and topography between noise generation and receptors.
Reservoirs and Powerhouse - Construction of the Project is anticipated to occur over a 5year period. Estimates for type, number, duration, and location of heavy equipment are preliminary at this time. However, equipment requirements and construction activities can be estimated based on similar construction projects and activities. Projects of this magnitude may be constructed under a two- or three-shift schedule, but construction schedules usually exclude any significant construction over weekends. Most of the noisegenerating project construction would occur at the upper and lower reservoir sites. Sources of construction noise would include chain saws, blasting, operation of the portable concrete batch plant, and use of large excavators, scrapers, cranes, loaders, dump trucks, concrete mixing trucks, concrete pumping trucks, generators and compressors, water trucks for dust suppression, and miscellaneous material delivery by over-the-road semi-tractor trailers. Because different equipment would be used during different phases of project construction, not all equipment would operate concurrently. For example, the first phase of upper reservoir construction will likely include tree and overburden removal, with chain saws, backhoes, and dozers; later phases would involve bedrock removal, with blasting, excavators, and dump trucks. The noisiest conditions are expected during excavation for the reservoirs and concrete pours for the reservoirs and powerhouse.
Transmission Line Installation - Construction of the transmission lines would also result in short-term and intermittent noise impacts as construction progresses along the ROW. The transmission lines would consist of steel monopole towers constructed on a reinforced concrete foundation. Construction would involve some excavation, followed by form work and concrete pours. A light-duty crane would be used to erect each monopole tower. Construction of one transmission line support tower would take a few days to a week, after which, construction crews would move to a new location. Noise would result from construction and transportation equipment, including vehicles and helicopters. Noise from truck traffic and increased worker trips along the right-of-way would temporarily contribute to existing traffic noise on local roads and highways but is not expected to result in an increase in average traffic noise levels. Where helicopters are used for conductor stringing and pole placement, their presence would result in noise levels that may exceed 100 dBA
for a brief period. Noise associated with helicopter use would be temporary and intermittent. Because the transmission lines would be constructed in rural areas that are located away from noise-sensitive uses and regularly experience machinery noise from agricultural practices, it is unlikely that overall noise levels would change significantly.
Mobile Source Noise - Construction materials, equipment, and construction workers would use public roadways, where available, to access the sites for the various components of the project. Where such roadways do not exist, new temporary or permanent access roads would be built. Construction traffic coming from the southwest would likely travel along Seminoe Road or from the southeast along Hanna Leo Draw Road to Kortes Road, as determined during development of the Traffic Management Plan that will be developed prior to construction. Some increase in noise levels associated with construction traffic along these routes is expected during construction of the project. The increase would be temporary and sporadic, occurring only during the daytime. Traffic (semi-trailer trucks or other carriers) related to materials deliveries for the penstocks, turbines, and other Project equipment is expected to total 800 to 1,000 trips over the 5-year construction effort. According to FHWA, a doubling of traffic increases noise levels by approximately 3 dB (FHWA, n.d.), and a 3-dB change in noise levels is barely perceptible. Additionally, the noise generated by one heavy truck (e.g., semi-trailer) traveling at 55 mph is about the same as the noise generated by 28 passenger cars traveling at 55 mph. In a worst-case condition where project-related traffic includes 8 truck trips per day and 500 worker trips per day along Seminoe Road, traffic would not double and noise from the increased traffic would be barely perceptible.
3.16.2.2 Operation
The Project includes three pump-turbine units, enclosed within an underground powerhouse. Noise from operation of the proposed project, including the powerhouse, is not expected to be noticeable at any noise-sensitive area. The facility would employ a small staff who would likely travel to the facility by automobile. No traffic noise increase is anticipated as a result of the small staff. Black Canyon will comply with all regulations regarding worker exposure to noise during operation of the Project.
In conclusion, noise levels in the vicinity of the Project are expected to be temporarily elevated during construction.
3.16.3 Cumulative Environmental Effects Related to Noise
As noted in Table 3.2-1, the geographic scope for noise during construction is within 1 mile of construction of the upper reservoir, underground powerhouse, power tunnel, tailrace tunnel, new intake in the existing Seminoe Reservoir, powerhouse access tunnel, highvoltage transmission tunnel, and switchyard and within 0.25 mile of construction of transmission lines. Noise from construction of the reservoir and powerhouse facilities could affect receptors up to 1 mile away while the areas in the immediate proximity of transmission lines would have the potential to be affects by construction noise. The noise levels due to Project operations are expected to be negligible and therefore were not included in the cumulative effects analysis. As detailed in Table 3.2-2, there are four
projects that occur within the geographic scope for construction noise: 1) WPCI Project, 2) Two Rivers Wind Energy Project, 3) Gateway West Transmission Line Project, and 4) Gateway South Transmission Line Project. However, only two projects overlap with construction workspaces of the Projects: Gateway West Transmission Line Project, and Gateway South Transmission Line Project. These projects tie into the existing Aeolus Substation, which represents less than 7 percent (approximately 462 acres) of the Project’s Footprint of Potential Disturbance and the only physical proximity between the Project and others within the geographic scope for potential effects on noise.
Issues Identified for Analysis
Reasonably foreseeable future actions with potential to impact noise include most development projects, since all would create noise during construction. Surrounding areas within approximately 1 mile from areas of future development would be periodically subject to construction and potentially operation noise. The degree to which sensitive receptors may experience noise impacts would depend on proximity to new sources of noise. Noise in these areas, particularly during construction, could displace wildlife or impact the experience for visitors to public lands in areas where the development occurs. Long-term noise impacts across the landscape would be less discernable in areas that are already developed, although construction activities would likely increase noise above existing conditions.
Results
Existing noise conditions occur in the geographic scope and are expected to be within the range for a rural area, with periodic louder noise intrusions from boat traffic on Seminoe Reservoir or overhead airplanes. Completing earthwork construction elements of the Project and the other projects within the geographic scope would create a temporary increase in noise. Specifically, noise would have the greatest impact during the following activities:
• Large-scale excavation and blasting to construct the upper reservoir, • Blasting and tunneling to construct the underground powerhouse and related systems (piping, pumps, penstocks, and power turbines), • Increased truck traffic to and from construction sites.
There are few homes in the geographic scope and effects from noise are expected to be temporary and occur in areas where very few people could be affected. The scattered residences in the geographic scope would experience some increased noise during construction. If multiple projects were to occur within the geographic scope at the same time, the effects of construction noise on nearby residents would be cumulative. However, these residences are sheltered from some noise by hills, mountains, vegetation, and distance, and reasonably foreseeable other projects will not be in construction during the same time period as the Project.
It is anticipated that the installation of the transmission lines would require limited equipment and result in minimal noise emissions. Since the Gateway West Transmission
Line Project has completed construction (within the geographic scope) and Gateway South Transmission Line Project is undergoing construction and is expected to be completed prior to Project construction, cumulative noise impacts would be negligible since there would be no construction overlap. Wind energy projects, such as the Two Rivers Wind Energy Project, would have the potential to increase ambient noise levels postconstruction during their operation. However, they are required to adhere to industry noise standards and requirements to reduce and mitigate potential direct and cumulative noise impacts, and are physically distant from the Project.
Cumulative impacts from noise are highly localized and attenuate quickly as the distance from the noise source increases. If cumulative impacts were to occur, noise levels in the geographic scope would return to baseline levels post construction. Based on publicly available information, it is not anticipated that the Project activities at any one location within the geographic scope would occur concurrently with other projects and therefore cumulative impacts from noise are not anticipated.
3.16.4.1 Agency Consultation
The NOI and PAD for the proposed Project were filed with the FERC on April 20, 2020. Comments were received from several agencies including BLM and WGFD, and individual stakeholders. Black Canyon held a virtual joint public-agency meeting on July 21, 2020, and has continued consultation with stakeholders since that time. Black Canyon distributed its proposed resource study plans for the Project on August 3, 2020, and March 23, 2021. Black Canyon distributed the DLA on June 6, 2022. Responses to stakeholder comments and Black Canyon’s Record of Consultation are provided in Appendix A. BLM and WGFD provided comments on noise in their comments on the DLA. Responses to comments on the DLA are provided in Appendix L.
3.16.4.2 Applicant Recommendations
As described in Table 2.1-5, the following PM&Es are applicable to noise:
• Noise: To minimize the effects of noise related to construction and operation of the
Project, Black Canyon will utilize several strategies to manage noise associated with construction, including sequencing of the use of noise-producing machinery and siting laydown areas and other construction activities to take advantage of natural buffering of noise from vegetation and topography between noise generation and receptors.
4.0 Developmental Analysis
This section evaluates the Project’s use of environmental resources for hydropower purposes to see what effect various environmental measures would have on the Project’s cost and power generation. Following the Commission’s approach to evaluating the economics of hydropower projects, as articulated in Mead Corp. 24, this section compares the current Project cost to an estimate of the cost of obtaining the same amount of energy and capacity using the likely alternative source of power for the region (cost of alternative power). In keeping with the policy as described in Mead Corp., the economic analysis is based on current elective power cost conditions and does not consider future escalation of fuel prices in valuing the Project’s power benefits.
For each of the alternatives, the analysis includes an estimate of: (1) the cost of individual measures considered for the protection, mitigation, and enhancement of environmental resources affected by the Project; (2) the cost of alternative power; (3) the total Project cost (i.e., for construction, operation, maintenance, and environmental measures); and (4) the difference between the cost of alternative power and total Project cost. If the difference between the cost of alternative power and total Project cost is positive, the Project produces power for less than the cost of alternative power. If the difference between the cost of alternative power and total Project cost is negative, the Project produces power for more than the cost of alternative power.
4.1 Power and Developmental Benefits of the Project
The United States has set a goal to reach 100 percent carbon pollution-free electricity by 2035. A key benefit of this Project is to facilitate the integration of zero-carbon, variable energy generation in line with this national goal. In Wyoming, wind generation is also the lowest cost form of energy generation. The Project will provide flexibility to the operations of the grid of the future, enabling absorption of excess renewable energy when it is abundant, and store that energy to be released at a later time when transmission line capacity is available and/or when the grid is in need of dispatchable generation.
A pumped storage generating facility includes an upper reservoir, a lower reservoir, and a reversible pump-turbine unit in between the two reservoirs. In generating mode, water from the upper reservoir flows through the reversible unit to the lower reservoir. The water turns the turbine, which is attached to a generator, producing electricity that is transmitted to the electric grid. In pumping mode, power is drawn from the electric grid to “motor” the unit in reverse to act as a pump, pushing water from the lower reservoir back to the upper reservoir. There is a roundtrip efficiency loss, therefore pumped storage facilities are net
24 See Mead Corporation, Publishing Paper Division, 72 FERC ¶ 61,027 (July 13, 1995). In most cases, electricity from hydropower would displace some form of fossil-fueled generation, in which fuel cost is the largest component of the cost of electricity production.
energy consumers. The value of the pumped storage facility is in bridging the temporal mismatches between generation and load.
There are a number of wind generation facilities planned or proposed throughout Wyoming due to the state’s abundant wind resource. The variability of the output of these facilities can be problematic to the electric grid. Such facilities typically work best when they are located close to generating facilities that can provide system balancing capabilities, such as those provided by pumped storage facilities and gas-fired combustion turbines installed specifically to work in concert with solar and wind farms to provide system stability. Pumped storage facilities are designed to be able to change modes rapidly and can fill gaps due to wind and solar power variability.
The ability of pumped storage facilities to be switched from pumping to generating and back again very quickly, as needed, provides unique benefits to the electric grid. Pumped storage facilities can provide a number of ancillary services to the grid to enhance overall grid reliability. Among these services are spinning reserve, non-spinning reserve, frequency regulation, voltage support and regulation, load following capability, peak shaving, and black-start capability. The following discussion provides more detail of these various services.
• Spinning reserve is the extra generating capacity that is available by increasing the power output of generators that are already connected to the power system. Nonspinning reserve or supplemental reserve is the extra generating capacity that is not currently connected to the system but can be brought online after a short delay. • Grid frequency is a system-wide indicator of overall power imbalance. These imbalances are removed by requesting generators to operate in frequency control mode, altering their output continuously to keep the frequency near the required value. • System voltage levels vary over the course of the day due to a variety of factors, including: (1) the location of the local distribution ling, (2) proximity to large electricity consumers, (3) proximity to utility voltage regulating equipment, (4) seasonal variations in overall system voltage levels, and (5) load factor on local transmission and distribution systems. • Pumped storage facilities can operate as base load, load following, or peaking power facilities and change operating modes seasonally and daily. Most hydroelectric facilities have the ability to start within minutes, if not seconds, depending upon available water supply. When in load following mode, the output of the pumped storage facility can be adjusted as necessary to meet widely varying load requirements. • Pumped storage facilities can be operated at a generating level that is much lower than a base load facility and can therefore avoid the need to run a base load unit at low efficiencies below the minimum loading rate of the base load unit. • A pumped storage facility can generate electricity during peak periods when demand is high and available generating output is near its limits and then pump during off-peak periods when demand is low when available generating output is lower. • Black-start is the procedure to recover from a total or partial shutdown of the transmission system, which has caused an extensive loss of supplies. This entails
isolated power stations being started individually and gradually being reconnected with each other in order to form an interconnected system again.
4.2 Comparison of Alternatives
The alternative to this Project, consistent with the national goal to reach 100 percent carbon pollution-free electricity by 2035, is to either build other energy storage facilities sufficient to meet the national goal and replace the Seminoe Pumped Storage project, or else to overbuild transmission capacity as well as wind and solar generating capacity and then rely on curtailing the overbuilt capacity when it is not needed to meet load.
4.2.1 No-action Alternative
Under the no-action alternative, the Project would not be constructed and would not provide any capacity resource or flexibility for operations of the grid in support of achieving 100 percent carbon pollution-free electricity by 2035. The United States would either miss the goal of producing 100 percent carbon pollution-free electricity, or else an alternative portfolio of energy resources would need to be constructed capable of replacing the capability of the Project. Any of the no-action alternatives would have associated environmental impacts that are challenging to specifically quantify.
One option for replacing the capability of the Project would be to construct a similar sized battery storage project, or several smaller battery storage projects with a cumulative capability equivalent to the project. The impacts of those projects include the mining of rare earth minerals, likely dependence on internationally produced battery supply from entities that are not friendly to the United States, and the site impacts from construction and operation of those facilities. As explored in Exhibit D, battery storage projects are not cost competitive with pumped storage hydro for equivalent durations of energy storage.
Another alternative would be to overbuild transmission capacity through construction of additional transmission lines, and a concomitant overbuild of wind and solar capacity so that the minimum expected generation capacity would always exceed peak load demand. The excess capacity would then be curtailed when generation exceeds load, which would be most of the time. This alternative would involve a low utilization of those overbuilt resources to ensure that generation is always available to meet demand. The resulting environmental impacts of those excess capacity projects would very likely exceed the impact of the Seminoe Pumped Storage project.
4.2.2 Black Canyon’s Proposal
Black Canyon proposed numerous environmental measures as presented in Table 4.3-1. The Project would have an installed capacity of 972 MW and generate an average of approximately 3,200,000 MWh of electricity annually, assuming a full energy storage cycle each day for 90% of the day through the year.
4.3 Cost of Environmental Measures
Table 4.3-1 provides the cost of each of the environmental enhancement measures considered in the analysis.
