9676 - Laserfiche WebLink

Home Browse Search

The annual costs estimated in the table on page 9 may be an underestimation of the impacts to hydropower generation. This can be attributed to not including such cost factors as increased maintenance, the lack of an evaluation of power system operational factors, escalation of annual costs, and the volatility of the power market as experienced in recent years. The cost estimates were based on average annual generation without consideration given to the peaking capabilities at Morrow Point and Blue Mesa Powerplants where the generation can be adjusted frequently to meet power system demands. The value of the power is greater when produced during peak demand periods. Also, during periods of spilling at Crystal Dam it is necessary to curtail peaking operations at Morrow Point Powerplant so as to avoid large fluctuations in the river below Crystal Dam. Power system economic impacts should be evaluated using power system models so that a more accurate representation of system operations is portrayed. These economic impacts would then be incorporated into Western's repayment study to determine the need for a rate increase to its customers. Reclamation staff did not have this capability in-house nor the time available to work with Western to perform power system modeling and an assessment of economic impacts and the associated potential rate increase to power and project use customers. As a consequence of national and regional electric reliability requirements, Reclamation and Western are required to maintain adequate reserves to assist in providing power system regulation and emergency response capability, Morro-i,v Point and Blue Mesa Powerplants are important assets in meeting these requirements. However, during the modeled operational scenarios to meet flow recommendations, Morrow Point and Blue Mesa Powerplants would not be able to provide regulation or respond to power system emergencies as frequently as in the past due to increased Crystal spills, which limit peaking. Additionally, other CRSP generating facilities such as Flaming Gorge and Glen Canyon outside the Aspinall area may not have the capability to provide regulation or to respond to the emergency or may be limited in their response by transmission constraints. The proposed scenarios create other power system operational difficulties with associated economic impacts. During power system interruptions, Morrow Point is the only hydroelectric powerplant of sufficient size that can bring coal-fired powerplants in Western's service area back online quickly. Also, under the modeled alternatives, frequency control is reduced by the Aspinall Unit and would need to be purchased from other resources. Operation and Maintenance The modeled operational scenarios to meet the recommended flows would require increased use of bypass valves, spillway gates, spillways, and stilling basins as compared to the baseline, At Blue Mesa and Morrow Point Dams, use of the bypass valves would increase in both frequency (number of years) and duration, while usage of the spillways would remain approximately the same. At Crystal Dam, use of both the bypass and the spillways would increase in frequency and duration. The original design for these structures did not contemplate routine annual operation or extended use. These structures were intended to operate on a limited basis when needed to pass high flows attributed to unusual hydrologic events. Prior to implementation of any of the proposed scenarios, it would be necessary to conduct a thorough analysis of the structures and the associated design and maintenance parameters to determine if the structures would function properly under the new operation scenarios. Part of this analysis would be to identify costs to modify structures and to 8