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<br />001594 <br /> <br />9. Power Generation <br /> <br />9.1 General <br /> <br />The CRSM computes monthly electrical power generation and energy genera- <br />tion for Fontenelle, Flaming Gorge, Blue Mesa, Morrow Point, Crystal, <br />Glen Canyon, Hoover, Davis, and Parker powerplants. Power generation is <br />computed in units of kilowatts and energy generation is computed in <br />units of kilowatt hours. <br /> <br />An iteration procedure is necessary to determine the discharge through a <br />powerplant. The iteration procedure begins with the quantity of <br />discharge that would occur operating at maximum horsepower. The <br />discharge is used to compute tailwater elevation, which is subtracted <br />from the reservoir elevation to obtain gross head, which in turn is used <br />to compute a value of actual discharge. The new discharge is compared <br />with the old discharge and, if they differ more than 5 ft3/s, the com- <br />putations are repeated starting with the new discharge. When the itera- <br />tion process is complete, the horsepower produced by the powerplant is <br />computed as a function of the gross head. The total kilowatts produced <br />is then determined from this horsepower. The iteration procedure is <br />further described in section 9.2. <br /> <br />! <br />i <br />~ <br /> <br />" <br /> <br />The method used to determine the number of hours that power is produced <br />and subsequently the amount of energy produced in kilowatt hours is dif- <br />ferent for the Upper and Lower Basins. The Upper Basin computations <br />assume the powerplant is operatin9 at maximum horsepower at all times. <br />Lower Basin computations assume two levels of power generation, the <br />first level at maximum horsepower, called peak power generation, and the <br />second level at an off-peak or base level of power generation. The <br />powerplant discharges corresponding to the base power generation are <br />specified in the CRSM control file. <br /> <br />9.2 Modeling Procedure <br /> <br />The first step in the power generation modeling procedure is to deter- <br />mine whether the gross head is greater than the minimum rated head. For <br />this initial check, the gross head is computed from the average reservoir <br />release for the month. If the gross head is less than the minimum rated <br />head specified in the CRSM control file, no power is produced for the <br />month. If the gross head is greater than the minimum rated head, then <br />power generation is computed using the steps below. <br /> <br />In the power computations, discharge is computed as a function of gross <br />head using a third-degree polynomial equation. Horsepower is likewise <br />computed from gross head. Tailwater elevation is computed from <br />discharge using a third-degree polynomial equation for all dams except <br />Hoover. Tailwater elevation at Hoover Dam is computed as a function of <br />Lake Mohave's water surface elevation and Hoover Dam's discharge. <br /> <br />The first set of computations determines the discharge when operating at <br />maximum horsepower. The generator capacity in kilowatts is computed <br /> <br />44 <br />