OCR Text |
Show expected, the solutions for Oneida and Amalga are quite different from that in the previous application. The most notable change is the reduced generation capacities for Hydropower at each of the reservoirs. This results from the observation that the most efficient use of a generator is made when the monthly fluctuation in release is a minimum and a higher head is available for power generation. In such a case the peak power generation ( and hence the generator capacity), is very close to the average power production. This leads to high degree of efficiency in the utilization of the generator. Such a situation was possible in the earlier application, where no significant sets of M& I, Irrigation and other demands were posed downstream of the reservoir, and higher dead storages were provided. When the system is operated with a number of downstream constraints, including flow maintenance, the release from the reservoirs sees a higher degree of fluctuation, leading to a corresponding decrease in the economically efficient size of the generator. It may also be observed from Table 5.8 that the solution for Millcreek- Avon is almost identical to that obtained previously, with the exception of the generator size. The total M& I yield for all demand areas that can be served by a combination of reservoirs other than Millcreek- Avon is at its upper bound, suggesting that more water could be developed profitably by further developing the reservoirs with total storage capacity less than the upper bound. This conclusion is supported by the magnitude of the Dual activities associated with these constraints. Amalga, in particular seem to be a promising candidate, for further development. A similar statement applies to the Irrigation yields that are at their upper bounds. Table 5.9 presents the statistics for this application. The net annual benefits for Millcreek and Avon are at the same levels as in the previous application. Those for Oneida and Amalga are considerably reduced over their previous values. The primary reason for this was indicated earlier. Since, there are no constraints requiring that a minimum amount of hydroenergy be supplied from the system, generation of hydropower is reduced to accommodate increased downstream demands. The Benefit- Cost Ratio ( BCR) for the system at this solution is 5.12, which is quite attractive. By reservoir, the benefit- cost ratios are 1.68, 7.63,1.72,1.19, 3.91, 15.0, for Oneida, Amalga, Millcreek, Avon, Honeyville and E. Promontory respectively. The high BCR of E. Promontory is based on its lower cost per unit storage and the Benefit of $ 40/ Acre- foot associated with the Bird refuge. If this benefit level is reduced, the algorithm is likely to provide for increased storage of water for hydropower generation in those reservoirs. For instance, the storage allocated for 4000 Acre- feet of water supplied by Honeyville to the Bird Refuge, in excess of its demand of 341,000 Acre- feet is likely to be used for hydro releases. Parametric model runs varying the bird refuge benefit level, should be useful in answering this question. 133 |