plant is 573 MWt. If the diffuse energy is considered to be 12% of the total in a clear atmosphere location, the total power is 651 MWt. 423 MWt of the direct power is rejected on site. Assuming about 12% of the diffuse energy is absorbed in the skin of the collector and discarded at the plant site, another 9.4 MWt is left at the site of the collector. The remaining 68.6 MWt bounces off the dish and leaves the site. Therefore, the average rate of heat deposited at the site is 432 MWt. About 219 MWt leaves the site via electric power and reflected diffuse energy. Therefore, the effective albedo of the plant is 0.336 (219/651). The values reported for some soils typical of the Southwest are in the range of 0.26 to 0.30 (Ref. 11). Of the total of 651 MWt intercepted by this solar plant, 456 MWt would be absorbed by the soil {651 x (1 - 0.3)]. Thus, this plant is almost neutral and rejects slightly less heat (-24 MWt) than what would be absorbed by the soil. The assumptions upon which this analysis is based were discussed earlier in Section 4.1.2. A wet cooling tower was assumed for the Rankine plant. Some of the waste heat would be carried away by water vapor. With a 41% cycle efficiency, 1.1% pumping power and 2% loss for off design turbine performance, the heat rejected at the cooling tower is 222 MWt. Thus, slightly over half of the total heat rejected by the plant is contained in departing water vapor. The net result of using a distributed collector power plant with distributed generation and a wet cooling tower is to cool the area, provide localized shading, and introduce significant amounts of local moisture. The impact of this change in the local climate is unknown, but will probably be encouraging to the growth of vegetation. The cooling water required annually is 1100 acre ft/yr to operate the plant at a rating of 150 MWe with an annual load factor of 0.45. If a dry cooling tower was used with air cooling, the water consumption would be reduced significantly, but the overall system efficiency would be reduced to approximately
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