Size Of Installation

In the typical steam-based utility, it is the function of pumped storage to (1) furnish peaking capacity on the weekly load curve (Figure 1) and (2) generate full pumped storage in an emergency for from 10 to 15 h, as required by the particular system. On the basis of comparative cost estimates, the most economical size of installation is selected.

The principal features of a typical pumped storage project are shown schematically in Figure 2. The overall efficiency is about 2:3; that is, 3 kW of pumping power will yield 2 kW of peak generation. The economy of the process stems from the fact that dump energy for pumping is worth about 3 mills/kW • h, whereas peak energy is worth about 7 milli/kW • h. There is also an operating advantage. Because of the ease and rapidity with which it may be placed on-line and because of its low maintenance charges, pumped storage is ideally suited to peaking operation. On the other hand, for maximum economy, modern high-pressure, high-temperature thermal plants should operate continuously near full load on the base portion of the load curve.

Table 1 shows a typical calculation to determine the reservoir capacity needed for sustaining the weekly load curve. The reservoir capacity to carry full load for a 10- to 15-h emergency is obtained simply by equating the electrical energy in kilowatt-hours in the load to the potential hydraulic energy stored in the upper reservoir.

Survival Treasure

Survival Treasure

This is a collection of 3 guides all about survival. Within this collection you find the following titles: Outdoor Survival Skills, Survival Basics and The Wilderness Survival Guide.

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