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Economies of Scale

19 一月, 2016 - 17:17

Scale economies and diseconomies define the shape of a firm’s long-run average cost (LRAC) curve as it increases its output. If long-run average cost declines as the level of production increases, a firm is said to experience economies of scale.

A firm that confronts economies of scale over the entire range of outputs demanded in its industry is anatural monopoly. Utilities that distribute electricity, water, and natural gas to some markets are examples. In a natural monopoly, the LRAC of any one firm intersects the market demand curve where long-run average costs are falling or are at a minimum. If this is the case, one firm in the industry will expand to exploit the economies of scale available to it. Because this firm will have lower unit costs than its rivals, it can drive them out of the market and gain monopoly control over the industry.

Suppose there are 12 firms, each operating at the scale shown by ATC1 (average total cost) in Figure 10.1. A firm that expanded its scale of operation to achieve an average total cost curve such as ATC2 could produce 240 units of output at a lower cost than could the smaller firms producing 20 units each. By cutting its price below the minimum average total cost of the smaller plants, the larger firm could drive the smaller ones out of business. In this situation, the industry demand is not large enough to support more than one firm. If another firm attempted to enter the industry, the natural monopolist would always be able to undersell it.

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Figure 10.1 Economies of Scale Lead to Natural Monopoly 
 

A firm with falling LRAC throughout the range of outputs relevant to existing demand (D) will monopolize the industry. Here, one firm operating with a large plant (ATC2) produces 240 units of output at a lower cost than the $7 cost per unit of the 12 firms operating at a smaller scale (ATC1), and producing 20 units of output each.