Electric power distribution: economies of scale, mergers, and restructuring

Abstract

Electricity distribution is generally viewed as a natural monopoly and therefore as having the least potential for the kinds of reforms that have swept the electric power sector in many countries. Mergers among distribution companies and efforts at retail competition have nonetheless altered the operation of the distribution stage. This research into US electric utilities uses a much larger and less selective data base than previously available to examine the scale properties of distribution with respect to output, distance, and customer numbers, and for different functions within distribution. It finds significant economies at low output levels, holding system size and customer density constant, but the cost gradient is otherwise modest. It also finds that geographic size and customer numbers are quite important and that economies are significantly stronger for the infrastructure or ‘wires’ business than for the marketing function performed by distribution utilities. These results lend credence to efforts at retail competition that separates these functions, but cast doubt on the benefits of mergers between distribution systems.