Selecting Optimal Incentive Price Regulation Model for the Electricity Distribution in Iran Considering Externalities

Almost in the entire history of 20th century, vertically integrated monopolistic companies have controlled the electricity industry. In this traditional method, these firms were the only service provider in their territory; including power generation, transition, distribution and retail. Necessity of economic efficiency deployment, resulted in structural reform in electricity industry that has created variety of subjects such as restructuring, unbundling, deregulation, reregulation and privatization. Electricity industry restructuring means breaking up vertical monopolistic control of governments on industry through unbundling into competitive and uncompetitive sectors. Electricity distribution sector essentially has natural monopoly characteristics therefore is not competitive and should work under regulation. The main objective of this research is to find the most efficient incentive regulation model for electricity distribution sector of Iran by which social welfare function may be maximized. Price and revenue cap models are the most prevalent incentive schemes that have been compared with each other. To design this model, cost function of 38 electricity distribution companies has been estimated and marginal cost of each company has been assumed as the first best price. Efficiency of these companies has been calculated by means of data envelop analysis method. Afterward 2 price regulation schemes has been modeled for years 1388 until 1390. Finally, residential electricity demand function has been estimated by means of autoregressive distributed lags method. Calculation of the difference between total welfare of each model with the first best price; indicates that without considering air pollution externalities, price cap scheme maximizes total welfare. However, considering the externalities, revenue cap model is found to have better effect on total welfare.