Price Regulation for Independent Transmission Companies

This paper considers methods of price structure regulation of electricity transmission in the context of an independent transmission company (TRANSCO). The focus is on two-part tariffs where the variable part would reflect congestion charges (and ancillary services) while the fixed part would reflect capacity costs. The two-part tariffs form a price-cap index, and the firm could rebalance prices, as long as the index satisfies the price-cap constraint. The firm would then have incentives to trade off congestion against capacity expansion in such a way that it becomes profitable to expand, whenever the costs of congestion on average exceed the costs of expansion. However, with chained Laspeyres weights in the price-cap index expansion may be suboptimal. We therefore discuss ways to improve the expansion factor. Implementing the regulatory schemes considered suggests a hybrid approach combining a TRANSCO with an independent system operator (ISO).