Rahimi - Principal Consultant, Open Access Consulting (OPAC) ۶۲۶۰ Oak Hill Drive, Granite Bay, CA ۹۵۷۴۶

The electric power industry is undergoing sweeping restructuring around the globe. The trend started in the 1980's in the U.K. and several Latin American countries, gained momentum in many countries in the 1990's, and is moving forward globally with different paces in different countries. The main motivation and driving forces for restructuring of the electric industry in different countries are not necessarily the same. In some countries, such as the U.K. and the Latin American countries, privatisation of the electric industry has provided a means of attracting funds from the private sector to relieve the burden of heavy government subsidies. In the countries formerly under centralized control (Central and Eastern Europe), the process has followed the general trend away from centralized government control and towards increased privatisation and decentralization; it also has provided a vehicle to attract foreign capital needed in these countries. In the U.S. and several other countries where the electric industry has for the most part been owned by the private sector, the trend has been toward increased competition and reduced regulation. A variety of restructuring models have been adopted in different countries. The unbundling of generation from transmission and distribution as separate businesses is prevalent among different models. The transmission sector is regarded as a natural monopoly, and in general remains regulated in order to permit a competitive environment for generation and retail services. In many structural models vertical unbundling involves only a functional separation. This is the case in the U.S., where Order 888, issued on April 24, 1996, by the Federal Energy Regulatory Commission (FERC), mandated functional unbundling of generation and transmission services, but did not require corporate restructuring. Transmission Open Access (TOA), i.e., nondiscriminatory accessibility and pricing of transmission, is generally mandated in order to facilitate competition in wholesale generation. The transmission sector and its products and services may be further unbundled allowing for different wholesale market players, products, and services, as well as the provision or trading of products and services as separate commodities if the transmission users so desire. The most usual wholesale market players are the Transmission Owners (TO), Independent System Operators (ISO), Power Exchanges (PX) and transmission users or their agents (often called Scheduling Coordinators; SC). The most usual unbundling of transmission services includes separation of basic network transport services ("wires" service) from transmission support services ("ancillary services"). The primary market commodities and services are energy, ancillary services, and transmission services (including congestion management). This article presents an overview of the evolving structural models of the deregulated electricity markets, a summary of the usual products and services transacted, and finally a omparative analysis of market designs adopted. Emphasis is placed on the wholesale electricity markets as the first step in electric ity restructuring. Retail open access is not treated here in any detail.