The Argentine electricity sector consists of four main groups: generation, transmission, distribution and large consumer companies.

Generators

According to a recent report issued by CAMMESA, there are 43 generation companies in Argentina, most of which operate more than one generation plant. As of December 31, 2007, Argentina’s installed power capacity was 24,352 MW.  Of this amount, 54% was derived from thermal generation, 42% from hydraulic generation and 4% from nuclear generation, provided by 40 private companies using conventional thermal equipment and hydraulic generation technology, 2 bi-national companies using hydraulic generation technology and one national state-owned company using nuclear generation technology.

Transmitters

Electricity is transmitted from power generation facilities to distributors through high voltage power transmission systems. Transmitters do not engage in purchases or sales of power. Transmission services are governed by the Regulatory Framework Law and related regulations promulgated by the Secretariat of Energy.
In Argentina, transmission is carried at 500 kV, 220 kV and 132 kV through the national interconnection system. The national interconnection system consists primarily of overhead lines and sub-stations (i.e., assemblies of equipment through which electricity delivered by transmission circuits is passed and converted into voltages suitable for use by end users) and covers approximately 90% of the country.

Distributors

Each distributor supplies electricity to consumers and operates the related distribution network in a specified geographic area pursuant to a concession.  Each concession establishes, among other things, the concession area, the quality of service required, the rates paid by consumers for service and an obligation to satisfy demand.  The ENRE monitors compliance by federal distributors, including us, Empresa Distribuidora Sur S.A. (Edesur) and Empresa Distribuidora La Plata S.A. (Edelap), with the provisions of our respective concessions and with the Regulatory Framework Law, and provides a mechanism for public hearings at which complaints against distributors can be heard and resolved.  In turn, provincial regulatory agencies monitor compliance by local distributors with their respective concessions and with local regulatory frameworks.
We and Edesur are the largest distribution companies and, together with Empresa Distribuidora La Plata S.A., originally comprised SEGBA, which was divided into three distribution companies at the time of its privatization in 1992.

Large Consumers

The wholesale electricity market classifies large users of energy into three categories:  Major Large Users (Grandes Usuarios Mayores, or GUMAs), Minor Large Users (Grandes Usuarios Menores, or GUMEs) and Particular Large Users (Grandes Usuarios Particulares, or GUPAs).
Each of these categories of users has different requirements with respect to purchases of their energy demand.  For example, GUMAs are required to purchase 50% of their demand through supply contracts and the remainder in the spot market, while GUMEs and GUPAs are required to purchase all of their demand through supply contracts.