This work deals with the study of the different factors affecting the cost of generation and distribution of electrical energy in our National Electricity System (SEN). It includes a model of the national network and the elaboration of a programa allowing the real time assessment of the different factors, the optimization of the system and decision making regarding the measures to be taken to respond to any foresreable (the more usual ones) or unforeseeable situation. The model developed takes into account the generation features of every available plant, the effect of losses in energy distribution, system operation and security restrictions, as well as environmental criteria for SO2 emissions control which are more abundant when using the national production crude oil.

Although systems similar to this one have been developed by important enterprises engage in the production and distribution of electriciity in developed countries and some of those systems are sold at very high prices, none of those systems would adapt to the specific conditions of our country.

Besides, the system developed contains the following novel elements:

• A mathematical treatment different from the equation system which makes possible the dynamic character of the real time assessment of the whole system of energy generation and distribution,
• The software developed makes possible the evaluation of generation and distribution cost , taking into consideration many factors such as oil transportation cost, the use of foreign and national crude oil, with different features and costs, security and efficiency of the different available plants and distribution stations.

At the same time, this system allows the planning of daily load and decisions making to react to any contingency and includes the evaluation of the influence on costs of environmental impact, which is based on a previous study carried out by CITMA.

The result of all of this work it is being exploited since January 2000 at the National Control Office for Power Generation and Distribution, where it is used everyday. The used of this program has allowed an estimated saving of 20 000 USD a day, not to mention its significance in the reduction of environmental impact, specially at some critical plants, such as Mariel and Santa Cruz del Norte. It has been acknoledged by the National Control Office for Power Generation and Distribution. The work was awarded with the Special Distintion at the 13th National Forum of Science and Technology. It has been presented in three scientific events, one of them international. The results have been published in 5 articles by important national reviews.