In order to harmonize a city, territorial energy planning is a possible solution for electricity supply. The objective is to opt for energy efficiency, i.e. to use energy rationally, and to take a step towards the energy transition. A partial equilibrium model is also used in this work for the classification of the instruments of energy saving control according to the cost effectiveness criterion for a fixed energy saving objective. On the prospective study side, the Grey GM(1,1) model is the future demand prediction tool, and scenarios have been developed to show the results of the planning application to the city of Antananarivo. To improve the rate of access to electricity in the city and to increase production by exploiting renewable energy, the grid-connected photovoltaic system is proposed, promoting self-consumption. The use of energy-saving goods and the awareness of users to energy efficiency, have been the most appropriate solutions to not waste resources.