First of all, it is necessary to specify that this study is an academic work carried out by a student. The hypothesis and the line of reasoning that aect the results obtained are proposed in the context of a master thesis. Electricity supply is a big challenge for West Africa. Indeed, the state members of the Economic Community of West African States (ECOWAS) face many problem of electricity as their production and distribution systems are not enough developed and reliable. A good and reliable electricity supply could allow to develop the industries and improve the attractiveness of the region. The purpose of the West African Power Pool (WAPP) is to develop the electricity sector in West Africa and guarantee a reliable and continuous electricity supply at a competitive cost. Creating an open market for the whole region seems to be the best strategy to achieve these goals. This kind of market could decrease the electricity price by the wholesale purchase of energy, a better resources management and the building of large centralized power plants. Investors can be attracted to invest in new power plants and develop the sector. The objective of the study is to analyze the benets of dierent electricity supply strategies for each country. An autarkic strategy for which each country use its local plants to produce electricity. An open market strategy for which the region is considered as a unique area with an open market.A part of independence strategy for which an open market is in place but the importing countries should produce a certain part of their electricity locally. Moreover a strategy introducing renewables technologies is assessed to evaluate the economical impact on an open market of these technologies. To evaluate these strategies, the expansion of the power pool is planned and evaluate on an economical point of view. The existing power pool is consider and candidate plants are added depending on the strategy and the country. In West Africa, the mainly used plants are thermal plants using natural gas, heavy fuel or diesel and some hydroelectric plants. The expansion is optimized using the software PLANELEC by the minimization of the net present cost (NPC). The economical evaluation is made on the NPC and the levelized cost of electricity (LCOE). The results demonstrate that the open market strategy provides the lowest LCOE. So all the countries will benet the creation of a market. The most used technology are combined cycle power plants and gas turbines using natural gas as a fuel. The renewable energy strategy will slightly increase the LCOE of the open market as these technologies are more expensive.