For different reasons the humans have been using the natural resources of planet Earth during the past. In the last couple of years the planet starts to change his characteristics. Global warming is the problem that occurred. One of the principal uses of natural resources extracted from the Earth is to generate electricity. The increase of the electricity expended in the last years lead to a lack of fossil fuels remaining in the planet. This problem is changing how the electricity is generated – from non-renewable resources to renewable resources. This change will lead to different economic results in each country depending of the type of market they have. The main topic of this thesis is to make a comparison between public monopoly and monopolistic competition in the renewable electricity generation markets. In this paper countries like Chile and France were chosen. Chile has a monopolistic competition as a model while France possess a public monopoly. Different theories show that these two types of market have different characteristics. Supply, demand, prices and investments are analyse to help to understand this two types of market.