In Brazil, despite the high share of renewable energy sources in the energy mix compared to the world average, the use of gas generated by landfills for power generation is still incipient. There are landfills recently implanted with the purpose to produce electricity from biogas, but the oldest installations do not have this structure. Since the oil industry is energy intensive, the article proposes the evaluation of waste gas use in the steam generation system of a typical refinery in Brazil to generate electricity and feed the refinery process units and considering the economic impact. In this sense, it presents an analysis based on real data to contextualize and quantify the waste biogas potential in a specific landfill in Brazil. The study considers a landfill at the end of life (17 years), and the reuse of the residual gas generated until the full depletion of gases considering a case study with real data obtained from an existing landfill.