We are a new consulting company specialized in elaborating studies on methodologies for evaluating the technical and economic feasibility of conversion technologies used in transforming biomass into biofuels or bioproducts, such as those used in so called biorefineries. Our team has accumulated experience during the last decade conducting feasibility studies for Petrobras. Such studies have focused on the so-called biomass conversion processes, as the Fischer-Tropsch synthesis processes – for the production of jet fuel – or the thermochemical synthesis for the production of ethanol and other higher alcohols, in both cases using inputs from renewable sources. Based on case studies of idealized industrial plants to process sugar cane bagasse in Brazil, two types of methodologies have been adopted. The first one, following a deterministic approach, takes into account the traditional methodology of discounted cash flow or net present value (NPV), while the second one applies stochastic methodologies in order to assess the economic feasibility of processes under uncertainty conditions. In this latter approach, prices of raw materials and products are modeled through stochastic processes, and the economic feasibility of each project considered is analyzed with the help of Monte Carlo simulations. The results obtained make it easier to take the investment decision.