Due to the need to replace fossil diesel in automotive engines, there is a growing demand for renewable fuels. However, to propose new fuels to be used efficiently and also, without causing damage to the environment, many studies are done. In this sense, the present study aims to evaluate two renewable fuels - farnesane and soybeam biodiesel - using the analytical technique DSC (Differential Scanning Calorimetry) for determining the oxidative thermal degradation energy of these biofuels compared to fossil diesel (reference fuel for diesel engines). The importance of studying this parameter is due to the principle that the lower the energy of oxidative thermal degradation, the best feature of burning fuel. In addition, these fuels were also tested in diesel engine OM 926 LA Euro 5 using the ESC test - European Stationary Cycle in order to monitor their performance and emissions. The results showed that the oxidative degradation of energy values was: 359.4 kJ / kg for farnesane, 2911,0 kJ / kg for biodiesel and 843.8 kJ / kg for fossil diesel. The tests done on the engine showed that the farnesane presented lower emissions NOx, HC e CO2 and even better performance compared to the other two fuels. This study shows that there is a direct correlation between energy oxidative degradation and engine performance.