The Paper mainly focuses on the constantly increasing demand for energy can result in a huge crisis at the end of fossil fuels era Biodiesel, with a history of more than a century, has always been a possible applicant. Biodiesel fuels have the ability to become a decent alternative for diesel which is used fairly to meet the present energy requirements Biodiesel can be produced from new or used vegetable oils, non-edible sources and animal fats, which are non-toxic, biodegradable and renewable. In vegetable oils, castor seed has higher oil yield than other oils Straight vegetable oils pose operational and permanency problems when subjected to long-term usages in diesel engines. These problems are projected too high viscosity, low volatility and polyunsaturated character of vegetable oils. The process of Transesterification is found to be an effective method of reducing vegetable oil viscosity and extinguishing operational and durability problems. In spite of the many advantages of using biodiesel, biodiesels produce higher NOx emissions compared to diesel, which is a deterrent to the market expansion of these fuels. Metal-based additives play a vital role in reducing NOx emission. In this thesis, performance analysis and other emission characteristics in a diesel engine without modification of Castor oil methyl ester and its blends with and without additive are done and compared with diesel. Results show higher blends of Castor oil have lower NOx emission and lower performance characteristics and vice versa for other blends of Castor oil.