Biofuel research. Conical flasks of various oils and solids demonstrating the stages used to produce biodiesel from a plant oil. The initial oil is extracted from the seeds of the plant, and the oil is then progressively refined by the removal of unwanted elements. The final product is biodiesel. Biodiesel is suitable for use in a conventional diesel engine. Biofuels such as biodiesel are clean, renewable sources of energy, and have less impact on the environment than fossil fuels such as diesel, petrol and coal. The plant oils being investigated here include palm oil and oil from the seeds of the Jatropha curcas plant.