Currently, biodiesel has marginally lower fuel economy and power (2% for B20).
B100 and is generally not suitable for use in low temperatures and there are some concerns about long-term effects on engine durability with pure biodiesel usage.
For very high blends of biodiesel operating in low temperature markets it’s recommended you consult your engine manufacturer for specifications.
Because of its solvent and cleansing properties, biodiesel is more susceptible to water contamination that petroleum diesel, but commonsense techniques can be employed to prevent this.
There are well-publicised concerns about biodiesel production competing with food crops and raising food prices, but this is not the case with crops like Jatropha. It’s a real but solvable issue mostly restricted to developed markets that use relatively low-yield ‘crossover’ crops.
It is possible to grow non-food crops for biodiesel production on low-grade soil and on non-croppable land that provides a renewable energy source without competing with food crops.
Professor Robert Henry of the University of Queensland, an authority in the food vs fuel biofuels debate, suggests that at least 40% of the cost of food is directly attributable to fossil fuel costs in sowing, harvesting and transportation – he advocates planting more energy feedstocks for consumption close to the point of harvesting, reducing cost and impact on the carbon footprint.