I think there are lots of posts to come on Biofuels, but this is a simple one to kick off to outline the differences between the options.
Replacement for – Petrol (Gasoline)
Made from – fermenting and distilling high sugar/starch crops. Examples of high sugar/starch crops are sugar beet, sugar cane or corn.
Availability – Bioethanol is available in a large number of service (gas) stations. Also different countries are allowing different blends, though the car manufacturers have a big say. The idea is that service stations can sell blended Bioethanol (say 5% bioethanol, 95% petrol) without branding it as such. This would allow a bioethanol manufacturing industry to get established. The problem is to what blend will car manufacturers will maintain their guarantees too.
Pros – Petrol is the norm in this world of ours – It is easy to convert petrol engines to bioethanol
Cons – Expense – Starchy crops are really expensive, fermentation and distillation plants are really expensive. Also very large factories are needed to effectively produce the fuel
Replacement for – Diesel
Made from – Rapeseed, palm, algae. The oil from these crops is “esterified” and mixed with regular diesel
Availability – Same as bioethanol really
Pros –Easier to make than bioethanol, diesel vehicles are generally larger, and so more economic to modify.
Cons –Rapeseed is not a standard crop.
Pure Plant Oil
Pure plant oil (PPO) is the oil that can be extracted from suitable vegetable matter, such as rapeseed or palm. When you hear about people using cooking oil from restaurants, this is what they’re talking about. The problem is that it is solid, or at least very thick, at room temperature, so it needs to be heated before it can be used. This means fitting a modification to a regular engine to heat the oil in the fuel tank.