Fuel fuel. They are also used to start a coal fire. Liquid fuels are combustible or energy-generating molecules that can be harnessed to create mechanical energy, usually producing kinetic energy; they also must take the shape of their container. It is the fumes of liquid fuels that are flammable instead of the fluid. Most liquid fuels in widespread use are derived from the fossilized remains of dead plants and animals by exposure to heat and pressure inside the Earth's crust. However, there are several types, such as hydrogen fuel (for automotive uses), ethanol, jet fuel and bio-diesel which are all categorized
Ethanol fuel by country label blends containing fuel ethanol on the dispenser. Due to ethanol's greater stability under pressure it is used by Shell in their 100 octane fuel. Similarly IFS add 10% ethanol to their 91 octane fuel, label it premium fuel and sell it more cheaply than regular unleaded. This is converse to the general practice of adding ethanol to a lesser quality fuel to bring its octane rating up to 91. Some concern was raised over the use of ethanol blend fuels in petrol vehicles in 2003, yet manufacturers widely claimed that their vehicles were engined for such fuels. Since then