ABSTRACT
Fuels are generally thought of as liquids because the two main fuels used for automotive applications are liquids at room temperature: petrol/gasoline; and diesel. In 2016 the worldwide average demand for oil and liquid fuels was over 90 million barrels per day. All fuels are highly flammable, some are corrosive and some are stored under very high pressure. In January 2013, the European Commission proposed a directive requiring Member States to adopt national policy frameworks for developing the market for alternative fuels and to ensure that minimum infrastructure is set up for their supply in road and water-borne transport. One key to the development of viable alternative fuels is energy density. Electric vehicle batteries, while improving all the time, have nowhere near the density of liquid fuels. However, electric cars are now available with operating ranges of 200 miles or more.
