Introduction

Oil makes up 35% of the world’s primary energy supply and the majority of this oil is used to produce the transport fuels petrol, diesel and kerosene. If biofuels are to be used to replace the liquid fuel produced from oil, the scale of the replacement needs to be appreciated. The world used in 2005 about 1900 Mtoe oil for transport, the USA 601 Mtoe, the EU 25 342 Mtoe and the UK 58 Mtoe. The fuels used for trans­port in the UK, the EU 25 and world are given in Table 6.1. At present almost all transport fuels are liquid and used in internal combustion, compression ignition and jet engines. The liquid fuels are predominantly petrol, diesel and kerosene. The pat­tern of fuel use will vary depending on the country as many use more diesel than petrol. In the EU, diesel use exceeds petrol use and the more recent figures for the UK indicate that diesel use has exceeded petrol for the first time.

The possible biofuel replacements for petrol and diesel were sketched out in Chapter 4, section ‘The Nature of Biofuels: First-, Second — and Third-generation Biofuels’, where the three generations of biofuels were explained. This chapter deals with biofuels which can supplement or replace petrol and include methanol, bioetha­nol, biobutanol and FT-petrol.

Table 6.1 gives the amount of liquid fuels used for transport in the UK in 2006 and in the EU 25 and world in 2005. In the UK, diesel use has increased rapidly and now exceeds petrol, following the trend set in the EU, whereas petrol use is greater on a global basis.