Although liquid fuels—mostly petroleum based—remain the largest source of energy, the liquids’ share of world marketed energy consumption is expected to fall from 34 % in 2010 to 28 % in 2040, a decrease of 6 % over the period, due to a foreseeable high world oil prices. This trend leads many energy users to switch away from liquid fuels when feasible.
The use of liquid fuels is expected to grow modestly or declines in all end-use sectors, except transportation, during the coming decades where in the absence of significant technological advances, liquid fuels will continue to provide much of the energy consumed in this sector. The use of liquid fuels for transportation is expected to increase by an average of 1.1 % per year, or 38 % overall, from 2010 to 2040. The transportation sector is expected to account for 63 % of the total increase in liquid fuel use from 2010 to 2040, and the remainder is attributed to the industrial sector, where the chemical industry is expected to continue to consume large quanti- ties of petroleum throughout the coming years. The use of liquid fuels is expected to decline in the other end-use sectors, particularly for electric power generation. Most nations are expected to respond to higher oil prices by reducing or eliminating their use for electricity generation opting instead for more economical sources of electricity, including coal, renewable energy sources, and nuclear power. Electricity generation from liquid fuels is expected to decrease by 0.4 % per year, from 0.9 trillion kWh in 2007 to 0.8 trillion kWh in 2035. However, the current low price of crude oil could change the situation described above at least in some countries.