Energy

Fossil fuels

58.    Fossil fuels are finite, and ultimately exhaustible, energy resources. In 1998, fossil fuels met 90% of global commercial energy demand. Crude oil accounts for over 98% of transport consumption. Energy consumption in transport is growing at a faster rate than for other sectors - people are buying larger cars and car ownership is increasing. Demand for aviation fuel is growing at about 5% per year ^[26].

59.    World oil production will soon peak^[27] . Thereafter oil production will continue for many decades, though at a declining rate.  Production is unlikely to cease before 2050. After that, coal, tar sands, heavy oil and oil shales could be used to produce liquid or gaseous substitutes for crude oil. As far as natural gas is concerned, by 2020, some 40% of that ultimately recoverable from conventional sources will have been produced.

Non-OECD burden

60.    Demand for energy is strongly correlated with GDP and climate. If oil demand was held constant to postpone the decline - the greatest burden would fall on the non-OECD countries where per capita oil use today is only 14% that of the OECD countries.

61.    Ultimately we need to find ways of using less fossil fuels especially as the expected growth in traffic volumes is likely to more than offset the expected gains in vehicle performance. Possible ways forward include reducing the demand for travel, particularly society’s dependence on the car; promoting non-motorised modes such as walking and cycling; encouraging a switch to more energy efficient modes (for example, collective transport); using fossil fuels more efficiently, developing alternative fuels and alternative vehicle technologies and enhancing public awareness of energy issues through media campaigns etc.

Energy efficiency

62.    The development of conventional internal combustion engines (ICEs) is far from fully exploited^[28] and there is potential to develop vehicles capable of tripling the fuel efficiency of today’s vehicles using technologies such as hybrid-electric propulsion, fuel cells, lightweight materials and regenerative braking.

Alternative fuels

64.    Many promising prototype technologies exist to use alternative fuels. Most are at an early concept stage. They have strong environmental advantages over conventional fuels - lower emissions and noise. The challenge of developing alternative fuel vehicles lies in making them affordable. Widespread use of any new fuels would require new fuelling infrastructures and better storage facilities at depots.

Natural gas and LPG

66.    Compressed natural gas (CNG) and LPG are alternative fuels that could have a role in improving air quality, although in 1997 they accounted for only 0.1% of final UK energy consumption. They are attractive for motor vehicle use because they are stored in liquid state and used in gaseous state, making it possible to obtain a high-energy storage density and achieve cleaner and quieter combustion. Some adaptation of existing fuel system technology is required to enable vehicles to run on these gases. In some countries there are networks of local filling stations providing these fuels and these are developing in the UK.

Renewable fuels

67.    The EU has set a target of 12% for the contribution of renewable sources to energy consumption by 2010^[30]. In 1997 renewable energy only contributed to 0.5% of UK consumption - the lowest in the EU.

Electric vehicles

69.    Electric vehicles (EVs) are the most familiar of the alternative fuel set. Practically all manufacturers are developing electric vehicles whose driving ranges are 2-3 times higher than earlier EVs. These are starting to capture a small part of the passenger and urban car market. Electric propulsion systems have been used for decades in mass transit. The key technological issue regarding EVs is batteries. With the exception of lead and NI-Cad batteries all other systems are prototypes.

Hybrid EVs

71.    The most promising type of electric vehicle is the parallel hybrid EV, which employs a combination of battery driven electrical and combustion driven mechanical drives. Toyota’s hybrid gas/electric vehicle "Prius" already available in Japan gets 66 mpg in stop-and-go traffic. GM will unveil demonstrator models of full size hybrid pickups this year^[31].

Fuel cells

72.    Use of fuel cells in cars appears promising and perhaps hold the greatest promise for the clean car of the future. Fuel cells convert the "free" energy of a chemical reaction, typically between hydrogen and oxygen, directly into low voltage direct current electricity and heat. They are similar in principle to batteries. Fuel cells can be designed to run on a variety of fuels.

Prototypes

73.    Several prototype hydrogen vehicles using fuel cells are under development. Japan is leading the commercial market with a small fleet of delivery trucks. BMW is developing vehicles which run on solar gathered pure liquid H_2, a process that is completely neutral to the earth’s environment. However, obstacles remain in hydrogen fuel cell technology - at present no major infrastructure exists to deliver H₂, and on-board storage is a problem.