Energy Resources

In the 19th century, coal became the leading source of heat energy in countries undergoing industrialization. Trains and ships were fuelled by coal, and coke, made by baking coal at incredibly high temperatures, was used in the manufacture of iron and steel. Because of the problems of transporting coal in the early years of the Industrial Revolution, industrial towns grew up around coalfields in places such as Selby, in North Yorkshire, and Cardiff, in Wales. With the introduction of oil and natural gas, which are far easier to transport than coal, industries could be established anywhere. Fossil fuels now account for nearly 90 per cent of the commercial energy, or energy that is sold to the public, used throughout the world, with hydroelectric power and nuclear energy supplying most of the rest.

Fossil fuels are non-renewable energy resources which are being used up far faster than they can be formed. In the future, they will become increasingly scarce and will eventually run out. In the mid-1990s, experts estimated that the proven reserves of petroleum would, at current rates of production, supply the world for 43 years. The reserves of natural gas were estimated to last for 66 years, while known coal reserves would be sufficient for 235 years at current production levels. Such figures must be treated with caution, since rates of demand and production change. Furthermore, such forecasts do not take account of new discoveries that periodically increase the proven reserves. As reserves of non-renewable resources decline, so costs will rise. For this reason, other methods of producing heat energy have been developed, notably hydroelectricity and nuclear energy, while others are under investigation.

Hydroelectric Power

Unlike fossil fuels, hydroelectricity is a renewable resource which is inexpensive once the initial construction costs have been recovered. It is also a clean form of energy, though environmentalists argue that rotting vegetation in the reservoirs behind dams produces substantial amounts of greenhouse gases, which contribute to global warming. Also, the construction of dams and reservoirs destroys natural habitats and uproots animals and people. In addition, the construction of China's Three Gorges Dam on the Yangzi will displace more than one million people by the time it is completed in 2009.

Nuclear Power

Nuclear power has disadvantages too. The stations take ten or more years to build and the capital outlay is high. Although costs vary from country to country, recent studies have suggested that the cost of electricity generated by nuclear power stations is more expensive than that generated by fossil fuels. Nuclear power stations also produce dangerous wastes that can remain radioactive for hundreds of years. The safe disposal of these wastes still constitutes an unresolved problem for the nuclear power industry. Nuclear accidents, such as the 1986 fire at Chernobyl’ station in Ukraine, have also damaged the image of the nuclear energy industry, and, under pressure from public opinion, some countries have begun to close down their stations. In 1980, a referendum in Sweden called for the phasing out of nuclear power by 2010.

Renewable Energy Sources

Solar energy is now used to power space stations, calculators, watches, and PV cells ( photovoltaic cells), which are semiconductor devices that generate electricity directly from sunlight, now bring power to homes in parts of Africa and South America. The cost of PV modules (clusters of PV cells) has plummeted since the 1970s. A number of multinational companies have become involved in promoting the development of solar energy, and in some cases are also investing in the planting of virgin forests in developing countries to revive the use of wood as a source of heat energy.

Wind power is another form of renewable energy. The building of large wind turbines to exploit this power has been extremely costly, and in California, which has half of the world's grid-connected capacity, subsidies have been necessary to operate the wind turbine systems. More recently, reports suggest that the best plants are close to becoming competitive with fossil fuels. Neither solar nor wind power are perfect, because the sun sometimes fails to shine and winds fail to blow, but if these forms of energy are used as part of a grid system incorporating other forms of energy, then fluctuations in output could be accommodated.

Tidal power is generated by trapping tidal waters behind a dam and then releasing them to drive turbines. The output of power is relatively small. This type of energy was first harnessed in 1968 in the estuary of the River Rance in northern Brittany, but it caused major environmental problems in the estuary. Research into harnessing energy from the constant up-and-down movement of waves in the sea has also been carried out, but the production of competitively priced heat energy from wave movements currently seems a distant prospect.

Another more practical area of development is the use of geothermal energy. At present, this form of energy is suitable only where hot rocks are close to the surface, as in areas with geysers. Volcanically active locations in Iceland, Italy, New Zealand, and the United States already have geothermal plants. Other methods of generating energy include the burning of waste products and the conversion of organic wastes, such as sewage, to produce methane which can be used as a fuel.

Some attempts to develop energy sources have proved to be uneconomic. In the 1970s, Brazil began a programme to produce ethanol (ethyl alcohol) from sugar cane. By 1983, with the use of massive subsidies, about 90 per cent of Brazilian cars were designed to be fuelled by alcohol. Unfortunately the project has proved to be expensive, because ethanol cannot not compete with petrol. The main benefit is that the use of ethanol-powered vehicles has reduced levels of air pollution in Brazil's cities. In the pursuit of a pollution-free transport system, the development of electric cars is an enticing prospect. But nobody has yet solved the problem that the batteries to power these cars must be large and need constant, time-consuming recharging in order to travel distances far shorter than those covered by conventional cars on one tank of petrol.

In 1996, the International Energy Agency (IEA) predicted that fossil fuels would still provide almost 90 per cent of energy needs by 2010. Thereafter, modern renewable sources could become increasingly important, provided that additional expenditure on research and development is available. None of the proposed sources of renewable energy are completely satisfactory. However, with all the problems of pollution associated with fossil fuels, and the fact that 40 per cent of the world's population still has no access to electricity, the search for economic forms of alternative energy has become a matter of urgency.