Energy and the Environment

Energy Consumption

For centuries, mankind has obtained energy by burning things. In the earliest days, people burned wood or other plant or animal matter (called 'biomass'). It is estimated that even today, nearly half the world's population relies on biomass for its fuel.

Coal was almost certainly burned by the Chinese some 2,000 years ago, but it is only in the last few hundred years that coal has become an important source of energy on a global scale and a major source of energy in generating electricity. Reserves of oil and gas have been developed only within the last hundred or so years.

However, there are three major problems in relying on fuels such as coal, oil and gas:

1. the reserves of these fuels are not evenly distributed;
2. supplies will eventually run out; and
3. fossil fuels are an important and scarce resource necessary for the making of chemicals, fertilisers and plastics.

A country's demand for energy does not only depend on how much fossil fuel the country has, but on its ability and desire to use its energy resources for industrial and domestic purposes. As economies develop, the demand for energy rises dramatically and more of their fossil fuels are used up; much of them in the generation of electricity.

Thus India, with 20% of the world's population, uses only 2% of the world's energy. In the USA, on the other hand, 6% of the world's population uses about 30% of the energy. India might well develop to use more of its fossil fuel, but will America be able to use less? Can countries such as India progress without using more coal? Can a country such as America develop other energy resources to reduce its dependency on coal and oil?

World Energy Needs

In 2008, world energy consumption not met by biomass was supplied from other sources in the following percentages:¹

Renewable and non-Renewable

Most power stations today need to burn fuel. They heat water until it turns to steam, and this steam drives a turbine which powers a generator to produce electricity.

The fossil fuels - coal, gas and oil - are 'non-renewable'. When we have used them all up, we cannot make any more. There are various predictions about how much of each fuel we have left. However, it is believed that oil reserves could run out in as little as 30 years if current rates of consumption do not fall. Reserves of gas are likely to be exhausted by the middle of the century and, while coal reserves still remain, they could be used up in a few hundred years at most.

Years of production left in the ground with the most optimistic proved reserve estimates.²

• Oil: 43 years (43 years using 2006 levels and flows)
• Gas: 167 years (61 years using 2006 levels and flows)
• Coal: 417 years (148 years using 2006 levels and flows)

Much of the coal, oil and gas which we use today is burned to produce electricity, leading to certain environmental effects.

The 'renewable' methods of generating electricity include wind power, solar power, wave and tidal power, geothermal energy and hydropower. They are called renewable because the winds will blow and the tides will rise and fall for many years to come.

To use renewable sources of energy may be more friendly to the environment. Renewable sources do not rely on burning fuels. They therefore do not pollute the atmosphere with carbon dioxide, sulphur dioxide or oxides of nitrogen. Using the Sun, the wind, or the waves to provide energy means that we are not using up scarce natural resources.

However, the contribution of renewable energy sources to the world's energy needs is still small. These methods of producing electricity are discussed in more detail in the Environmental Impacts section.

Electricity from Nuclear Power

Within the last 50 years, nuclear energy has become increasingly important in generating electricity. At its peak in 1997, 26% of the nation's electricity was generated from nuclear power. Nuclear power now contributes about 13% of the UK's electricity needs. In France, the figure is over 75%.³

In many ways, a nuclear power station operates in the same way as coal or gas-fired power stations. Water is boiled and turned to steam. This steam is used to drive a turbine and generator which makes electricity. The major difference is in the type of fuel which is used.

A nuclear power station relies on a controlled chain reaction among atoms of uranium.

Uranium atoms are the largest natural atoms and, when a small particle called a neutron strikes the centre of some uranium atoms, the atoms split apart giving off heat and more neutrons. These neutrons collide with other similar uranium atoms in the reactor and produce more heat and neutrons. This splitting of an atom is called nuclear fission.

Nuclear power stations use fuel manufactured from uranium which is found in many places including North America, Australia, Africa and Russia. Although supplies of uranium are finite, the fuel from nuclear power stations can be recycled (after 'reprocessing'). Unlike coal or oil, uranium can only be used for generating heat.