Energy Sources and Conservation

Solar power is also used in space, where the high-energy ultraviolet light wavelengths have not been filtered out by the atmosphere, to provide electricity for orbiting space vehicles.

Hydroelectric power (HEP) is electricity generated by moving water. Most HEP systems pipe water from reservoirs into water turbines, which is coupled to electricity generators. In pumped storage plants, water flowing through turbines is recycled.

HEP is an example of a renewable resource.

This is a photo of a working hydroelectric power plant.

Tidal energy is another renewable resource obtained from the tide. The tides mainly gain their energy from the gravitational forces acting between the Earth and the Moon. If water is trapped at a high level during high tide, perhaps by means of a barrage across an estuary, it may then be gradually released and its gravitational potential energy exploited to drive turbines and generate electricity.

Tidal energy contributes to another renewable resource, which is obtained by harnessing the energy of water waves, wave power. The British engineer Stephen Salter who developed the Duck, a floating boom whose segments nod up and down with the waves, introduced the first wave power scheme in 1974. Another device, developed in Japan, uses an oscillating water column to harness wave power. However, wave power hasn't the potential to be used around the world, as it won't contribute significantly to the world's energy needs.

Wind power can also be obtained as a renewable resource for the production electricity on a large scale by using wind turbines. Other simple, ancient ways of using wind energy are to sail ships and power windmills.

This is a photo of an

Operating wind turbine.

Wind turbines are

Usually found in large

Numbers.

A non-renewable resource is a natural resource, such as coal or oil, which takes thousands or millions of years to form naturally and can therefore not be replaced once it is consumed. The main energy sources used by humans are non-renewable. Non-renewable resources have high carbon content because of their origin lies in the photosynthetic activity of plants millions of years ago. The fuels release this carbon back into the atmosphere as carbon dioxide. The rate at which such fuels are being burned is resulting in rise in the concentration of carbon dioxide in the atmosphere.

Coal is a black mineral substance formed from the compaction of ancient plant matter in tropical swamp conditions. Coal burning is the main cause of acid rain. As a non-renewable resource, coal will eventually run out, and as an important industrial and domestic use, needs to be preserved.

Oil is composed mainly of carbon and hydrogen. Oils may solids or liquids. The three main types are essential oils, obtained from plants, fixed oils, obtained from animals and plants, and mineral oils, obtained mainly from the refining of petroleum. Essential oils are volatile liquids that have the odour of their plant source and are used in perfumes, flavouring essences, and in aromatherapy. Fixed oils are mixtures of lipids of varying consistency, found in both animals (i.e. fish oils) and plants (in nuts and seeds), they are used as foods and as lubricants, and in the making of soaps, paints and varnishes. Mineral oils are composed of a mixture of hydrocarbons, and are used as fuels and lubricants.

Natural gas is a mixture of flammable gases found in the Earth's crust. It is one of the world's three main fossil fuels along with coal and oil. Natural gas is a mixture of hydrocarbons. It is usually transported from its source by pipeline, although it may be liquefied for the transport and storage and is often used in remote areas where other fuels are scarce and expensive.

Nuclear fuels are another non-renewable resource. Nuclear energy or atomic energy is energy released from the inner core, or nucleus, of an atom. Electricity can be generated from the energy produced by nuclear fissions.

In nuclear power stations, fission takes place in a nuclear reactor. The nuclei of Uranium are induced to split releasing large amounts of heat energy. The heat is then removed from the core of the reactor by circulating gas or water, and used to produce the steam that drives alternators and turbines to generate electric power. Unlike fossil fuels, such as coal and oil, which must be burned in large quantities to produce energy, nuclear fuels are used in very small amounts and supplies are therefore unlikely to be exhausted in the future.

Edward Broom 10xh 21July 01