Heat from the ground, however, can be used safely, countries such as Iceland geothermal energy heats up water in geysers and springs. This is used to drive steam turbines in electric generators. The hot water is also used to provide a domestic heating system by pumping it through pipes directly through houses. This is a renewable resource which does not produce pollution or have a great impact on the environment. Geothermal springs also provide a huge source of relaxation in some areas of the world such as (in the image) Iceland. Solar Energy:
Solar Heating Systems: Solar heating panels take up radiated heat from the sun and use it to heat water. They are placed to obtain as much light as possible from the sun. In the northern hemisphere, the must face south in order to achieve this and vice versa in the southern hemisphere. The composition of a classic solar heating panel is shown on the next page. Water is pumped through Copper pipes fixed into a copper sheet. Copper is used because it is an excellent conductor. The surfaces of the sheet and the pipes have a matt black finish in order
to absorb as much heat radiation as possible. The glass traps a level of air above the copper to help insulate the unit and preserve heat. The backing is also designed to stop heat escaping to the surroundings. This kind of panel is reasonably efficient and the energy produced is more cost effective than that of the photovoltaic cell that is described next. Solar heating panels are used widely to provide water heating. Curved mirrors can also be used to focus thermal radiation onto a boiler or pipes containing water in order to heat them up and so produce steam.
The produced steam may then be used to drive a turbine and generate electricity. Non-renewable Energy Sources: No-renewable energy sources, such as fossil fuels, will run out, in other words, once we have used them, it will take millions of years to replenish those resources. Fossil Fuels: Burning fossil fuels affects the environment, mainly by releasing CO2 into the atmosphere. CO2 is a greenhouse gas, this means that it traps the suns heat in the earths atmosphere and so cause the average temperature of the atmosphere to rise, and so hence the term global warming.
Burning coal releases more CO2 than burning oil or gas. Of the most commonly used fossil fuels, natural gas produces the least CO2 for the same energy output. There is no practical way of avoiding the release of CO2 into the atmosphere when burning fossil fuels. Most types of coal and oil contain sulphur, which, when burned produce sulphur dioxide which in turn is released into the atmosphere. Once in the atmosphere, it reacts with the water molecules that will form rain and so producing sulphuric acid.
When sulphuric acid is rained, it causes damage to everything it lands on, from people to buildings and plants. It is possible to remove the sulphur from its source in the coal and oil but this greatly increases the cost of the energy produced. Fossil fuels also provide valuable chemicals that can be used in the manufacture of a wide range of useful products, for example synthetic dyes and gore-tex, however once the fossil fuel has been burned, these useful chemicals are lost forever and so this can be looked upon as being wasteful. Nuclear Power:
Nuclear reactors use uranium 235 to produce energy, the isotope 235 is needed otherwise the nuclear process cannot proceed. Although a reactor only needs a small amount of uranium, the uranium source is highly limited. Uranium was formed in the unique conditions at the start of the universe so there is no way of increasing our supplies of the radioactive material and so it is non-renewable. Power generated by the nuclear process has the big advantage of being clean energy and so does not produce any greenhouse gases or other pollutant.
The cost per unit of electricity is very low but nuclear power stations are expensive to build. Two large drawbacks of nuclear power is the risk of accidents and the problem of disposing of the nuclear waste once it has been used. The release of uranium or plutonium into the atmosphere can cause long term risks to all living things, such as the nuclear explosion at Chernobyl rendering the area unusable for decades. Nuclear power stations can be seen in more economically developed countries such as France and America. The image shows a nuclear power plant in Springfield, America(! )