Fossil fuels By S.M. Enzler MSc
Characteristics, origin, applications and effects of fossil fuels
Humans need energy for just about any type of function they perform. Houses must be heated, energy is required for industry and agriculture and even within our own bodies a constant flow of energy takes place. All processes that provide us with the luxuries of every day live we can no longer live without require energy generation. This is an industrial process that can be performed using various different sources. These sources can be either renewable or non-renewable. Renewable energy sources are replaced in time and will therefore not run out easily. However, non-renewable energy sources are threatening to run out if our standard of usage becomes too high.
Nowadays many renewable energy sources are available for use, for example solar and wind energy and water power. Ironically, we still gain most of our energy from non-renewable energy sources, commonly known as fossil fuels (figure 1). The non-renewability of these sources will probably cause prices to rise up to a point where they are no longer economically feasible.
Fossil fuels consist of deposits of once living organisms. The organic matter takes centuries to form. Fossil fuels principally consist of carbon and hydrogen bonds. There are three types of fossil fuels which can all be used for energy provision; coal, oil and natural gas. Coal is a solid fossil fuel formed over millions of years by decay of land vegetation. When layers are compacted and heated over time, deposits are turned into coal. Coal is quite abundant compared to the other two fossil fuels. Analysts sometimes predict that worldwide coal use will increase as oil supplies become scarcer. Current coal supplies could last for 200 years or more. Coal is usually extracted in mines. Since the middle of the 20th century, coal use has doubled. Since 1996 its application is declining again. Many developing countries depend on coal for energy provision because they cannot afford oil or natural gas. China and India are major users of coal for energy provision.
Energy gained from burning fossil fuels is converted to electricity and heat in commercial power plants. When fossil fuels are burned carbon and hydrogen react with oxygen in air to carbon dioxide (CO2) and water (H2O). During this reaction heat is released which further amplifies the reaction. Electricity is generated by transforming mechanical energy (heat) to electrical energy in a turbine or generator. Power plants are very expensive to build, but once they are present efficiency in converting fuel to energy is very high. Most of the time more electricity is created than is actually needed, because electricity cannot be stored. Electricity demands vary throughout the year and provision must meet the peak load, which means the highest possible demand within a year. If demands significantly exceed a power plant's capacity to generate energy this may cause temporary blackouts.
Historically, fossil fuels were available in plentiful supply that was easy to obtain and transport. But now signals are given that the supply is running out and that it will take centuries to be replenished. Both sources and sinks of fossil fuels are limiting in their use. Sources are deep earth layers and sinks are for example air and water, which absorb fossil fuel waste products.
Why than are we still using fossil fuels to such a large extend? The answer is simple; because this is cheaper than any type of reasonable alternative we now know. Some environmental scientists predict that fossil fuel prices will increase in the coming century because of scarcity. This may cause an eventual transfer to renewable energy sources. According to Bjorn Lomborg, this will eventually happen. The IPCC is not sure whether a fossil fuel future can be entirely ruled out.
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