Fossil fuels power our cars, our power stations, our aircraft; they make possible certain things like rubber tires and plastic bags. In fact, in 2006, 86 per cent of all energy spent was from fossil fuels. Fossil fuels are formed from the fossilized remains of plant and animal matter. Exposed to pressure and heat in the earth’s crust for over hundreds of millions of years these fossils eventually became the fuels we use today, the most commonly used being petroleum, coal and natural gas.
Fossil fuels are non renewable sources of energy. This means that the reserves we have are finite. At the rate of extraction taking place today it will not be too long before the supply of some of these fossil fuels has been exhausted. Thus there is a big push to find renewable, clean energy sources; part of the rationale being that these new technologies are much better for the environment, the other being that we will still be energy-dependent once these supplies have gone.
While fossil fuels can be partially credited to the industrial explosion of last century, it is also true that from the rivers and lakes, to the upper atmosphere, they have brought great environmental harm.
Crude Oil & Petrol
Petroleum, or ‘crude oil’, is a flammable liquid found in rock formations in the earth’s crust. Although the figures for known reserves make the picture seem not so bleak, in reality many of the known reserves will stay in place once the cost of extraction exceeds the oil’s worth. This is called the Peak Oil theory. The tar sands of Canada (bitumen) and Venezuela’s extra heavy oil are difficult to extract, are much more expensive to refine than more conventional crude oils. Yet the known reserves of these two non conventional oils is almost double those of lighter crude oils. As the cost of a barrel of oil grows more expensive, the more enticing it becomes to refine these non conventional oils.
By volume, petroleum is mostly used for producing oil and gasoline. These in turn can be converted into fuels such as gasoline, diesel, jet fuels, heating oils and various other oils. Oil has become the primary source of energy since the 1950′s, thanks in part to its easy transportation, high energy density and relative abundance. Petroleum is also the raw material for many pharmaceuticals, fertilizers, plastic bags, et cetera. One liter of gasoline is the result of of about 23.5 metric tons of ancient organic material deposited on the ocean floor.
For the last two decades in particular, it has become clear that petroleum is a leading greenhouse gas contributor. Over the years oil tankers have broken apart at sea, creating vast, toxic coastlines. In our homes petroleum based materials give off-gas heavy toxins. It is for these reasons, amongst others, that alternative methods of fuel and transportation are being developed. From the hydrogen fuel cell to the electric car, many people are working very hard to wean us off petroleum.
Coal, a fossil fuel, and one of the leading generators of electricity worldwide is also most responsible for carbon dioxide emissions, surpassing even petroleum. Every week a new coal plant is built in china. Coal is mined from the ground either by underground mining, or by large open pit mines. The destruction to the surrounding landscape can be dramatic; sometimes entire mountains have been flattened.
Initially coal was used to help forge iron instruments and was also used for heating. Once all the easily accessible coal was used up, coal shafts were sunk around 1300 AD. When the industrial revolution took place, coal became the most important source of energy, since it was coal that drove the steam powered equipment. Worldwide production of coal in 2006 was 6.19 billion tons. Today coal accounts for 40 per cent of worldwide electricity production.
Coal plants have been increasing in efficiency, but even so, 65 per cent of the heat created goes back into the atmosphere as waste energy. There is one bright light in clean coal, a catch-all term highlighting ‘improvements’ in the use of coal for electricity. The improvements include, washing minerals and impurities from the coal by chemical, treating the flue gases with steam to reduce sulfur dioxide, and carbon capture and storage devices to capture the carbon dioxide from the flue gas. It has been estimated that commercially viable clean coal plants , with carbon capture and sequestration, won’t be available until 2025. Many however believe the term ‘clean coal’ to be an oxymoron.
Natural gas is a gas whose primary component is methane. It is often found in association with petroleum, where, being lighter it forms a cap over the gas. It is also often found in coal beds, bogs, marshes and landfills. Natural gas must undergo extensive processing, removing almost all other components but methane before it can be used as a fuel. The byproducts are ethane, butane and propane, and occasionally, helium and nitrogen.
Through the use of gas and steam turbines, natural gas is a major source of electricity production. Compared to oil and coal, natural gas burns cleaner than other fossil fuels and produces less carbon dioxide per energy unit released, thus making natural gas the cleanest fossil fuel available. Natural gas, coupled with fuel cell technology may eventually create cleaner options for turning natural gas into electricity but it is, as yet, not price competitive.
Natural gas is used in homes be it for heating or cooking or both. Natural gas also runs considerably cleaner than other fuels when applied to the automobile. Natural gas is also far more potent than carbon dioxide when released into the atmosphere, but, thankfully, the instances of this happening are so small as to keep the worry level down.
Future use of Fossil Fuels
It is evident that fossil fuels have led to incredible advancements in our society. But those advancements have come at a staggering cost. It is not exactly clear where to go from here. Every year politicians tell us we are going to cut our reliance on fossil fuels, and every year consumption increases. There are many promising new technologies only coming to light now. Many countries have come to see the benefits of wind or solar power and it is evident we will be seeing a lot more of these technologies in the future.
Fossil fuels may be the most readily available answer to power demands and fuel for transportation, but we can hope, for the sake of unpolluted rivers and skies and clean air, that there will be cleaner, more efficient options available soon.