What are fossil fuels?
The three most common and widely used fossil fuels are coal, natural gas and oil. Fossil fuels are used to generate energy for electricity and heat.
They are formed by the decomposition of prehistoric animals and plants that died millions of years ago.
Combined, they provide around 66% of electrical power to the world, and in total, over 90% of the world’s energy is generated from fossil fuels.
Fossil fuels are classed as non renewable resources. Although, technically speaking they are renewable – but take millions of years to be produced.
In 100 years time, it’s expected that the scarce supply will be too difficult and expensive to excavate.
The burning of fossil fuels for energy contributes to 21.3 billion tonnes of the global carbon dioxide emitted. Only half of that can be absorbed by natural processes.
The other half is having a huge effect on global warming.
This is why government organisations are trying to reduce the need for fossil fuels and are promoting renewable sources for your home.
Renewable energy includes solar, wind, hydro and geothermal. This type of energy is free to collect, and cuts down on poisonous carbon and sulphur dioxide emissions.
How are fossil fuels used?
Coal is mined from the ground, which can be both dangerous and expensive. It is then crushed to fine dust and used to generate either electricity or heat through combustion.
The heat generated from the furnace is transferred to boiler water, which converts to steam. This steam is then used to power turbines, which generate the electricity.
Coal can also be liquefied through hydrogenation or carbonisation to create gasoline and diesel.
Coal provides 28% of the world’s energy needs, and 40% of electricity comes from this fossil fuel.
By 2030, it’s expected that the annual consumption of coal will hit 9.98 billion short tons, up 48% from today’s usage. (One short ton equals 2,000 pounds in weight).
However, it has serious drawbacks. The burning of coal produces sulfur dioxide which is an acidic gas.
This in turn is partly responsible for acid rain. Acid rain is notorious for its damaging effects on marine animals, infrastructure and plant life.
However, the amount of sulfur dioxide emitted can be reduced through desulfurisation. This chemical reaction takes place in a flue, before the gas is released into the atmosphere.
As a polar opposite of coal, oil is easier to exhume and cheaper to transport. This is because it can simply travel through a pipe network out of the ground.
Oil can be used to generate heat and electricity for energy purposes, while also having a place in household products.
Two examples where oil is found in the home, is in hair products and painting materials.
Oil is, however, most notoriously used as petroleum or diesel for vehicles.
For fuel purposes, the oil is pumped from the ground and transported to an oil refinery, where it is converted from its original state (crude oil).
Crude oil can be altered to become gasoline, diesel, kerosene, ethane and other heavier commercial fuels.
To generate electricity, oil is burnt in a similar way to coal. During the combustion stage, gas is produced, turning the turbines. This subsequently generates electricity.
The final fossil fuel to be explained is natural gas. It’s primarily methane and there are two ways that it would have been created. These mechanisms are biogenic and thermogenic.
Methane filled organisms from landfill sites, bogs and marshes produce biogenic gas. While thermogenic gas is created by organic matter much deeper in the Earth’s crust, under greater pressure and temperature.
However, before either can be used as fuel, they have to be cleansed of almost all other materials excluding methane.
When cleaned, natural gas can be burnt in power stations to produce electricity, or fed through the gas network to people’s homes.
Natural gas covers 20% of the word’s energy consumption and is the fossil fuel with the least damaging effect on the environment.
Other fossil fuels
There are a number of other fossil fuels that are being looked into, as the supply of the big three (coal, gas and oil) dwindles.
However, because of the expensive processing they’d have to undergo, they’ve not yet hit the global market.
These other fuels include bituminous (tar) sands and oil shale.
Bitumen is a stickier form of crude oil, while also being viscous and heavy in nature. It is refined in the same manner as crude oil, but turned into synthetic oil (syncrude).
This is because it’s too expensive to convert into gasoline or diesel. However, Canada and Venezuela have large areas of tar sands, so it’s economical for both countries to use bitumen for energy.
Benefits of fossil fuels
While the UK government is trying to cut carbon emissions created from the burning of fossil fuels by 2020, there are some advantages to these fuels.
- Fossil fuels can generate a lot of electricity, quickly and cheaply.
- Fossil fuel sites are scattered all around the world. They’re easy to find and are normally beneath the seabed or Earth’s crust.
- The excavation of gas and oil from the ground and transportation to refineries is cheap and easy. Sometimes it can be taken through a pipe network.
- Power stations run by natural gas are very efficient.
- Power stations catering for fossil fuels can be built and run anywhere. They do not rely on a renewable source, such as wind.
Drawbacks of fossil fuels
The world has really started to take notice of renewable energy. It’s free to use, cuts your carbon footprint, and saves you money on your bills.
With the government’s intention that renewable sources should replace fossil fuels as the chief energy suppliers, what is so wrong with the current setup?
- First and foremost, the burning of fossil fuels for energy has a huge contribution to the globe’s pollution problem.
- Coal burning produces more carbon dioxide emissions than gas and oil, but all three chip in to worsen the greenhouse effect. This contaminates the atmosphere and is partly responsible for the hole that’s appeared in the ozone layer over the Antarctic.
- The burning of coal also produces sulfur dioxide, which, along with nitrogen oxides, is an ingredient of acid rain. Acid rain has a damaging effect of plant life, aquatic animals and infrastructure.
- Coal mining is also extremely difficult and dangerous. Only last year, a collapsed mine in Chile trapped 33 people for over two months.
- The mining of coal can also destroy large areas of landscape during excavation.