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What is non-renewable energy?
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Energy exists freely in nature. Some of them exist infinitely (never run out, called RENEWABLE), the rest have finite amounts (they took millions of years to form, and will run out one day, called NON-RENEWABLE).
Non-renewable energy is energy from fossil fuels (coal, crude oil, natural gas) and uranium. Fossil fuels are mainly made up of Carbon. It is believed that fossil fuels were formed over 300 million years ago, when the earth was a lot different in its landscape. It had swampy forests and very shallow seas. This time is referred to as ‘Carboniferous Period‘
Fossil fuels are usually found in one location as their formation is from a similar process. Let us take a look at the diagram below to see how fossil fuels are formed:
1. Millions of years ago, dead sea organisms, plants and animals settled on the ocean floor and in the porous rocks. These organic matter had stored energy in them as they used the sun’s energy to prepare foods (proteins) for themselves (photosynthesis).
2. With time, sand, sediments and impermeable rock settled on the organic matter, trapping its’ energy within the porous rocks. That formed pockets of coal, oil and natural gas.
3. Earth movements and rock shifts creates spaces that force to collect these energy types into well-defined areas. With the help of technology, engineers are able to drill down into the sea bed to tap the stored energy, which we commonly know as crude oil.
The good thing is about fossil fuels is:
Unlike many renewable sources of energy, fossil fuels are relatively less expensive to produce. This is probably why it is in higher demand as it tend to cost less.
The bad thing about fossil fuels is: Fossil fuels are made up mainly of carbon. When they are burned (used) they produce a lot of carbon compounds (carbon dioxide and other greenhouse gases) that hurt the environment in many ways. Air, water and land pollution are all consequences of using fossil fuels.
In the pages that follow, we shall take a look at what each source of non-renewable energy is made of, and how they are used.
Note that not all non-renewable energy comes from fossil fuels. There is also uranium, which is not a fossil fuel.
What is coal?
Coal is a combustible black or brownish-black sedimentary rock composed mostly of carbon and hydrocarbons.
Coal is made of the remains of ancient trees and plants that grew in great swampy jungles in warm, moist climates hundreds of millions of years ago. The chemical and organic process these dead organisms undergo to become coal is known as Carbonization. Coal is ranked very high if is has undergone a longer carbonization period. An example is Anthracite. Coal that has not undergone too much carbonization is ranked low, and an example is Peat.
How is coal converted into electricity?
Let us take a look at the diagram below:
1. Coal is milled to a fine powder, allowing it to burn more quickly. It is blown into the combustion chamber of a boiler where it is burnt at high temperature.
2. The hot gases and heat energy produced converts water in tubes lining the boiler into steam.
3. The high-pressure steam is passed into a turbine containing thousands of propeller-like blades. The steam pushes these blades causing the turbine shaft to rotate at high speed. The steam is condensed and returned to the boiling chamber where it is heated again.
4. The shaft rotation engages the wire coils and magnets in a generator connected to it. This charged magnetic field produces electricity
5. Electricity is sent to the switchboard (transformer) where it is regulated and sent via on-land cables to homes.
Using coal to produce energy causes many some problems, usually on a greater scale than the use of oil or gas. These problems include acid rain, sulfur oxide emission, carbon dioxide emission, poorer land, hazardous waste and others.
Several forms of coal exist in the world. Anthracite, bituminous coal, lignite, and sub-bituminous coal are all different types that are used by humans.
What is Petroleum (Crude Oil)?
Crude oil (a non-renewable resource) is usually found in underground areas called reservoirs. It is liquid in nature and yellowish black in colour. They are composed mainly of hydrocarbons and organic compounds. They are usually discovered by oil prospecting scientists.
Sometimes, petroleum and crude oil are used to mean the same thing, but petroleum itself is a broad range of petroleum products including crude oil itself.
We use the term ‘petroleum products after crude oil is refined in a factory.
Crude oil can exists either deep down in the earth’s surface or deep below the ocean beds. Oil drills mounted in the oceans are known as offshore dills
In oil drilling, a structure called ‘derrick’ is built with pipes going down to the reservoir and bringing the oil to the surface.
Saudi Arabia, USA, Russia, China and Iran are among the top crude oil producers in the world, and USA is the world’s biggest consumer of crude oil, followed by China. (source: USEIA)
The process of generating electricity from crude oil is very similar to that of thermal coal, which we saw in the previous page.
Below is a summary of the process that turns crude oil into electricity:
Oil is burnt in turbines in power stations to produce extreme heat, which is used to create high-pressure steam.
This steam is used to spin a turbine very fast by pushing against metal blades.
The blades turn a generator containing wires and magnets and magnetic field produces electricity.
The electricity flows to a transformer, which changes it to very high voltage electricity. The transformer also regulates the amount of electricity that is produced and supplied.
Electricity is sent to homes, factories and other places in the world.
But Crude Oil can be used for other things too:
A great chunk of all the total crude oil in the world is processed as gasoline, which we use for our cars. They can also be processed into liquid products such as rubbing alcohol, or solid products such as nail polish, water pipes, shoes, wax and crayons, roofing, vitamin capsules, and many other items.
Because crude oil is liquid in nature, spills from offshore drills and fuel tankers harm the environment a lot, especially marine life. Here are some facts on sme disasters that occured as a result of minng for crude oil… CLICK HERE
What is Natural Gas?
Natural Gas is colorless, shapeless, and odorless in its pure form. Unlike other fossil fuels, natural gas is clean burning and emits lower levels of potentially harmful byproducts into the air. It is therefore called “Clean Gas’.
While natural gas is formed primarily of methane, it can also include ethane, propane, butane and pentane. It is one of the gases that are formed by the same formation of fossil fuels.
The main ingredient in natural gas is methane, a gas (or compound) composed of one carbon atom and four hydrogen atoms.
Natural gas supplies about 23.8 percent of the world’s energy. Gas is extracted by drilling wells deep into the ground, through many layers or rock to reach the gas deposits.
Natural gas comes in two main types: The first and conventional type is found in permeable sandstone reservoirs. The second, unconventional types are found in other places such as in coal deposits (eg. Coal Steam Gas, CSG) or shale rock formations (eg. Shale Gas)
In recent time, shale gas has become very popular in the USA and is mainly drilled by a process called Hydraulic Fracturing (fracking). It is popular because its carbon emission is about half that of coal, and is seen as environmentally friendlier. The USA is known to be the world’s largest producer of shale gas.
“The International Energy Agency currently estimates that global recoverable shale gas resources stand at 7,345 trillion cubic feet, so it’s conceivable that this resource could one day offer similar benefits to other countries”. Source: Chevron
Similar to other energy types, natural gas is burned to produce pressurized gas that spins the blades of turbines. The spinning causes some metal coils and magnets in a generator to produce electrical current, that is connected to a transformer and further supplied to homes.
What is Propane?
Propane is an energy-rich gas. Its chemical formula is C3H8.
It is one of the liquefied petroleum gases (LPGs) that are found mixed with natural gas and oil. Propane and other liquefied gases, including ethane and butane, are separated from natural gas at natural gas processing plants, or from crude oil at refineries. The amount of propane produced from natural gas and from oil is roughly equal.
LPG provides a convenient means of powering heating, cooking and other processes, regardless of where your home is located.
How does LPG compare with other fuels?
LPG produces no harmful or dangerous waste
LPG, when burned, produces less CO2 than coal and oil
LPG burns cleanly with no soot and very few SO2 and NOx emissions
LPG poses no ground and water pollution hazards
LPG delivers significant fuel cost savings, and is approximately 50% cheaper than diesel
LPG is a by-product so there is no wastage
LPG boilers are cheaper to install than oil boilers and less expensive to maintain
LPG can be used alongside renewable technologies (Source BP)
What is Uranium (Nuclear Energy)?
Nuclear energy is energy in the nucleus (core) of an atom. Atoms are tiny particles that make up every object in the universe. There is enormous energy in the bonds that hold atoms together.
It is usually in a form of heavy metal, naturally occurring in most rocks, soil, and even in the ocean! It is found in many places in the world. Energy from uranium is called nuclear energy.
Power generated from nuclear reaction is similar to that of fossil fuels because they all use heat to turn blades (turbines) to generate power.
A nuclear power plant uses uranium as fuel. Uranium pallets are combined into large fuel assemblies and placed in a reactor core.
In that chamber (reactor), uranium atoms can be made to split, or fission, to release heat. ‘Fission’ is the process of splitting the uranium atom to form smaller atoms. A kilogram of natural uranium produces as much heat as 20 tonnes of coal. This is harnessed to make steam and generate power.
Uranium was first discovered by a German Scientist called Martin Klaproth in 1789. The chamber in which the fission takes place is called a Reactor. In this reactor, uranium fuel is assembled in such a way that a controlled fission chain reaction can be achieved.
It is believed that Uranium was named after the planet Uranus, and it provides the main source of heat inside the earth. Uranium (say: yoo-ray-nee-um) is NOT a fossil fuel. As of 2013, there are over 430 nuclear power reactors in 30 countries and many more are being built.
CO2 emissions from nuclear fuel is very low, even lower than hydro-power. Nuclear power plants are very expensive to build. It also produces very dangerous waste in the form of radio-active waste, even though the amount of waste is small (about 3% of the plants waste). These are usually disposed of very deep underground where geological conditions are stable and far from human or environmental exposure.
In 2011, a tsunami struck Japan and caused problems with its nuclear power plant in Fukushima. After that tsunami, there has been a couple of leakages of highly radioactive water from the plants storage tanks into its environment. Radioactive materials are very dangerous to humans and the environment.
There are laws that check that countries with unclear plants comply with safety rules and also do not misuse their plants for developing nuclear weapons.