Crude oil (a non-renewable resource) is in underground areas called reservoirs. It is a yellowish-black liquid and is composed mainly of hydrocarbons and organic compounds. They can be 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.

We use the term ‘petroleum products’ after crude oil is refined in a factory.

Crude oil can exist either deep down in the earth’s surface or deep below the ocean beds. Oil drills mounted in the oceans are known as offshore drills.

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, the USA, Russia, China, and Iran are among the top crude oil producers in the world, and the 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 on 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 turbines or metal blades.
• The blades turn a generator containing wires and magnets, and a 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 then sent to homes, factories, and other places in the world.

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. It can also be processed into liquid products such as rubbing alcohol and nail polish. It can be also be processed into solids such as water pipes, shoes, wax and crayons, roofing, vitamin capsules, and many other items.

Because crude oil is liquid, it can spill during drilling. Spills from offshore drills and fuel tankers harm the environment a lot, especially marine life.