Fossil Fuels - Energy Transformation

Introduction to Energy Transformation

A fuel is a substance that provides a form of energy (such as heat, light, electricity, or motion) as a result of a chemical change.
This change from one form of energy to another is called energy transformation.
When fuels are burned, the released chemical energy can be used to generate other forms of energy, including heat, light, motion, or electricity.
The process of burning a fuel is known as combustion.

Most of the energy used today comes from fossil fuels.
Fossil fuels are energy-rich substances formed from the remains of once-living organisms.
Over millions of years, layers of sand, rock, and mud buried dead organisms. Heat and pressure transformed these materials into fossil fuels.
The three major fossil fuels are coal, oil, and natural gas.
Fossil fuels are composed of hydrocarbons, which are energy-rich chemical compounds containing carbon and hydrogen atoms.

Coal

Coal is a solid fossil fuel that forms from decaying plant matter.
Known deposits of coal and other fossil fuels that can be obtained using current technology are called reserves.
Coal is the most plentiful fossil fuel in the United States.
It is relatively easy to transport and provides a lot of energy when burned.
However, coal mining can lead to erosion and water pollution.
When burned, most types of coal cause more air pollution than other fossil fuels.
Coal mining can also be a dangerous job.

When lignite is buried deeper for a significant period, increased pressure and temperature transform it into a harder, more superior type of coal with a higher percentage of carbon.
As temperature and the amount of time the coal was buried increased, soft black bituminous coal and then hard black anthracite coal (the highest rank) were formed.

Oil, also known as petroleum, is a thick, black liquid fossil fuel.
Oil is formed from the remains of small animals, algae, and protists.
Most oil deposits are found deep beneath the Earth's surface.
Oil pumped from the ground is called crude oil.
A refinery is a factory where crude oil is separated into various fuels and other products by heating.
Petrochemicals are compounds made from oil.

Oilfields and gas fields are formed where an impermeable layer of rock prevents the migration of oil and natural gas, allowing them to accumulate gradually.

Natural gas is a mixture of methane and other gases.
It forms from the same organisms as oil.
Being less dense than oil, natural gas often rises above an oil deposit, creating a pocket.
Natural gas produces lower levels of many air pollutants compared to coal or oil and is fairly easy to transport.
However, natural gas is highly flammable, and a gas leak can cause a violent explosion and fire.

People currently rely heavily on fossil fuels.
Fossil fuels are considered nonrenewable resources because they take hundreds of millions of years to form.
They are being used at a rate faster than they are formed.
New energy sources are needed to replace the decreasing fossil fuel reserves.