Non-renewable energy

Non-renewable energy comes from sources that will run out or will not be replenished in our lifetimes—or even in many, many lifetimes. 

Most non-renewable energy sources are fossil fuels: coal, petroleum, and natural gas. Carbon is the main element in fossil fuels. For this reason, the time period that fossil fuels formed (about 360-300 million years ago) is called the Carboniferous Period. 

All fossil fuels formed in a similar way. Hundreds of millions of years ago, even before the dinosaurs, Earth had a different landscape. It was covered with wide, shallow seas and swampy forests. 

Plants, algae, and plankton grew in these ancient wetlands. They absorbed sunlight and created energy through photosynthesis. When they died, the organisms drifted to the bottom of the sea or lake. There was energy stored in the plants and animals when they died.

Over time, the dead plants were crushed under the seabed. Rocks and other sediment piled on top of them, creating high heat and pressure underground. In this environment, the plant and animal remains eventually turned into fossil fuels (coal, natural gas, and petroleum). Today, there are huge underground pockets (called reservoirs) of these non-renewable sources of energy all over the world.

Advantages and Disadvantages

Fossil fuels are a valuable source of energy. They are relatively inexpensive to extract. They can also be stored, piped, or shipped anywhere in the world.

However, burning fossil fuels is harmful for the environment. When coal and oil are burned, they release particles that can pollute the air, water, and land. Some of these particles are caught and set aside, but many of them are released into the air.

Burning fossil fuels also upsets Earth’s “carbon budget,” which balances the carbon in the ocean, earth, and air. When fossil fuels are combusted (heated), they release carbon dioxide into the atmosphere. Carbon dioxide is a gas that keeps heat in Earth’s atmosphere, a process called the “greenhouse effect.” The greenhouse effect is necessary to life on Earth, but relies on a balanced carbon budget.

The carbon in fossil fuels has been sequestered, or stored, underground for millions of years. By removing this sequestered carbon from the earth and releasing it into the atmosphere, Earth’s carbon budget is out of balance. This contributes to temperatures rising faster than organisms can adapt.

Coal

Coal is a combustible rock of organic origin composed mainly of carbon along with variable quantities of other elements, chiefly hydrogen, sulfer, oxygen and nitrogen. It is a sedimentary rock formed from accumulated vegetable matter that has been altered by decay and by various degrees of temperature and pressure over millions of years. Interlayered with other sedimentary rocks, it forms beds ranging from less than a millimetre to many metres thick. The considerable diversity of coal type, grade and rank depends on the differences in mode of formation.

Black coal is so called because of its colour. It varies from having a bright, shiny lustre to being very dull, and from being relatively hard to soft. The term 'black coal' is used in Australia to refer to anthracite, as well as bituminous and sub-bituminous coals (Table 3.7). Black coal is higher in energy and has lower moisture content than brown coal. Brown coal, also called lignite, is a low-ranked coal with high moisture content that is used mainly to generate electricity.

Oil

The term oil encompasses the range of liquid hydrocarbons and includes crude oil and condensate:

• Crude oil is a naturally-occurring liquid consisting mainly of hydrocarbons derived from the thermal and chemical alteration of organic matter buried in sedimentary basins. It is formed as organic-rich rocks are buried and heated over geological time.
• Condensate is a liquid mixture of pentane and heavier hydrocarbons found in oil fields with associated gas or in gas fields. It is a gas in the subsurface reservoir, but condenses to form a liquid when produced and brought to the surface.

Australia has about 0.3 per cent of the world oil reserves. Most of Australia’s known remaining oil resources are condensate and liquefied petroleum gas (LPG) associated with giant offshore gas fields in the Browse, Carnarvon and Bonaparte basins. In addition oil resources are identified in the Perth, Canning, Amadeus, Cooper/Eromanga, Bowen/Surat, Otway, Bass and Gippsland basins.

Uranium

Australia does not have any nuclear power reactors and there are currently no plans for Australia to have a domestic nuclear power industry. Australia exports all of its uranium to countries within its network of bilateral safeguards agreements, which ensure that it is used only for peaceful purposes and does not enhance or contribute to any military applications. Australian mining companies supply uranium under long-term contracts to electricity utilities in the United States of America, Japan, China, the Republic of Korea, Taiwan and Canada as well as members of the European Union including the France, Germany, Sweden and Belgium. Since 2007, Australia has negotiated bilateral safeguards agreements for the export of uranium to China, Russia and the United Arab Emirates and, in December 2011, negotiations commenced with India on a bilateral safeguards agreement.

Gas

• Natural gas is formed when accumulations of organic matter are buried and exposed to increasing heat and pressure over geological time. The generated gas consists of a mixture of methane and often other heavier hydrocarbons, as well as other gases including carbon dioxide, nitrogen, hydrogen sulphide and helium.
• Liquefied natural gas (LNG) is a natural gas that has been cooled to minus 162°C, a process that is commonly done for gas export purposes as it reduces the volume of the transported gas.
• Australia has substantial conventional gas resources, the largest of which are located offshore, and significant onshore unconventional gas resources.
• Australia is the seventh largest gas producer in the world.
• Exports of LNG have increased significantly over the past decade, with several new facilities commencing production including Wheatstone, Ichthys and Prelude. In 2020, Qatar and Australia were the world’s largest LNG exporters.