How are Fossil Fuels Stored?

Identification

• Fossil fuels are aged materials leftover from the Carboniferous Period, which took place around 286 to 360 million years ago. The name Carboniferous refers to the element carbon, which is what fossil fuel materials are made of. Settled deep underground, fossil fuels are made up of trees and plants that were covered by sand and clay formations, according to Energy Quest, an educational resource site. Over time, they formed a soft peat layer that was eventually covered by layers of sedimentary rock. After millions of years, the compressed peat materials lost their moisture content, leaving the materials coal, oil and natural gas in their place.

Function

• The value of fossil fuels lies in the energy contained inside them. These materials are held together by hydrocarbon molecular bonds that release large amounts of energy when these bonds are broken, according to the University of Michigan. Solar energy is the original source of these bonds, obtained through photosynthesis processes while the trees and plants were living. Combustion, or the burning of fossil fuels, provides the means for releasing these stored energy reserves. Through combustion, heat and light energy can be converted into usable forms.

Natural Gas

• As a non-solid, the physical makeup of natural gas allows for a variety of different storage methods. The most common method of storage is in underground formations, according to the U.S. Department of Energy. Reservoirs that once held oil, or natural water-bearing rock formations, can serve as storage areas for natural gas. Within the United States, there are approximately 400 underground storage areas containing up to four trillion cubic feet of gas. These storage facilities are situated near major natural gas markets within the United States.

Oil

• Oil storage facilities within the United States are located along the Gulf Coast around the Texas and Louisiana coastlines, according to the U.S. Department of Energy. Also known as strategic petroleum reserve storage sites, emergency supplies of crude oil are contained within area salt caverns. These areas provide a secure location that's easily accessible to the nation's commercial oil transport network. The reserve is made up of 62 underground caverns, with each capable of housing anywhere from 6 to 35 million barrels of oil.

Coal

• As the most abundant fossil fuel type on hand, the United States provides an estimated 27 percent of global coal reserves, according to the Office of Indian Energy and Economic Development. Coal storage facilities, or coal mines, are present in the Appalachian and Gulf Coast regions, throughout the West and Midwest and along the Great Plains. Mining sites are located underground, and contain the facilities needed to handle and store coal supplies, as well as areas for waste disposal. Sites vary in size depending on the type of mining done--underground versus surface mining--and the amount of coal being stored.