Fossil fuels Fossil fuels include petroleum , coal and natural gas . Petroleum is the primary fuel used in electricity production in the United States . It is obtained by drilling a hole approximately one meter in diameter and inserting a steel pipe . A drill bit with a pipe , referred to as a drill collar , is used to cut through the rock . A drill string is attached to the bit and is extended as the well becomes deeper . Once the hole is drilled , steel pipe , or casing , is inserted . A drilling rig is typically employed for this process since it is equipped with all of the implements required to carry out these operations . Perforations are made in the casing to allow oil to flow into the pipe from the rock . The
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