Region 4: The Great Plains

The Great Plains region contains extensive oil and gas resources, specifically from the Hugoton-Panoma gas fields across the northern end of the region and the Permian Basin in Texas. Wind energy is also a major component of power generation in the Great Plains, and some of the largest wind farms in the world are located here.

Oil and Gas

At its southern end in Texas, the Great Plains region contains the Permian Basin, which extends beneath an area approximately 400 kilometers (250 miles) wide and 480 kilometers (300 miles) long (see Figure 7.5). During the Permian, western Texas was covered by an inland sea that featured an ecologically diverse reef system of sponges, algae, bryozoans, and brachiopods. The basin’s reservoir rocks are formed from an extensive, porous framework of preserved limestone and dolostone reefs, formed in a shallow marine setting when the basin was isolated from the accumulation of weathered sediments. Organic-rich shales laid down below, around, and within these reef complexes are the source rocks for the petroleum in the basin. Reservoirs in the Permian Basin have been tapped for oil since the early 20th century (Figure 7.17). Conventional drilling in the Permian Basin had been declining for several decades before hydraulic fracturing was introduced in the late 2000s, restoring the Permian Basin as one of the top US oil producing basins.

Figure 7.17: An oil pumpjack near Electra, Texas. Pumpjacks are part of piston pumps used to lift liquid out of oil wells lacking enough internal pressure to push oil to the surface unaided.

The Hugoton-Panoma gas field, with reservoir rocks including Pennsylvanian and Permian sandstone, limestone, and dolomite, covers 22,000 square kilometers (8500 square miles) across southwestern Kansas, the panhandle of Oklahoma, and northwest Texas (Figure 7.18). Discovered in 1918, it is an extensive natural gas field from which fuel was extracted in large quantities through conventional drilling from the 1930s onward. It was one of the most productive gas fields in the world at its peak in the 1960s and 1970s, producing 19.4 million cubic meters (684.9 million cubic feet) of gas in 1968. The total amount of gas produced is estimated to be 693.8 million cubic meters (24.5 trillion cubic feet) with reserves estimated at 792.9 million cubic meters (28 trillion cubic feet). Unconventional drilling in shale gas units, however, has overtaken the prominence of the Hugoton field. By 2011, production had dropped to 3.7 million cubic meters (129.4 million cubic feet). Hugoton also happens to have long been one of the world’s primary sources of helium, which has recently become the primary drilling target there.

Figure 7.18: Extent of the Hugoton-Panoma gas field.

Wind Farms

In Texas, oil and gas may be king, but in the low, flat land of the Great Plains, wind energy is fast becoming a major component of energy production. The South Central currently has the highest wind energy capacity in the US, primarily due to wind farms in western and central Texas (but also in parts of the panhandle of Oklahoma, and southwest Kansas). There are more than 50 major wind energy power plants in this area, with proposals for even more plants to come online. The area’s largest wind farms, some among the world’s largest, are located just south of where the Great Plains region borders the Central Lowland (e.g., in the counties of Nolan, Tyler, Sterling, and Coke) (Figures 7.19 and 7.20). In these areas, wind speed is relatively high and the population is relatively sparse, making broad-scale wind farms more practical than in some other parts of the country. Because of challenges in transmitting large amounts of electrical energy, however, most of this energy is used locally.

Figure 7.19: Wind speeds in the South Central US. Locations of the largest wind farms are marked in green. Smaller wind farms, not indicated, are much more broadly distributed.

Figure 7.20: The Roscoe Wind Farm in Roscoe, Texas, has 634 wind turbines and a total capacity of 781.5 MW, making it the sixth largest wind farm in the world and the third largest in the US.