Photograph of a gas flare in the Bakken Formation of North Dakota at night. The photo shows flame come from the end of a pipe. The remainder of the landscape is mostly dark.

Energy in the Great Plains

Simple map showing the Great Plains region of the northwest-central United States.

Page snapshot: Introduction to energy of Great Plains region of the northwest-central United States.

Topics covered on this page: Overview; Oil and gas; Coal and coalbed methane; Wind energy; Nuclear power; Resources.

Credits: Most of the text of this page comes from "Energy in the Northwest Central US" by Carlyn S. Buckler and Robert M. Ross, chapter 7 in The Teacher-Friendly Guide to the Earth Science of the Northwest Central USedited by Mark D. Lucas, Robert M. Ross, and Andrielle N. Swaby (published in 2015 by the Paleontological Research Institution; currently out of print). The book was adapted for the web by Elizabeth J. Hermsen and Jonathan R. Hendricks in 2022. Changes include formatting and revisions to the text and images. Credits for individual images are given in figure captions.

Updates: Page last updated September 4, 2022.

Image above: A gas flare (nature gas being burned off) in the Bakken Formation, North Dakota. Photo by Joshua Doubek (Wikimedia Commons, Creative Commons Attribution-ShareAlike 3.0 Unported license, image cropped and resized).


The Great Plains region is a broad expanse of flat land underlain by thick sequences of sedimentary rock and primarily covered in grassland and prairie. Ancient sedimentation patterns and tectonic activity have favored the placement of widespread fossil fuel resources in this region. Organic-rich sediments were deposited in inland seas that spread across much of the region, and Cenozoic swamps contributed plant matter to form thick beds of coal. The Great Plains’ sedimentary basins contain vast oil, gas, and coal reserves that dominate energy production here, but the area’s topography and climate also make it appropriate for large wind farms.

Map of the northwest-central region with state boundaries outlined in black. Major sedimentary basins are shaded medium blue, and major sources of fossil fuels are shaded dark blue. The Williston Basin mainly in western North Dakota and eastern Montana has the Bakken Formation, and the Powder River Basin in eastern Montana and Wyoming contains the Niobrara Formation. Other basins include the Bighorn Basin (Montana, Wyoming), the Greater Green River Basin (southwestern Wyoming), the Hanna Basin (south-central Wyoming), the Denver Basin (Wyoming-Nebraska-South Dakota border region), Salina Basin (central Nebraska), and the Forest City Basin (southeastern Nebraska).

Sedimentary basins containing significant fossil fuel accumulations in the northwest-central U.S. Modified from a map by Wade Greenberg-Brand that was originally published in The Teacher-Friendly Guide to the Northwest Central US.

Oil and gas

Oil deposits from the Great Plains region are also among the largest in the U.S. It is possible to make sense of why we find petroleum and natural gas in these areas by understanding the history of marine environments. Mud with relatively high organic matter content tends to accumulate in shallow continental seas and in coastal marine environments. The northwest-central U.S. has been home to both types of environments throughout its geologic past.

Reservoir rocks in the Great Plains include dolomites, chalks, and organic-rich shales. There have been estimates of some 400 billion barrels of untapped oil in the Bakken Formation and large reserves of both oil and natural gas in the Niobrara Formation, although estimates of the size of oil and gas reserves that can or will be economically extracted are in dispute. Thanks to these geological units, this region is a net exporter of energy, providing much of the central U.S. with its oil and gas.

Map of the northwest-central region with state boundaries outlined in black and petroleum-producing regions shaded in blue. Petroleum occurs in parts of Wyoming, central and eastern Montana, western North Dakota, northwestern South Dakota, and in western Nebraska.

Petroleum-producing regions of the northwest-central U.S. Modified from a map by Wade Greenberg-Brand, adapted from an image by Peter Nester, originally published in The Teacher-Friendly Guide to the Northwest Central US.

Williston Basin (Bakken Formation)

The Bakken Formation formed in the late Devonian and early Mississippian, in a continental sea that filled what we now call the Williston Basin. The Bakken is known only from coring, as it does not outcrop at the surface. The source rock for the formation’s oil is present in its upper and lower dark shale layers, and a reservoir layer of dolomite lies between the shales. Since 2000, oil production rates in the Bakken Formation have expanded enormously through the application of horizontal drilling combined with high volume hydraulic fracturing. 

Unlike some famous “fracked” formations in other areas, such as the Barnett Shale in Texas and Marcellus Shale in Pennsylvania, the part of the Bakken Formation most intensively hydraulically fractured has been its dolostone reservoir unit rather than the dark shale source rock. This unconventional drilling activity is centered in North Dakota, which has become the nation’s second largest oil-producing state after Texas.

Photograph of segments of a core drilled through the Bakken Formation. The photo shows two boxes, each containing three elongated-rectangular segments of rock core. The rock varies from very dark gray to light gray in color. Each core segment is about 1 meter (a little more than 1 yard) long.

Core of the Bakken Formation. Source: USGS.

Photograph of an oil drilling rig in Williston, North Dakota. The photo shows a tall drilling rig (It looks like a metal scaffold tower attached to a base with storage tanks and other equipment around it) in a flat landscape, with red earth in the foreground and a grassy area in the background.

Drilling rig, Williston, North Dakota, 2011. Photo by Lindsey G (flickr, Creative Commons Attribution 2.0 Generic license, image resized).

Photograph of oil pumps at wells in North Dakota.

Pumpjacks at oil wells in the Bakken Formation, North Dakota. Photo by USGS (public domain).

A nighttime satellite photograph of part of the north-central United States. Clusters of lights indicate the positions of cities. Labeled cities include Williston, Minot, Bismarck, and Fargo North Dakota and Minneapolis-St. Paul in Minnesota. A concentration of lights in the area near Williston indicates the intensity of oil and gas development in the Bakken Formation.

North Dakota and surrounding region at night, 2012. The lights in the large area around Williston are not a large city, but the lights from oil and gas development in the Williston Basin. Source: NASA Earth Observatory image by Jesse Allen and Robert Simmon (used following NASA's image use policy).

Niobrara Formation

The Niobrara Formation, also known as the Niobrara Chalk or Niobrara Shale, extends from the Gulf of Mexico to the Arctic, and originates from sediments deposited in the Late Cretaceous Western Interior Seaway. Where the formation outcrops at the surface, it is famous for its fossil faunas. The Niobrara is tapped for fossil fuels in the Denver Basin (also known as the Julesburg or D-J Basin), which underlies northeastern Colorado, a small corner of southeast Wyoming, and southwest Nebraska. The formation contains alternating chalks and organic-rich marls and shales; the marls and shales are a source of petroleum, and the adjacent chalks have become reservoir rocks. Natural gas and oil from conventional drilling have been extracted from the Niobrara since the early 1900s. Unconventional drilling below about 1830 meters (6000 feet) has greatly increased oil production in southeastern Wyoming in recent years.

Coal and coalbed methane

Map of the northwest-central region with state boundaries outlined in black. Major coal deposits are indicated by shades of blue. Bituminous coal (light blue) is found in eastern Montana and the western Dakotas. Lignite (dark blue) is found in north-central to south-central Montana. Subbitumious coal (medium blue) is found in Montana, Wyoming, and a very small part of western Nebraska.

Coal-producing regions of the northwest-central U.S. Modified from a map by Wade Greenberg-Brand, adapted from an image by the USGS, originally published in The Teacher-Friendly Guide to the Northwest Central US.

Williston Basin (North Dakota)

The world’s largest known lignite coal deposit, weighing in at an estimated 351 billion tons, is found in western North Dakota’s Williston Basin. This area is known as the Fort Union coal region, named after the Fort Union Formation, a thick sequence of Paleocene-aged coal deposits lying above Cretaceous-aged marine sediments from the Western Interior Seaway. North Dakota’s supply of lignite is estimated to last more than 800 years, and the deposits are used for synthetic fuels (made of carbon monoxide and hydrogen) as well as fuel for nearby power plants. Coal mining in this area began in the 1870s, when small seasonal mines sprung up along the main routes of transportation in the area. Over 250 mines were in operation by the 1920s. Today, there are only six large coal mines in western North Dakota, from which 32 million tons of coal are extracted annually. One of these, the Freedom Mine, is the 12th largest coal mine in the US.

Photograph of a thin black coal seam in an outcrop. The coal seam is flanked by beige soil or rock above and below.

Coal seam, Paleocene Sentinel Butte Formation, North Dakota. Photo by James St. John (flickr, Creative Commons Attribution 2.0 Generic license, image resized).

Powder river basin (Wyoming)

In Wyoming, great quantities of coal are produced annually from the Powder River Basin. Like the Williston Basin, the Powder River Basin contains a thick sequence of Cretaceous marine shales and sandstones formed in the Western Interior Seaway, overlain by Paleocene-aged coals of the Fort Union Formation. These coals have experienced greater heat and pressure from burial than those in the Williston Basin, and thus are higher-grade sub-bituminous coals. In fact, the Powder River Basin contains the largest resources of low-sulfur, low-ash, sub-bituminous coal in the U.S. These deposits provide more than 40% of the U.S. coal supply, making Wyoming the largest coal-producing state. The Black Thunder Coal Mine is currently the most productive coal mine in the U.S., providing 8% of the country’s coal and 20% of Wyoming’s total coal production. This mine utilizes the world’s largest dragline excavator, employed to strip the overlying rock and sediment and expose the underlying coal seams.

The Powder River Basin hosts significant quantities of coalbed methane. Coal mines have long been vented to the atmosphere, in part because of the buildup of methane (CH4, the primary gas in natural gas) released from fissures around the coal. This methane is a byproduct of the process of coalification, by which ancient plant material was transformed into coal, and it accounts for over 5% of US methane production. Wyoming is one of the three leading US states for coalbed methane production (approximately equal to that of Colorado and New Mexico), each of which account for about 25% or more of the national total.

Aerial photograph of an open-pit coal mine in the Powder River Basin of Wyoming. The photo shows a large pit with roads along its rim and also running to it. One side of the pit has terraced (stair-step like) walls. Water has pooled in the deepest part of the pit. 

Open-pit mine in the Power River Basin, Wyoming. Photo by BLM Wyoming (Bureau of Land Management on flickr, Creative Commons Attribution 2.0 Generic license, image cropped and resized).

Photograph taken in a coal mine in the Powder River Basin of Wyoming. The photo shows the wall and floor of an open-pit mine with several levels. Mining machinery, including two draglines, can be seen on three of the levels; the machinery is pained orange. The lower levels of the mine appear black, the upper levels are light gray to beige.

Open-pit mine in the Power River Basin, Gillette, Wyoming, 2008. Photo by Greg Goebel (flickr, Creative Commons Attribution-ShareAlike 2.0 Generic license, image cropped and resized).

Photograph of a front-end loader at work in a coal mine. The photo shows a vehicle with a shovel attached to the front. The machine appears to be dropping a load of rock onto a pile. Next to the pile and behind the front-end loader, a thick, vertical wall of coal can be seen. The wall of coal is much taller than the machine.


The Great Plains of Montana also produce sub-bituminous coal from the northern extension of the Powder River Basin and lignite from the western extension of Williston Basin deposits. Montana ranks 6th in the nation among coal-producing states. Considerably more coal resources lie below currently mineable depths, that is, below about 150 meters (500 feet). Not surprisingly, these zones are being considered for potential underground coal gasification projects that would convert coal to gas below the surface and then bring the gas to the surface through wells.

2-panel image showing machinery in the Spring Creek Mine, Montana. Panel 1: Photograph of a dragline excavator scooping up rock. The excavator is painted white. Panel 2: Photograph of a large yellow truck with a bed full of coal.

Machinery at Spring Creek Mine, Montana, including a dragline (left) and a truck hauling coal (right). Left photo and right photo by BLM (public domain).

Wind energy

The Great Plains (in this case referring to the full area that runs from Texas to Montana and into Canada) has been called the “Saudi Arabia of Wind Energy,” at least in terms of potential. Wind energy provides about a third of the renewable energy produced in the U.S., with hydroelectric representing about half; solar, geothermal, and biomass account for the remaining sixth.

In contrast to hydroelectric, wind energy is growing rapidly. Wind grew tenfold on a national scale from 2004 to 2014, and wind farms on the Great Plains have played a significant role in that growth. In the northwest-central region, the five Great Plains states are among the top 16 states for wind energy as a percentage of state electricity generation (South Dakota 25%, North Dakota 18%, Wyoming 9%, Nebraska 7%, and Montana 7%). This is all the more remarkable considering the rate of local petroleum and coal extraction.

Map of the northwest-central region with state boundaries outlined in black and wind energy potential indicated by shades of blue, with white to light blue areas having the lowest potential and dark blue areas having the highest potential. The Great Plains and Central Lowland regions generally have medium to high potential. The highest-potential areas are in parts of the Rocky Mountains, although the mountains also have regions of no potential.

Wind energy potential in the northwest-central U.S. Map modified by a map by Wade Greenberg-Brand, adapted from image by National Renewable Energy Laboratory, originally published in The Teacher-Friendly Guide to the Earth Science of the Northwest Central US.

Aerial photograph of a flat of landscape covered with brown vegetation and dotted with pothole lakes. About seven large white wind turbines and scattered on the landscape.
Photograph of wind turbines near Judith Gap, Montana. The photo shows two large white wind turbines on a landscape of low rolling hills covered with yellowish grass. In the foreground, a bit of a gravel road can be seen. In the background, in front of the turbines, a herd of cows are grazing.

Wind turbines near Judith Gap, Montana, 2009. Source: USDA, NRCS on flickr (public domain).

Nuclear power

Uranium used in nuclear power plants is mined from certain sedimentary rocks in the Great Plains. Economic deposits of uranium are found in Paleocene and Eocene sandstones in the southern Powder River Basin of Wyoming and in Oligocene rocks in northwest Nebraska (Crow Butte). The Paleocene lignitic coals of North Dakota also contain significant uranium content. Despite the prevalence of uranium resources throughout the Great Plains, however, nuclear power is not generated here.

Black-and-white aerial photograph of the Highland Uranium Mill near Casper, Wyoming, in the 1970s. The photo shows a cluster of buildings and other structures and ponds on a flat landscape.

Highland Uranium Mill, Casper, Wyoming, ca. 1973. Photo source: U.S. Department of Energy HD.11D.001 (USDOE on flickr, U.S. government work).


Resources from the Paleontological Research Institution

Earth@Home: Earth Science of the South-central U.S.: Energy in the Great Plains and Basin and Range (covers the Great Plains in Kansas, Oklahoma, and Texas):

Earth@Home: Earth Science of the Southwestern U.S.: Energy in the Great Plains (covers the Great Plains in Colorado and New Mexico):

Earth@Home: Introduction to Energy:

Go to the full list of resources about energy in the northwest-central U.S.

Go to the full list of resources about energy