In 1940, the coal production of the United States was higher than any of the major European powers. Germany had the highest coal production in Europe in 1940, however a large part of this was down to the de-facto annexation of Alsace-Lorraine, where Germany took control of much of the French coal industry. The Western European powers had virtually no oil industry at this time, while the U.S. oil output was roughly six times larger than that of the Soviet Union.

In the early 1900s, the Dutch East Indies (present-day Indonesia) was the largest producer of crude petroleum in the Pacific. Following the U.S. cessation of oil exports to Japan in 1941, and the lack of oil access at home, Japan's invasion of China was at threat of coming to a halt. In order to keep its armies supplied, Japan launched an invasion of Southeast Asia on December 8. 1941, with the annexation of Indonesia as one of its top priorities. This invasion also included the attack on Pearl Harbor, where Japan sought to neutralize the U.S. Pacific Fleet to prevent American interference. This brought the U.S. military into the Second World War, but it was not until mid-1942 when the Allies then halted the Japanese advance in Southeast Asia and started pushing them back through Southeast Asia in a grueling three-year long campaign. One of the keys to the Allies' success was the disruption of Japan's oil supply from Indonesia to Japan's armies in China and at home.

The United States is the world's largest crude oil producer. In 2024, it had an output of 20.1 million barrels worth of oil per day. This was nearly 13 million barrels more than in 2010 and largely a result of advances in unconventional tight oil production. Saudi Arabia and Russia ranked second and third, at around 10.9 and 10.8 million barrels daily respectively. Oil production includes crude oil, shale oil, oil sands, and natural gas liquids. Distribution of U.S. oil production The U.S. is divided into five regional divisions for oil production, known as Petroleum Administration for Defense District’s (PADD), which were created during World War II. The main goal was to organize the allocation of fuels from petroleum products and for data collection purposes these regions are still currently used. Out of all PADD's, PADD 3, including the Gulf Coast states, has recorded by far the largest daily crude oil production, at some 7.9 million barrels in 2021. By comparison, PADD 1 (East Coast) production volumes were 74 thousand barrels per day. The importance of PADD 3 to the country’s overall oil output is hardly surprising as Texas is by far the state with the largest crude oil production. U.S. natural gas production Besides being the world's largest oil producer, the U.S. is also the world’s largest natural gas producer. It produced over one trillion cubic meters in 2024, despite ranking fifth in terms of proved natural gas reserves .

How does improving access to the supply of energy affect regional specialization in manufacturing? We evaluate the long-run employment impacts of pipelines constructed by the U.S. government during World War II to transport oil and gas from the oil fields of the Southwest to wartime industrial producers in the Northeast. The pipelines were built rapidly to connect end points along a direct path that minimized use of scarce construction materials. Postwar they were converted to supply en route customers, giving counties close to the pipelines access to a cheap and plentiful source of energy. Over 1940 to 1950, counties with better access to pipeline gas had larger increases in their share of employment in energy-intensive industries. These impacts persisted to the mid-1980s for all energy-intensive industries and to the late 1990s for the subset of industries intensive in the direct use of electricity, despite the disruptive effects of the 1970s energy crisis. Our findings are relevant for understanding energy-related path dependence in local economic development patterns and how government intervention in energy markets affects industry location in the short and long run.

During the early 20th century, Germany was the largest producer of steel of Europe's Axis powers by a significant margin, and was also the largest steel producer in Europe when compared to Allied and neutral countries. The Austro-Hungarian Empire was the second largest producer of the Axis powers in Europe, before output fell drastically following its dissolution, and then Italy emerged as the second largest steel producer within the group. Iron and steel output among the other Axis nations was much lower in comparison; in the 1930s German trade with Eastern European countries had a significant impact on their economic structure, and the demand for agricultural products from these regions was much greater than the demand for metals.

Of the major Allied powers in the early 20th century, the United Kingdom was the largest producer of steel until the 1920s, before French output rose after the First World War following the transfer of Alsace-Lorraine and occupation of German territories, and then the Soviet Union's steel production rose significantly in the 1930s. Trends in steel production heavily follow those of iron production, and steel was instrumental for the industrialization and war effort of each respective country. When output from the Allied countries is compared with Axis countries in this period, Germany was the largest steel producer in Europe by a large margin and had the highest steel output in almost every year.

Proved oil reserves refer to the quantity of oil that is available in a certain area, and has at least a 90 percent chance of being extracted for use. Reserves, along with production and demand, are the three most important factors when oil prices are being set, and certain countries or companies can use their proved reserves to have some control over international prices. Development of the U.S. oil industryToday, the United States is the largest oil producer in the world, but it is outside of the top 10 in terms of its reserves. In the early 1900s, the U.S. overtook the Russian Empire as the world's largest oil producer, as oil booms in Texas and California, as well as heightened demand during the progression of industrialization, saw the industry grow exponentially. Apart from a dip during the Great Depression, the volume of U.S. reserves grew throughout the first half of the 20th century, although the growth of oil industries elsewhere in the world, particularly in the Middle East, saw the OPEC bloc emerge as the most influential force in the global oil pricing. The exploration of major oil fields in Alaska saw U.S. reserves spike in 1970, before both reserves and output fell in the final decades of the 20 th century. The U.S.'s position as the world's largest consumer of oil meant that it has been a net importer since WWII - however, the development of the unconventional oil industry in the 2010s has put the United States on course to become a net exporter in the 2020s.

With little fossil fuel resources of its own, Japan has largely depended on foreign petroleum imports for more than a century. Throughout the 1930s, imports from the United States fulfilled over 80 percent of Japan's oil needs, however, growing tensions between the two powers in the wake of Japan's invasion of China in 1937 saw the U.S. gradually cut trade ties with Japan. The U.S. was reluctant to cease this oil supply as it believed this would be taken as an act of war, but after Japan seized control of airfields in French Indochina (therefore blocking U.S. supply routes into China), the U.S. placed an oil embargo on Japan in August 1941. Japan's next invasion Japan's oil demand was already very high due to its military actions in China, and the U.S. believed that this move would bring the invasion to a halt. However, it had the opposite effect. On December 8, 1941 (Dec. 7 for Pearl Harbor due to time differences) Japan launched a full-scale invasion of Southeast Asia and the Pacific, with the intent of capturing the oil-rich regions of the Dutch East Indies and Burma. Europe's colonial powers were too preoccupied by war at home to respond effectively, and the attack on Pearl Harbor had temporarily neutralized the U.S. Navy's Pacific Fleet - within six months, Japan controlled virtually all of Southeast Asia. A new dilemma By mid-1942 Japan was in possession of the East Indies, the region's largest oil producer, but it now had to transport this oil roughly 6,000 kilometers to the metropole or China - a role that had previously been fulfilled by Western powers. A tanker manufacturing program was started immediately, with most Japanese oiler classes having a displacement between 10,000 and 20,000 tons each. In 1942, the U.S. Pacific Fleet became operational once more, but it was not until 1943 that U.S. submarines began aggressively targeting these new Japanese oilers. This campaign proved to be an enormous success, with Japanese losses exceeding production each year between 1943 and 1945. Without these actions, the Japanese may have been able to strengthen their position in the Pacific or push further into China and Burma, as the disruption of Japan's oil supply greatly weakened its ability to transport manpower and resources, or to run its tanks, aircraft, and navy.

During the early 20th century, Germany was the largest producer of coal in Europe. In fact, Germany's output was several times larger than the output of all other European Axis powers combined, as it was the major industrial power within the group. Compared to the Allied powers of Europe, the only country that comes close to German output was the United Kingdom, whose annual coal output ranged between 200,000 and 300,000 tons in most years. Major events caused noticeable fluctuations in Germany's coal output, such as the hyperinflation of 1923 or the Great Depression in the early 1930s, as well as the world wars. During the world wars, however, the trajectory of output varied; during the First World War, output dropped due to mass mobilization and disruption, but output rose steadily throughout the Second World War as coal mining was prioritized for the war effort, and this was boosted through the annexation of coal-rich territories elsewhere in Europe.

Of the other Axis powers, Austria's output was highest before the dissolution of the Austro-Hungarian Empire, when it lost it coal-producing territories in Czechoslovakia and Poland. Romania is not included here as its coal output was lower still than the other countries, although it was the second largest producer of oil or natural gas in Europe at the time, after the USSR.