Total primary energy supply (TPES)

Summary: The total primary energy supply (TPES) is a key indicator of energy availability. The focus on TPES will certainly increase as the desire for environmentally sustainable and renewable energy supplies intensifies in the future.

At its most abstract, the total primary energy supply (TPES) is the total amount of energy available for performing work. The specific calculation of TPES can vary by calculator, but an international standard has been established by the International Energy Agency (IEA): TPES = production + imports - exports - international marine bunkers - international aviation bunkers ± stock changes

The IEA’s total primary energy supply is calculated for whole nation-states and also for the total world; the latter calculation omits the subtraction of international marine and aviation bunkers (which are the deliveries of fuels to ships and aircraft for use in international travel). The IEA reported TPES in million tons of oil equivalent (Mtoe), a common measure that standardizes the energy values of various fuel sources based on their caloric content, and terajoules (TJ). A terjoule is equal to one trillion joules or 0.278 gigawatt hours. Another common measure is million barrels of oil equivalent (Mboe). Secondary energy production, such as electricity generated in coal-fired power plants, is not included in TPES; the energy in the primary source, in this case the coal, is counted instead.

Fuel Source Categories

The categories of fuel source and their percentage share of world TPES in 2019, according to the IEA, were as follows: oil (30.9 percent); coal (26.8 percent); natural gas (23.2 percent); biofuels and waste (9.4 percent); nuclear (5 percent); hydrological (2.5 percent); and, other, including geothermal, solar, wind, and heat (2.2 percent). One of the major changes in TPES has been the shifts from wind, water, and biomass (wood being the most important biomass source), as the largest sources of primary energy for many millennia, to coal by the middle of the nineteenth century and to oil by the middle of the twentieth century, with hydrocarbons (oils and gases) making up the largest share since 1960. The fuel mix has remained relatively similar since the 1970s, with oil, coal/peat, and gas making up 80 percent or more of total world TPES between 1970 and 2019.

The world TPES in 2008 was approximately 12,267 Mtoe, an increase of almost 101 percent from 1973’s level of 6,115 Mtoe. This reflects a continual increase in TPES, as population has grown over time, particularly since the Industrial Revolution began in the latter half of the eighteenth century. There are large differences across nation-states in their use of the world TPES. For example, in 2008 the nation that used the largest quantity was the United States at 2,283.72 Mtoe, while Gibraltar used the smallest quantity, at 0.16 Mtoe. Of course, population size is an important determinant of energy use, although the much larger India had a TPES of 620.97 Mtoe and China was also slightly smaller, 2,116.43 Mtoe. On a per capita basis, the highest rate was Qatar’s (18.83 toe per person) and the smallest was Eritrea’s (0.14 toe per person).

Other national factors have an impact on the TPES as well, such as the availability of domestic energy resources, climate, the size of the country, and the structure of the economy (that is, the mix of services, industry, and agriculture). It should also be noted that a country could have a low TPES yet consume large amounts of energy-intensive goods by importing those goods.

In 2021, the global TPES was 617,950,232 TJ. This reflects an increase of 47 percent since the start of the century.

The IEA also reports TPES per thousand dollars of gross domestic product (GDP), a measure of the energy intensity of an economy, and also tons of carbon dioxide emissions per TPES, a measure of the climate change contribution from a country’s TPES (also known as its carbon intensity).

The main sources of the oil, coal, and natural gas in the primary energy supply are concentrated in certain parts of the earth. The Persian Gulf-Zagros Basin contains approximately 60 percent of the world’s crude oil reserves. Much of the undiscovered oil is predicted to exist in offshore undersea fields (which now produce around one-third of all crude oil) and small onshore reservoirs. The United States, Russia, and China currently contain more than two-thirds of known coal reserves; Australia also has large reserves and is the largest exporter of coal in the world. The largest suppliers of natural gas are the United States, Russia, Iran, China, and Canada.

Looking Ahead

The outlook for the world TPES is that production will have difficulty keeping pace with increasing demand unless alternatives to fossil fuels—particularly oil, which may be nearing or may have reached its peak production—are further developed. Environmental concerns, particularly over climate change from fossil fuel combustion, will continue to influence the makeup of TPES. As with most energy-related issues, technological, economic, and political concerns will be the main drivers of the TPES of the future.

Bibliography

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Podobnik, Bruce. Global Energy Shifts. Philadelphia: Temple University Press, 2006.

Smil, Vaclav. Energy in Nature and Society: General Energetics of Complex Systems. Cambridge, MA: MIT Press, 2008.

"Supply." International Energy Agency, 2021, www.iea.org/reports/key-world-energy-statistics-2021/supply. Accessed 6 Aug. 2024.