Why does every country’s energy system look different?

Draw seven national energy balances as flow diagrams, switch from primary to final to useful energy, count reactors and wind farms three ways, and see how imports, resources, climate and institutions line up with each mix

F10 of Energy Systems, Step by Step: guess a country from its energy mix; compare the United States, the European Union, China, India, Brazil, Norway and the fictional Prairieland as Sankeys from their own statistics; switch between primary, final and useful energy and between the conventions that count nuclear, hydro, wind and solar; then open the regional cards.
  • Foundations · L1
  • 20 min guided · about 10 min practice
  • After F4

Seven energy systems, one data year each, in EJ (1 EJ = 1,000 PJ, about 278 TWh)

Country Year Primary energy Fossil share Renewable share: physical content / substitution Imports
United States 2025 101.8 EJ 82% 9% / 14% net exporter: net exports 12% of its supply
European Union (27 countries) 2024 55.8 EJ 67% 20% / 29% 57% of its supply imported
China
Partial estimate: NBS's 'other energy' left out		 2023 152.1 EJ (estimate) 90% 7% / 15% 23% of its supply imported
India
Traditional biomass is not in the balance		 fiscal year 2023-24 (provisional) 37.8 EJ 95% 4% / 8% 40% of its supply imported
Brazil 2025 13.8 EJ 48% 49% / 59% not on the pages read
Norway 2025 1.17 EJ 50% 48% / 68% (waste, 1.6%, not split) net exporter: net exports 6.9 times its own supply
Prairieland 2025 3.50 EJ 85% 10% / 21% 40% of its supply imported

Prairieland is fictional; its numbers are illustrative.

Primary, final and useful energy, in EJ

Country Primary Lost or used before the meter Final (share of primary) Useful (share of final)
United States 101.8 EJ 20.8 EJ 74.1 EJ (73%) about 48.0 EJ (65%, what-if)
European Union (27 countries) 55.8 EJ 14.1 EJ 36.8 EJ (66%) about 25.0 EJ (68%, what-if)
China
Partial estimate: NBS's 'other energy' left out		 152.1 EJ (estimate) China's statistics count the electricity users buy at the coal burned to make it, so its final energy cannot be drawn on the same basis as the others; this page shows its primary energy only.
India
Traditional biomass is not in the balance		 37.8 EJ 12.1 EJ 24.7 EJ (65%) about 17.5 EJ (71%, what-if)
Brazil 13.8 EJ 2.51 EJ 10.6 EJ (77%) about 6.61 EJ (63%, what-if)
Norway 1.17 EJ 0.32 EJ 0.76 EJ (65%) about 0.50 EJ (66%, what-if)
Prairieland 3.50 EJ 0.79 EJ 2.71 EJ (77%) 1.81 EJ (67%)
  • Useful energy. Official statistics stop at final energy. For the real countries, useful energy here is a what-if: their final energy by sector at Prairieland's sector efficiencies (illustrative), not a measurement.
  • Final energy. Final energy here leaves out non-energy use (feedstocks); the energy industry's own use sits before the meter unless the country's note says otherwise.
  • United States. U.S. final energy is EIA's end-use energy, which keeps some of the energy industry's own use: natural gas lease and plant fuel in industry, pipeline fuel in transport.

One balance, flow by flow: the United States, 2025, in EJ (physical energy content)

From To EJ
Coal Primary energy 9.15
Oil Primary energy 38.1
Natural gas Primary energy 36.5
Nuclear Primary energy 8.65
Hydro Primary energy 0.89
Wind Primary energy 1.67
Solar Primary energy 1.52
Geothermal Primary energy 0.12
Bioenergy Primary energy 5.12
Other Primary energy 0.03
Primary energy Industry (with farms and mining) 21.2
Primary energy Transport 29.8
Primary energy Buildings (homes and services) 23.0
Primary energy Non-energy use (feedstocks) 6.90
Primary energy Lost or used before the meter 20.8
  • Physical energy content. Nuclear counts as its reactors' heat (measured, or electricity ÷ 0.33 if unknown); hydro, wind and solar as the electricity they make.
  • Substitution. Every MWh from nuclear, hydro, wind and solar counts as the fuel a thermal plant would burn to make it.
  • Direct equivalent. Every MWh from nuclear, hydro, wind and solar counts at its electricity, 3.6 GJ.
  • China. China publishes 17.9% for primary electricity and other energy, in coal equivalent, a kind of substitution; by physical energy content its nuclear, hydro, wind and solar come to about 9.6% (the page's estimate).

With JavaScript on, you guess a country from its mix, switch between countries and conventions, turn on four lenses and open the regional cards.

  • As published. Six national balances from their statistics offices (EIA, Eurostat, China's NBS, India's MoSPI, Brazil's EPE, Statistics Norway), one data year each, read between 2 and 7 November 2026; converted to EJ with the UN's conventional factors.
  • Estimates. China's physical-content figures are this page's partial estimate; every real country's useful energy is a what-if at Prairieland's sector efficiencies. Both are labelled where they appear.
  • Illustrative. Prairieland is fictional; its numbers are illustrative, from the course's shared national data.

Need a refresher? F4 on how plants turn fuel into electricity; F3 on primary, final and useful energy in a home.

What you just did, as diagrams

One picture per country
A national Sankey shows where energy comes from and where it goes; no two of these seven look alike.
Primary, final, useful
Final energy is 65% to 77% of primary energy here; useful energy is less again, and for the real countries only a what-if.
Conventions
Norway's renewable share is 48% by physical energy content and 68% by substitution: the method moves the number.
Why mixes differ
Resources, imports, climate and institutions each line up with part of a mix; none explains it alone.
Regions
The regional cards set each country in its grid, its institutions and its open research questions.
Go deeper · AnalystWhy the substitution method enlarges electricity
  • The rule. A thermal plant at efficiency η burns 3.6 ÷ η PJ of fuel for each TWh it makes. Substitution counts every TWh from nuclear, hydro, wind and solar that way: 2.5 times its electricity at 40%, about 3 times at 33%.
  • Nuclear under physical content. Its reactors' heat: measured where it is reported (the EU), from the plants' average heat rate (the U.S.), or electricity ÷ 0.33 where the heat is not known (India, Brazil, this page's China estimate).
  • Recompute the share. Substitution changes nuclear's assigned energy (electricity ÷ 0.40) and enlarges hydro, wind and solar, so the total changes too: the United States' nuclear is 8.5% by physical content, 6.7% by substitution.
  • Direct equivalent counts every TWh at 3.6 PJ, so nuclear's energy falls to about a third of its physical-content value.
  • China's coal equivalent is a substitution at the year's coal burned per kWh in thermal plants.
Go deeper · AnalystWhere each country's numbers come from
Country and data year Published Counting method Coverage Changes on this page
United States, 2025 96.5 quads of primary energy consumption (Table 1.3). Nuclear at its plants' average heat rate; hydro, wind, solar and geothermal electricity at 3,412 Btu per kWh since September 2023, close to physical energy content. Final energy is EIA's end-use energy (Tables 2.2 to 2.5); it keeps gas lease and plant fuel in industry and pipeline fuel in transport (Table 4.3). Farms sit inside industry. Non-fuel use (6.5 quads) shown apart as non-energy use; geothermal (0.117 quads) drawn as its own source; solar includes small-scale solar (Table 10.6).
European Union (27 countries), 2024 55,790 PJ of gross available energy. Physical energy content: nuclear as reactor heat; hydro, wind and solar photovoltaic as their gross electricity (nrg_bal_peh). Includes 1,704 PJ of fuel for international shipping, shown apart. Bioenergy is renewables less the other renewable sources, so it holds the renewable part of waste; non-renewable waste sits in 'other'. Coal includes peat and oil shale; solar includes solar heat (164 PJ); geothermal, ambient heat and tide drawn as one source.
China, 2023 571,327 × 10,000 t of coal equivalent (5.71 billion t, about 167 EJ): coal 54.8%, oil 18.8%, gas 8.5%, primary electricity and other energy 17.9%. Coal equivalent: nuclear, hydro, wind and solar electricity counted at the coal burned per kWh in the year's thermal plants, a kind of substitution. Partial: the 'other energy' inside NBS's 17.9% is not split by NBS and is left out. Final energy is not drawn. Physical content is the page's estimate: fossil fuels as published, plus the four sources' TWh (nuclear ÷ 0.33). Solar from the 2023 Communiqué; the rest from the 2025 Yearbook.
India, fiscal year 2023-24 (provisional) 903,158 ktoe (37,813 PJ) of total primary energy supply. Hydro, wind and solar at their electricity (1 GWh = 0.086 ktoe); nuclear at its electricity ÷ 0.33. No row for firewood or other traditional biomass: every share here is of the sources the balance covers. Coal includes lignite; oil is crude oil less net exports of products. Wind, solar and other renewable power includes bio-power and small hydro. 'Other' final use is farms and non-specified uses.
Brazil, 2025 328.5 Mtep of domestic energy supply (Oferta Interna de Energia). Hydro, wind and solar at their electricity (1 kWh = 860 kcal); nuclear at its electricity ÷ 0.33. Bioenergy: sugarcane products 52.0, firewood and charcoal 27.1, black liquor and other renewables 29.2 Mtep. Hydro includes imported electricity; solar includes solar heat. The energy sector's own use, inside BEN's final consumption, moved before the meter, as the others count it. Services, farms and the energy sector split by their published shares.
Norway, 2025 326 TWh of net domestic energy supply (Table 2; its rows add to 326.2). Electricity at its own energy content (1 MWh = 3.6 GJ): production less net exports, not split by source (hydro made 89.9% of 2025's generation). Waste (5.2 TWh) is not split into renewable and non-renewable parts: the page counts it as neither. Buildings are households only: services sit in 'other' with farms and fishing.
Go deeper · ModelerPrairieland in full: refinery, power plants and carriers

With JavaScript on, Prairieland's full balance appears here as a six-column Sankey from the course's national data: sources, primary supply, the refinery and power plants, carriers, sectors and useful energy. Prairieland is fictional; its numbers are illustrative.

Go deeperWhat this lesson leaves out
  • Energy per person and per unit of GDP: they need population and output figures this page does not use.
  • Emissions, prices and who pays.
  • Hours and seasons: a year's balance hides the coldest week.
  • How each country makes its energy policy, and its scenarios for the future.

Check yourself

Practice, about 10 minutes: three myths, then four questions.

Myth or fact? “A country's renewable share of primary energy is a single, fixed number.”

  • Myth
  • Fact
Answer

Myth. Norway's is 48% by physical energy content and 68% by substitution, for the same plants in the same year.

Myth or fact? “A country that produces more energy than it uses imports none.”

  • Myth
  • Fact
Answer

Myth. Norway produced 2,593 TWh in 2025 and still imported 124 TWh, while exporting 2,380 TWh.

Myth or fact? “If every country used energy at Prairieland's sector efficiencies, most of its primary energy would end up as useful heat, motion and light.”

  • Myth
  • Fact
Answer

Myth, in this what-if: for the five real countries drawn here, 43% to 48% of primary energy would become useful energy. Their real efficiencies differ and are not in official statistics.

Which of the seven gets 60% of its primary energy from coal and lignite and imports 40% of its supply?

  • India
  • The European Union
  • Brazil
Answer

India (fiscal year 2023-24): coal and lignite 60% of the sources its balance covers (traditional biomass is not in the balance); net import dependency 40.27%, as MoSPI publishes it.

By substitution at 40% efficiency, 1 TWh of wind electricity (3.6 PJ) counts as how many PJ of primary energy?

  • 3.6 PJ
  • 9 PJ
  • 10.9 PJ
Answer

3.6 ÷ 0.40 = 9.0 PJ: the fuel a thermal plant at 40% would burn to make it, 2.5 times the electricity.

The EU's import dependency was 57.3% in 2024. What does Eurostat divide by what?

  • Net imports ÷ gross available energy
  • Imports ÷ production
  • Production ÷ gross available energy
Answer

Net imports (imports less exports) ÷ gross available energy, the EU's primary energy.

China publishes 17.9% for primary electricity and other energy, in coal equivalent. By physical energy content, nuclear, hydro, wind and solar come to about…

  • the same
  • a little more
  • about half as much
Answer

About 9.6% (the page's estimate): coal equivalent counts each kWh as the coal a thermal plant would burn, so NBS's figure is 2.6 times the four sources' electricity (it also holds some other energy).

Numbers, sources and what’s next

Numbers to remember

Number What it means Source
57.3% The EU's energy import dependency in 2024: net imports as a share of gross available energy. Eurostat, Energy statistics: an overview · data extracted September 2026; data for 2024
11.1 quads U.S. net energy exports in 2025: production 107.2 quads against consumption of 96.5. EIA, Monthly Energy Review, Table 1.1 · October 2026 edition; data for 2025
54.8% Coal's share of China's total energy consumption in 2023, in coal equivalent. National Bureau of Statistics of China, Statistical Yearbook 2025, Table 9-2 · 2025 edition; data for 2023
1 ÷ efficiency The factor by which the substitution method enlarges each MWh from nuclear, hydro, wind and solar: 2.5 at 40%. this lesson's arithmetic · –

Keep going

Back to the course map

Sources and further reading

The twelve regional cards set each country in its region.

The six balances, as published (one data year each):

Prairieland (fictional; the course's shared national data), the parts used here:

  • Learn (this course). Prairieland parameter card (the course's national-strategy dossier, section 8.0) (no link). Fact-checked 2 Nov 2026. 20 million people; GDP $1.2 trillion; primary energy 3.5 EJ (oil 35%, 80% imported through one strait; gas 30%, LNG 40% of it; coal 20%, all from Ridge County; nuclear 5%; wind, solar and hydro 10%); energy CO2 214.9 Mt; Ridge County 3% of the workforce, coal 40% of its local tax.
  • International Energy Agency. Statistics questionnaires FAQ. Read 7 Nov 2026. The physical energy content method: nuclear's primary energy is its heat, estimated from generation at 33% efficiency; hydro, wind and solar photovoltaic count at their electricity output; the IEA left the substitution method.
  • Our World in Data. Primary energy measurement change. Read 7 Nov 2026. How the substitution and physical energy content methods count nuclear, hydro, wind and solar.

Spotted an error, or stuck? Write to hlli@ksu.edu. Corrections are made in place and dated here.

Text licensed CC BY 4.0, code MIT: teachers and students may reuse and adapt it, with credit to Honglin Li.