AP® Environmental Science review sheet from Aim for Five (aimforfive.com/enviro/units/6/6-2)
Unit 6 · Topic 6.2
6.2 Global Energy Consumption
This topic looks at who uses the world's energy, how much, and what kinds. Fossil fuels supply most of it, wealthy countries use far more per person than poorer ones, and the fastest growth in demand now comes from developing countries as they industrialize.
Key terms
- energy consumption
- per capita
- developed country
- developing country
- industrialization
Where the world's energy comes from
Roughly 80 percent of the world's primary energy (energy in its raw form, before it is turned into electricity or fuel) comes from fossil fuels: oil, coal and natural gas. Oil is the largest single source, mainly because almost all transportation runs on it. Nuclear power, hydroelectric power and other renewables make up the rest, and renewables are the fastest-growing share.
Fossil fuels dominate because they are energy-dense, easy to store and ship, and backed by more than a century of built infrastructure: pipelines, refineries, power plants and gas stations.
Developed versus developing countries
A developed country has a high income per person and a lot of industry, like the United States, Japan or Germany. A developing country has lower income per person and is still building up industry and infrastructure.
Developed countries use far more energy per capita (per person). The United States has about 4 percent of the world's people but uses roughly 15 percent of its energy. An average American uses roughly ten times as much energy as an average person in India.
Total use is a different measure. China now uses more energy in total than any other country, because it has a huge population and a large manufacturing sector, even though its per capita use is well below the US level. Always check whether a question is asking about total or per capita use.
Why demand is rising
Industrialization, the shift from farming economies to factories and cities, drives up energy use. People move to cities, buy cars and appliances, and connect to the electric grid. Most of the growth in world energy demand is now in developing countries in Asia and Africa, while use per person in many developed countries is flat or falling slightly thanks to efficiency.
Population growth adds to this. More people, each using more energy, multiplies total demand.
What decides which fuel a country uses
- Availability: countries tend to use what they have. Coal-rich countries such as China and India burn a lot of coal.
- Cost: the cheapest reliable option usually wins, which is why cheap natural gas from fracking replaced much US coal power after about 2008.
- Government policy: taxes, subsidies, regulations and climate goals can push a country toward or away from a fuel.
- Technology and infrastructure: you can only use a fuel if you have the plants, pipes and grid to deliver it.
- Location and climate: sunny, windy, mountainous or volcanic places have different renewable options.
Worked examples
Try each one yourself first, then open the solution.
- Example 1Calculator allowed
Per capita versus total energy use
Country A has 330 million people and uses 95 × 10¹⁸ joules (95 exajoules) of energy a year. Country B has 1.4 billion people and uses 40 × 10¹⁸ joules a year. (a) Which uses more energy in total? (b) Calculate the per capita energy use of each in gigajoules (1 GJ = 10⁹ J). (c) How many times more energy does a person in A use than a person in B?
Show the solutionHide the solution
- Step 1: (a) Compare totals directly: 95 × 10¹⁸ J is more than 40 × 10¹⁸ J, so Country A uses more in total.
- Step 2: (b) Per capita means divide total energy by population. Country A: 95 × 10¹⁸ J ÷ 3.3 × 10⁸ people ≈ 2.88 × 10¹¹ J per person = about 288 GJ per person.
- Step 3: Country B: 40 × 10¹⁸ J ÷ 1.4 × 10⁹ people ≈ 2.86 × 10¹⁰ J per person = about 29 GJ per person.
- Step 4: (c) 288 ÷ 29 ≈ 10. A person in Country A uses about ten times as much energy as a person in Country B.
Answer: (a) Country A. (b) A ≈ 288 GJ per person; B ≈ 29 GJ per person. (c) About 10 times as much.
- Example 2
Explaining a trend
A graph shows that from 2000 to 2020, energy use per person stayed nearly flat in a group of developed countries but more than doubled in a group of developing countries. Give one explanation for each trend.
Show the solutionHide the solution
- Step 1: Developing countries: industrialization means more factories, more people moving to cities, more cars and appliances, and more homes connected to electricity. Each of those raises energy use per person.
- Step 2: Developed countries: most people already have cars, appliances and electricity, so there is less new demand. Efficiency gains, such as better appliances, LED lighting and more fuel-efficient cars, offset the growth that remains.
Answer: Developing countries' per capita use rose because of industrialization and rising living standards; developed countries' stayed flat because demand was already met and efficiency improvements offset growth.
Common mistakes
- Mixing up total and per capita use. China uses the most energy in total; the US uses far more per person.
- Saying renewables now supply most of the world's energy. Fossil fuels still supply roughly four-fifths of primary energy.
- Giving only 'population growth' to explain rising demand. Industrialization and rising living standards matter at least as much.
On the exam
- Expect data tables or bar graphs comparing countries. Read the units and the axis labels to see if the numbers are total or per person before you answer.
- When asked to explain a country's fuel choice, name a specific factor (availability, cost or policy) and connect it to that country.
Connected topics
Videos
Check yourself
5 questions on 6.2 Global Energy Consumption. Pick an answer to see if you got it, and why.
| Country | Population | Energy use per person (gigajoules per year) |
|---|---|---|
| A | 50 million | 280 |
| B | 200 million | 60 |
| C | 100 million | 15 |
Hypothetical data
What is Country B's total yearly energy use?
Country C is industrializing quickly. Based on global trends, which change is most likely over the next few decades?
| Country | Population (millions) | Energy use per person (GJ per year) | Fossil fuels (% of energy) | Traditional biomass: wood, charcoal, dung (% of energy) | Other sources (% of energy) |
|---|---|---|---|---|---|
| P | 60 | 160 | 78 | 2 | 20 |
| Q | 120 | 20 | 35 | 60 | 5 |
Hypothetical data
Country Q has twice the population of Country P. Country Q's total yearly energy use is what percentage of Country P's?
Which statement best explains why Country Q gets most of its energy from traditional biomass?
About how many times more fossil fuel energy does the average person in Country P use than the average person in Country Q?
0 of 5 answered