Unit 6 · Topic 6.2 Beta

Global Energy Consumption

The world runs mostly on fossil fuels, about 80 percent of its energy.

Practice 5: Data Analysis

Part 1 · Hook

Why this matters

A family in a city in a wealthy country runs a furnace, a refrigerator, two cars and a dozen screens. A family in a rural village elsewhere cooks over a wood fire and has one light bulb. Multiply those differences by billions of people and you have the pattern of world energy use: who uses how much, of which fuel, and why it keeps rising.

Part 2 · Before you start

What this builds on

Part 3 · Prerequisite check

Quick check before you start

1. Which describes a developed country compared with a developing country?

Higher income per person and more industry
A faster-growing population
More people working on farms
A higher birth rate

Show the answer

Developed countries are richer per person and more industrialized; developing countries usually grow faster.

Correct: Higher income per person and more industry:
A faster-growing population:
More people working on farms:
A higher birth rate:

2. Which fuels are nonrenewable?

Coal, oil and natural gas
Sunlight and wind
Firewood regrown each decade
Moving river water

Show the answer

Fossil fuels exist in fixed amounts and form over millions of years.

Correct: Coal, oil and natural gas:
Sunlight and wind:
Firewood regrown each decade:
Moving river water:

3. A value rises from 40 to 50. What is the percent change?

25%
20%
10%
125%

Show the answer

$\frac{50 - 40}{40} \times 100 = 25\%$ .

Correct: 25%:
20%:
10%:
125%:

Part 4 · See it

See it first

Stacked bars of energy use per person in gigajoules per year for four invented countries from less to more developed: A 15 (10 biomass, 5 fossil fuels), B 40 (8 biomass, 30 fossil fuels, 2 other), C 110 (4 biomass, 92 fossil fuels, 14 other), D 230 (5 biomass, 185 fossil fuels, 40 other). Invented data for practice. — Energy use per person in four invented countries, from less to more developed. Use rises with development, and fossil fuels supply most of it in richer countries. LevlPrep original diagram.

Part 5 · Step by step

How it works, step by step

A country industrializes and incomes risefactories, vehicles, appliances and heating or cooling spread
Each of these runs on fuel or electricityenergy use per person rises, often more than tenfold
Most new supply still comes from cheap, available fossil fuelsworld use of coal, oil and natural gas keeps growing
Total use is population times use per personworld energy use rises as developing countries grow in both

Part 6 · Key ideas

Key ideas

Fossil fuels supply about 80 percent of the world's energy. Oil is the largest single source, used mostly for transportation; coal is the largest single source of electricity worldwide.
Energy consumption per person is highest in developed countries. The United States has about 4 percent of the world's people and uses roughly one sixth of its energy.
Use is rising fastest in developing countries as they industrialize. About 2.1 billion people lack clean cooking fuels and burn mostly wood, charcoal, crop waste or dung.
Total use = population × use per person. Read graphs for both the total and the per-person value, and compare with numbers.

Part 7 · Misconception

A common mistake

The wrong idea: The country with the most people uses the most energy per person.

What actually happens: Population raises a country's total energy use, but use per person depends on wealth, industry and climate. A small rich country can use many times more per person than a large poor one.

Part 8 · Check yourself

Check yourself

Exam-style questions. Anything you miss goes into your review queue.

1. Which group of sources supplies most of the world's energy today?

Wind and sunlight together with moving water
Nuclear power and Earth's internal heat combined
Wood, charcoal, crop waste and other biomass
Fossil fuels: oil, coal and natural gas

Show the answer

Oil, coal and natural gas together supply about four fifths of the world's energy (80 to 86 percent, depending on the source).

Wind and sunlight together with moving water: Wind, sunlight and moving water are growing fast but supply far less than fossil fuels.
Nuclear power and Earth's internal heat combined: Nuclear power supplies only a few percent of the world's energy, and Earth's internal heat less.
Wood, charcoal, crop waste and other biomass: Biomass is the main fuel for many poorer households, but a small share worldwide.
Correct: Fossil fuels: oil, coal and natural gas: Right: fossil fuels supply about 80 percent.

2. The United States has about 4 percent of the world's people and uses roughly one sixth of the world's energy. What does this show?

The United States uses about 4 percent of the world's energy
Energy use per person in the United States is far above the world average
The United States uses less energy per person than most countries
Most of the world's energy is used by the United States

Show the answer

A share of energy (about 16 percent) roughly four times its share of people (about 4 percent) means use per person about four times the world average.

The United States uses about 4 percent of the world's energy: Four percent is the share of people, not the share of energy.
Correct: Energy use per person in the United States is far above the world average: Right: about 16 percent of the energy for about 4 percent of the people.
The United States uses less energy per person than most countries: A larger share of energy than of people means more per person, not less.
Most of the world's energy is used by the United States: One sixth is a large share, but it is not most of the world's energy.

3. A country's energy use rose from 1,200 petajoules in 2000 to 1,500 petajoules in 2020. Write the setup for the percent change, then give the answer.

Type the setup as on the exam, with brackets and units, then the answer.

Show the answer

Percent change is (new minus old) divided by old, times 100: $\frac{1{,}500 - 1{,}200}{1{,}200} \times 100$ $= 25\%$ .

Setup: $\frac{1500 - 1200}{1200} \cdot 100$ ; answer 25 %

Data

World energy use by source, 1980 to 2020

Renewables include moving water, wind, sunlight and modern biomass. 1 exajoule (EJ) = 1,000 petajoules.

4. Which fuel supplied the most energy in every year shown?

Oil
Coal
Natural gas
Renewables

Show the answer

The oil line sits above the others at every point, from 130 to 180 exajoules.

Correct: Oil: Right: oil is highest in each year.
Coal: Coal is second for most of the period.
Natural gas: Natural gas grows steadily but stays below oil.
Renewables: Renewables are the smallest in each year shown.

5. Write the setup for the percent change in natural gas use from 1980 to 2020, then give the answer.

Type the setup as on the exam, with brackets and units, then the answer.

Show the answer

$\frac{140 - 50}{50} \times 100$ $= 180\%$ . Natural gas use nearly tripled.

Setup: $\frac{140 - 50}{50} \cdot 100$ ; answer 180 %

6. Between 2000 and 2020, which source grew the most in percent terms?

Coal
Natural gas
Renewables
Oil

Show the answer

Renewables went from 30 to 70 exajoules: $\frac{70 - 30}{30} \times 100 \approx 133\%$ . Coal grew $\frac{150 - 95}{95} \times 100 \approx 58\%$ , gas $\frac{140 - 90}{90} \times 100 \approx 56\%$ , oil $\frac{180 - 155}{155} \times 100$ $\approx 16\%$ .

Coal: Coal grew about 58 percent: a large amount, but a smaller percent than renewables.
Natural gas: Natural gas grew about 56 percent.
Correct: Renewables: Right: about 133 percent, far more than any fossil fuel.
Oil: Oil grew about 16 percent.

Part 9 · Summary

Summary

The world runs mostly on fossil fuels, about 80 percent of its energy. Energy use per person is far higher in developed countries, while total use is growing fastest in developing countries as their populations and incomes rise. Reading energy data means comparing totals and per-person values with numbers, and percent change is (new - old) / old × 100.

Part 10 · Up next

What comes next

Part 11 · Connections

Connections

Question set for this topic