Energy Excursions

Global Primary Energy

In the previous lesson we learned about the difference between primary and secondary energy. As a refresher, by definition, “primary energy (PE) is an energy form found in nature that has not been subject to any human engineered conversion process. It is energy contained in raw fuels and other forms of energy, including waste, received as an input to the system. Primary energy can be non-renewable or renewable.1Wikimedia Foundation. (2021, August 30). Primary energy. Wikipedia. Retrieved September 21, 2021, from https://en.wikipedia.org/wiki/Primary_energy#:~:text=Primary%20energy%20(PE)%20is%20an,be%20non%2Drenewable%20or%20renewable. 

 The graph below, published by the web publication Our World in Data, plots global direct primary energy consumption from 1800-2020. The direct primary energy sources include: 

  • Traditional biomass
  • Coal 
  • Oil 
  • Gas 
  • Nuclear 
  • Hydropower 
  • Wind 
  • Solar 
  • Other renewables 
  • Modern biofuels 

On the plot, global energy consumption is measured in terawatt-hours (TWh). Energy consumption on such a large scale is often measured in terawatt-hours, and one terawatt-hour is equivalent to one-trillion watts per hour or 3.6 * 1015 joules. 

Using the interactive graph, answer the series of questions that follow to gain a better perspective on the changes in global primary energy sources consumed over time. To view primary energy consumption in percentages first check the ‘relative’ box in the upper left hand corner. From there you can toggle your mouse throughout the chart to view percentages for each year. 

Traditional biomass is plotted on the graph. Prior to the use of fossil fuels and modern renewables, humans primarily relied on biomass to satisfy their energy consumption needs. By definition, biomass is “plant or animal material used as fuel to produce electricity or heat.”2Wikimedia Foundation. (2021, September 11). Biomass. Wikipedia. Retrieved September 21, 2021, from https://en.wikipedia.org/wiki/Biomass. Biomass is a renewable energy source.

What do you think was the primary global biomass source in the 1800’s?

Wood

Correct. 

Wood was the primary global biomass source, for example, used for heating and cooking,  in the 1800’s. 

Coal

Incorrect. 

Animal Waste

Incorrect. 

Starting in 1800, estimate the successive doubling time for energy consumption. (i.e., how long did it take to double the first time, then how long to double again, etc.). Much of the chart has been completed – calculate the numbers for the blanks in the table below where you can refer to them (TWh rounded to nearest 100s).

YearConsumption, TWhTime to double, years
18005,600No data to determine
190012,100100
40
196040,60020
1978
159,00041
Is annual energy consumption still growing? Is the rate of growth increasing? What data supports your answer?

Annual energy consumption is not continuing to grow, therefore the growth rate is decreasing.

Incorrect. 

Annual energy consumption is still continuing to grow; however, the growth rate is decreasing.

Correct.

Annual energy consumption is still growing (through 2019), however the rate of growth is decreasing. We can note the doubling time in Question Two increased from 18 years (1960-1978) to 41 years (1978-2019). 

Annual energy consumption is still continuing to grow, as well as at an increasing growth rate.

Incorrect. 

Click to See the Completed Table

YearConsumption, TWhTime to double, years
18005,600
190012,100100
194022,50040
196040,60020
197881,00018
2019159,00041

According to the data in the chart, when did crude oil initially become the most significant source for consumption? What primary energy source did it replace as most significant? What was its percent share in that year and more recently (=2019 on the chart) (check the relative box on the chart to get percentages)? How would you describe the trend in global crude oil consumption over the last ~50 years?

Crude oil initially became the most significant source for consumption in 1978, when consumption of crude oil hit 36,426 TWh, surpassing all other sources of energy listed in the data chart.

Incorrect. 

Crude oil initially became the most significant source for consumption in 2016, when consumption of crude oil hit 51,920 TWh, surpassing all other sources of energy listed in the data chart.

Incorrect. 

Crude oil initially became the most significant source for consumption in 1965, when consumption of crude oil hit 18,109 TWh, surpassing all other sources of energy listed in the data chart.

Correct.

The percent share in 1965 of crude oil consumption was 36%, surpassing the contribution from coal. More recently (2019) the percent share of crude oil consumption is 34%. The percentage share of crude oil consumed by the world has essentially remained stable for the last ~50 years. 

For 2019, which is the most significant renewable energy source and its percent share? In this case, think about the ‘renewable’ energy sources used by many people in 3rd world countries.

Solar

Incorrect. 

Wind

Incorrect.

Traditional Biofuels

Correct.

For 2019, the most significant renewable energy source is traditional biofuels (wood, dung, etc.) at 7% of total global energy consumption.

What are the percentages for wind and solar in 2019? If you were to describe the global significance of wind and solar to someone, what would you say?

For 2019, wind is .9% and solar is .5% of total global energy consumption

Correct.

Wind and solar are each less than  1% of total global energy  consumption. 

For 2019, wind is 0.01%and solar is <0.01% of total global energy consumption

Incorrect. 

For 2019, wind is 0.43% and solar is 0.09% of total global energy consumption

Incorrect. 

TEKS Standards
College Board Units and Topics