Energy and Human Ambitions on a Finite Planet, 2021a

7 The <strong>Energy</strong> L<strong>and</strong>scape 111
the global energy, corresponding to about 5.5 times the global average
per citizen. Today, the ratio is closer to 4.
The right side of Figure 7.9 similarly explores U.S. share of renewables.
The only up-trending resource is biomass, due to m<strong>and</strong>ates for ethanol
usage. 18 But it is a minor player in the scheme of things. Solar <strong>and</strong> wind 18: More on biofuels in Chapter 14.
are interesting, in that the U.S. initially held a large global share as
pioneers of the technology before the rest of the world joined in.
7.3 Upshot: Go to the Source
The purpose of this chapter was twofold: first to introduce students to
sources of reliable information on national <strong>and</strong> global energy production;
<strong>and</strong> second to communicate the l<strong>and</strong>scape of energy use. What emerges
is a picture of a world still firmly in the grip of fossil fuels, whose annual
usage continues to increase. Wind <strong>and</strong> solar are making inroads, but only
at the few-percent levels thus far. The U.S. has played an outsized role in
global energy relative to its population, especially in the mid-twentieth
century.
7.4 Problems
1. Referring to Figure 7.1 <strong>and</strong> Figure 7.2, figure out the following
measures:
a) What percentage of energy consumption in the U.S. is from
petroleum?
b) What percentage of transportation is powered by petroleum?
c) What percentage of petroleum goes directly to transportation? Not the same as previous question.
d) What percentage of petroleum goes directly to industrial
processes (ignoring via electricity)?
2. The electricity block at the bottom center of Figure 7.2 is said to be
38.3 qBtu in size. Using the qBtu numbers in the sources at left, <strong>and</strong>
the percentages of each going to electricity, figure out how many
qBtu each line connecting to the left side of the electricity block
represents. 19 What is the total, <strong>and</strong> does it match the 38.3 qBtu
expectation, within reasonable rounding errors?
19: Example 7.1.1 may offer guidance.
3. Building off the result in Problem 2, calculate the percentages 20 of 20: Verifying that they add to 100% is a
contributions coming into the left side of the electricity block in good check.
Figure 7.2? Which is the dominant input?
4. Following a similar approach as for Problem 2, 21 concentrate on 21: See also Example 7.1.1.
the output side of electricity production 22 <strong>and</strong> figure out how
many qBtu are delivered to each sector on the right-h<strong>and</strong> side of
the figure, based on input percentages to each of the four sectors
22: 13.0 qBtu delivered; implying 34% conversion
efficiency from primary sources to
delivered electricity
© 2021 T. W. Murphy, Jr.; Creative Commons Attribution-NonCommercial 4.0 International Lic.;
Freely available at: https://escholarship.org/uc/energy_ambitions.