Teaching Life-Cycle Perspectives: Sustainable
Transportation Fuels Unit for High-School and
Undergraduate Engineering Students
Susan E. Powers, M.ASCE1; J. E. DeWaters2; and M. Z. Venczel3
Abstract: Classroom units were developed for high-school environmental science and college industrial ecology classes to introduce lifecycle perspectives and systems analysis of transportation fuel/vehicle systems. The units at both levels emphasize the need to consider energy
and environmental issues related to the nation’s transportation sector that extend well beyond the gasoline pump and vehicle emissions. The
units include several lessons to introduce environmental issues, understand the fuel and vehicle technologies (high-school level only), and
conceptually and quantitatively evaluate differences among the expected future fuels through a life-cycle assessment. The quantitative assessment of the high-school students shows that the units helped students to significantly raise their energy knowledge and change their attitudes.
Anecdotal information from the students indicates that the increased awareness about the seriousness of energy issues has caused them to be
more conservative and conscientious about their energy consumption behaviors. The evaluation of the class in the 2009–2010 academic year
(AY09) was excellent, suggesting that the addition of the life-cycle assessment activities described in this paper were well received by the
students. DOI: 10.1061/(ASCE)EI.1943-5541.0000059. © 2011 American Society of Civil Engineers.
CE Database subject headings: Engineering education; Energy consumption; Energy efficiency; Energy sources; Transportation
management; Life cycles; Sustainable development; Students; Undergraduate study.
Author keywords: Engineering education; Energy consumption; Energy efficiency; Energy sources; Transportation systems; Life-cycle
assessment.
Introduction
Converting transportation fuels to biofuels, electricity, or hydrogen
is touted by many as a solution to the nation’s growing energy crisis, which includes a waning supply of oil, global climate change,
and increased health effects attributable to poor air quality in most
major cities. But are these new fuels really viable and sustainable
solutions? The hydrogen or biofuel economy and current efforts to
“electrify” transportation systems must be understood and addressed. This will require analysis at a broad systems perspective
before one can ask society to readily accept new fuel and vehicle
technologies. Preparing engineering students to assess these types
of problems is necessary as they move into a profession that has
similar complex and highly interdependent systems.
Americans use about 380 million gal. of gasoline every day,
for a total of 138 billion gal. (17% of total U.S. energy consumption) in 2008 [U.S. Energy Information Association (U.S. EIA)
2010]. This fuel is required to power 249 million vehicles that
1
Professor, Clarkson Univ., Institute for a Sustainable Environment, 8
Clarkson Ave., Potsdam, NY 13699-5715 (corresponding author). E-mail:
sep@clarkson.edu
2
Ph.D. candidate, Clarkson Univ., Institute for a Sustainable Environment, 8 Clarkson Ave., Potsdam, NY 13699-5710. E-mail: dewaters@
clarkson.edu
3
Ph.D. candidate, Clarkson Univ., Institute for a Sustainable Environment, 8 Clarkson Ave., Potsdam, NY 13699-5710. E-mail: venczemz@
clarkson.edu
Note. This manuscript was submitted on March 18, 2010; approved on
October 8, 2010; published online on January 24, 2011. Discussion period
open until September 1, 2011; separate discussions must be submitted for
individual papers. This paper is part of the Journal of Professional Issues
in Engineering Education and Practice, Vol. 137, No. 2, April 1, 2011.
©ASCE, ISSN 1052-3928/2011/2-55–63/$25.00.
travel an average of 12,000 mi per year. The combustion of petroleum fuel is not sustainable. It contributes both to the depletion of a
nonrenewable resource and the increase in the mass of fossil-based
greenhouse gases (GHGs) that are accumulating in the atmosphere.
In 2008, the U.S. transportation sector was responsible for the
emissions of 1,785 Tg CO2 equivalents (eq.) (U.S. EPA 2010). This
represents 31% of the total GHG emissions from the United States
and 5.9% of the total global GHG emissions.
Federal initiatives and regulations related to fuel use have
affected vehicle fuel and efficiency standards for decades. Some
of these efforts have been very effective toward reducing the environmental effects of the transportation sector. For example, tetraethyl lead is no longer used in the United States. It has been banned
since 1996, but it was phased out starting in 1976 because of its
incompatibility with the newly required catalytic converters. Since
lead was removed from gasoline, the concentrations of lead in soil
and airborne particles have significantly decreased. But later efforts
to add oxygenated compounds to gasoline to reduce air emissions
through the 1990 Clean Air Act Amendments lead to the addition
of methyl-tert butyl ether (MTBE) to gasoline and the rapid and
widespread contamination of groundwater aquifers with MTBE
(Zogorski 1997; Franklin et al. 2000). This additive is quite soluble
in water relative to other gasoline constituents and is difficult to
biodegrade. Thus, it is highly persistent in groundwater systems
(Powers et al. 2001). Problems with MTBE highlighted the need
to consider a broader systems perspective when evaluating transportation fuels to avoid unintended consequences.
With the passage of the 2007 Energy Independence and Security
Act (EISA 2007) in the United States, there is currently significant
effort to understand and assess the scope of the potential consequences as the nation transitions to a greater dependence on ethanol
as a fuel additive. EISA requires that the United States produce
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15 billion gal. per year (BGY) of corn ethanol by 2015 and an
additional 16 BGY of advanced biofuels and 5 BGY biodiesel
for a total of 36 BGY of biofuels by ,022. Ethanol is added to gasoline at a concentration of 10% by volume (E10) or 85% (E85).
E85 is available in selected markets, especially in the Midwest.
Over the past several years, the debate on ethanol as a suitable
and sustainable fuel has evolved, starting with initial concerns
about the net energy value of the fuel relative to the energy required
to make the fuel (Shapouri et al. 2002; Pimentel and Patzyk 2005;
Granda et al. 2007; Lavigne and Powers 2007). More recent analyses have include concerns related to nutrient discharges from corn
farming to surface water bodies that are degraded by eutrophication
(Powers 2007; Donner and Kucharik 2008), the net greenhouse gas
emissions, especially related to nitrous oxide emissions from fertilizer transformations in soil (Crutzen et al. 2008; Smeets et al.
2009), the amount of water required to grow corn and process ethanol (NRC 2008; Dominguez-Faus et al. 2009), and global and indirect changes in how land is used in response to the changing
economic market for biomass crops for fuel (Searchinger
et al. 2008).
Biofuels are currently considered to be transition fuels to reduce
dependence on imported petroleum and, although still subject to
debate, reduce greenhouse gas emissions. Biofuels enable the implementation of a new fuel technology with minimal requirements
for a new fleet of vehicles or new fuel production and distribution
infrastructure. Although there are many challenges associated with
the use of biofuels, emerging “second generation” biofuels will
contribute to transportation fuels in the near to midterm future.
Over the longer term, however, advances in hydrogen powered fuel
cell vehicles (HFCVs) or electric vehicles (EVs) are required to
really transform the transportation sector away from a petroleum-based economy. The debate among these fuel-vehicle
systems has been ongoing for years. For example, in President
G. W. Bush’s 2003 State of the Union address, he promoted
the concept of the Hydrogen Economy, and in the 2007 State of
the Union address, he proposed that the solution to reduce dependence on foreign oil for transportation fuels had shifted to biofuels.
Current initiatives point more toward the future role of electric
vehicles, especially as a component of a new “smart grid” for electricity delivery that could utilize energy stored in vehicle batteries
as a source of power when the vehicle is parked (U.S. DOE 2008).
In addition to the advances in vehicle and fuel production technologies that are necessary for a transition to widespread use of
HFCVs or EVs, it is critical to analyze the environmental impacts.
A real benefit of these vehicles is the use of an electric motor for
propulsion. Electric motors are far more efficient than internal combustion engines used with gasoline or biofuel-powered vehicles.
Hydrogen is most efficiently produced by steam reforming of natural gas. This releases CO2 and consumes substantial electrical energy, approximately 50% of which currently comes from coal-fired
power plants. Jacobsen (2007) found that converting to HFCVs
may improve air quality, health, and climate significantly because
of reduced emissions directly from the vehicle. However, HFCVs
utilizing hydrogen produced from coal electricity would damage
climate more than fossil/electric hybrids.
Clearly, the shear magnitude of fuel consumption in the United
States has far-reaching impacts. The question of how extensive the
system boundaries should be when evaluating major changes in the
fuel system is a moving target. The analysis must take into account
impacts on the environment, the economy, and infrastructure—
vehicles and filling stations—that collectively will define the
sustainability of future transportation sector options.
Understanding the environmental sustainability of these types of
very different and complex systems requires a life-cycle perspective
that includes evaluation of all system components, the energy,
materials, and emissions required to produce those components,
and their ultimate fate or disposal. A life-cycle assessment (LCA)
provides a family of methods for evaluating materials, services,
products, processes, and technologies over their entire life. The
main goal of an LCA is to evaluate the environmental effects of
a particular process or product from the point where raw materials
are extracted from the earth, manufactured into the product, used,
and disposed (ISO 2006; Powers and Williamson 2004). An LCA
has become a critical analysis tool to provide the broad perspectives
needed to address complex problems of sustainable systems. The
introduction of this perspective and development of the skills required to quantitatively assess complex systems should be included
in the education of today’s engineers (Mihelcic et al. 2003). Thus,
including the concept of a life-cycle perspective and the skills necessary to complete an LCA should be a component of classes
addressing sustainability.
In addition, energy issues are inarguably the most hotly debated
topics in today’s world. As society moves toward a future with
dwindling fossil fuel resources and worsening environmental
conditions, it is becoming increasingly entrenched in a struggle
to define new directions with respect to energy consumption
and energy independence. Unfortunately, a number of surveys have
shown generally low levels of energy knowledge and awareness
among U.S. students and the general public. [Shelton 2008; National Environmental Education and Training Foundation (NEETF)
2002]. Energy literacy, which includes broad, citizenship knowledge as well as attitudinal and behavioral aspects, will enable people to embrace appropriate decisions and behaviors with respect to
energy in everyday life. An informed public will be better equipped
to make responsible energy choices and actions.
Objectives and Scope
In general, effective educational programs will make strides toward
improving students’ perspective on sustainable energy, fuel systems, and energy literacy. More specifically, integrating LCA concepts into high-school and undergraduate engineering classrooms is
feasible because of the highly relevant topic of automobiles and
fuels to young adults. They have first-hand experience with fuels
and fuel prices and are therefore receptive to learning more about
the future of transportation systems.
A unit on transportation fuels and their environmental impacts
has been developed and taught in both high-school environmental
science classes and an undergraduate industrial ecology class.
The objective of this paper is to share the content of these units
and the assessment of their impact on students. This project draws
from educational research data that show the benefits of using
project-based or inquiry-based approaches to improve student
understanding and retention of content matter (e.g., Elliott et al.
2001), as well as ideas from proponents of STS (Science-Technology-Society) education who maintain that embedding scientific
topics within a societal context will help students become engaged
because they realize the relevance of the material to their own lives
(e.g., Fensham 1988; Solomon 1992; Yager 1996).
The units presented in this paper use a systems perspective
to consider the pros and cons of various vehicle/fuel systems.
Participants investigated transportation fuel needs, completed activities and research to understand the value, risks, and process of
implementing alternative fuels, made hydrogen and biofuels, built
and tested a fuel cell, and analyzed these systems from a life-cycle
perspective. Several options have been used for a culminating
project. In all cases, the students used their newly gained perspective on the problem and alternative solutions to recommend and
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defend a suitable way to move forward with improved sustainability of vehicles and fuel systems.
Classroom Settings
The transportation fuels unit was initially developed for a highschool advanced placement environmental science (APES) class;
it was subsequently modified to increase the quantitative rigor
for use in an undergraduate industrial ecology (IE) class. The APES
unit has evolved over the course of five years of implementation;
the unit has been used once in the IE class.
The APES class does not require a New York State Regents
exam, but it does provide opportunity for advanced college credit
and attracts students from multiple grade levels and a range of
academic abilities, usually with a higher concentration of college-bound students. The 3–4 week transportation fuel unit has
been taught as a special session within this course, with instruction
primarily provided by a graduate student funded through Clarkson
University’s NSF-GK12 Project-based Learning Partnership
Program (DeWaters and Powers 2006). Students enrolled in the
course in 2007–2009 underwent a rigorous assessment of their energy literacy to assess if this type of project helped them to understand broad energy perspectives, including their knowledge,
attitudes, and behaviors. The sample size was 39 students total
(17, 11, and 11 in AY07, AY08, and AY09, respectively).
The industrial ecology class was taught at Clarkson University to
junior and senior students in the fall semester 2009. The students
were predominantly from environmental engineering, with some
students from civil engineering, mechanical engineering, environmental science and policy, and engineering and management majors.
The overall goal of this class was to introduce sustainability concepts, tools, and practices as applied to engineering. Several different
tools that allow engineers to assess the sustainability of a process or
product and integrate environmental impacts into their decision
making process were introduced and used throughout the semester,
including green engineering principles, green accounting, and lifecycle principles and assessment. In this case, the transportation fuel
project was used as a means of exploring the insight and interpre-
tation that can be made from comprehensive life-cycle inventory and
life-cycle impact analyses. There was little to no emphasis on the
particular technologies involved in making the fuels or vehicle energy-conversion processes. Transportation fuels were the subject of
one lecture with a second class period devoted to an in-class workshop quantifying and interpreting LCA results. The students’ work
from this class was evaluated as a homework assignment to assess
their ability to think critically and make decisions on the basis of
environmental sustainability with a systems perspective.
Overview of Sustainable Transportation Fuels Unit
The transportation fuels units have all been taught in a projectbased mode, starting with understanding the problem and finishing
with the justification of a recommended solution. The students are
introduced to their problem, or “guiding question,” at the beginning
of the course, and all activities performed throughout the module
are designed to provide them with the knowledge and skills they
need to fulfill the assignment. The unit is interdisciplinary (integrating science, math, technology, writing, and communication) and
approaches the investigation and application of new automobile
technologies and transportation fuels within a societal and global
context. The key concepts covered in these units are described in
the appendix. Table 1 summarizes the general outline of the highschool course, which follows a standard engineering problemsolving approach. In any given year, the specific details have varied
within this framework. The entire module is designed to extend
over a total of 16 to 20, 40-min class periods. Detailed unit
and lesson plans for this module are available online (Clarkson
University 2009).
In the most recent year that these units were implemented, the
overarching theme and project assignment related to the vast differences among the future fuel/light-duty vehicle transportation
systems and how they impact energy consumption and the environment. Society is accustomed to evaluating fuels and fuel efficiency
by using “miles per gallon.” This is an effective metric for the
energy efficiency of liquid fuels. But it does not help to assess other
environmental impacts or the efficiency of systems that use gaseous
Table 1. Standard Engineering Problem-Solving Process Used in High-School Energy Module
Problem solving approach
Classroom activities
General problem introduction
Background—transportation, vehicles, fuel consumption, other impactsa
Class project introduceda
Research activity—by groups on various impacts [fossil fuel depletion (peak oil), vehicle fuel economy,
air pollutants, polar ice cap size, CO2 concentrations, global temperatures]
Carbon footprint activitya
Cars of the future introductiona
Hydrogen fuel cell vehicles
• How they work—two fuel cell construction activities
• Where hydrogen comes from—electrolysis activity
Electric vehicles
• Batteries and battery activity
Biofuels
• Biofuel options
• Making biodiesel activity
• Heat of combustion of biofuels activity
Energy efficiency activity
Life-cycle perspective activitya
Work days
Final presentation/debate/debrief
Detailed analysis of problem
Identification of potential solutions
Assessment of potential solutions
Selection of recommended solution
a
Activities also included in industrial ecology class. Details of the lessons and activities are available (Clarkson University 2009).
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fuels or electricity, which are not measured by volumetric units.
This question was addressed to different levels at the two grade
levels with results from a transportation fuels LCA model—
GREET. GREET was developed at Argonne National Laboratories
under the direction of Dr. Michael Wang (GREET 2008; Wang
2001) and is continually updated with new data as available.
The spreadsheet version of the GREET 1.7 model was used by
the instructors to generate life-cycle inventory data for the fuel/
vehicle combinations. These data were then compiled and summarized in spreadsheets to share with students in the classes.
The project statement for the APES class was “Issues surrounding our fossil fuel based transportation system, including environmental impacts, limited fuel supplies, and increased economic
burden, have inspired the development of new light-duty vehicles.
Many of these are powered by new types of engines and a variety of
fuels, making it difficult to compare energy use in terms of our
traditional “miles per gallon” standard. Develop a new way to compare the fuel consumption that makes more sense in our changing
society and transportation choices.”
For the undergraduate industrial ecology class, students
were required to identify and quantify several life-cycle impact categories that could be used to compare the fuel economy and environmental impacts of several different fuel/light-duty vehicle
systems:
• Gasoline vehicle—conventional gasoline;
• Gasoline vehicle—low-level ethanol blend with gasoline;
• Flex-fuel vehicle—ethanol fuel (E85);
• Dedicated E85 vehicle;
• Compression ignition diesel with biodiesel;
• Electric vehicle—grid power;
• Fuel cell VEHICLE—gaseous hydrogen; and
• Fuel cell VEHICLE—liquid hydrogen.
They specifically had to define:
• “What life-cycle impact assessment (LCIA) categories
would you use to compare these eight vehicles? Explain and
justify relative to the impacts on which you place the highest
priority.”
• “What are the values of these LCIA categories?”
Fig. 1. Example life-cycle system for production and consumption of conventional gasoline [the circles (impacts) and rectangles (processes) were
printed and cut out for students, who then had to select the components they needed and paste them together on poster board; this example was created
by the writers and is more complete then most of the student-generated posters]
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• “Which car would you recommend? Why? Use a quantitative
discussion to justify your choice.”
Two of the activities that were most critical to the life-cycle perspective was the creation of a poster with a pictorial description of
the fuel production system and the utilization of quantitative LCA
results to formulate a response to the questions posed previously.
These activities are subsequently described in more detail.
Example Activities
Life-Cycle Poster for Fuel Systems
A first step in any LCA is to envision the breadth of the system
boundary. Students at both levels generally have not had prior experience thinking beyond a single or simple combination of unit
operations. Providing a concept of how extensive the system of
concern is for an energy system is eye opening. The specific
key concepts included in this activity include
1. Use of alternative fuels can come with environmental impact
trade-offs;
2. A life-cycle perspective can improve understanding of the (hidden) impacts of using alternative fuels and can help to identify
“best” choices;
3. Use of alternative fuels influences impacts that occur upstream
of the use phase; and
4. Lifestyle choices have effects upstream and downstream of the
immediate setting.
To provide a balance between illustrating this concept and taking too much class time drawing posters, a set of predrawn and cut
system components were prepared and distributed to each group.
Materials were provide to groups to make one of five different
posters: biodiesel, hydrogen—electrolysis with power from wind
turbines, hydrogen—electrolysis with power from coal-fired power
plant, gasoline, and ethanol. The students then had to determine the
interconnections among the system components and locations that
energy is consumed and emissions released. Fig. 1 provides an example of a completed poster. Following the completion of their
poster, the students were required to write a brief report about their
system and address the following questions:
1. What is the initial source of energy for your fuel production
life-cycle?
2. What are the intermediate processes required to make this fuel?
3. What environmental impacts concern you the most? What process (or processes) is responsible for these impacts?
4. Can you suggest any changes to the fuel production process
that might reduce these environmental impacts?
Review of the completed posters showed that although some
students did not accurately depict all of the primary processes, they
did understand the integration of upstream processes to make the
fuel. For example, including a couple of different processes to make
electricity (mostly coal, hydroelectric, and nuclear in the northern
New York region) and including the variable emission among these
different power production methods.
Interpretation of GREET LCA Model Results
The analysis of results from the GREET transportation fuel lifecycle assessment model provided a more quantitative approach
to understanding the nature of environmental impacts along
the well-to-wheels life-cycle. GREET is organized as a complex
spreadsheet model that includes numerous fuels, a database of upstream energy and materials use and emission values, and vehicle
efficiency and emissions to enable many energy and emission
Table 2. Example of GREET 1.7 LCA Results Used for Industrial Ecology Class Project
Item
Energy-related (Btu=mi)
Total energy
Fossil fuels
Coal
Natural gas
Petroleum
Emissions-related (g=mi)
CO2
CH4
N2 O
VOC: total
CO: total
NOx : total
PM10 : total
PM2:5 : total
SOx : total
VOC: urban
CO: urban
NOx : urban
PM10 : urban
PM2:5 : urban
SOx : urban
Feedstock
Fuel
Vehicle operation
Total
177
171
33
82
56
946
934
174
314
445
4631
4535
0
0
4535
5755
5639
207
396
5036
1:05E þ 01
4:22E 01
3:42E 04
1:59E 02
3:01E 02
1:13E 01
8:74E 03
3:97E 03
2:64E 02
2:71E 03
1:27E 03
5:03E 03
1:76E 04
1:28E 04
2:82E 03
7:06E þ 01
8:33E 02
6:20E 03
1:09E 01
4:22E 02
1:15E 01
3:83E 02
1:30E 02
7:95E 02
6:92E 02
1:97E 02
4:54E 02
3:68E 03
2:60E 03
3:47E 02
3:56E þ 02
1:46E 02
1:20E 02
1:80E 01
3:74E þ 00
1:41E 01
2:86E 02
1:48E 02
5:81E 03
1:12E 01
2:33E þ 00
8:77E 02
1:78E 02
9:21E 03
3:61E 03
4:37E þ 02
5:20E 01
1:85E 02
3:05E 01
3:82E þ 00
3:69E 01
7:57E 02
3:18E 02
1:12E 01
1:84E 01
2:35E þ 00
1:38E 01
2:16E 02
1:19E 02
4:11E 02
Note: Only one vehicle/fuel system is included in the table as an example: conventional or reformulated gasoline (CG/RFG) used in an average internal
combustion engine. These data were provided to students as an MS Excel worksheet to facilitate quantitative analysis. APES class only received detailed fuel
consumption and total GHG emissions for a simpler analysis.
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values to be estimated for the feedstock production, fuel production, transportation, and fuel consumption stages of the life-cycle.
Final results are presented on a per-mile driven basis to provide a
comparable function among all of the systems included. Although
it was found that directly using the spreadsheet model is too
advanced of a task for students within the time available in a
classroom setting, the students can readily interpret the results
of the model (Table 2).
The students had to choose their highest priority for impact and
compare automobiles on the basis of that metric (conventional gasoline, E85 in a flex-fuel vehicle, an EV with current electricity mix,
and an HFCV with gaseous fuel). They considered some basic metrics that are readily available from the GREET output: total energy
used as a measure of energy efficiency, total life-cycle fossil fuels
consumed as a metric for nonrenewable resource depletion, GHG
emissions for climate change, or life-cycle petroleum consumed as
an inverse measure of energy security.
The industrial ecology students received data in a less aggregated form (Table 2). Before they made their comparison, they
had to convert these inventory data into midpoint impact categories
to aggregate the values on the basis of equivalency factors. On the
basis of their earlier class work, the students were prepared to transform the inventory values into total energy, fossil fuel or petroleum
energy consumed, global warming potential, PM10 formation
potential ,and acidification potential.
Fig. 2 provides the results of the analysis. These graphical results show that the GREET model predicts the overall superiority of
the HFCV over conventional fuel/vehicle systems and biofuels.
EVs are nearly as good as the HFCVs.
Some key points that can be interpreted from the GREET results
include the following:
• Biofuels require substantial energy to generate the feedstock
and fuel. However, only a small fraction of this is petroleum,
so a fuel with a high percentage of a biofuel (E85) substantially
reduces dependence on imported petroleum.
• Fuel cell–gas vehicles have the highest efficiency and lowest
resource demand and lowest global warming potential.
• Fuel cell–gas vehicles have from 4 to 150 times lower lifecycle petroleum requirements than other systems.
• Fuel cell–gas vehicles have 238 g CO2 eq./mi compared to conventional gasoline vehicles that have 456 g CO2 eq./mi emitted
over its life-cycle of feedstock and fuel production and use.
• Fuel cell–gas vehicles consume the lowest amount of energy/
mile of the vehicles compared (3470 Btu=mi)
This overall superiority of HFCVs and EVs is defined on the
basis of the criteria and the assumptions in the GREET model.
These results do not adequately include the variability in batteries
used (Notter et al. 2010) and potential electricity sources used to
generate hydrogen or plug in EVs (Colella et al. 2005). GHG emissions, for example, can vary by orders of magnitude if the power
comes from renewable versus fossil fuel sources. Colella et al.
(2005), for example, analyzed differences in electricity generation.
They showed that the benefits of replacing current vehicles with
hybrids would reduce GHG emissions by 6%. HFCV would reduce
GHG emissions by 14% if the hydrogen is generated from natural
gas, 23% if wind power used, or only 1% if coal is used. Given
rapid advances in both vehicle and energy production technologies,
the predictions made with this version of the GREET model are
likely to be obsolete in a relatively short time. The GREET model
is consistently updated to reflect these advances and new versions
of the GREET model should be used when available.
Fig. 2. Example results from the analysis of life-cycle inventory results
provided to college students for eight different fuel/vehicle systems
and three different environmental/energy impact categories: (a) total
energy consumed; (b) petroleum energy consumed; (c) global warming
potential
Assessment
Methods
The study used a mixture of quantitative and qualitative methods
for assessing the change in the high-school students’ perspectives
and understanding of energy systems. A quantitative energy literacy survey that was developed as one aspect of this overall energy
education project (DeWaters and Powers 2011) was used both before and after the classroom unit was implemented. The survey was
developed following rigorous established psychometric principles
for classroom administration. It uses a combination of multiplechoice and Likert-type scales to address energy-related knowledge,
attitudes toward energy issues, feelings of self-efficacy, and energy
consumption behaviors and intentions. Questions contained in the
energy literacy survey are intentionally broad in nature, and are not
intentionally related to the course content.
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Table 3. Student Scores, Energy Literacy Assessment Questionaire
Survey section
Knowledge
Attitude
Self-efficacy
Behaviors/intentions
Prea
Posta
Differencea
p valueb
0:60 0:14
0:80 0:10
0:71 0:18
0:63 0:17
0:68 0:12
0:81 0:10
0:75 0:15
0:69 0:17
0:084 0:075
0:014 0:090
0:043 0:112
0:052 0:092
≪ 0:0001
0.177
0.014
< 0:001
Note: n ¼ 39 students.
Mean Standard Deviation.
b
Statistical significance of pre/post gain calculated with paired sample; 1-tailed t test ¼ values with p less than the target of 0.05 are highlighted as bold.
a
Table 4. Student Evaluation of the High-School APES Transportation Fuels Unit
Percentage of students who responded positivelya
Evaluation statement
I found the topic interesting.
I found the topic relevant to my own life.
How much did you learn about the specific energy topic you studied?
How much did you learn about other energy-related issues, not
necessarily related to the specific topic we studied?
a
AY07
AY08
AY09
82
87
82
75
69
75
82
82
100
91
91
100
Positive response is “definitely yes” or “yes” for the first two statements, “a lot” or “quite a bit” for the second two statements.
Additional qualitative procedures for assessment consisted of
classroom observations, postprogram focus group interviews, reflective essays, and questionnaires that contain a combination of
closed- and open-ended questions. Parent questionnaires provide
information about the extent to which students shared their learning
at home. Finally, teachers were interviewed to obtain in-depth information about the extent and depth of energy education in the
classrooms.
Assessment Results
Student mean scores on the energy literacy survey, pre- and postprogram, are quantified in Table 3 for all three program years combined. In general, student scores on the knowledge subscale are
quite low (mean values pre and post of 0.60 and 0.68, respectively),
although the increase in knowledge was statistically significant
(p ≪ 0:001), showing a positive impact of this unit. Scores on
the attitude subscale were substantially higher, a finding that is consistent with earlier research (e.g., Bang et al. 2000). Self-efficacy
and behavior scores were higher than knowledge but not as high as
general attitude scores. This progressive decline in student scores,
from attitude to self-efficacy to behavior, is understandable if the
nature of the items in these scales is considered. For example, it
may be easier for a student to indicate strong or moderate agreement with a generalized attitude statement such as “Americans
should conserve more energy,” as compared with a personalized
self-efficacy statement like “I believe I can contribute to solving
energy problems by making appropriate energy-related choices
and actions.” Agreement becomes even more difficult when discussing statements that reflect actual behaviors, such as “I turn off my
computer when it’s not in use.” The relatively high attitude scores
and significant improvement seem to indicate that these students
hold views that embrace the significance of the energy problems
they face, yet they may lack the appropriate knowledge to take
effective action toward a solution.
The life-cycle assessment aspect of the APES unit was only introduced in AY09. The student evaluation of this course indicates
that they greatly appreciated the content of this unit (Table 4). The
evaluations this year were significantly higher than in previous
years when the overall systems perspective on the issues was
not emphasized as much. Some highlights from the student reflective essays and postquestionnaire items indicate the following:
• 45% of students (AY09) indicated that they talked more with
their families about energy issues after taking the course. Parent
surveys verified this finding, indicating that their child seemed
more interested and concerned about energy issues and energy
consumption;
• 81% (AY07, AY08, AY09) wrote that the course increased their
awareness of the energy problem, negative impacts related to
energy use, and the need to conserve energy. Seven students
reported specifically that they were more aware that, as Americans, we consume too much energy and create too much waste;
• 54% (AY08, AY09) expressed an increase in feelings of selfefficacy, agreeing that their actions and behaviors as individuals
can help solve problems related to the energy situation (limited
fossil fuel supplies, environmental impacts from production and
use). “[The course] convinced me that our individual actions do
affect the world as a whole and energy conservation should be
taken seriously…”;
• 81% (AY07, AY08, AY09) expressed their willingness to assume responsibility for solving energy problems instead of
leaving them for future generations (students agreed that it is
[completely or mostly] their generation’s responsibility to solve
the energy problems that face our world);
• 60% (AY07, AY08, AY09) reported positive changes in their
energy consumption behaviors. “I am surprised to see how
much I have applied [this learning] to my everyday life.”;
• A full 55% (AY07, AY08, AY09) reported making an effort to
use less energy through such specific actions as driving less/
walking or carpooling more, recycling more, using less water,
and being more cognizant of turning off lights and appliances
when not in use.
One student expanded about the way the course influenced her
overall motives for saving energy: “Before, I would limit driving
because I didn’t want to waste money for gas… but now it is a
different motive. I understand the effects of driving a car even just
one mile. The amount of energy needed just to put the fuel in my
car, the quantity combusted, and the emissions… are significant
even if it’s just for one mile.”
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Summary and Conclusions
Classroom units were developed for high-school environmental science and college industrial ecology classes to introduce life-cycle
perspectives and systems analysis of transportation fuel/vehicle
systems. The units at both levels emphasized the need to consider
energy and environmental issues related to the nation’s transportation sector that extend well beyond the gas pump and vehicle—the
aspects that the students see in their everyday lives. The units
include several lessons to introduce the environmental issues,
understand the fuel and vehicle technologies (high-school level
only), and conceptually and quantitatively evaluate differences
among the expected future fuels through a life-cycle assessment.
Variations on the unit have been taught at the high-school level
for sufficient years to generate sufficient data for legitimate assessment. The quantitative results show that the units helped students
to significantly raise their energy knowledge and change their
attitudes. Their knowledge scores, however, remained low (68%
correct answers) even after the unit. Anecdotal information from
the students indicates that the increase awareness about the seriousness of our energy issues has caused them to be more conservative
and conscientious about their energy consumption behaviors. The
evaluation of the class in AY09 was excellent, suggesting that
the addition of the life-cycle assessment activities described in this
paper were well received by the students.
Acknowledgments
This work was sponsored by the National Science Foundation,
Grant Nos. DUE-0428127 and DGE-0338216. The findings and
opinions presented here do not necessarily reflect the opinions
of the funding agency.
Appendix. Key Concepts Covered in the
Transportation Fuels Units
• On the basis of the present understanding of the amount of
economically extractable crude oil, petroleum fuels will not
be sufficient to meet future demands.
• Fuel cell and hydrogen production technologies, electric cars,
and biofuels production are rapidly advancing and are proposed
for use in transportation vehicles.
• Fuel cells and battery-operated electric vehicles operate on the
basis of an electrochemical reaction to generate electricity that is
used in an electric motor to power the car. (This concept is not
covered in the college-level industrial ecology class because the
emphasis was on using and interpreting LOCA data, not the
specific technologies themselves.)
• Energy conversions require systems and subsystems, and more
components result in lower efficiency. Efficiency can increase as
technologies improve.
• Hydrogen, electricity, and biofuels must be generated; these
processes require energy.
• Choosing an alternative fuel source requires an understanding of
the entire fuel/vehicle system and the trade-offs from many
different perspectives.
• Emissions from hydrogen use in a vehicle are very clean,
although there are emissions associated with energy consumption to make the hydrogen.
• Energy use and environmental impacts depend on both the
source of energy as well as the conversion processes.
• Changes in future transportation vehicles and fuels will require
technological advances but also social, business, and policy
changes.
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