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\centerline{MONT 104N -- Modeling the Environment}
\centerline{Chapter 3 Project}
\centerline{October 4 and 7, 2019}
\vskip 10pt
\noindent
\subsection*{Introduction}
To solidify your confidence in dealing with quantitative information, this project 
summarizes ideas developed in the previous two
chapters, as well as a few data visualization topics that we have not mentioned
before.  The subject will be the whole United States energy economy in recent years.


\subsection*{Background}
This project is inspired by a similar project developed for the book
{\it Quantitative Reasoning and the Environment} by 
Greg Langkamp and Joseph Hull (Prentice Hall, 2007), but 
uses different and more recent data.

Figure~\ref{fig:USEnergy2018} shows estimated
energy production and end-use consumption data for all major sectors in 
the United States energy economy for the year 2018.
\begin{figure}
\begin{center}
\includegraphics[angle=90,width=5.0truein,height=8.0truein]{Energy_US_2018.png}
\caption{The U.S. energy sector in 2018.}
\label{fig:USEnergy2018}
\end{center}
\end{figure}
Figure~\ref{fig:USEnergy2010}, given later, shows the analogous data for the year 2010.
Similar diagrams have been produced each year by the Lawrence Livermore National Laboratory,
using data provided by the Energy Information Administration, a division of the U.S. Department 
of Energy.

\subsection*{Reading the Charts}
To read these diagrams, you will want to rotate the page or the screen by $90^\circ$ clockwise, 
then follow the flow of energy by reading from left to right.  On the far left are boxes representing
the major energy sources labeled Solar, Nuclear, Hydro, Wind, etc.  The 4 boxes towards 
the right (Residential, Commercial, Industrial, Transportation) are the four largest end-use 
sectors of energy consumption.  Some of the basic source energy is first converted to electricity before 
it is transmitted to the four end-use sectors, as shown by the box labeled ``Electricity 
Generation.''\footnote{At the top of the diagram, you 
can also see that there is a very small amount of electric energy that was imported 
(mostly from hydroelectric plants in Canada).  This
is so small that it is essentially negligible in the big picture.}  On the far 
right, two boxes in the diagram indicate the total amount of energy that is lost 
or wasted (``Rejected Energy") and the amount that is used for its intended purpose 
(``Energy Services").  The ``pipelines'' joining the boxes represent how much energy
originating in the box to the left was delivered to the box on the right.  The numerical 
amounts are given as the numbers printed next to the pipelines in units to be discussed 
below.\footnote{The numbers aren't always near the source, so you may need to hunt for them!}
The width of each energy flow (pipeline) is also in direct proportion to the amount 
of energy in that flow so you can judge the 
importance visually.  

\subsection*{Units}
The header on the top of the chart states that the estimated total energy consumption in 
2018 was 101.2 Quads.  This means 101.2 quadrillion BTUs.  
One quadrillion is $1 \times 10^{15}$.   All energy measurements on the diagram have units of 
quadrillion British thermal units (BTU's), or ``Quads'' for short.  The BTU is an English system
unit of energy; we use it rather than a corresponding metric unit
because that is the way these charts from the Lawrence Livermore National
Laboratories are reported to interested parties in the United States. 
One BTU is the quantity of heat needed to raise the temperature of 1 pound of water by  
$1^\circ$ F at or near $39.2^\circ$ F.  Some approximate conversion factors for the 
energy content of common energy sources are given below, in units typically used to 
measure those forms of energy by consumers.
\index{conversion factors}
\begin{table}[ht]
\renewcommand\arraystretch{1.5}
\caption{Energy content of various energy sources.}
\label{EnergyEquivalents}
\[
\begin{array}{|c|c|}
\hline
\text{Energy source} & \text{Equivalent (BTU)} \\ 
\hline
\text{1 ton coal} & 21,400,000\\
\hline
\text{1 barrel (42 gal.) oil} & 5,800,000\\
\hline
\text{1 cubic foot natural gas} & 1000\\
\hline
\text{1 kilowatt-hour electricity} & 3,400\\
\hline
\end{array}
\]
\end{table}
In most cases, the numbers on the chart have been rounded to 1 or 2 decimal places 
(tenths or hundredths of a Quad).  Because of this rounding, the total Quads listed 
next to each production sector and end-use sector might not exactly equal the sum of the individual components.

\subsection*{Questions}
\begin{enumerate}
\item[(A)]  Rank the energy sources from highest to lowest in Quads and compute the percentage each accounts for in the total U.S.
energy sector.  Construct a \emph{pie chart} representing this information.  (You can do this in Excel, for instance, or construct the 
pie chart by hand.)
\vskip 5pt
\item[(B)]  Using Table~\ref{EnergyEquivalents}, determine the answers to the following.
\vskip 5pt
\begin{enumerate}
\item[(1)] What is the equivalent amount of coal used in 2018 in units of tons?\vskip 5pt
\item[(2)] What is the equivalent amount of natural gas used in 2018 in cubic feet?
\end{enumerate}
\vskip 5pt
\item[(C)]  Construct a table showing the total natural gas energy used by each of the four end-use sectors.  
Note that some of the natural gas is used for Electricity Generation, and that electricity is then used in the end-use sectors.  In other words, 
do not miss the portion of the end-use sectors that use natural gas by way of electricity generated by burning gas.    (How will you 
account for the fact that only a part of the Electricity Generation is done by burning natural gas?)
\vskip 5pt
\item[(D)]  Which of the energy sources are based on \emph{fossil fuels}?  Which of the energy 
sources are \emph{renewable energy} sources?  What percentage of the total energy 
produced is accounted for by renewables?
\vskip 5pt
\item[(E)]  {\bf Analysis of the Electricity Generation sector.}  Many sources of energy flow into the electric power sector, 
which then distributes electricity to the end-use sectors.  Petroleum, coal, natural gas and biomass are burned in conventional 
power plants to produce heat to boil water.  The steam from the boiling water spins turbines which then produce electricity.  
Nuclear fuels can be used to produce electricity in much the same way: nuclear reactions in power plants make the heat 
which produces the steam, which spins the turbines, which produce the electricity.  Other sorts of energy are also used
to generate electricity.   Both conventional-electric and nuclear-electric 
power plants have the property that a large amount of the fuel energy is lost in the process of making electricity and then more
is lost during transmission along electrical lines.  \vskip 5pt
\begin{enumerate}
\item[(1)]  The 2018 diagram indicates that the electric power sector converted various energies to 38.2 Quads of electrical energy. 
What were the top two sources of energy for the electric power sector?  \vskip 5pt
\item[(2)]  How many Quads of electricity were successfully distributed from power plants, and how many Quads were lost at the power plants? \vskip 5pt
\item[(3)] The \emph{efficiency} of an energy system is defined as the percentage of the total energy used for the intended purpose.  
Determine the efficiency of the U.S. electric power sector, using your previous answers and 
\emph{ignoring losses after distribution}.\vskip 5pt
\item[(4)] Natural gas contributed 11.0 Quads of energy to the electric power sector.  How many Quads of that contribution were 
immediately lost by the electric power sector?  Explain any assumptions you are making.\vskip 5pt
\item[(5)]  Give two practical reasons why so little electricity is distributed to the transportation sector.\footnote{There is \emph{some} electric
power used for transportation, though.  The Amtrak Northeast Corridor passenger rail lines between Boston and Washington, DC use electric power, as do most subway and light rail mass transit systems in cities, for instance.}
\end{enumerate}
\vskip 5pt
\item[(F)]  {\bf The industrial sector.}  The Industrial sector includes manufacturing industries, mining, construction, agriculture, fisheries and forestry.  \vskip 5pt
\begin{enumerate}
\item[(1)] The industrial sector consumed 26.3 Quads through \emph{six} forms of energy.\footnote{You will need to look carefully to find them all, but
they are there!}  Draw a bar chart to illustrate the number of Quads used for each of those six form of energy.  Label each bar with its energy name and amount.\vskip 5pt
\item[(2)] Natural gas energy is directly consumed by the Industrial sector through the burning of natural gas.  But the Industrial sector also consumes 
natural gas energy indirectly by using distributed electricity. Compute the total Quads of natural gas energy consumed by the industrial sector.  
Ignore energy losses.  \vskip 5pt
\end{enumerate}
\item[(G)]  {\bf Petroleum and transportation.}  \vskip 5pt
\begin{enumerate}
\item[(1)] The transportation sector is primarily fed by the energy derived from Petroleum, with small contributions from Biomass,  Natural gas, and Electricity.  
What percent of the total Petroleum energy is consumed by the transportation sector?  You can ignore the small amount of oil energy that is first converted 
to electricity.\vskip 5pt
\item[(2)]  What percent of the energy consumed by the transportation sector was wasted in 2018?  Consider all forms of energy.  \vskip 5pt
\item[(3)]  Multiply the percentages found in the last two parts to find the percentage of all Petroleum energy that was wasted by the transportation 
sector.  How many barrels of oil is that?  How many gallons?
\end{enumerate}
\vskip 5pt
\item[(H)]  {\bf Heating homes.}
Most homes and apartments today are heated with electricity or natural gas.  (The exception to this general rule comes in New England, where 
many homes are still heated by burning oil.)  Electric heaters are 100\% efficient because all of the energy that goes into the heaters is turned into 
heat (the intended purpose).  Natural gas furnaces vary considerably in how efficiently they burn gas.  The most efficient ones turn about 95\% 
of the gas energy into heat (the intended purpose); the other 5\% of the gas energy is wasted through the furnace exhaust.  
Comparing the numbers (100\% versus 95\%), one could argue that electric heaters are slightly better than even the most efficient gas furnaces.  
Explain what is wrong with this argument, using numbers to support your answer.  \vskip 5pt
\item[(I)]  {\bf Electric power again.}  
\begin{enumerate}
\item[(1)]  Some of the electricity generated by the Electricity Generation sector was successfully distributed to users, but much was lost in the system 
(see question (E)).  Some of the electricity that is distributed to the Residential, Commercial, Industrial, and Transportation sectors is further wasted
(i.e. lost).  Compute the total amount of electricity that is wasted after it is transported to these 3 sectors.\vskip 5pt
\item[(2)]  Determine the total amount of electric energy that is distributed and then used, and the total amount that is wasted, for the U.S. electric 
power system.  \vskip 5pt
\item[(3)]  In your answer to part (2) you were making a certain proportionality assumption about the end-use sectors.  Explain.
\end{enumerate}
\vskip 5pt
\item[(J)]  Based on the 2018 data, if you were asked to recommend \emph{two aspects} of the U.S. energy economy where changes might increase 
total efficiency most, 
what would they be?  What sorts of changes would be necessary?  Would they be matters of better technology, changes in attitudes of people, etc.?\vskip 5pt
\item[(K)]  Now consider the diagram for 2010 in Figure~\ref{fig:USEnergy2010}.  \vskip 5pt
\begin{enumerate}
\item[(1)] What major changes do you see between 2010 and 2017?  Which forms of energy have increased
as a share of the total?  Which have decreased?  What accounts for those changes?  What political and 
social issues are raised by those changes?
 (If you need to look up information
to answer this, as always, document your sources!)  \vskip 5pt 
\item[(2)] Is the U.S. energy economy more or less efficient in 2017 than it was in 2010?  Explain the criteria you are using to derive your answer.  Does this surprise you?
\end{enumerate}
\end{enumerate}
\subsection*{Assignment}
Write up your computations and answers to the questions above in a technical report.

\begin{figure}
\begin{center}
\includegraphics[angle=90,width=5.0truein,height=8.0truein]{US_Energy_2010.eps}
\caption{The U.S. energy sector in 2010.}
\label{fig:USEnergy2010}
\end{center}
\end{figure}

\subsection*{References for this Project}
\begin{enumerate}
\item[1] Lawrence Livermore National Laboratory, Energy Flow Charts, downloaded from\\
{\tt https://flowcharts.llnl.gov/commodities/energy}, accessed October 1, 2019.
\end{enumerate}

\end{document}


