Chapter 14
However, the issues remain abstract, and aside from the immersion that you have just experienced in this book, there is no escape from the realization that for most of us it will remain necessary to follow or believe in somebody who is willing to do the work of inspecting the data and forming an informed opinion. My own very limited experience with people who read preliminary versions of this book, including a selection of students, colleagues, friends, and family members, is that they always end up asking, “OK , now what can we do about it?”
If the top-down approach through the political process is not yet functioning, then how are we doing individually through the bottom- up approach? The data that we presented in the last chapter are not too encouraging. It was obvious from the time of the Earth Conference in 1992, when the issue came to the forefront of public discussion, that energy use and the carbon footprint per capita is rising in developing countries because of their rapid development whereas it approximately remains constant in developed countries. Even the factor- of- two difference between the United States and most other developed countries is not budging. If we want to improve our bott om- up
207
performance, then we first need to know how we are doing. Th e first step in this direction is to estimate our energy use and carbon footprint and identify the practices that can be improved.
I will start with my personal energy audit and reflect on this audit to the much larger numbers that characterize the national and global scenes. Such an audit will not only account for the larger energy picture and its environmental consequences but also empower us with the tools to translate relevant political issues to more controllable issues and may even save us some money in the process.
My personal audit starts with my energy utility bills. Examples of my electricity and gas bills are shown in Figure 14.1. First, notice that aside from the bott om line of how much I have to pay, everything else is hardly transparent. For us these are hardly “energy” bills; they are separate bills for gas and electricity. If I wanted to choose between gas cooking and electric cooking, then I have very little information to go on unless I do my homework and work my way through the often complicated unit conversions. This is not a universal phenomenon—I asked my British friends to send me copies of their bills, which are shown in Figure 14.2.
The American and British electric and gas bills come with the same units—gas in 100 ft3 (nearly equivalent to therms; see Appendix 1) and electricity in kilowatt- hours (kW·h). However, the British gas bill takes the extra step of converting gas usage into its equivalent energy content in kilowatt- hours by using the same process we use in Box 14.1 and unit conversions similar to the ones in Appendix 1. The same practice is followed in other European countries (I checked only in France). In England, we can now make an informed decision about gas cooking and electric cooking because we can immediately see that 1 kW·h equivalent of electricity is priced at the approximate rate of 9 p (taking the average of first and next rates) and 1 kW·h equivalent of gas is priced at 2
p. In Chapter 11 we saw that electricity is not a primary energy source. We need fuel to boil water to make steam to run a turbine. The second law of thermodynamics (Chapter 5) imposes strict limits on this conversion. The conversion efficiency of a typical electrical generator is about 30%, so we need much more fuel to get the same unit energy from electricity as we get from natural gas, and hence it is much more expensive. Interestingly, if we compare the electric prices in England and the United States using an approximate exchange rate for October 2005 of $1.70/1£, then the prices that I pay and my English friends pay for a kilowatt- hour are about the same (though I end up paying more because of the fixed service charge and the sales tax). Box 14.1 goes into the details of my energy audit, and Table 14.1 summarizes the results. In the box, where we go to the elementary processes, I calculate the energy in Calories (or Cal). Later, to be a bit more compatible with everyday experience in the United States, I convert the units to Btus.
Figure 14.1. Examples of my monthly electric and gas bills
Figure 14.2. Electric and gas bills from England Table 14.1.
My personal energy audit
| Energy form | Energy (Btu/day) | CO2 produced (kg/day) | Source | Fuel (kg/day) |
|---|---|---|---|---|
| Food | 10,000 | 1 | Solar | 0.67 of sugar equivalent |
| Gas (cooking) | 23,000 | 1.2 | Natural gas | 0.5 of methane equivalent |
| Gasoline | 125,880 | 8.4 | Gasoline | 2.7 of octane equivalent |
| Electricity | 89,744 | 4.7 | Natural gas | 1.7 of methane equivalent |
| Space and water heating | 840,000 | 44 | Natural gas | 16 of methane equivalent |
Box 14.1
If I count my calories, I eat, on average, food equivalent to 2500 Cal/day. On average I drive 20 miles per day— I divided my total mileage by the number of days I have owned the car. At home I took my electric and gas bills for few months, added the numbers, and divided by the number of months to get my average monthly usage of electricity and gas. I then divided these amounts by the total number of days to get my average daily use for this period. I ended up using 7.9 kW·h/day of electricity and 0.23 therms/ day of natural gas. At home I directly use natural gas only for cooking. To calculate my space and water heating, however, I had a slight problem: I live in an apartment building that has 42 apartments in a cooperative arrangement in which we own shares. We pay the heating bill collectively and mostly use natural gas for heating. I had to estimate the energy that we use for heating by assuming that my share of the heat energy is equal to the fraction of shares I own, which approximately scales to the area of the apartment. In addition, space heating is very seasonal; we heat only during the winter. To adjust for that, I took the yearly average and divided it by the number of days in the year. If a significant fraction of the electricity bill is going toward air- conditioning, one should do similar averaging. After all this, my average heat consumption came out to be equivalent to 8.4 therms/day (we use therms here because we mostly use natural gas for heating).
To make my life (or at least this calculation) easy, I will assume I am getting all my calories from simple sugar— the same glucose that we explored in Chapter 2.The complete digestion of the sugar generates energy through the following reaction (from Box 2.1):
C6H12O6 + 6O2 → 6CO2 + 6H2O + energy. [14.1]
The amount of energy we generate in this reaction is 673 Cal/mole and 1 mole of glucose is 180 g. Assuming that all my daily caloric consumption comes from glucose, my daily consumption of 2500 Cal amounts to 2500/673 = 3.7 moles of glucose (0.67 kg). Equation 14.1 tells me that a complete oxidation of 1 mole of glucose results in the formation of 6 moles of carbon dioxide. Because each mole of carbon dioxide weighs 44 g, I will end up exhaling 446 × 3.7 = 977 g or about 1 kg of CO2/day.
The main component of natural gas is methane (Box 2.2). Combustion of methane takes the following form:
CH + 2O→ CO + 2HO + energy. [14.2]
42 22
The amount of energy that we generate is 210 Cal/mole. Appendix 1 tells us that 1 therm of natural gas (approximately equivalent to 100 ft3 of natural gas) is equal to 25,000 Cal. So my daily consumption is equal to 0.23 × 25,000 = 6500 Cal/day. Dividing this number by 210 Cal/mole gives the number of moles of CH4 we consume daily: 5750/210 = 27 moles/day. One mole of CH4 weighs 16 g and, from equation 15.2, burning 1 mole of methane results in the formation of 1 mole of CO2 that weighs 44 g. So my daily consumption of natural gas requires burning 16 × 27 = 432 g of methane and will release 44 × 27 = 1188 g (or 1.2 kg) of CO2.
Gasoline is a mixture of light hydrocarbons produced mainly by distillation of petroleum. I will use octane as an example. (What hydrocarbon I use for this demonstration makes very little difference; I use octane because of the general association of a “high octane number” with the quality of the gasoline, although the octane in the octane number is not the straight hydrocarbon chain I use here as an example.) The chemical reaction that describes the combustion of octane is
2CH + 25O→ 16CO + 18HO + energy. [14.3]
8182 22
The amount of energy we generate through this reaction is 1313 Cal/mole. Appendix 1 tells us that combustion of 1 gallon (US) of gasoline produces 31,470 Cal of energy. Because I am using 1 gallon of gasoline/day on average, my energy consumption is 31,470 Cal/day. Dividing this number by 1313 Cal/mole gives the equivalent number of moles of octane that I burn: 31,470/1313 = 24 moles/day. One mole of octane weighs 114 g and, from equation 15.3, burning of 1 mole of octane produces 8 moles of CO2 (because we form 16 moles of CO2 by burning 2 moles of octane). So my daily gasoline consumption requires 114 × 24 = 2736 g (2.7 kg) of gasoline and will release 24 × 8 × 44 = 8,448 (8.4 kg) of CO2.
Appendix 1 tells me that 1 kW·h = 3414 Btu. This appendix also tells me that 1 Btu =
0.25 Cal.
3414 Btu 0.25Ca l
Following our previous discussion, 1kwh = 3414 × 0.25 Cal = 853
1kwh 1Btu
Cal. So my average daily electric consumption is 7.9 × 853 = 6739 Cal/day. The typical conversion efficiency of an electric generator is 30%. So the actual energy needed to supply my 6739 Cal/day of electricity usage is actually 6739/0.3 = 22,463 Cal/day. As was discussed in Chapter 11, my utility company can use many primary fuels to produce this energy. I will use natural gas as an example, so our previous calculations for natural gas become relevant.The number of moles my utility company will need to produce my daily electric energy is 22,463/210 = 107 moles/day of methane.This corresponds to 107 × 16 = 1712 g (1.7 kg) of natural gas, the burning of which will produce 107 × 44 = 4708 g (4.7 kg)
CO2. The calculations will change slightly (creating more CO2) if my utility company is using coal to produce the steam and change in a major way (creating no CO2) if my utility is using nuclear energy to boil the water or hydropower to run the turbines.
As was mentioned at the beginning of this box, I have calculated that on average I am using 8.4 therms/day of natural gas to heat my apartment and supply the heat for my hot water.This amounts to 8.4 × 25,000 = 210,000 Cal/day. This energy amounts to 210,000/210 = 1000 moles of methane (16 kg). Burning this methane will release 1000 × 44 g = 44,000 g (44 kg) of CO2. Many of us use oil for space heating. Heating oil is a mixture of hydrocarbons heavier than the ones used for gasoline. A typical compound is hexadecane (C16H34). The input information we get is the average number of gallons of oil that we use per day. From this information we proceed in a similar way to our calculation of the contribution of gasoline use to our personal energy audit.
Let us first compare this to the US national scene and then attach a price tag to it. Th e total US energy consumption (2005) is 1017 Btu/year. This energy is equivalent to 1017/365 = 2.7 × 1014 Btu/day. There are around 300 million people in the United States, so the average energy consumption per person is approximately 2.7 × 1014 Btu/3 × 108 people = 900,000 Btu/day. per person. Summing up all my energy usage from the second column of Table 14.1 yields 1,090,000 Btu/day. W hen you consider that I am an old guy, I live with my wife, and we share all our energy use (aside from the food), my energy audit is really an audit for two people. So the national average is well above my own numbers (which is usually the case for city dwellers with decent mass transit). How much do I pay for all this (not counting the food)?
My energy costs are $31/day for natural gas (directly [heat + cooking] and indirectly [electricity]) and $3/day for gasoline.
Amounting to more than $11,300/year, $31/day for energy is a significant expense. W hat can I do about it? Some of these expenses result from my choice of lifestyle. My apartment is much larger than I actually need, and if I moved to a smaller place, then I would cut my energy expenses considerably. I often drive to work in spite of the fact I have excellent public transport available to me. However, I cannot deny I waste a lot of energy for the simple reason that I do not bother to change my habits. Before I go any further into detail, let me expand a bit on the sort of waste that does not add very much to my lifestyle choices.
The following examples were taken from Robert L. McConnel and Daniel C. Abel’s book Environmental Issues: Measuring , Analyzing , and Evaluating. 1 I sometimes use this book to teach environmental quantitative reasoning to students who wish to be elementary school teachers.
• Video cassett e recorders (VCR s). In the United States, 88% of households own at least one VCR . (In 2005 VCRs are already considered in many circles passé, so this statistic might be somewhat suspect— however the numbers are still large enough for the general message to be valid.) About 20% of VCR owners cannot program the clock. Th ese VCRs end up with “12:00” flashing constantly on and off .
The population of the United States is around 300 million, with an average of 2.6 people per household. The number of households in the United States is about 115 million. If we have, on average, one VCR per household with 20% of them having flashing clocks, then the resulting number of such clocks is around 23 million. Each clock consumes around 2 W of electricity for every 24 hours/day, 365 days a year. The amount of electricity required to run one of these nonfunctioning clocks in a year is
24 hours 365da ys 1kw
(2 wa tts )()()( )= 17.5 kW·h. [14.4]
da y yea r 1000 w
The amount of energy required to run all these clocks is 17.5 × 2.3 × 107 = 4 × 108 kW·h (400 million kW·h). I pay for electricity around 18 cents/kW·h (November 2005). Assuming that everybody pays the same price, the total cost of this ignorance is about 4 × 108 × 0.181 = $7 × 107 or $70 million/year. This is a lot of money that could be put to much better uses. However, if we divide this by the number of VCRs— the result will be $3/year per VCR with a nonfunctioning clock. This is nothing to write home about. However, these kinds of nonfunctioning gadgets are not restricted to VCRs, and before we know it, we are talking real money. The climate change consequences follow similar reasoning. In Box 14.1 we calculated that 1 kW·h of electricity produced by burning natural gas emits 0.6 kg of CO2. The 17.5 kW·h the unadjusted VCR wastes produces about 10.5 kg/year of CO2. Daily, this amounts to only 0.05% of my average daily CO2 production (Table 14.1), but it is totally avoidable without a sacrifice. Such a waste is not limited to VCRs but is common with many electronic instruments, and the numbers add up.
1kw 24 hrs 365da ys
(40 wa tts )( )()()x (2. 8 x 10 8 ) = 9.8 × 1010 kW·h/year. [14.5]
1000 wa tts da y yea r
This energy is about 25 times more than the energy that we waste on the ice cubes. Now we are talking about a national waste of more than $10 billion (for reference, the United Nations (UN) entire direct administrative budget is around $1.2 billion, not including operations such as peacekeeping, which has its own separate budget). Th e CO2 emission that results from this energy use is around 196 kg/person per year or around 1% of my average CO2 budget. Th is convenience is not restricted to TVs.
My own energy audit is not typical of anything or anybody but is something that I familiarized myself with and a focus that I clearly can do something about. My energy choices are a direct result of my family’s choices and circumstances. The resulting numbers do not deviate considerably from the national average. The energy audit of every family is specific to that family, yet the results accumulate to represent collective choices that bear directly on collective energy use and the resulting climate changes.
My own audit shows that space and water heating is by far my largest energy consumption category. I actually found out how much energy I am using for this purpose only recently following the recent sharp increase in the price of natural gas. I was not surprised. In my apartment building, we use a furnace and central distribution system for space and water heating. Our furnace can use both natural gas and oil. We pay for the fuel through our regular maintenance bill that approximately scales with the size of our apartments but not with the amount of energy we actually use. It is not unusual in such a setting to hear residents occasionally complain that they are forced to open windows in the middle of the winter because of overheating whereas others complain of cold apartments. A rough estimate of the energy cost of an open window in the middle of the winter can be obtained by calculating the outside air infiltration through a relatively small 1 m × 1 m window open to the outside with an ambient temperature diff erence of 20°C (38°F). The heat loss through such an opening is approximately 14,000 Cal/hour (56,000 Btu/hour). The energy loss through such an open window for an entire day exceeds my family’s daily energy use. The sight of an open window in a heated building in the middle of the winter (or in a centrally air- conditioned building in the middle of the summer) is very common. Heat loss through infiltration is estimated to account for 30%– 50% of the energy used for space heating. In my building there are approximately two modular air- conditioning units per apartment. Usually, window installations of such units leave practically half of the window exposed to the outside (as it is often covered with a thin, sometimes cracked, plastic board). Every energy audit professional, as well as utility companies and government agencies, strongly recommend removal of such units during the winter time— with very litt le compliance.
Heat distribution is more difficult to personalize than electric power distribution. In some cases where a centralized electric- metering system was modified to include submetering of individuals, there have been energy savings that exceeded 30% of consumption. Most of these savings are attributed to behavioral savings because people start to pay attention to their energy use. Wasteful appliances and other electronic gadgets, and wasteful energy practices, some of which were examined here, start to get attention, resulting in choices that take energy use into consideration.
A good place to begin participating in the climate debate is to personalize key parts of the international agreements on climate change and to understand their impact on our personal lifestyle choices. We can then relate much more closely with the collective eff orts, whether on the community, national, or global levels, and thus join the discussion at our own comfort level. The following are three statements and commitments taken from the UN Framework Convention on Climate Change (UNFCCC) document (Chapter 13 and Appendix 3) that we can easily personalize.
Common Concern
“Concerned that human activities have been substantially increasing the atmospheric concentrations of greenhouse gases, that these increases enhance the natural greenhouse eff ect, and that this will result on average in an additional warming of the Earth’s surface and atmosphere and may adversely affect natural ecosystems and humankind.”
Personal translation: We believe the science and we care enough to do something about it.
Economic Justification
“Recognizing that various actions to address climate change can be justified economically in their own right and can also help in solving other environmental problems.”
Personal translation: Steps that we decide to take to mitigate the environmental stresses might also save us some money and help to mitigate other concerns.
Awareness
“Develop, periodically update, publish and make available to the Conference of the Parties, in accordance with Article 12, national inventories of anthropogenic emissions by sources and removals by sinks of all greenhouse gases not controlled by the Montreal Protocol, using comparable methodologies to be agreed upon by the Conference of the Parties.”
Personal translation: The best way to accomplish the mitigation is to audit our energy use and keep our eyes open for more sustainable ways use resources such as energy sources.
We can use my metaphor of “feeding transition” to organize our eff orts. Once we accept the necessity for the transition, because of either climate consequences or the availability of resources, we will follow with attempts to control the two main aspects of the transition, the rate of the transition and the availability of alternative energy sources, in economically sustainable ways. We control the rate of the transition by energy saving that, over the long run, does not affect adversely our present and future economic well- being. Adopting the language used throughout the book, we try to reduce our own energy intensity—that is, the amount of energy that we require to sustain our own gross domestic product per capita. None of the wasteful practices I described earlier in this chapter makes any positive contribution to our economic well- being. In most cases these are practices we did not care to address simply because energy was cheap and we did not care about excessive use. By all accounts this period is over. If we do a good job and reduce energy waste in economically feasible ways, and the price of fuel stays high and does not fall precipitously (similar to the events that took place 30 years ago described in Chapter 10) and our concerns for climate consequences stay high, then some of our neighbors might notice and try to adopt some of our practices. Some might even fi nd effective practices we did not think about. Hopefully, politicians will take notice and start formulating policies that will enhance and expand the eff ort.
Governments are already moving in this direction on many fronts, but in most countries it is still a political struggle. In the United States the political struggle is probably more intense than in many other countries, with no obvious winners as of yet. However, many steps are already being taken that contribute to the effort. I will expand on one such step that directly relates to the wasteful energy practices described earlier.
In 1992 the US Environmental Protection Agency (EPA) introduced the Energy Star project, a voluntary labeling program designed to identif y and promote energy effi cient products. In 1996 the program was expanded so that the US Department of Energy (DOE) would off er energy-savings labels for activities such as new home construction and the energy effi ciency of commercial and industrial buildings. To qualif y for the label, products must meet strict energy- efficiency guidelines set by the program’s administrators. The products that qualif y are advertised on the Internet2– 3 and through other channels. Typically, energy savings for Energy Star products save about 30% of the energy requirement of an equivalently functional, nonparticipating product. The program is now in the process of coordinating its activities with similar programs in other countries.
New technologies are helping with many of these issues. To a large degree, their success or failure depends on whether we, as consumers, are willing to try the technologies by buying the devices and on the government’s willingness to subsidize the devices by recognizing that these technologies help solve a long-range societal issue and that they need time to be fully exposed to direct competition with fossil fuels.
Some of the new technologies help us use energy more efficiently and some offer ways to capture alternative primary energy sources such as solar energy. Two new technologies that help us use energy more efficiently are hybrid engines for automobiles and microturbines for electric power distribution. Hybrids help by significantly increasing the fuel effi ciency of automobiles by capturing energy produced through braking and converting it to electrical power stored in batteries used to assist the internal combustion engine. Microturbines help by using the heat generated in the conversion process of heat to electricity for space and water heating.
Alternative energy sources independent of fossil fuels were discussed in Chapter 11. Some of these technologies, such as solar heating, photovoltaics, small wind turbines, and engines that use biological fuels such as farmed agricultural and forest products, can be adopted by individuals and small communities such as apartment buildings. Other alternative technologies, such as nuclear power, large-scale wind power, hydroelectric, or wave-generating power stations, can be adopted by larger entities with distributing capacities such as electric utilities.
If the decision is left to us, then how do we decide on the economic viability of a new technology? For the conversion process to be sustainable, we must do the economic analysis. Even if we philosophically agree to subsidize the alternative technology, we need to approximate the size of the subsidy. Otherwise, when the time comes to pay, we might live to regret the decision, be the laughingstock of the neighborhood, and set back the whole process.
How do we compare the technologies? Some of this was discussed in Chapter 11 in a similar context, but here we discuss it in the context of an individual doing the price estimate, not as a standardized procedure adopted by business. The elements we consider are the capital cost, operating costs, and maturity of the technology, all of which will help us decide how much we should believe the promises from advocates of these technologies. The operating costs include fuel costs (including future estimates of the fuel prices over the lifetime of the power source), maintenance, and approximate downtime. As was mentioned in Chapter 11, most alternative technologies, and especially alternative energy sources, involve signifi cantly higher capital cost justified through savings in operating cost realized through the saving of fuel. In order to estimate such a trade- off, we have to convert (on paper) the capital cost into operating costs. How can we do the conversion? We can decide (again on paper) not to put our own money into the purchase but instead get a loan from a bank for the expected lifetime of the device. If we take a fixed- rate loan, then we can find the prevailing rates and compare the operating costs.
Economic analysis of future technologies is not an exact science. It is only as good as our assumptions. Even with this caveat we need to put a lot of work into this analysis. We might choose not to do the work by hiring a consultant who will serve as our epistemological lawyer. Doing that, we will miss out on the fun.
