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Energy: Past, Present, and Future Forests to precede civilizations, deserts to follow ~ Francois Rene Chateaubriand (1768-1848) CHAPTER 1 The future ain’t what it used to be ~ Pogo Since the introduction of internal combustion engines, petroleum has played an ever-increasing role in our lives. The estimates of petroleum resources and its remaining life have been very crude at best. Following W WI, US geologists estimated that US petroleum reserves would only last for 30 to 40 years, but in the mid 1920s the predictions changed after the discovery of huge oil deposits in Texas and Oklahoma. In fact, the huge petroleum surplus forced oil companies to sharply lower their prices, which made Middle Eastern oil largely irrelevant for many decades.1 With the mass production of internal combustion engines, the rapid rise in consumption of petroleum, and the nationalization of oil industries by several major oil-producing countries in the 1950s and 1960s, new concerns arose over the long-term availability of oil reserves. In 1970, the Club of Rome, an international think-tank of scientists, economists, businessmen and political leaders commissioned a study which focused on the earth’s physical limits to investigate the long-term economical and environmental consequences of the prevalent patterns of population and consumption on the depletion of natural resources. The result of the study was published in a book entitled The Limits to Growth2, and concluded that unless major steps were taken to limit population and slow industrialization, natural resources would quickly deplete, resulting in global economic crises, famine, and irreversible environmental damage.3 Based on their model, at the prevailing rate of growth, within a time span of less than 100 years, the world’s population is expected to increase to 10 billion, per capita food production to drop by three quarters, pollution to increase tenfold, and all of the oil and gas supplies would deplete.4 In 1973, following the Arab-Israeli War and the oil embargo by the Organization of Petroleum Exporting Countries (OPEC), and again in 1979, as a result of the Iranian Revolution, the doomsday scenarios predicted by earlier forecasts seemed to become even more authentic, and within a decade the price of oil increased sharply (Figure 1.1). The 1 2 2007 Dollars $100 Standard Oil Established $80 $ / BARREL $60 Iran-Iraq War Iranian Revolution US Invasion of Iraq $40 Oil Embargo $20 OPEC Established $0 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 World Oil Prices (1870 - 2007) Figure 1-1 Crude oil prices since 1870 adjusted to 2007 values. Source: Data prior to 2006 was adapted from Transportation Energy Data Book, 2007. M ann, Charles C., Getting Over Oil, MIT Technology Review, January/February 2002. Meadows D., The Limits to Growth: A Report for the Club of Rome’s Project on the Predicament of Mankind , Universe Books, 2nd Ed, 1972. 3 The model assumed exponential growth for the rate of population increase and consumption of depletable resources, but a fixed source of supply, which necessitates an eventual collapse. Models such as this are widely referred to as “pessimist”, or “neo-Malthusian” models. 4 It should be noted that this point of view had its own critics. For example, Kahn, H., et al [The Next 200 years: A Scenario for America and the World, W illiam Marrow, 1976.] argue t hat human ingenuity will, at the critical moments, intervene to devise technologies that can assure continuous development and better use of resources. Therefore, according to t hese technological optimists, resources are not finite but grow as needs arise. As we will argue throughout the book, we believe even with technological innovation and, at this time, additional unknown resources, the resources can eventually run out and we will, sooner or later, have to face the unwanted consequences of our resource mismanagement. higher price of oil brought a profit windfall for oil companies, but also a major recession throughout the world. As the oil scare spread, so did calls for development of alternative sources of energy and higher efficiency. It also accelerated the search for new petroleum resources, which eventually led to the discovery of new oil fields in the Caspian Sea, Africa, the North Sea and Mexico, which caused oil prices to drop once again. To prevent prices from falling, OPEC countries cut production, putting an even greater burden on its member countries that heavily depended on oil revenues for their economic livelihood. To boost their revenues, some countries actually sold their oil below market prices and at volumes above the limit set by the organization. The problem became so widespread that OPEC lifted the quotas by the mid-1980s. Since then, OPEC has tried several times to manipulate the prices by limiting production. Their attempts have failed every time, however, because they could not agree on a unified pricing policy and because developed countries made the transition to other resources such as coal, gas, and nuclear power. As we begin the twenty-first century, energy has once again become a primary concern. A six-fold population increase during the past century and higher energy demands by developing countries, along with the rapid depletion of fossil resources have resulted in new tensions, that began with the 1991 invasion of Kuwait by Iraq resulting in the First Gulf War and continued with the US invasion and occupation of Iraq in 2003. It appears that unless concrete steps are taken to decrease the dependence of the industrialized world on foreign oil imports, many more wars will be fought and regional conflicts will continue to destabilize the world for many decades to come. It is impossible to consider issues related to energy without looking at its effect on the environment. As we put more and more pollutants into our atmosphere, primarily as a result of human activity and the increasing use of fossil fuels, we are also affecting the earth’s climate. When burned, fossil fuels produce carbon dioxide, nitric oxides, carbon monoxide and other harmful gases. Most of these gases adversely affect human and animal health and degrade material property. They are also the primary cause of depletion of ozone in the stratosphere and formation of acid rain and acid fog in the troposphere. Carbon dioxide is not considered a pollutant by most; however, it has a blanketing effect that prevents heat from escaping the atmosphere, causing the environment to warm up. As petroleum resources are used up, we must switch to alternative sources of energy. Unfortunately, the public so far has shown little interest because the cost of utilization of these resources is higher than those of conventional fuels. How quickly we will be able to meet challenges posed by depleting non-renewable energy resources and the deteriorating environment depends on the way we measure the cost to society and on 2 Chapter 1- Introduction how far we are willing to go to level the playing field by transferring these costs to energy producers. For example, costs associated with petroleum are not limited to the transactions borne by the buyers and sellers. The true cost must include military costs associated with oil security, various subsidies to oil producers and customers in term of tax breaks and other exemptions, and environmental and health damage resulting from fossil fuels. If the polluters are forced to pay for these damages and if the many fossil fuel subsidies are eliminated, prices will have to be raised, which may help to encourage better efficiency through the use of more environmentally friendly “green” products. Different approaches have been suggested to internalize these costs. Some economists propose the passage of additional “nuisance laws” that allow the public to sue for damages caused by reckless release of noxious emissions and toxic pollutants into the atmosphere. Two examples that they often cite and have had some success within the last few years are the costs incurred by tobacco companies to pay for health damages caused by cigarette smoking and the clean-up of the Exxon Valdez oil spill in Alaska. Environmental activists are pushing for a “carbon tax” to account for future costs of climate change and to cover other health costs and damage to the environment. How much the cost will be and how much tax should be levied is very difficult to predict. No matter which approach is adopted, polluting companies are far from being supportive of these measures; they spend a lot of money to fight against lawsuits and new regulations that limit their activities, ultimately passing the costs back to the customers and making the battle a difficult one to win. What is Energy? Energy is generally regarded as the single most important concept in all of science. Human cultures are defined largely by their uses of energy resources. Every interaction in our universe involves a transfer of energy between two points or a transformation of energy from one form to another. The word “energy” is bandied about so often that we normally take its meaning for granted. We hear people described as being “full of energy,” the world as having “an energy crisis,” and the need to “conserve energy.” Despite the immense impact of energy on our lives, the term “energy” does not lend itself to a simple definition. The difficulty in producing a precise definition for energy is derived from the fact that energy is a concept, an abstract idea, and not a material object such as an apple or a tree. As Heinberg points out in his book The Party’s Over,5 “few understand exactly what energy is and yet we know that it exists. Indeed, without it, nothing would exist”. We can extend this description to define energy as what is required to make anything happen. Given that, energy 5 Heinberg, Richard, The Party’s Over: Oil, War and the Fate of Industrial Societies, New Society Publishers, Gabriola Island, BC, Canada, 2003 3 must be defined indirectly, in terms of what it does or is capable of doing. In fact, the presence of energy is revealed only when changes take place. Defining Energy In physics, energy is defined as the ability or potential to perform work or cause changes. As this definition implies, a system with energy need not do any work or cause a change, it only has to have the capacity to do so. A piece of wood sitting at rest some place does not do any work even though it has the capacity to do so (for example by burning it in a furnace to boil water to steam which then turns a turbine). The piece of wood therefore contains energy. In fact, all objects have energy by virtue of their own mass. Origin of Energy The scientific theory of the creation of the universe is based on a huge explosion (big-bang), which took place some 12-15 billion years ago. The explosion resulted in the birth of a cosmic nuclei “egg” consisting of a very condensed mass of elementary particles. This nucleus led to the formation of our stars, galaxies, and planets. These processes were of a type which, today, we call thermonuclear, i.e. matter converted into energy. Hydrogen was the first (and simplest) element that was formed and is still the most common element in the universe. It also makes up the core of our sun, which is estimated to be at a temperature in excess of 15 million degrees and a pressure of many billions of atmospheres. Every hour approximately 16 billion tons of solar mass is converted into energy through fusion of hydrogen to heavier atoms. The cores of heavier and bigger stars are at even higher temperatures and pressures. This allows the fusion of other atoms to form heavier elements such as carbon, oxygen, silicon, and eventually iron. Most of the energy known to us has its source in the sun, i.e. solar energy. The sun radiates energy in all directions in the form of electromagnetic waves, including heat and light. A tiny fraction of this energy is beamed toward the earth, of which one-third is reflected back to the sky before ever reaching the ground. Of the remaining two-thirds, some is absorbed by the atmosphere, causing it to heat. The rest is intercepted by the earth in the form of light and heat, of which a mere 0.03% is transformed into biomass through photosynthesis. Biomass can be used as food and consumed by animals and humans, directly burned, or used to produce secondary fuels such as methanol and ethanol. If biomass is shielded from air, it decays and under suitable conditions, can eventually turn into fossil fuel-- coal, oil, and natural gas. Because of different vegetation and rock formations, solar radiation does not heat the land and the ocean uniformly. Differential heating of land and water surfaces results in wind patterns and the ocean waves, two major sources of renewable energy. The earth is also being affected by 4 Chapter 1- Introduction the gravitational forces of its neighboring celestial bodies, most notably the moon, which is the cause of tides and much of the wave patterns in open channels. Tidal power plants are constructed to exploit the variation in the tides’ potential energy in the same way that hydroelectric power stations use the potential energy from falling water. Both nuclear fuel and geothermal energy have roots in the earth’s early stages of development. Uranium fuel is the remains of the radioactive decay of the heavy materials and isotopes formed during the early stages of cosmic nuclei cooling. Uranium can be extracted from earth and processed for use as fuel in a nuclear reactor. What remains inside the earth continues to produce heat and form magma that can find its way to the earth’s surface. Along the way it heats rocks, minerals, and water reservoirs which together constitute our geothermal resources. Forms of Energy There are many different ways that we can classify energy. For example we can classify all forms of energy as potential or kinetic, external or internal, primary or secondary, renewable or non-renewable, or in terms of its application as thermal, mechanical, chemical, electrical, nuclear, etc. Potential energy is stored energy. This energy can be stored in atomic nuclei, molecular bonds, or gravitation. Kinetic energy is energy in action such as microscopic motion of atoms and molecules (heat), or gross motion of matter (falling rock, wind or river). External energy is defined with respect to some outside frame of reference. Energies contained in winds, waves, and falling waterfalls -- commonly referred to as mechanical energy -- are of this type. Internal energy is energy locked within the internal structure of atoms and molecules. Examples are mass, chemical, thermal, light, and nuclear energy. Mass is energy of matter by virtue of its own existence. Until 1905, when Einstein formulated the general theory of relativity, mass was not considered a form of energy. Einstein’s famous formula E = mc2 (where m is the mass and c is the speed of light in vacuum) gives a relationship between mass and the energy associated with it. It expresses the amount of energy that is given off if matter is completely annihilated. Chemical energy is the energy locked in the molecules of various substances. The energy stored in a molecule of carbon dioxide is that energy which holds two atoms of oxygen with one atom of carbon together. Biomass and fossil fuel store their energy as chemical energy. Thermal energy, or heat, is the energy associated with the random motion of individual molecules of matter. It can be considered as kinetic energy at the microscopic level. Geothermal and a big portion of solar energy are in the form of thermal energy. Light energy (also called radiant or electromagnetic energy) is the energy associated with a quantum of energy called a “photon” as it 5 travels through outer space. The sun is the source of light energy. Nuclear energy is the energy trapped in the nucleus of an atom. This energy can be liberated by splitting apart a large nucleus to form two or more lighter atoms (fission) or by combining two light atoms to form a heavier atom (fusion). Depending on its source, energy can also be divided into primary or secondary. Primary energy sources are those sources that can be directly converted to heat or mechanical work. The human intervention is limited only to extraction, cleaning, and separation, without changing the physical or chemical characteristics of the sources.6 There are five main sources of primary energy that we use today; these include fossil fuel, nuclear, geothermal, solar, and tidal.7 Secondary energy comes from transformation of primary energy. Electricity is a secondary source of energy that can be produced from any of the primary sources mentioned above. (Table 1-1). Table 1-1. Energy Forms Primary Fossil fuel Solar (Wind, Hydro, Biomass) Tides Geothermal Nuclear Secondary Town gas (from coal); Gasoline, heating oil, diesel, and jet fuel (from crude); Alcohol, synfuel, and charcoal (from coal, oil shale, biomass) Hydrogen (from fossil, nuclear, solar) Electricity (from anything) Depending on their long-term availability, energy resources can also be classified as either renewable or non-renewable. Renewable resources are those that will replenish themselves naturally in a relatively short period. Examples of renewable energy are solar, wind, hydroelectric, ocean thermal, waves, and tides. Nonrenewable resources are fossil fuels and uranium. Geothermal hot water, steam reservoirs and some material such as peat (decayed vegetable matter) and wood can be considered renewable if the rate of usage is small enough so as to allow their natural replenishment over time. Units of Energy There are two major systems of measurement in the world today: The United States Customary System (USCS) and the International System of Units (SI or metric). The metric system was adopted by the General Conference on Weights and Measures as the international system of units to be used in all international commerce. The scientific community, for the most part, has adopted this system to report findings and carry out scientific calculations. The United States is the last major industrial nation which has not converted fully to the metric system, a delay that has put us at a disadvantage in world trade. 6 7 OECD/IEA/Eurostat, Energy Statistics Manual, 2005. Some consider waste as a primary source, as it is a surplus from any other process that has no further use for that particular process. 6 Chapter 1- Introduction Each system has its own fundamental units and other quantities (including energy) can be expressed in terms of them. The fundamental units of the USCS are foot (for length), pound (for weight) and second (for time). All other units can be reduced to these units. For example, velocity is given in feet per second (ft/s), work and energy are given in pound-feet (lb-ft), and power is given in horsepower – equal to 550 lb-ft/s. In the SI system of units, fundamental units of measurements are kilogram (for mass), meter (for length), and second (for time). Weight is a derived quantity defined as the force of gravity acting on an object of a given mass: W=m.g (1-1) The unit of weight is newton, defined as the force of acceleration of a mass of 1 kg by 1 m/s2 (1 N = 1 kg. m/s2). In this equation, m is mass in kilogram and g is the gravitational acceleration. On earth g = 9.8 m/s2 = 9.8 N/kg. In other words, objects on the influence of the earth gravity will accelerate at the rate of 9.8 meters per second (22 miles per hour) for each second they fall. Alternatively, it can be concluded that objects experience a force of 9.8 newtons per each kilogram of mass they posses. In Chapter 2, we will define work as the energy needed to displace a force by a certain distance; it is therefore reasonable to conclude that a newtonmeter commonly referred to as joule, is an appropriate unit for both work and energy (1 J = 1 N.m). Other units that have been derived and are used in this text are the watt (1 W = 1 J/s) for power, the ohm (W) for electrical resistance, the volt (V) for electromotive force, and the ampere (A) for electric current.8 A Note on Notations... I FYI ... Power of ten notations Prefix 10-12 10-9 10-6 10-3 pico nano micro mili kilo Mega (million) Giga (billion) Tera (trillion) Peta Exa Zeta Yotta t is customary that units are represented by their letters in lower case (except at the beginning of a sentence) when they are spelled out -- kilograms, pascals, newtons, and meters. When abbreviated, they remain in lowercase unless they are proper names-- kg, Pa, N, and m. When we are speaking of individuals, we use the capital letters in accordance with English nomenclature-- Newton, Volt, or Pascal. Prefixes follow the notations shown in the table on the right. Example: According to Newton’s second law of motion, the weight of an object (in newtons) is measured as the product of its mass (in kilograms) and the gravitational acceleration constant (in meters per second squared). Calculate the weight of an average-sized apple with a mass of 0.1 kg at a point with a gravitational acceleration constant of 10 m/s2. Solution: Weight is found from equation (1-1) as: W = m.g = (0.1 kg)(10 m/s2) = 1 N (or 1 newton) Symbol p n m m k M G T P E Z Y 103 106 109 1012 1015 1018 1021 10 24 8 The NIST Reference on Constants, Units, and Uncertainty ( 7 The fact that the SI system is based on 10 and is much easier to use than US customary units is not the reason the SI has found the popularity that it receives today. The main difference is the choice of weight in USCS and mass in the SI system as the fundamental units. A truck that has a mass of 2,000 kilograms in Detroit is still 2,000 kilograms in Los Angeles, or in Paris. In fact, if you load the truck and take it to the moon, it still has the same mass. On the contrary, a truck which weighs 4,000 pounds in Detroit will have a slightly different weight in Paris. Even the weight in Detroit varies by day, as the temperature and pressure changes. If you ship the same truck to space, it will have no weight at all. In addition to the USCS and SI units, other units have been traditionally used (and unfortunately are still in use today). In the case of energy, these are BTU, therms9, quad10, barrels of oil11, and even tons of TNT12. In order to conform to the rest of the world, we will concentrate primarily on SI units in this text. Since many people, especially in the United States, are most familiar with the USCS units, we will include these units when we feel the digression aids in comprehension. The unit conversion tables are given in Appendix B. Example 1-1: The latest data gives the US energy consumption in 2007 as 101 Quads. Express this in BTU, joules, barrels and cubic kilometers of oil. Solution: From the table of unit conversion given in Appendix B: 1 Quad = 1 Quad x 10 15 BTU Quad x barrels of oil 5.80x10 6 BTU x 0.159 m3 barrel Or: 101 Quads = 1.01x1017 BTU = 1.07x1020 J = 1.74x1010 barrels of oil = 17.4 billion barrels of oil (bbo ) = 27.6 cubic kilometers of oil Example 1-2: Express the weight of a 180-pound person in newtons. Solution: A person weighing 180 pounds (we mean pound -force or lbf) has a mass of 180 pounds (we mean pound-mass or lbm). The same person has a mass of 180/2.2 = 82 kilograms and a weight of 82x9.8 = 800 newtons. Energy Supply and Energy Demand Throughout history, humans have depended on energy to meet their needs for cooking, heating, transportation, and other daily activities. The primitive man depended on energy in the form of food for his survival. Therm is used mainly in the United States for metering household natural gas (1 therm=100,000 BTU). A quad is 1015 BTU or 1.055 EJ. 11 A barrel of crude oil: 5.8 million BTU. 12 Trinitrotoluene commonly known as TNT is a major constituent of many explosives, with the energy equivalent of one million food calorie per ton (strange but true!). TNT has a lower energy density than gasoline (32.2 MJ/kg), or even sugar (17 MJ/kg). The main attractiveness of TNT is that it does not have to be mixed with air to burn and in its ability to release this energy rapidly. 9 10 8 Chapter 1- Introduction Table 1-2. Daily Per Capita Consumption of Energy (x1000 kcal) Primitive man 1,000,000 years ago Hunting man 100,000 years ago Early agricultural m an 5,000 years ago Advanced agricultural m an 1,000 years ago Industrial man 100 years ago Modern technological m an today Transportation Machinery* Heating Food** Total 2 2 2 3 5 4 4 4 12 1 7 12 6 26 14 24 32 7 77 63 91 66 10 230 * Agricultural and industrial ** Including animal feeds Source: Cook, E., “The Flow of Energy in an Industrial Society,” Scientific American, p. 135, 1971. The hunting man depended on energy 2.5 times more than the primitive man, as he learned to burn wood for cooking and heating. The demand increased even more when early human used animals to harvest crops. As agricultural society became more developed, wind and wave energies were harnessed to complement animal power to provide energy needed for farming and for transportation. The industrial revolution brought about by invention of the steam engine required increasingly more energy, mainly coal (See Table 1-2). By mid twentieth century, as society became more technological, and as demand for energy grew, coal was supplemented by petroleum, natural gas, and nuclear fuel. As Figures 1-2 and 1-3 indicate, the demand for energy has increased dramatically in the last few decades and is expected to continue to increase for the next few decades. Because of various economical and technological factors, most of the energy used today is from non-renewable sources – mainly fossil fuels. Worldwide, petroleum makes up most of the world energy production, followed by natural gas, coal, hydroelectric and nuclear resources. Excluding hydroelectric, renewable energy has been almost completely ignored and constitutes around 1-2% of the total energy production.13 Energy Use in the United States Figure 1-2 World Energy Consumption, 1990-2030. Source: International Energy Outlook, 2007, Report No. DOE/EIA-0484. Currently, energy consumption in the United States is one of the highest in the world and is expected to remain so in the foreseeable future.14 The US, however, has long passed its peak oil production, and the reduction in petroleum had to be offset with other fuels, mainly coal and natural gas, or by foreign imports.15 W hat is clearly evident is that energy resources are continuing to dwindle as both population and per capita consumption increase. Question: At the current rate of consumption, every American uses energy at about twice the rate of Japanese or Europeans, and 13 14 15 Figure 1-3 Historical and projected trends in energy demand between 1990-2030 Source: International Energy Outlook, 2007, Report No. DOE/EIA-0484. US DoE, Energy Information Administration, Monthly Energy Review, July 2003. A s we shall see later, energy cannot be consumed, only transformed from one form to another. “Annual Energy Outlook with projection to 2025,” Energy Information Administration website ( 9 E Did You Know That ...? US Per Capita Energy Consumption very year, an average American consumes energy equivalent to: • 10 tons of coal, or • 10,000 m3 of natural gas, or • 10,000 liters of petroleum. Table 1-3. Total U.S. Energy Consumption by Source, 2003 Energy Source Petroleum Natural Gas Coal Nuclear Hydro All others Total Total Energy (Quad) 38.2 23.5 22.5 7.8 2.7 3.3 98 Percent of Total 39.0 24.0 23.0 8.0 2.7 3.3 100 compared to Indians, the per capita consumption is 28 times greater. W hat contributes to the Americans’ higher rate of energy use? Answer: The large discrepancy is not only due to the large economies of the United States (and Canada), but is also a reflection of North Americans’ appetite for large cars, luxury items, and personal comfort. Primary energy consumption in the United States by sources is given in Table 1-3 and Figure 1-4. About 86% of all energy used in the United States is from fossil fuels. All forms of renewable energy (biomass, hydroelectric, solar, wind, etc) make up 6% of energy needs. Because of its portability, convenience of use, and relatively greater energy density, oil is the fuel of choice for a variety of applications. The United States, as the biggest consumer of energy, uses one quarter of the total 85 million barrels per day of petroleum produced around the world. Petroleum consumption is limited mainly to transportation (Figure 1-5) and certain industrial processes (primarily petrochemical). Figure 1-6 gives the US total energy consumption by sectors. Each of the transportation, industrial processes, and residential and commercial sectors consume roughly a third of all energy. The pattern of energy use described here is not limited to the US alone; similar trends are observed in other regions of the world. Energy Use in Other Parts of the World Source: EIA, Annual Energy Outlook, Report No. DOE/EIA-0383 (2005). Nuclear 8% Renewable (including Hydro) 6% Petroleum 39% Coal 23% Natural Gas 24% Figure 1-4 US total energy use by source. Industrial 25% Transportation 67% Residential 4% Commercial 2% Electric Utilities 2% The recent data on energy consumption suggests moderate to rapid increases in the rates of fossil fuel consumption for various countries (Table 1-4). Russia’s growth was small due to instability following the breakup of the Soviet Union. US, Canada, and other industrial countries have had moderate growths in the past 20 years, whereas energy use in many developing countries increased significantly. For example, for the same 20 year period, the energy consumptions in China and India were tripled. Even Iran, a country with vast petroleum reserves used much of its production for domestic consumption. The rapid increase is explained by a relatively faster rate of population growth and a higher per capita consumption reflected in higher total industrial outputs of these countries. It is expected that in a near future, many under-developed countries will demand a greater portion of the world’s petroleum resources. The increase will be higher in developing countries that aggressively push for industrialization and more rapid economical growth. Figure 1-5 US petroleum consumption by sector. 10 Chapter 1- Introduction Rail 2.3% Highway Vehicles 77.1% Marine 8.5% Air 9.2% Metal 26% Other 40% Petroleum 14% Transportation 28% Industrial 33% Chemical 20% Building 39% Heating and Cooling 40% Hot Water Heating 14% Lighting 46% Figure 1-6 US total energy use by sector Energy Reserves It is very difficult to predict the total amount of energy reserves in the world, as by definition, renewable energy sources will be infinite. W hat is certain is that we will sooner or later run out of nonrenewable resources, primarily fossil fuels. The time that it will take to use up the remaining fossil resources is closely related to the accuracy of estimates of proven energy reserves and the rate at which new resources are found and extracted. The rate of consumption of fossil fuels is equally hard to predict, as it is affected by numerous factors such as population growth, economic activity, cost, environmental concerns, and the availability of other resources. Many studies suggest that within the next 30 to 50 years, we will have depleted most, if not all, of the natural gas and oil in the world. Even coal has a limited life and cannot be the answer to our longterm energy needs. Doubling Time and Exponential Growth Many phenomena (such as population growth, savings in a bank, and the spread of an epidemic) behave in a nonlinear fashion such that their changes vary in an exponential manner from one year to the next. An important characteristic of exponential growth is that a quantity grows by a certain percentage each year. This might not seem to be much at the beginning, but the cumulative amount can become quite staggering over time. For example, consider a city of 100,000 inhabitants. Because of immigration, increased birth and decreased death rates, its population expands at a rate of 5% annually. After the end of the first year, population will grow to 105,000 and then to 110,250 at the end of the second year. Table 1-4. Energy Consumption for selected Countries (Quads) Country 1984 1994 2004 % rise per year Canada United States England Japan Russia China India Iran World Total 9.8 76.8 8.4 15.7 NA 20.5 5.5 2.2 299.9 12.0 89.3 9.5 20.2 29.3 34.0 10.0 3.7 357.3 13.6 100.4 10.0 22.6 30.0 59.6 15.4 6.4 446.4 1.6 1.3 1.0 1.8 0.2 5.3 5.2 5.3 2.0 Source: EIA, Annual Energy Outlook, Report No. DOE/EIA-0383 (2006). 11 FYI ... The Incredible Power of the Power of Twoi A s legend has it, chess was invented by a mathematician who served the king of Persia. When the king asked what the inventor wanted as a reward for his great game, the man simply asked for one grain of rice in the first square of the chess board, and double the number in the next square until all the squares are filled. The king laughed at this humble request; little did he know that the country would be bankrupt before long. As you might have guessed, the number becomes staggering as it climbs to 2 in the second square, 4 in the third, 8 in fourth, and 263 ~ 1019 grains of rice in the last square, equal to the empire’s total rice production for roughly two thousand years. Although we cannot attest to the accuracy of this story, this example should be a reminder of how exponential growth can quickly lead to amazingly large numbers in a relatively short time. Some contend that chess was adapted from the India game “Chaturanga”, but archaeologicall evidences point to the origin to Sasanid Dynasty in Persia (224-651 CE). See http:// i A simple calculation shows that this city will double to 200,000 people in about 14 years, double again to 400,000 in 28 years, reach 3 million after the passing of one generation (70 years) and grow to over 13 million after a century. Old French Riddle: At first there is only one lily pad in the pond, but the next day it doubles, and thereafter each of its descendants doubles. The pond completely fills up with lily pads in 30 days. When is the pond half full? Answer: on the 29th day. It is constructive to give a convenient method to express the growth of quantities that vary in this fashion (that is, those which grow by a fixed percentage every year) in terms of their doubling time. Doubling time is defined as the time it takes a quantity to double, and can be reasonably approximated by dividing 70 by the percentage growth rate:16 70 T2 = Percentage Rate of Growth (1-2) As we will see in Chapter 11, the same equation can be used to calculate the time which it takes a sample which decays in population (i.e. has a negative growth rate) to reduce in half. This is known as half-life, an example of which is the activity of radioactive material or any other sample which decreases yearly by a fixed percentage. Example 1-3: A couple is planning to save money to pay for their new-born son’s college tuition by putting aside $1000 a year. How much would the child have when he enters college at 18-years of age, if his parents decided to deposit the money in a) a safe deposit box, or b) a saving account that paid 7% interest annually? Solution: If the money is put in a deposit box, the growth is linear— the annual increase is always the same. The saving is $1,000 after the first year, $2,000 after the second year, etc. At age 18, the child will have $18,000 in savings. If the money is invested in a saving account, the percentage rate of Linear vs. Exponential Growths $40,000 $35,000 Savings ($) $30,000 $25,000 $20,000 $15,000 $10,000 $5,000 $0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Age Ex. 1-3 E quation 1-2 assumes that growth is taking place continuously. This is definitely true in the case of population growth and energy consumption. In many other instances, such as i nterest paid by a bank, growth comes in steps. For example a bank that pays 3% interest per annum compounded monthly pays 3/12=0.25% each month which results in a slightly d ifferent growth rate. As we will see in Chapter 15, banks and other financial institutions often apply the “Rule of 72” - divide 72 by the interest rate to find the time in which a saving deposit doubles in value. 16 12 Chapter 1- Introduction increase is the same each year but the total increase is exponential. Let’s say the parents deposit $1,000 on the child’s first birthday. The bank pays 7% ($70) in interest for the first year. With the additional $1000 deposit at the end of the first year, the total money saved after the second birthday is 1,000(1.07)+1,000 = $2,070, and 2,070(1.07)+1,000 = $3,215 after the third. By his 18th birthday, the total deposit has grown to nearly $34,000 instead of $18,000 he would have had if no interests were paid.17 The difference between the linear and exponential growths becomes substantial by the time the boy is ready for college. Example 1-4: It is estimated that the world’s petroleum production will peak sometime around 2005-2010, at which time we will have used up one half of all our petroleum reserves. If the total cumulative amount of oil which has been produced from the early days of discovery in the 1860s until today is estimated at 800 billion barrels, how long would it take before we deplete all our petroleum reserves? According to the latest projections,18 the world energy consumption will increase by 57% between 2002 and 2025. Solution: W hat may come immediately to mind is that since it took us 145 years to use half of our reserves (1860-2005), we will have oil for another 145 years. This is unfortunately far from the truth! In fact we will use as much oil as we have previously used in only one doubling time. Assuming demand continues to grow at the rate of 2.47% a year (57% in 23 years), the doubling time is calculated from Equation 1-2 as 70/2.47 = 28.3 years. Unless we cut consumption or find new reserves of oil and new sources of energy, we expect to run out of oil approximately 28 years after its peak -- by 2033-2038. Example 1-5: According to a US Census, in 1973, the national birth and death rates were 15.6 and 9.4 per thousand. Furthermore, the Immigration and Naturalization Services (INS) data showed that 400,000 people or roughly 1.5 persons for every 1,000 people immigrated into the United States during that year. Calculate the population growth rate in 1973. If the population were to increase at the same rate, when would the US population reach twice that of 1973? Solution: The growth per 1,000 persons was 15.6-9.4+1.5 = 7.7 or 0.77%. If growth were to continue at this rate, the US population would double the 1973 population in 70/0.77 = 91 years, in year 2064. Example 1-6: W hat is the rate of population increase in a community in which there are only two children per family? Answer: The community has zero rate of population increase. Essentially, each parent replaces their children for themselves. 17 18 The cumulative value of all payments can be calculated by applying Equation (15-4) directly. “ World Energy and Economic Outlook”, Energy Information Administration, DOE/EIA-0484, July 2005. 13 Example 1-7: A bacterial colony fills up a jar at 12:00 pm. If the bacteria double in population every minute, when is the jar 1/16 full? Answer: The jar is half full one minute before noon at 11:59, ¼ full at 11:58, 1/8 full at 11:57, and 1/16 full at 11:56. The data on the use of petroleum shows that the world had used only 1/8 of its reserves in 1973, and the consumption has doubled every ten years for the last few decades. As of the writing of this text, roughly half of all petroleum reserves are used up; we are at 11:59 hours. The clock ticked 11:56 am during the oil crisis of early 1970s. Example 1-8: A popular brand of antibacterial cleaner advertises that it kills 99.9% of all kitchen bacteria. Assuming that bacteria can double their population every 24 hours, how often must the disinfectant be applied to maintain kitchen bacteria in check? Answer: Assuming the company’s claim is accurate, after the antibacterial application 0.1% (or 1 in every 1000) bacteria remain. For the population to reach its original level, it must increase 1000 fold or about 10 doubling times. The disinfectant must be applied at least once every 10 days! Energy and the Environment As nonrenewable energy sources are depleted, the level of pollution in the environment is rising. Because fossil fuels make the bulk of our energy use today, most pollution is combustion generated. The harmful effects of these pollutants on the environment are becoming more pronounced, as evidenced by increased level of toxins in our atmosphere, rise in global warming, and depletion of ozone in the stratosphere. In addition to fossil fuels, the burn-up of nuclear fuel has resulted in pile up of tremendous amount of nuclear waste. Unlike other pollutants that can become ineffective in periods of many months or years, the nuclear waste material remains radioactive for a very long time and practically permanent relative to the span of human life. Technology Options Options for averting future energy crises exist on both the demand and supply sides. Demand-side management19 implies a reduction of consumption by consumers of energy, either voluntarily or mandated by the government. It often implies promoting technologies that increase efficiency without sacrificing comfort.20 Examples of demand-side management are better insulation, fluorescent lighting, energy-efficient appliances, hybrid vehicles, and using waste energy to produce heat (cogeneration). M any consider the demand-side management as tools and strategies for reducing energy use at a particular time as well as total consumption, irrespective of its impact on the environment or inconvenience that it causes on consumers. Here we concentrate only on technologies that are sustainable, i.e. do not harm the environment or the people. 20 A ccording to this definition, reducing the speed limit from 65 mph to 55 mph and turning down the thermostat from 70 oF to 65oF in winter are not considered efficiency measures because they are accompanied by a certain degree of sacrifice. 19 14 Chapter 1- Introduction Supply-side management requires finding new resources and processes that increases the chance of discovery, facilitates extraction, and allows more efficient processing (higher yields). New exploration techniques are available that can detect deeper and more out-of-reach locations in mines and reservoirs. Advances in engineering have made it possible to exploit vast hydro and solar resources with costs fast approaching those of conventional energy sources. Nuclear breeder technology is extending the lifetime of our nuclear supply by order of magnitudes. We are finding unconventional sources of energies (hydrates, tar sands, oil shale, etc.) that may open the door to vast sources of energy. Finally, in the not-toodistant future, fusion technology may provide us with the ultimate source of clean and cheap energy. Status of Energy Technologies Until the advent of the industrial revolution in the 18th century, humans used mainly animal power and mechanical power provided by wind and water. During the eighteenth century wood became the primary energy source used for cooking, space heating, and to fuel the industrialization. As forests diminished, coal became the primary fuel for powering steam locomotives. New applications were also found in the form of coke in casting and smelting, and as town gas for lighting. Coal consumption increased throughout the nineteenth century and peaked as petroleum was being discovered as a more convenient fuel that could be transported in pipelines and used directly in internal combustion engines (Figure 1-7). As new petroleum resources were discovered and better techniques were developed for refinement, petroleum found more and more applications in a wide variety of technologies (including pharmaceutical, petrochemical, and other industrial sectors) and still dominates the energy market as the fuel of choice. As a result of the rapid industrial growth, it is estimated that 30% of all stocks of nonrenewable energy (including fossil fuels) was used in the twentieth century. Although most of nonrenewable energy resources remain, the reign of fossil fuel is not expected to last much longer. It is believed that world oil has already peaked or is soon to peak in its production, and will be depleted by the end of this century. Use of nuclear fission is closely following the trend of fossil fuel as uranium reserves deplete, nuclear waste piles up, and problems associated with reactor safety make nuclear technology increasingly less attractive. 40 Petroleum Quads 30 20 Hydroelectic Power Coal Natural Gas Nuclear Electric Power 10 Wood 0 1650 1675 1700 1725 1750 1775 1800 1825 1850 1875 1900 1925 1950 1975 2000 Year Figure 1-7 US Energy Consumption (Quads) by Source, 1635-2000. Source: Energy Information Agency website, html. 15 Wood Coal Oil Fission Hydrogen Fusion Figure 1-8 Energy sources: past, present, and future. Resource use 1400 1600 1800 2000 2200 Years As energy becomes more scarce, the pressure to find alternative sources and switch to more efficient technologies increases. Although there have been major efforts to promote renewable sources of energy, most cannot compete economically with fossil and nuclear energy sources yet. However, much research is being done and many have great hopes that renewable resources will play an ever-increasing role in meeting our energy needs during this century. Nuclear fusion remains a dream for the future and is not expected to be commercially plausible until the last decades of this century (Figure1-8).21 In the following chapters we will study some of these resources and how they will play a role in reaching our energy goals. New technologies are being developed to harness wind, biomass, tidal energy, and ocean currents, as well as thermal gradients in the oceans and under the ground. New materials are being found to produce cheaper photovoltaic, thermophotovoltaic, and fuel cells. The next decade may prove to be one of the most interesting eras for energy enthusiasts. In fact, some economists proclaim, energy and the environment (as well as biotechnology and information technology) will become the most dominant sector affecting the economy in this century. Among the changes occurring in various energy sectors are: Hydropower is going through major changes. The traditional methods of hydropower generation were waterwheels and hydroelectric plants. Although hydroelectric energy has already been exploited to its maximum potential in the United States and much of the industrialized world, small-scale hydro projects may serve as valuable resources in most of the developing countries. Research efforts are also underway, and some demonstration facilities have been built, to show the potential to harness the rise and fall of tides, underwater currents, and the motion of ocean waves. Wind is another significant source of power. New advances in manufacturing processes have allowed the manufacture of lighter and stronger blades. Power electronics have also developed to a stage where variable-speed wind turbines with sophisticated control strategies have 21 “Careers in renewable energy”, DOE/GO-102001-1130, January 2001 ( 16 Chapter 1- Introduction resulted in wind turbine designs with a wider range of operation and higher efficiencies. Biomass is not only the source of all our food, but can also be used to generate energy. Although biomass is a renewable resource, it is not clean and, if burned, produces the same type of pollutants as fossil fuels. However, unlike fossil fuel, biomass does not produce greenhouse gases, and the overall emission is lower. Newer technologies allow higher productivity and cleaner burning. Genetically modified crops can be produced that are tailored to yield high heating values and burn with considerably less pollution. Geothermal resources include hot water, steam, magma, and dry rock. With today’s technology only hot water and steam reservoirs can be economically exploited, but works are underway to exploit the earth’s natural thermal gradients. Geothermal heat pumps are available that use the relatively uniform temperature in shallow ground to provide winter heating and summer cooling with a payback time of only a few years. Solar is another potentially huge, clean, and renewable source of energy, capable of producing both heat and electricity. Flat panel solar collectors are becoming increasingly more efficient and economical. For higher temperatures applications concentrators such as parabolic and dish collectors are manufactured with lighter yet durable materials. For electrical power generation, solar energy can be concentrated by means of a large array of mirrors and dishes (called a heliostat) that can heat up water in a receiver or be used to run a Stirling engine. Alternatively, electricity can be generated directly by photovoltaic cells which are becoming more and more efficient and at a cost of only a fraction of what they were just a few years ago. Thin films and organic plastics have been found that could substitute for silicon semiconductors -- the material used to manufacture most photovoltaic chips. Spherical solar cells are also being introduced in the market, which collect light from all directions, resulting in significantly better collection efficiency. Hydrogen is considered by many to be the fuel of the 21st century, as much as wood was in the eighteenth, coal was in the nineteenth, and fossil fuel was in the twentieth century. Hydrogen is the cleanest of all fuels, whether it is burned or used to power a fuel cell. The only byproducts are heat and water vapor. The hydrogen technology is still in its infancy, and may still face unanticipated problems. Nuclear Fission is the most controversial source of energy. Although power generated is clean and the cost is comparable to electricity generated by fossil fuels and hydroelectric plants, the unresolved issues of nuclear waste disposal and safety associated with these plants are daunting. In light of the terrorist attacks of September 11, 2001, these safety issues have taken 17 an even higher priority. Work is being done to design safer reactors. One such design is called a Pebble Bed Reactor, designed originally by Germans and perfected by South Africans. Small grains of uranium, 0.5–mm in diameter, are placed in microspheres covered by layers of porous carbon and silicon graphite coating. Thousands of these microspheres are packed into pebbles, and then the pebbles are arranged in modular forms. The design is considered inherently safe, because fuel can never reach the melting temperature. Thus, the danger of meltdown scenarios similar to those in Three-Mile-Island and Chernobyl are considered highly unlikely. Furthermore, the graphite will act as a casket to contain the radioactive material even after the fuel is burned, eliminating the possibility of any radiation leak. Nuclear Fusion is still considered the ultimate source of energy. About forty years ago, many had predicted that by the year 2000 fusion reactors would be operational producing cheap, clean, inexhaustible energy. Today, we are still coping with many of the same problems we were facing in the 1960s. The current prediction is that fusion may become practical only in the second half of this century. Time will tell whether we have to revise our predictions again. Summary After food, air and water, energy is the most basic need of human beings for survival. Without it we could not cook, provide heating or cooling, move from place to place, and could not have achieved any of the technological advances of the present time. The unprecedented economic growth of the past century was made possible only by the availability of vast resources of cheap petroleum. At the present time we are relying primarily on the following sources for satisfying our energy needs: • Fossil fuels provide roughly 80% of total global consumption. Fossil fuels are, however, associated with many environmental problems such as global warming, ozone depletion, acid rain, and toxic air pollutants such as oxides of nitrogen, sulfur, and carbon. Nuclear energy is responsible for about 6.6% of the world’s total consumption. However, it generates radioactive and toxic wastes that can remain for a very long time. Hydroelectric and biomass energy constitute 7% of total consumption. Hydroelectricity has relatively minor environmental impact and is renewable. Biomass is mainly in the form of wood and is renewable as long as it does not result in deforestation of existing forests. All the other forms of energy including solar, wind, and geothermal make up only between 1-2% of the total energy consumption. • • • With an expected increase in consumption of fossil fuels, we would also 18 Chapter 1- Introduction expect an increase in the rate of carbon emission into the atmosphere. As petroleum and natural gas reserves dwindle, coal will probably be the ultimate source for their replacement. When burned, coal, peat, and other solid fuels produce more emissions per unit amount of heat than petroleum or natural gas. They are also the fuel of choice for many developing countries that have the largest expected percentage increase in consumption, and who have limited financial resources to buy cleaner petroleum and natural gas. In the next couple of decades, the environmental consequences of fossil fuel consumption will undoubtedly be a major source of contention among various industrial and developing countries. As we are depleting our valuable fossil fuel resources, we must find solutions to our increasing energy needs, which must take one or more of these three forms: to stop or even reverse the population growth, to conserve energy and reduce consumption, or to find new energy supplies, mainly in the form of renewable resources. How the future looks will largely depend on how we act to achieve these goals today. Additional Information Books 1. Meadows, D. H., et al., The Limit to Growth, Universe Books, 1972. Also see, The Limit to Growth: The 30-Year Update, Chelsea Green Publishing Company, 2004. 2. Diamond, J., Collapse: How Societies Choose to Fail or Succeed, Penguin Group, USA, 2004. 3. Cleveland, C. J., Encyclopedia of Energy, Elsevier Direct Science, 2004. Periodicals 1. The International Journal of Energy, Science Direct Elsevier Publishing Company. 2. Applied Energy, Elsevier Publishing Company. 3. Journal of Energy Resource Technology, ASME International. 4. The Energy Journal, The quarterly journal of the IAEE’s Energy Education Foundation, ( journal.aspx). Government Agencies and Websites 1. Energy Citation Database, US Department of Energy (http://www. 2. Environmental Protection Agency ( 3. US Department of Energy ( 4. The NIST Reference on Constants, Units, and Uncertainty (http:// 1. The Club of Rome ( 2. The Sierra Club ( 19 Non-Government Organizations and Websites Exercises I. Essay Questions: 1. Why has per capita energy use in technological society increased so much? Do you expect this trend to continue in the 21st century? 2. What are the main factors responsible for the rapid rise in energy consumption in the developing world? 3. Imagine that China and India were to enjoy the same high standard of living as people in Canada and the United States. What percentage of the global energy supply would these countries demand? How would this affect the energy supply to the rest of the world? Discuss political and environmental implications. 4. Describe why natural gas is a cleaner fuel than heating oil. Why is coal considered to be the dirtiest fossil fuel? 5. Some argue that, if external costs associated with different fuels were considered, renewable energy sources would not necessarily be more expensive than fossil fuels. Explain and give examples. 6. What are the major problems with using biomass as a fuel? 7. What are the sources of nuclear, wind, wave, and geothermal energies? 8. What forms of energy sources constitute renewable resources, and what forms constitute non-renewable energy? How is the distinction made? 9. What is the difference between internal and external forms of energy? Give examples of each. 10. Indicate whether each unit represents energy (E), power (P), or neither (N) a. joule b. megawatt c. newton d. kilowatt-hour e. joule/day 20 f. g. h. i. j. watt/day newton-meter horsepower ton of coal billion barrels of oil per year II. Problems 1. Express the weight of a 220-lb man in newtons. W hat is his mass in kilograms? 2. A candy bar has 100 Calories. What is its food energy content in joules? 3. If the total energy consumption in the US was about 100 quads in 2006 and assuming the doubling time is 20 years, calculate the expected energy consumption in 2046. 4. According to the US Department of Energy, the total US energy consumption was 100 Q in 1996. During the same period, US crude oil production was 5 million barrels per day. Another 12 million barrels of crudes and 3 million barrels of petroleum products were imported daily. Express the US daily petroleum consumption in quads. What percentage of total US needs was provided by petroleum? 5. How much does an apple with a mass of 100 grams weigh in newtons? 6. According to the data, there are 22 births and 9 deaths annually for every 1000 persons living in the world. What is the annual rate of growth in the world’s population? 7. The US used roughly100 quads of energy in 2006. Express the US annual energy consumption in: a. BTU b. EJ c. kWh d. Barrels of oil III. Multiple Choice Questions: 1. According to the predictions by the Club of Rome scientists, the world supply of petroleum a. Will diminish in the next 10 years Chapter 1- Introduction b. c. d. e. Will continue to increase for the next 20 years Will diminish by 2100 Should have already been depleted Would never run out, because new reserves would always be found a. b. c. d. e. Residential Commercial Industrial Transportation Military 2. The rise in oil prices of the mid-1970s can be attributed to a. The Arab-Israeli war b. The Arab oil embargo c. The energy crisis d. Additional investments for discovery of new oil reserves e. All of the above 3. Compared to gasoline, natural gas produces a lower amount of greenhouse gases because a. Gasoline is a byproduct of distillation, which involves processes that produce carbon dioxide b. Gasoline contains additives that produce carbon dioxide c. Gasoline has a smaller number of carbon atoms per molecule than natural gas d. Gasoline has a higher ratio of H/C than natural gas e. Gasoline has a lower ratio of H/C than natural gas 4. Energy is needed to a. Exert a force through a distance b. Lift a mass to a higher elevation c. Move an electric charge through a wire d. Accelerate a mass from rest to a higher velocity e. All of the above 5. Which of the following is considered to be a secondary form of energy? a. Geothermal b. Tides c. Food d. Electricity e. None of the above 6. What sector of the US economy consumes the greatest volume of petroleum? 7. Which of the following statements are correct? a. Hydro energy refers not only to the energy from falling water from dams, but also to energy contained in tides, waves and ocean currents. b. Nuclear fission refers to the energy released from the breaking an atom apart. Fusion is the energy released from recombining two lighter atoms to a heavier atom. c. Heat is the thermal energy associated with the random motion of molecules. d. Solar thermal energy refers to harnessing the sun’s rays to produce heat. e. All of the above. 8. Nuclear is the most controversial source of energy because a. Its cost is high compared to fossil fuels b. It will be a long time before the technology is matured c. The danger from the release of radioactive gases and the storage of radioactive wastes is too large d. Uranium, the fuel for nuclear reactions, is depleting quickly e. All of the above 9. The source of nuclear fuel can be traced back to a. The thermonuclear reaction in the sun b. The reaction between atomic particles in interstellar space c. The early stages of the earth’s formation d. Photosynthesis e. All of the above 10. Some examples of renewable sources of energy are a. Nuclear, fossil, and geothermal b. Wind, ocean waves, solar, and nuclear c. Fossil, ocean thermal, biomass, and tidal d. Ocean currents, waves, solar, and biomass e. Mechanical, chemical, nuclear, and electrical 21 11. Chemical energy is a. Energy locked in molecules b. Energy by the virtue of an object’s own mass c. Energy locked in a nuclei d. Energy associated with the motion of molecules e. Energy associated with the position of molecules 12. The SI system is preferable to the USCS because the a. SI system is easier to use b. SI units are independent of the location of the measurement c. SI system is finally adopted by the United States d. SI system has been universally used for a very long time e. Both a and b 13. Two convenient units for expressing a very large amount of energy are a. BTU and calorie b. Therms and Calorie c. Quad and TJ d. Tons of TNT and kWh e. All of the above 14. What is the approximate weight of a bag containing ten medium-sized apples? a. ~1 N b. ~10 N c. ~100 N d. ~ 1 kg e. ~ 1 lbm 15. A million people each have one million dollars. Their total assets are a. $ 2 M b. $ 1 B c. $ 1 G d. $ 1 T e. $ 1 P 16. One thousandth of one microsecond is a. 1 ms b. 1 μs 22 c. 1000 μs d. 1 ns e. 1 ps 17. Per capita energy consumption in a modern technological society is roughly ___________ times that in the primitive society. a. 5 b. 10 c. 50 d. 100 e. 500 18. Which of the following countries had the highest rate of per capita energy consumption in the last 20 years? a. Canada b. The United States c. England d. China e. Russia 19. A 1200-W hair dryer has been operating for 20 minutes. What is the power and energy consumed by the dryer? a. 400 W, 400 J b. 400 W, 0.4 kWh c. 1200 W, 400 J d. 1200 W, 0.4 kWh e. 400 W/hr, 1200 J 20. Electricity can be generated using a. Mechanical energy b. Chemical energy c. Radiant energy d. Nuclear energy e. All of the above 21. In a modern nuclear power plant, energy is produced by a. Combining uranium atoms b. Burning uranium atoms c. Splitting uranium atoms d. The reaction between plutonium and uranium atoms e. All of the above Chapter 1- Introduction 22. Worldwide, which source provides the most energy? a. Petroleum b. Coal c. Natural gas d. Hydroelectric e. Nuclear 23. Which source of energy is used most by Americans? a. Petroleum b. Coal c. Natural gas d. Hydroelectric e. Nuclear 24. Which of the following gases is considered most responsible for global warming in the atmosphere? a. Sulfur dioxide b. Carbon dioxide c. Water vapor d. Nitrous oxide e. Ozone 25. Solar, wind, hydropower, biomass, and geothermal are all renewable sources of energy because they a. Are free and abundant b. Can be converted directly into electricity c. Can be replenished by nature in a relatively short period of time d. Are relatively clean and pollution free e. All of the above 26. What percentage of the US electricity generation comes from renewable energy? a. 1% b. 6% c. 15% d. 30% e. 50% 27. Which of the following renewable energy sources currently provides the US with the most energy? a. Wind b. Waves c. Geothermal d. Solar e. Hydropower 28. Electricity is the movement of a. Photons b. Atoms c. Molecules d. Electrons e. Protons 29. Kinetic and potential energy are energies of __________ and __________, respectively. a. Springs and gravity b. Solids and liquids c. Position and motion d. Motion and position e. Velocity and height 30. _________ followed by ________ has the largest per capita consumption of energy. a. US, Canada b. Canada, US c. US, Russia d. US, Japan e. US, England 31. In comparison to an individual living in Japan, every American is using roughly ___________ energy. a. Half as much b. The same amount c. Twice as much d. 5 times as much e. 10 times as much 32. Every American on the average consumes energy equivalent to a. 10,000 liters of petroleum b. 10,000 liters of natural gas c. 10,000 barrels of oil d. 10,000 tons of coal e. 10,000 kilograms of TNT 33. The average American consumes most energy for a. Lighting b. Heating water c. Heating and cooling rooms d. Refrigerating foods 23 e. Transportation 34. Although the US has only _______ percent the world’s population, it uses roughly ____ percent of the world energy. a. 1, 10 b. 1, 25 c. 5, 5 d. 5, 25 e. 25, 25 35. Which of the following renewable energy resources is currently the most heavily used in the world? a. Solar b. Biomass c. Geothermal d. Hydro e. Wind 36. Which of the following nonrenewable energy resources is currently the most heavily used in the United States? a. Natural gas b. Petroleum c. Coal d. Nuclear e. Hydro 37. Which of the following energy resources is currently the most produced in the United States? a. Natural gas b. Petroleum c. Coal d. Nuclear e. Hydro 38. Which of the following is not considered a source of energy? a. Fossil fuels b. Wind c. Geothermal d. Electricity e. Nuclear 39. As developing countries become increasingly industrialized a. They will need to import more oil b. There will be less oil available for industrialized 24 countries c. There will be stiff competition for control of the oil resources d. The tension between third world and industrial countries will increase e. All of the above 40. The US’s (and the world’s) total output of energy in the order of decreasing resources are a. Coal, natural gas, and petroleum b. Petroleum, wind, and nuclear c. Petroleum, natural gas, and coal d. Petroleum, nuclear, and solar e. Petroleum, hydro, and nuclear 41. The sun gets its energy from a. Burning hydrogen b. Burning biomass c. Nuclear fission d. Nuclear fusion e. All of the above 42. Which of the following resources are considered primary? a. Biomass b. Alcohol c. Hydrogen d. Town gas e. None of the above 43. Most renewable energy sources can be traced back to a. Solar energy b. Hydro energy c. Nuclear fission d. Nuclear fusion e. All of the above 44. Which of the following statements is correct? a. Geothermal energy meets a large portion of today’s energy demand. b. Geothermal energy includes steam and hot water reservoirs, magma, and dry rock. c. Geothermal energy has its roots in the interaction between earth and the moon. d. Dry rock plays a significant part of geothermal energy exploited today. e. All of the above. Chapter 1- Introduction 45. Which fuel is used to generate the most electricity in the US? a. Coal b. Petroleum c. Natural gas d. Nuclear e. Wood 46. Which of the following sets of numbers represents a linear growth? a. 5, 8, 11, 14, 17 b. 5, 8, 12, 17, 20 c. 4, 8, 16, 32, 64 d. All of the above e. None of the above 47. Which of the following sets of numbers represents an exponential growth? a. 5, 8, 11, 14, 17 b. 5, 8, 12, 17, 23 c. 4, 6, 9, 13.5, 20.25 d. All of the above e. None of the above 48. For several decades, American petroleum consumption doubled every decade. This corresponds to an annual percent growth rate of a. 2% b. 5% c. 7% d. 10% e. Not sufficient data 49. It is expected that by the end of the century, the primary source of energy will be a. Hydrogen b. Fission c. Coal d. Petroleum e. Wood and other biomass 50. For large high-temperature applications such as those requiring superheated steam, a more convenient method of using solar energy is a. Photovoltaic cells b. Flat-plate collectors c. Dish collectors d. Heliostat e. All of the above IV. True or False 1. The main cause of global warming is the burning of fossil fuels. 2. The higher the H/C ratio in the fuel, the dirtier the combustion will be. 3. Many environmentalists advocate the imposition of a “carbon tax” as a mechanism for reducing the budget deficit. 4. Fuel cells are devices in which hydrogen and fuel react to produce steam. 5. The rate of increase in energy consumption per capita in India is larger than in the US. 6. Pebble-bed nuclear reactors are widely used in Europe. 7. More than 80% of all the energy used in the world is from fossil fuels. 8. A person weighs less on the moon than on the earth because the gravity is weaker on the moon. 9. Electricity is a primary source of energy. 10. All forms of energy can be divided into kinetic or potential energy. V. Fill-in the Blanks 1. The ___________ is still commonly used in the petroleum industry. It is equal to 42 gallons. 2. _________ is used to express large quantities of energy. It is equal to 1015 BTU. 3. ________ will likely replace fossil fuels as the main source of energy within the next two centuries. 4. $120 invested at 7% compound interest will grow to $240 in about _____ years. 25 5. _________and __________ are the two countries with the highest rate of energy consumption in the world. 6. There is a good chance that within the next hundred years _________ is going to be the most widely used fuel. 7. Natural gas is transported mainly by_________. 8. The next most logical number in the series 3, 9, 15, 21 is ______. 9. The next most logical number in the series 2, 6, 18, 54 is ______. 10. A person with a mass of 60 kilogram, has a weight of _________ newtons. VI. PROJECT I - US Population Projection The US population marked its 300,000,000th birth sometime during October 2006. The figure was derived from the 2000 population census, and assumed there are one live birth every seven seconds, one death every 13 seconds, and one net increase in immigration per 30 seconds. Assuming that this trend continues for a foreseeable future, calculate: 1. 2. 3. 4. The percentage annual growth rate The doubling time The year when population reaches 600,000,000 Using equation C.1 (p.479), find the projected US population in 2050 a spreadsheet tabulating the latest published data for several developed and developing countries. Search the internet to find the latest population and economic data. Good sources for this information are the World Bank and the Energy Information Agency. CIA’s Fact Book may also be consulted. 1. Plot the per capita energy consumptions of these countries versus their GDP and GNP on a log-log scale. 2. Calculate the ratio of the total energy consumption and GDP for the United States, China, India, and the country of your birth. Which country uses energy more efficiently? 3. Discuss the pattern, and whether such a correlation exists or not. If not, explain the discrepancy. PROJECT III - Energy and the Environmental Literacy In this exercise you are to evaluate the students’ understandings of current issues related to energy and the environment. Prepare a questionnaire with 20 or more questions asking students about topics of importance to energy and the environment. Sample questions of great importance are (but definitely not limited to) population growth, the availability of fossil fuels, patterns of use, renewable energy sources, nuclear safety, environmental impacts, regional conflicts, policy issues, and economics. You need to interview as many students as needed (among those who are taking the course with you and from randomly selected students in your college or university) to have a minimum of 10 respondents to each of the questions. Tabulate responses and write a short essay summarizing your findings. From these results, discuss whether these students benefit if they would enroll in a similar course? Do you see any statistically significant differences between male and female students? Between native and foreign-born students? PROJECT II - Energy and the Affluence From the discussion given in this chapter it appears that industrialized countries consume considerably more energy than developing and under-developed countries. In fact many economists see a strong correlation between a country’s wealth as measured by Gross Domestic Product (GDP), or Gross National Product (GNP) and the per capita energy consumption. In this project, you are asked to prepare 26