1 Introduction

Revised 8/25/08

WE ARE ALL CITIZENS OF EARTH  The blue and white planet, with South American and Antarctic visible.  Photo JPL, NASA.

WE ARE ALL CITIZENS OF EARTH
The blue and white planet, with South American and Antarctic visible.
Photo JPL, NASA.

1.1 Comments on Energy and Society
1.2 Types of Energy
1.3 Renewable Energy
1.4 Advantages/Disadvantages
1.5 Economics
1.6 Order of Magnitude Estimates
1.7 Growth (Exponential)
1.8 Solutions
  References
  Problems

1.1 Comments on Energy and Society

Industrialized societies run on energy, a tautological statement or an oxymoron in the sense that it is obvious. Population, gross domestic product (GDP), consumption and production of energy, and production of pollution for the world and the United States will be considered. The United States has less than 5% of the world population, however it generates around 24% of the gross production and 25% of the carbon dioxide emissions (Fig. 1.1). Because population has increased and the amount of energy per person has also increased in the developed countries, the developed countries consume the most energy and produce the most pollution. On a per person basis, the U.S. is the worst (most energy use and most pollution generated).

Figure 1.1.  Regional comparison for world population, gross domestic production and carbon dioxide emissions. Other developed countries includes Australia, New Zealand, and Japan. Source of data, United Nations.Figure 1.1.  Regional comparison for world population, gross domestic production and carbon dioxide emissions. Other developed countries include Australia, New Zealand, and Japan. Source of data, United Nations.

Figure 1.1. Regional comparison for world population, gross domestic production and carbon dioxide emissions. Other developed countries include Australia, New Zealand, and Japan. Source of data, United Nations.

The energy consumption in the United States increased from 32.0 Quads to 98.5 Quads from 1949 to 2000 (Fig. 1.2). 1 Quad = 1015 British Thermal Units (discussed in Ch. 2) There is an increase in efficiency in the industrial sector, primarily due to the shock of the oil crisis of 1973.

Figure 1.2.  United States consumption of energy by sector for year 1949 and 2000. See table below for size of a Quad. Source of data, Energy Information Agency.

Figure 1.2. United States consumption of energy by sector for year 1949 and 2000. See table below for size of a Quad. Source of data, Energy Information Agency.

However you must remember that correlation between gross domestic production (GDP) and energy consumption does not mean cause and effect. The oil crisis of 1973 showed that efficiency is a major component in gross national product and the use of energy.

It is enlightening to consider how the United States has changed in terms of energy since WWII. Ask your parents or even your grandparents about their lives in the year 1950 and then compare with your family today. One dilemma in the developing world is that a large number of villages and others in rural areas do not have electricity.

A thought: A solar clothes drying (a clothes line) does not add to the GNP, but every electric and gas dryer does. They both do the same function. We may need to think in terms of results and efficiency ways to accomplish that function or process.

1.2 Types of Energy

There are many different types of energy. Kinetic energy is energy available in the motion of particles, for example wind. Potential energy is the energy available because of the position between particles, for example water stored in a dam, the energy in a coiled spring, and energy stored in molecules (gasoline). There are many examples of energy: mechanical, electrical, thermal (heat), chemical, magnetic, nuclear, biological, tidal, geothermal, psychic, and so on.

In reality there are only four interactions (forces between particles) in the universe; nuclear, electromagnetic, weak, and gravitational. In other words all the different types of energy in the universe can be traced back to one of these four interactions. This interaction or force is transmitted by an exchange particle. The exchange particles for electromagnetic and gravitational interactions have zero rest mass and with this comes the speed limit of light, 3 * 108 m/s or 186,000 miles/hr for transfer of energy and information. Even though gravitational interaction is very weak, it is noticeable when there are large masses. The four interactions are a great example of the how a scientific principle covers an immense amount of phenomena.

Interaction Particle Strength Range, m Exchange Particle
Nuclear (strong) Quarks 101 = 10 10-15 Gluons
Electromagnetic Charge 100 = 1 Infinite Photon
Weak Leptons 10-15 10-18 Weakons*
Gravitational Mass 10-39 Infinite Graviton

The source of solar energy is the nuclear interactions at the core of the sun, where the energy comes from the conversion of hydrogen into helium. This energy is primarily transmitted to the earth by the electromagnetic waves, which can also be represented by particles (photons). In this course we will be dealing primarily with the electromagnetic interaction, although hydro and tides are energy due to the gravitational interaction.

We will use exponents to indicate large and small numbers.  The exponent indicates how many times the number is multiplied by itself, or how many places the decimal point needs to be moved. Powers of ten will be very useful in order of magnitude problems, which are rough estimates.

We will also use meter, kilogram, andseconds for units with English units in parenthesis () to give you a feel for value.
Note there is a discrepancy between the use of billions in the US (109) and England (1012). If there is a doubt, we will use exponents or the following notation for prefixes.
 

Small Large
Nano 10-9 Kilo 103
Micro  10-6 Mega 106
Milli 10-3 Giga 109
Tera 1012
Quad (quadrillion BTU)* 1015

* = British Thermal Unit (BTU)

1.3 Renewable Energy

Solar energy is referred to as renewable and/or sustainable energy because it will be available as long as the sun continues to shine. Estimates for the life of the main stage of the sun are another 4 to 5 billion years. The energy from the sunshine, electromagnetic radiation is referred to as insolation. The other main renewable energies are wind, biomass, tides, waves, and geothermal. Wind energy is derived from the uneven heating of the earth's surface due to more heat input at the equator with the accompanying transfer of water by evaporation and rain. In this sense, rivers and dams for hydro energy are stored solar energy. The third major aspect of solar energy is the conversion of solar energy into biomass by photosynthesis. Animal products such as whale oil and biogas from manure are derived from solar energy. Tidal energy is primarily due to the gravitational interaction of the earth and the moon. Another renewable energy is geothermal, due to heat from the earth from decay of radioactive particles. Volcanoes are fiery examples of geothermal energy reaching the surface from the interior, which is hotter than the surface.

Overall 14% of the world's energy comes from biomass, primarily wood and charcoal, but also crop residue and even animal dung for cooking and some heating. This contributes to deforestation and the loss of topsoil in developing countries.

In contrast, fossil fuels are stored solar energy from past geological ages. Even though the quantities of oil, natural gas, and coal are large, they are finite and for the long term of 100s of years they are not sustainable.

1.4 Advantages/Disadvantages

The advantages of renewable energy are: sustainable (non depletable), ubiquitous (found everywhere across the world in contrast to fossil fuels and minerals), and essentially non-polluting.

The disadvantages of renewable energy are: variability, low density, and generally higher initial cost. For different forms of renewable energy, other disadvantages or perceived problems are visual pollution, odor from biomass, avian with wind plants, and brine from geothermal. I am sure that wherever a large renewable facility is to be located there will be perceived and real problems to the local people. For conventional power plants using fossil fuels, for nuclear energy, and even for renewable energy there is the problem "of not in my backyard".

1.5 Economics

Business entities always couch their concerns in terms of economics. We cannot have a clean environment because it is uneconomical. Renewable energy is not economical. We must be allowed to continue our operations as in the past, because if we have to install new equipment, we cannot compete with other energy sources. We will have to reduce employment, jobs will go overseas, etc.

The different types of economics to consider are pecuniary, social, and physical. Pecuniary is what everybody thinks of as economics, DOLLARS.

Social economics are those borne by everybody and many businesses want the general public to pay for their environmental costs. A good example is the use of coal in China. They have laws (social) for clean air, but they are not enforced. The cost will be paid in the future in terms of health problems, especially for the children today. If environmental problem(s) affect(s) someone else today or in the future, who pays? The estimates of the pollution costs for generation of electricity by coal range from $0.005 to 0.10/kWh.

Physical economics is the energy cost and the efficiency of the process. There are fundamental limitations in nature due to physical laws. In the end Mother Nature always wins or the corollary, pay now or probably pay more in the future.

On that note, we should be looking at life cycle costs, rather than our ordinary way of doing business, low initial costs. Life cycle costs refer to all costs over the lifetime of the system.

Finally, we should look at incentives and penalties for the energy entities. What each entity wants are subsidies for themselves and penalties for their competitors. Penalties come in the form of taxes, environmental and other regulations, while incentives come in the forms of break on taxes, do not have to pay social costs on their product, and the government pays for research and development. How much should we subsidize businesses for exporting overseas? It is estimated that we use energy sources in direct proportion to the incentives that source has received in the past. There are many examples of the above.

1.6 Order of Magnitude Estimates

In terms of energy consumption, production, supply and demand and design for heating and cooling, estimates are needed and an order of magnitude estimate will suffice. By order of magnitude, we mean an answer to within a power of ten.

Example: How many seconds in a year. With a calculator it is easy

Order of magnitude estimate.  For the above multiplication round each number with a power of ten, then multiply and add the powers of ten, so if i wanted to do that same example with order of magnitude estimates it would be:

1.7 Growth (Exponential)


Our energy dilemma can be analyzed in terms of fundamental principles. It is a physical impossibility to have exponential growth of any product or exponential consumption of any resource in a finite system.

The present rate of consumption and the size of the system give a tendency for people to perceive the resource as either infinite or finite. The total energy output of the sun and the amount of mass in the solar system appear to be an infinite source at the present rates of use, even though the solar system is finite. The energy dilemma is defined within the context of the system and our present energy dilemma is due to the finite amount of fossil fuels on the earth. 

The easy way to understand exponential growth (Fig. 1.3) is to use the example of money.  Suppose Sheri receives a beginning salary of $1/year with the stipulation that the salary is doubled every year, a 100% growth rate. It is easy to calculate the salary by year (Table 1.1). After 30 years, her salary is one billion dollars per year.

Figure 1.3.  Exponential growth curve

Figure 1.3.

Exponential growth curve

Table 1.1. Salary by year with a growth rate of 100%, doubling time of one year.
Year Salary, $ Amount = 2t Cumulative $
0 1 20 1
1 2 21 3
2 4 22 7
3 8 23 15
4 16 24 31
5 32 25 63
... ... ... ...
30   1 * 109 231 - 1
t  2t 2t+1 - 1

Notice that for any year, the amount needed for the next period is equal to the total sum for all the previous periods plus one. Like in year 5 you can see from year 4, the total spent on Sheri's salary was 31 dollars, but next year (year 5) she gets 32 dollars. This is a very loyal employee, but she begins to cost the company about year 20, ( 220 = $1,048,576 / year). And those last 5 years before she retires shes earning oil company executive type income.

There are numerous historical examples of growth; population, 2-3%/yr; gasoline consumption, 3%/yr; world production of oil, 5-7%/yr; electrical consumption, 7%/yr.  Notice that if we plotted the value per year for smaller rates of growth (Fig. 1.4), the curve would be the similar toas Figure 1.3, only the time scale along the bottom would be different.  Notice that for population growth, the projection for the future assumes that the growth rate will decrease from 1.35% today to 0.5% in 2050. The United Nations projects a leveling off at 11 billion people by 2200.

HOWEVER, EVEN WITH DIFFERENT RATES, THE FINAL RESULT IS STILL THE SAME. 

WHEN CONSUMPTION GROWS EXPONENTIALLY, ENORMOUS RESOURCES DO NOT LAST VERY LONG.

This is the fundamental flaw in term of ordinary economics ($) and announcing growth in terms of percentages. How long do they want those percentages to increase? Nobody wants to discuss how much is enough. The theme since President Reagan is that all we need is economic development and the world's problems will be solved.

Figure 1.4a  Growth of human population (millions) since the year 1000 A.D.
Figure 1.4a Growth of human population (millions) since the year 1000 A.D.

Figure 1.4b  Human population (millions) since the year 1900.  Squares are predicted values by UNDP.

Figure 1.4b Human population (millions) since the year 1900.  Squares are predicted values by UNDP.

Suppose a small growth is used, the doubling time (T2) can be calculated by,

T2  =  69/R  -- where R is the percent growth per unit time 1.1

Doubling times for some different yearly rates are given in Table 1.2.

Table 1.2. Doubling times for different rates of growth.

Growth
%/year
Doubling Time
years
1 69
2 35
3 23
4 18
5 14
6 12
7 10
8 8
9 8
10 7
15 5

1.8 Solutions

We do not have an energy crisis, since you will learn energy cannot be created or destroyed. We have an energy dilemma because of the finite amount of readily available fossil fuels. Fossil fuels are our main energy source today.

The problem is twofold: population is 6.6 * 109 and developing countries want the same standard of living as developed countries. The world population is so large that we are doing an uncontrolled experiment on the earth's environment. However the developed countries are the major contributors to this uncontrolled experiment and growing toward 11 * 109

The solution depends on local, national, and world policies. What do you do as an individual, and what policies do we implement as a society at the state and national level? I have mine, what are yours?

References

Links

Books and articles are included for general information

Articles from Scientific American, March 1998.

Problems