Geothermal Energy

An Alternative Resource for the 21st Century

Harsh K. Gupta, Sukanta Roy

• Verlag: Elsevier Science
• Jahr: 2006
• ISBN:
  9780080465647
• Thema: Physical Sciences
• Thema: Geophysics

More than 20 countries generate electricity from geothermal resources and about 60 countries make direct use of geothermal energy. A ten-fold increase in geothermal energy use is foreseeable at the current technology level. Geothermal Energy: An Alternative Resource for the 21st Century provides a readable and coherent account of all facets of geothermal energy development and summarizes the present day knowledge on geothermal resources, their exploration and exploitation. Accounts of geothermal resource models, various exploration techniques, drilling and production technology are discussed within 9 chapters, as well as important concepts and current technological developments.

• Interdisciplinary approach, combining traditional disciplines such as geology, geophysics, and engineering
• Provides a readable and coherent account of all facets of geothermal energy development
• Describes the importance of bringing potable water to high-demand areas such as the tropical regions

Chapter 1

THE ENERGY OUTLOOK

Publisher Summary

This chapter discusses the world’s growing demands for energy because of increasing world population, industrialization, improvement, and standard of living. It is generally believed that prior to 8000 B.C., agriculture was not known, and our ancestors at that time made living by hunting and gathering. In the recent years, the increase in energy consumption has been at least as dramatic as the population explosion. A table in the chapter shows an estimation of the world’s energy consumption and production for the years 1980, 1985, 1990, 1995, 2000, and 2003. These statistics have been obtained from the data available for 220 countries (International Energy Annual, 2003 of Energy Information Administration). The population estimates in this table have been obtained from the Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat. The chapter also provides information on the development of new and more efficient method for the production, recovery, and distribution of energy. As the demand for energy continues to grow, new energy-efficient technologies in power generation, delivery, and conversion can play an increasingly important role in moderating the growth in future energy demands and reducing environmental impacts.

INTRODUCTION

With the increase in world population, industrialization and improvement in the standard of living, there has been a continuous increase in consumption of energy. In the absence of substantial historical data to estimate world population prior to the seventeenth century, circumstantial evidence is often used. It is generally believed that prior to 8000 B.C., agriculture was not known and our ancestors at that time made living by hunting and gathering. Speculating on the basis of the population densities of the hunting and gathering tribes of today, and that only about one-third of the world’s total land area could be used for such living, the world’s population of 8000 B.C. is estimated to have been 5 million people. An examination of archeological remains and census figures for agricultural societies suggest a world population of about 250 million people at the time of Christ, which doubled to a population of about 500 million by A.D. 1650. As a consequence of cultural, agricultural, industrial and medical revolutions, time for the population to double has reduced from about 1500 years (approximated for the period 8000 B.C.–A.D. 1650) to 45 years during the period 1930–1975. Table 1.1 shows the alarmingly decreasing trend in the doubling time. With the current rate of population growth, the United Nations forecast that the world population would exceed 6 billion before entering the twenty-first century has come true. However, it is unlikely that by 2010, world population will reach 8 billion as anticipated in 1975.

Table 1.1

World population and the doubling time (United Nations, Statistical Office, Demographic Year Book)

Year	Estimated world population (in millions)	Approximate time for population to double (in years)
8000 B.C.	5	1,500
A.D. 1650	500	200
A.D. 1850	1,000 (1 billion)	80
A.D. 1930	2,000 (2 billions)	45
A.D. 1975	4,000 (4 billions)	35
A.D. 2010	8,000 (8 billions)?	35?

In the early times, say 400,000 years ago in the “early man” era, the energy consumption of an individual was limited to what he ate (approximately 2000 calories) and this energy was obtained from the sun through vegetable and animal life. Gradually he tamed animals and used them to bear his burden of labor. Invention of the wheel improved the efficiency in the use of energy. Then man learned to harness the energy of wind and water, which became two prime movers. At about the time of the beginning of the Christian era, water and windmills were invented and were put to a variety of uses. In the seventeenth century, coal began to be used for heating and the mining industry developed in Europe. The invention and improvement of the steam engine in the eighteenth century made power available readily and ushered in the industrial revolution. By the turn of the nineteeth century, all coalmines in England were equipped with steam engines to haul coal and men, and to pump water. Use of these steam engines for motive power on mine railroads in 1828 was so successful that railroads spread all over the world in the next 4–5 decades.

Michael Faraday’s discovery of electromagnetic induction in 1831 laid the foundation of the immense electrical industry of today. The invention of electric light by Edison, although it has a more profound effect on living, does not constitute a major factor in energy consumption. Then came the invention of the internal combustion engine, which has proved itself to be extremely robust and reliable, and with it there has been an ever-increasing demand for oil and discoveries of oil fields.

In the recent years, the increase in energy consumption has been at least as dramatic as the population explosion. Table 1.2 shows an estimate of the world’s energy consumption and production for the years 1980, 1985, 1990, 1995, 2000 and 2003. These statistics have been obtained from the data available for 220 countries (International Energy Annual, 2003 of Energy Information Administration). The population estimates in Table 1.2 have been obtained from the Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat (World Population Prospects: The 2004 Revision, 2005). The global trend of a continuously increasing demand for energy is evident from this table. There has been an almost 50% jump in world energy consumption during the period 1980–2003, arguably because of (i) about 42% increase in world population and (ii) worldwide improvement in the standard of living, particularly in the developed and developing countries. Fig. 1.1 shows the past and projected future growth of the world population, based on the United Nations’ “medium fertility projection” and of total and per capita energy consumption. The present world population of about 6.5 billion is expected to reach 7.9 billion in 2025 and 9.1 billion in 2050 despite the projected declining fertility rates in the next few decades. The projected population growth has been attributed largely to the least developed countries and to a lesser extent, the developing countries. These are the regions where energy consumption is expected to grow exponentially due to emerging economies and increasing standards of living. In the world scenario, energy consumption is projected to increase further, about 57% by 2025.

Table 1.2

World population, total primary energy consumption and production (Data sources: United Nations, Statistical Office, World Energy Supply Series; World Population Prospects: The 2004 Revision, 2005; International Energy Annual, 2003 of the Energy Information Administration)

Year	Population (billion)	Total production (10^6 metric tons of coal equivalent)	Total consumption (10^6 metric tons of coal equivalent)	Consumption per capita (kilograms of coal equivalent)
1951	2.59	2,822	2,710	1,075
1961	3.08	4,418	4,329	1,387
1966	3.41	5,621	5,506	1,653
1971	3.78	7,260	7,096	1,931
1973	3.94	8,485	7,885	2,074
1980	4.44	10,358	10,205	2,311
1985	4.84	11,057	11,114	2,310
1990	5.28	12,598	12,508	2,384
1995	5.69	13,121	13,165	2,315
2000	6.08	14,303	14,395	2,364
2003	6.30	15,038	15,178	2,402

Fig. 1.1 World population, energy consumption and per capita energy consumption details and future scenarios. Energy is expressed in tons of coal equivalent (tce) to facilitate comparison with previous estimates.

It is interesting to note how closely per capita income and per capita energy consumption are related. Per capita income is often used as a measure of wealth of a population. The United States of America, the most affluent country in the world today, with ~4.6% of the world’s total population, consumes energy amounting to about one-fourth (23.4%) of the world’s total energy consumption (Annual Energy Review, 2004 of the Energy Information Administration). When comparing countries with vastly different socio-economic scenarios, a more useful statistic relative to per capita income is the Human Development Index (HDI). The HDI is a composite index computed by the United Nations that measures the average achievements in a country in three basic dimensions of human development: a long and healthy life, as measured by life expectancy at birth; knowledge, as measured by the adult literacy rate and the combined gross enrollment ratio for primary, secondary and tertiary schools and a decent standard of living, as measured by GDP per capita in purchasing power parity (PPP) U.S. dollars. HDI and per capita energy consumption for a global representative sample of countries covering industrialized, developing and poorly developed regions for the year 2002 are plotted in Fig. 1.2. The global sample contains the 60 most populous countries, which represent nearly 90% of world population and 90% of world energy consumption (Pasternak, 2000). Among the 60 countries, four countries, Afghanistan, Taiwan, North Korea and Iraq for which HDI values are not reported, have been excluded in Fig. 1.2. The industrialized countries are way ahead of others both in terms of energy consumption as well as human development index. The differences between developed countries and least developed countries are startling. The correlation between HDI and per capita energy consumption suggests that in general, HDI reaches the highest values (0.90–0.95) when per capita energy consumption exceeds about 100 Btu per annum. The correlation also points to large, additional energy requirements in the next two to three decades as the developing economies strive to compete with the developed economies and the least developed nations move ahead towards “developing nations” status. Projections for three economic growth scenarios, low, medium and high, visualize ever-growing energy demands in the coming d...