Geothermal Power Plants

Principles, Applications, Case Studies and Environmental Impact

Ronald DiPippo

• Editorial: Butterworth-Heinemann
• Año: 2011
• ISBN:
  9780080554761
• Edición: 2
• Categoría: Technology & Engineering
• Categoría: Electrical Engineering & Telecommunications

Ron DiPippo, Professor Emeritus at the University of Massachusetts Dartmouth, is a world-regarded geothermal expert. This single resource covers all aspects of the utilization of geothermal energy for power generation from fundamental scientific and engineering principles. The thermodynamic basis for the design of geothermal power plants is at the heart of the book and readers are clearly guided on the process of designing and analysing the key types of geothermal energy conversion systems. Its practical emphasis is enhanced by the use of case studies from real plants that increase the reader's understanding of geothermal energy conversion and provide a unique compilation of hard-to-obtain data and experience. An important new chapter covers Environmental Impact and Abatement Technologies, including gaseous and solid emissions; water, noise and thermal pollutions; land usage; disturbance of natural hydrothermal manifestations, habitats and vegetation; minimisation of CO2 emissions and environmental impact assessment.The book is illustrated with over 240 photographs and drawings. Nine chapters include practice problems, with solutions, which enable the book to be used as a course text. Also includes a definitive worldwide compilation of every geothermal power plant that has operated, unit by unit, plus a concise primer on the applicable thermodynamics.* Engineering principles are at the heart of the book, with complete coverage of the thermodynamic basis for the design of geothermal power systems* Practical applications are backed up by an extensive selection of case studies that show how geothermal energy conversion systems have been designed, applied and exploited in practice* World renowned geothermal expert DiPippo has including a new chapter on Environmental Impact and Abatement Technology in this new edition

Part 1 Resource Identification and Development

• Geology of Geothermal Regions
• Exploration Strategies and Techniques
• Geothermal Well Drilling
• Reservoir Engineering

“A man must stand in fear of just those things that truly have the power to do us harm, of nothing else, for nothing else is fearsome.”

Dante Alighieri, The Divine Comedy: The Inferno – 1306–1321

The first part of the book deals with the geological aspects of geothermal resources – how the forces of nature shaped the earth in a way to create reservoirs capable of supplying energy for geothermal power plants. We discuss the means to identify and characterize geothermal prospects, and the techniques for drilling wells into geothermal formations to extract the hot fluids for use in power stations. The last part of this section of the book examines the physical principles of fluid flow through the porous rocks that constitute the reservoir, and the modern computer simulation methods that are used to model the behavior of the reservoirs.

Volcan Rincon de la Vieja, Guanacaste province, Costa Rica. Location: 10.8N, 85.3W Elevation: 6,286 feet (1,916 m) Photo by Federico Chavarria Kopper, published by Smithsonian Inst. Global Volcanism Program website: http://www.volcano.si.edu/world/volcano.cfm?vnum=1405-02=[WWW].

Volcan Pacaya (foreground) Location: 14.38N, 90.60W Elevation: 8,371 feet (2,552 meters), and Volcan Aqua (background), Location: 14.5N, 90.7W Elevation: 12,333 feet (3,760 m), Guatemala. Ref: Volcano World, U. of N. Dakota. http://volcano.und.nodak.edu/vwdocs/volcimages/south_america/guat/pacaya.html[WWW].

Chapter 1 Geology of Geothermal Regions

1.1 Introduction

1.2 The earth and its atmosphere

1.3 Active geothermal regions

1.4 Model of a hydrothermal geothermal resource

1.5 Other types of geothermal resources

1.5.1 Hot dry rock, HDR

1.5.2 Geopressure

1.5.3 Magma energy

References

Problems

“Birth and death. Like us, geothermal features begin and end, moving through cycles of their own. We draw towards them, lured by change, beauty, and an unusual cast of the familiar – water, rocks, and heat. We search them for answers to mysteries in our own lives, like birth and death.”

Susan F. Hodgson – 1995

1.1 Introduction

Geothermal energy – earth heat – can be found anywhere in the world. But the high-temperature energy that is needed to drive electric generation stations is found in relatively few places. The purpose of this opening chapter is to provide the geologic framework within which high-temperature geothermal resources can be understood, both with regard to their occurrence and their nature.

Readers who are unfamiliar with the rudiments of earth science may wish to consult any of the standard texts on the subject, e.g., Refs. [1–4]. Those interested in the history of geologic thought, dramatic geological events, and of ancient geothermal energy usage will find fascinating reading in Refs. [5–8]. W.A. Duffield provides an excellent, brief introduction to modern geologic theory of volcanoes in a beautifully illustrated book [9]. In selecting general texts on geology, one must be aware that any book written before 1970 will not include the most recent thinking on the structure of the earth and the dynamic mechanisms that give it its life. We refer to the theory of plate tectonics, now universally accepted, and which provides us with the basic tools to understand the origins of high-temperature geothermal resources.

1.2 The earth and its atmosphere

In 1915 A.L. Wegener (1880–1930) put forth a highly controversial theory of continental drift in the first edition of his book The Origin of Continents and Oceans [10]. Although he elaborated on it in later editions of his book in 1920, 1922 and 1929, the controversy persisted. His theory was motivated by the observation that the continents, particularly South America and Africa, seemed to be pieces of a global jig-saw puzzle that had somehow been pulled apart. He reasoned that all land masses were once connected in a gigantic supercontinent he named “Pangaea”. He posited that the now separated continents floated and drifted through a highly viscous sea floor. This part of his theory was later proved incorrect but the basic notion of drifting continents was right. Wegener’s problem was in identifying correctly the forces that ripped apart the pieces and in fact keeps them moving.

Studies that began in the 1950s and continued into the 1960s matched the ages of rocks found along the northeastern coast of South America and the northwestern coast of Africa [11]. The correlation of rock ages ran from Recife in Brazil to Trinidad off the coast of Venezuela on the South American side, and from Luanda to Sierra Leone on the African side. Oceanic research also showed that new land was being created on either side of the mid-Atlantic ridge, the so-called “sea-floor spreading” phenomenon [12]. By dating these deposits, earth scientists were able to confirm the movement of the vast plates that constitute the crust of the earth. Continents are part of the crust and have been in constant motion since the beginning of the earth some 4.5 billion years ago.

An excellent animation of this motion starting about 740 million years ago can be viewed at the web site of the University of California at Berkeley’s Museum of Paleontology [13]. From this animation it is clear that Pangaea existed as a supercontinent for only a blink of geological time, around 200 million years ago, having itself been formed from the collision of several land masses beginning in the Precambrian era.

While there is no controversy today over the theory of plate tectonics, there remains much uncertainty about the detailed structure of the inner earth. A great deal of research has gone into exploring and characterizing the earth’s atmosphere but only one or two projects have aimed at probing the depths of the earth. One of them, Project Moho, intended to drill through the thinnest part of the oceanic crust (about 5 km thickness) to enter the mantle. In 1909 Croatian scientist A. Mohorovičic (1857–1936) had observed, at a certain depth, a discontinuity in the velocity of seismic waves caused by earthquakes. He deduced that this represented a boundary between the generally solid crust and the generally molten mantle. This interface has become known as the Mohorovičic Discontinuity (or simply the Moho) in his honor [1]. However, Project Moho was halted in 1966 apparently for lack of funds and produced no results.

Another deep drilling effort, the Salton Sea Deep Dr...