CHAPTER 6 GEOTHERMAL RESOURCES: WATER AND OTHER CONFLICTS ENCOUNTERED BY THE DEVELOPER -- An Alternative Energy Source which is "Gathering Steam"
| Jurisdiction | United States |
(Jan 1977)
GEOTHERMAL RESOURCES: WATER AND OTHER CONFLICTS ENCOUNTERED BY THE DEVELOPER -- An Alternative Energy Source which is "Gathering Steam"
Vranesh & Musick
Boulder, Colorado
INDEX
I. INTRODUCTION
II. WHAT ARE GEOTHERMAL RESOURCES
III. ENVIRONMENTAL CONSIDERATIONS
SEISMIC EFFECTS and SUBSIDENCE
THERMAL POLLUTION
AIR POLLUTION
NOISE POLLUTION
LAND USE PLANNING
RESOURCES CONSERVATION
EFFECT ON THE HYDROLOGIC SYSTEMS OF GROUND AND SURFACE MATTERS
IV. LEGISLATION AND CASE LAW
THE UNION OIL CASE
CONSIDERATION BY STATE COURTS
ADDITIONAL FEDERAL LEGISLATION AFFECTING GEOTHERMAL RESOURCES
V. COLORADO TREATMENT OF GEOTHERMAL RESOURCES
VI. CONCLUSION
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I. INTRODUCTION
Rising oil and natural gas prices and the rapidly diminishing availability of fossil fuels are most certainly related to increased interest in alternative energy sources and may be the precursors of a new energy era. One such alternative for commercially producing electricity1 is geothermal energy.
In the broadest sense, geothermal energy is the natural heat of the earth.2 It is an attractive alternative energy
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source because it is not dependent on fossil fuels, it has a long term capacity including a possibility of recharge, and is environmentally more desirable in the recovery process. While projections of recoverable energy quantities within the United States vary widely,3 an optimistic forecast of the actual contribution of geothermal energy to total electric power requirements has been an estimate of 15% by the year 1985.4
The task force for Geothermal Energy, in the Federal Energy Administration Project Independence Blueprint Report of November, 1974, established a goal for 1985 of 20,000 to 30,000 MWe. The latter value representing an equivalent energy supply of one million barrels of oil per day.5
It is this substitution for fossil fuels and resultant ease on consumption of admittedly limited resources that "red flags" the imperative nature of alternative development.
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To facilitate exploration, development, and utilization of geothermal resources, the federal government implemented the Geothermal Steam Act of 1970.6 The Act provides for development by private industry of federally-owned geothermal resources through competitive and non-competitive leases.7 The potential for these areas has apparently been recognized, as demonstrated by the initial responses in competitive bidding for geothermal leasehold rights8 and noncompetitive geothermal lease applications.9
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Does this mean there will be a "great geothermal resource rush" much like the gold rush of pioneer days? Will there be geologists scurrying about the west in search of geothermal energy sources? Such an occurrence may be more real than hypothetical though the magnitude of economic, legal and developmental problems cannot be discounted as deterrents. The path is not clear for developers and in fact is strewn with acknowledged uncertainties.
At present, we are at liberty to speculate as to what is possible developmentally, environmentally, and legally for developers of geothermal resources — but such forecasts must eventually give way to resolving the deficiencies. Litigation of geothermal resources is as yet a very small body of law though it is certain to increase. The rights and interests of parties involved in geothermal operations, the rights of owners of land overlying the resource and the rights of owners of associated resource interest, such as oil and gas, water, and minerals in solution cannot continue to be undefined.
The body of this paper will be concerned with briefly describing geothermal resources, reviewing various environmental, legal, and technical obstacles, outlining federal and state legislation and case law which might affect geothermal development if the resource is treated as either mineral or water, summarizing the treatment of geothermal resources in one jurisdiction-Colorado and suggesting possible legal solutions necessary to meet a goal of fuel sufficiency which is prudently accountable both environmentally and technologically.
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II. WHAT ARE GEOTHERMAL RESOURCES?
In reviewing the problems encountered by the geothermal developer, it is necessary to quickly review the nature, occurrence and magnitude of geothermal resources. Latent heat energy exists throughout the earth. In some areas the heat temperatures are anomalously high, because of some geologic anomalies.10 These "hot spots" are generally referred to as geologic resources or resource areas, even though in other areas the latent regional heat itself technically constitutes a geothermal resource. The heat, primarily stored in rocks and to a lesser extent in liquid water and/or stem-filling pores and fractures, may be transferred through the medium of steam or hot water from the source to a point of capture or use.
White11 approximates the potentially accessible heat (for drilling purposes this is at about a depth of six miles) at 1024 British thermal units. Dr. White's estimate, expressed in metric terms, i.e. stored energy at a depth of 10km, is about 3×1023 Kcal, which has been transposed into an equivalent heat content of 4.5×1016 short tons of coal or 3.5×1020 kWh.12 This immense quantity of heat is misleading, however, since much of this energy is too diffuse to be exploitable as a potential resource. Further, heat alone does not constitute a commercially feasible resource. The reservoir must be at an attainable depth
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to permit drilling, at temperatures sufficient for processing (greater than 150 F. 400 F. depending on the procedure), of adequate volume and sufficient recharge.13
Although the location and magitude of geothermal resources cannot, as yet, be precisely determined, a prediction can be made from the distribution of hot springs and from environments of volcanism and tectonism within the past five million years.14 Using available geologic, geochemical and geophysical data, the Bureau of Land Management has classified approximately 2.8 million acres of land (about 60% federally owned) as Known Geothermal Resources Areas.15 Another 100 million acres (about 50% federally owned) were designated as potentially valuable.16 These "hot spots" are found
...primarily in the western states along the circum-Pacific belt of recent volcanism and where the Pacific ridge system intersects the North American continent along the Gulf of California and the Imperial-Coachella Valley of California.17
Geothermal resources are presently known to exist in four basic types of systems: (1) hydrothermal convective systems
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which include both hot water and dry steam systems;18 (2) geopressured systems;19 (3) impermeable hot dry rock mass systems20 ; and (4) volcanic and magmatec deposits.21
The hydrothermal convective system is currently about the only practical method for tapping geothermal energy.22 Where
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the fields produce clean, dry steam, that is, steam that contains little or no liquid water and is largely free of dissolved minerals, the efficiency of the system increases. Where these ideal conditions do not exist, viz., where there is appreciable condensed water and dissolved minerals, it is termed a wet system. More common then the vapor dominated system, the liquid system must contend with decreased efficiency, and clogging and corroding of machinery.
While the latter three systems (geopressured, impermeable hot dry rock mass, and volcanic) are presently not economically or practically developable, they probably are even more abundant than the resources currently exploited. The experimental status of exploration and development of these systems could eventually mature into an established, feasible practice and may therefore eventually provide not merely a speculative source, but suitable deposits with tremendous life spans.
It should be clear that these four types of systems vary in their particular geophysical structure and geochemical composition. But common to all systems is the essential heat energy of the earth's core23 conducted by a medium at atypically high temperature level.
Therefore, geothermal energy is a product of the physical character of the resource environment and not its chemical composition. Such a distinction is important to later discussions
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in this paper about the nature of the resource and concomitant legal regulations.
Briefly, and in a very simplified illustration, the energy resulting from a geothermal source could be compared to the energy potential present in the head of water at the top of a turbine flume or a mill dam. It is exploitable because of a physical quality — concentrated heat flow near the surface of the earth — which may be tapped at, or near, the site of the anomaly. There it must be converted into a more readily transportable, possessable form such as electricity. Like the stream flow which produces the head of water behind a dam, and unlike fossil fuel resources, geothermal resources are virtually inexhaustible,24 recharging dynamic systems.
It is precisely on this aspect of physical nature that confusion has hampered full scale development of geothermal resources. Development must function within the legal and political universe—but questions remain unanswered: What is a geothermal resource? Who "owns" the right to use this anomaly?
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III. ENVIRONMENTAL CONSIDERATIONS
While geothermal power generation operations are not environmentally pure, the relative impact of development is considered to be slight when compared to other systems.25 Despite the fact that geothermal power plants are less efficient in terms of thermal efficiency than nuclear or fossil fuel plants,26 the pollution from their operation is usually a minor consequence, limited to the close proximity of the plant site.
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