History of Development at the Geysers Geothermal Field, California

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Geothermal Resources Council, Monograph on The Geysers Geothermal Feld, Special Report No. 17,1991

HISTORY OF DEVELOPMENT AT THE GEYSERS GEOTHERMAL FIELD, CALIFORNIA

James B. Koenig

GeothermEx, Inc., 5221 Central Avenue, Suite201 Richmond, Calfonah 94804

INTRODUCTION

LOCATION AND DESCRIPTION - empty into San Francisco Bay. Some tributaries flow all The Geysers - the world’s largest developed geother- year; others are seasonal, becoming dry or almost dry in mal field - is located in mountainous terrain of the Mayaca- summer and early fall. masRange,about75miles (120km)northofSanFrancisco, There are two climatic seasons: a hot, dry summer and in Sonoma and Lake Counties, California (Figure 1).This a cool, wet winter. Average temperature varies greatly part of the northern Coast Ranges is characterized by with elevation. Summer temperatures occasionally reach narrow, linear, northwest-trending ridges and valfeys. or exceed 100°F (38°C);freezing temperatures and even Ridge tops commonly reach,over 3,000 feet (900 meters) snowfalls are experienced in winter months. The change above sea level; valley floors typically are 1,000 to 1,600 between rainy and dry seasons is often abrupt, usually feet (300 to 500 m) in elevation. The-highest point within occurring in May and again in October. the geothermal field is Cobb Mountain, at 4,722 feet (1,440 Amounts of annual precipitation also vary with local m) elevation. elevation, ranging in average between 35 and over 80 To the south, elevations decline and the terrain becomes inches (90 to over 200 an).This falls almost entirely be- gentler. Broad valleys open southward towards San Fran- tween the months of October and April, and peaks during cisco Bay. To the north, the rugged terrain increases in the winter months of December through March. average elevation. Clear Lake, located some dozen miles (20 km) north of The Geysers, is the largest permanent SETTLEMENT AND HUMAN ACTIVITY body of water in the region. Its elevation is 1,325 feet (400 m) above sea level. Mount Konocti, on the southwest edge Because of its rugged terrain, this part of the California of the lake, has an elevation of 4,200 feet (1,280 m). There Coast Ranges was not settled extensively during the several areas of flat to gently rolling terrain near the Spanish occupation in the eighteenth and early nineteenth southern margins of the lake. centuries. Large land grants were made to settlers in the Hydrologically, The Geysers region is drained by fertile Napa and Santa Rosa valleys, some distance to the tributaries of the Russian River, and Clear Lake empties south. The brush-covered, poorly accessible uplands were via Cache Creek. Tributary streams generally follow the left to hunters and mineral prospectors. northwest-southeast grain of the country, cutting south- Mercury ore was discovered in the 1850s. An extensive ward or northward through narrow gaps in the ridges to mining industry developed in the Mayacamas Range in join larger tributary streams and eventually to join either the latter half of the nineteenth century, supplying mer- the Russian River in its course to the Pacific Ocean, or to cury to the mines of the Sierra Nevada foothills for use in

7 History of Development at The Geysers Geothermal Field

Mendo

.---

e Heo/ds bur g

Sonoma Co. '. Napa Co. -; i

n SCALE IN MILES

Figure 1. Location of The Geysers geothermal field.

a James B. Koenig

The earliest known photograph of The Geysers geothermal field, Sonoma County, California, taken on December 17,1909 by Gerald A. Waring of the US. Geological Survey near the southern entrance to the field. The photo was included in Mr. Waring's publication SprinSs of California, 7915, U.S. Geological Survey Water Supply Paper 338. The steam in the photo is from fumaroles. Notice the thermally-altered terrain. (US. I Geological Survey)

the recovery of gold by amalgamation. The Mayam power generation first began, was less than 100. And Range continued to produce mercury episodically into the within the 100 square mile (250 square km) area that 196Os,when environmental and economic considerations includes the neighboring small towns of Cobb and Mid- closed the last of the operations. Over 100 years of mmry dletown, population was under 2,500. Even today, the production earned the Mayacmas Range the rating as the year-round population of this region is not over 5,000 largest mercury-producing district in North America, and persons. possibly in the western hemisphere. Since 1960,and especially since the early 70s, increasing In addition to mining and sport hunting, the Mayacmas numbers of persons in the region have earned their living region became famous for its remation activities. Spas directly or indirectly from the geothermal field. Geother- existed at the numerous thermal springs from the 1860s mal activity now rivals recreation and agriculture as one onwards, and boating and bathing flourished in Clear of the principal tax bases of the area. Lake. However, the steepness of the terrain and the mag- nesian serpentinite soils limited agriculture to certain valley areas, especially near Clear Lake where the soils pre- THERMAL FEATURES OF THE GEYSERS dominantly are volcanic, and where fruit orchards and AND VICINITY vineyards were established. It is widely recognized that The Geysers is a misnomer; Roads either followed the topographic grain,generally at the time of its discovery in 1847 by William Bell Elliott, northwest-southeast, or took erratic and complex courses of the JohnC. Fremont expedition, them were widespread of switchbacks amss the ridges and canyons. There were areas of fumaroles, mud pots and steaming ground, and no major settlements in the immediate Geysers area. To the minor hot springs in the canyon of Big Sulphur Creek, but south, communities in the Napa and Santa Rosa valleys nogeysers. These fumarolesand mud pots were sufficient- prospered and grew. Small resort communities and fm- ly impressive that this 1847 survey party referred to the ing towns dotted the shores of Clear Lake. However, area as both "The Geysers" and "The Gates of Hell." This within the 20 square mile (50 square km) area of the latter designation apparently reflected the popular im- geothermal field, the permanent population in 1960,when agination of the time; the devil and his abode were per-

9 History of Development at The Geysers Geotheimal Field ceived almost everywhere at The Geysers ("Devil's Pul- pit," "Devil's Toll Gate," "Devil's Laboratory," etc.). Thdsprings are common through this part of the northem Coast Ranges, and thermal activity is especially intense at Calistoga, 20 miles (35km) to the southeast, and at Sulphur Bank on the eastern margin of Clear Lake. other thermal springs are the sites of old resorts, among them Siegler Springs, Howard Springs and Wilbur Springs. This widespread and intensive thermal activity usually is described in relation to the episodes of Late Tertiary and Quaternary volcanism that helped to shape the region. Nowhere, however, was thermal activity as widespread, intensive or high temperature as at The Geysers. E.T. Allen and A.L. Day, in their 1927 Carnegie Institution report, "Steam Wells and Other Thermal Activity at The Geysers, California," described a 5 mile (8 km)thermally active zone along Big Sulphur Cdc: beginning in the upper reaches of the Big Sulphur Canyon and extending to the west of The Geysers, this zone was characterized by patches ofsteaming ground and fumaroles. Allen and Day noted that intense hydrothermal alteration had led to the Traveling to The Geysers Resort by stagecoach. (Geothermal formation of extensive suites of secondary sulfate, oxide, Resources council) and silicate minerals. The ground in these areas was bleached tan or white, or was stained yellow by sulfur. The pervasive smell of rotten eggs indicated the discharge of in the late 185Os, ultimately becoming capable of accom- H2S-rich gases. modating over 200 guests. People traveled by train to Healdsburg or Calistoga and then by stagecoach over twisting, dusty (or muddy, depending upon the season) DEVELOPMENT AS A SPA roads. After the automobile had gained acceptance, a gaso- The heyday of recreational spas in the United States line pump was installed at the resort for the convenience was the last three decades of the nineteenth century and of daring motorists. the first decade of this century. Mineral springs and wells One early visitor, California state geologist W.H. Brew- were prized for their supposed therapeutic value in the er, in 1861 described the trip by horseback before the road years before antibioticsand vitamin pills. When the waters was completed. The trail, he said, was so hard, "charges at were not only mineralized, but also naturally hot and the hotel so extortionate", and the fumaroles and springs found in an area of scenic beauty, their popularity was so overrated, that the trip was hardly worth the effort. assured. So it was with The Geysers. Perhaps his was a minority view. A road was completed into the area in 1863. A resort Allen and Day's 1927 report and various earlier photo was built on Big Sulphur Creek in several stagesbeginning collections show ladies in long dresses, carrying parasols, and gentlemen in white flannels, with bow ties and straw boaters, standing among the fumaroles and bubbling mud pots. Presidents Ulysses Grant and Theodore Roosevelt were among the notables who visited and had their photos taken, along with members of foreign royalty, the wealthy of several continents, and thousands of ordinary Ameri- can citizens. Activities ranged from strenuous climbs in the hills to gently rocking on the hotel porch. Swimming and bathing, breathingthesteam, and drinking themineral waters were a part of the routine. The Geysers had become a California institution. Modern medicine and the increasingly fast pace of View of Geyser Canyon in the 19209. (Geothemal Resources American life put an end to the leisurely routines of the Council) recreational spas. Another factor may have contributed at

10 James B. Koenig

3 L, \'

Visitors to The Geysers Resort enjoy Pluto Creek (Big Sulphur Creek). From a stereograph by Andrew Price. (Library of Congres)

The Geysers: it became a subject of common rumor in the days just before World War I that the waters of The Geysers and its rival spa Calistoga were an effective treatment for venereal disease. Therefore, to suspicious minds, anyone visiting The Geysers must be venereally infected.Atten- dance at these resorts declined almost at once. The resort burned on several occasions; after the last fire in the 1940s it was never rebuilt. Several cabins, a restaurant and bar, and a rarely used swimming pool were all that remained. Through the 40s and 50s patronage had decreased steadily. By the time of the first geothermal power plant in 1960, resort activities were down to ham- burgers, coffee and beer served to occasional visitors. In the middle 70s, upon the retirement and death of its elderly owners, the resort ceased to function. Shortly before its closing, The Geysers resort hosted one Well No. 2 completed at The Geysers on June 6, 1923. It is 318 feet deep, with a temperature of about 153°C (307°F) and a pressure last group of recreational users for a brief period. The of about 63 pounds per square inch, measured on Jbne 27, 1925. owner, Frank Curry, allowed a group of 60s flower child- (Geothermal Resources Council) ren to camp along Big Sulphur Creek, just below the remains of the old resort. Visitors to the geothermal operations invariably commented on the "naked hippies" bath- John D. Grant, aresidentof Healdsburg, Californiawho ing in the creek. was familiar with the thermal features at The Geysers, may not initially have been familiar with the successful development of geothermal electricity at Larderello, Italy. In the ELECTRIC POWER - THE EARLY YEARS attempt, conscious or otherwise, to duplicate this, Grant The first attempt to develop geothermal electricity at formed a company and raised money for drilling on lands The Geysers was not commercially successful. It did rcsult owned by the resort. Between 1921 and 1925, eight wells in the production of low-pressure steam from shallow (usually designated as Geysers I through VIII) were drilled wells and the generation of up to 35 kW for several years to depths of 200 to 640 feet (60 to 190 m). Several flowed to light The Geysers Resort. steam at pressures of 150 to ncarly 300 psig (10 to 20 bars).

11 History of Development at The Geysers Geothermal Field

Tabk 1. Geothermal power plants at The Geysers. -P=h cumuktiv.ca~, UnY Start-up Dote MW (grad MW (gross) PG&E 1 09/60 12 12 PG&E 2 03/63 14 26 &&E 3 04/67 28 54

I I I SMUDGE0 1 I 10183 I 72 I 1363 Santa Fe 04/84 80 1443 DWR Rack 03/85 56 1498 PG&E 16 10/85 119 1617 PG&E 20 10185 119 1736 NCPA 3 & 4 11/85 110 1846 CCPA- Cddwater Creek 1 05/88 65 1911 CCPA - Coldwater Creek 2 10188 65 1976 Bear Canyon 09/88 20 1996 West Ford flat 12/88 27 2023 Adlin 06/89 20 2043

Two wells were connected to the turbine generator located Although the project was a technical success, and al- in a building adjacent to the resort. Despite problems with though the city of Healdsburg was interested in connect- stearn supply and turbine generator maintenance, electric ing the geothermal field into its electrical distribution power was generated and utilized. system, the project could not be carried out economically The projcct finally was abandoned in the early 1930s after lighting The Geysers resort for several years. During the depression years and World War 11, a period of a decade and a half in which people were preoccupied with keeping alive, no one wondered much about The Geysers or geothermal electricity. It was not until the boom years of the 50s that interest was renewed. In 1955, the visionary developer B.C. McCabe established Magma Power Company to leasegeothermal rightsand drill wells at The Geysers. His associate Dan McMillan, Jr., founded Thermal Power Company in the following year, and formed a joint venture with Magma Power to develop and The 35 kW power plant, the first geothermal power plant in the United States constructed and operated by The Geysers sell geothermal energy. Together they raised a quarter of Development Company. (Geothemal Resources Council) a million dollars for geothermal field development.

12 James B. Koenig

therefore were faced with uncertain and difficult choices: Should they lease only from those private parties who clearly owned all surface and subsurface rights? Should they also pursue (and possibly lose their investment in) geothermal rights via mineral claims, underground water rights, or oil and gas leases, on lands where the federal or state govenunents held subsurface rights? These thorny problems were to result in lawsuits that plagued the geothermal industry in the 1970s. In the late 50s and 60s, the several developers pursued differentstra- tegies. Magma Power and Thermal Power quickly leased the geothermal rights to over 6,000 acres (3,700hectares) in the vicinity of the steaming ground of Big Sulphur Creek from private owners. Although the title to some of these acres later came into question, this block of land formed the basis of the initial development at The Geysers. Magma Power's first well (Magma 1) was drilled in 1955, followed by Thermal 1 through 5 during the next 2 years. The deepest of these was only 1,400 feet (430 m). Each encountered steam, although several had mechanical problems, and one well (Thermal 4) blew out. Despite extensive effortsover many years to seal it, quench it and relieve the steam pressure by drilling directional wells, it continued to blow steam to the atmosphere in reduced amounts for many years. In December 1957, flow tests by Thermal Power indi- B.C. McCabe (left) and Dan McMillan. Jr. (riaht).- " .- in 1957 at The cated that four wells could supply 300,OOO pounds of Geysers geothermal field. These two geothermal pioneers were the chief executive officers for the Magma Power Co. and Thermal Power steam per hour (over 140 metric tomes per hour) at well- Co., respectively. They are obviously congratulating each other. head pressure of 115 psig (8 ah).Further tests conducted (Geothermal Resources Council) in 1958 at the bequest of PacificCas and Electric Company confirmed these values. On October 30,1958,PG&E and Tounderstand this phase of development it isnecessary the Magma-Thermal venture signed their first contract, to briefly review American policy and practice with regard under which the venture agreed to supply steam to PG&E to natural resources. Unlike the situation in most coun- for the generation of electricity. This was the first commer- tries, where the nation owns all underground resources, cial contract for geothermal energy in the United States. in the United States title to such resources is vested with The terms of this contract established a pattern of supply the initial surface landowner, private or public. Title may and use that dominated the American geothermal indus- be retained by the initial owner when disposing of surface try for the next 20 years. ownership. Title may be transferred to subscquent parties Electric utilities have had the status of sanctioned and with or separate from the surface land ownership. In The regulated monopolies within their service districts. They Geysers region, land is owned variously by the federal have constructed power generating plants and transmis- government, the state of California, and numerous private sion lines, purchased fuel, and generated and sold elec- parties,individually or corporately. In many cases, the title tricity to their customers on an exclusive basis. Thus, there to subsurface resources has been severed from the surface existed no other market for geothermal steam than the title. There have been cases in which one party owned the electric utility within whose service district the field was surface land title, another had leased (or otherwise had located, unless that electric utility was willing to transmit aquired) the right to surface occupancy, and another had the electricity to a neighboring utility over its lines. Geo- leased or acquired in ownership the subsurface mineral thermal steam, therefore, was a fuel with a very limited rights. market. In practice, the situation is even more complicated To ensure its rnarketabiliph the Magma-Thermal ven- because in the early years of geothermal development the ture agreed to acccpt a price equal to an average of other federal government and the state of California did not (nonhydro) fuel prices available to PG&E, and to receive have any legal mechanism to lease the rights to geothermal payment for electricity generated rather than energy sup- energy resources to would-be developers. Developers plied. In a period of abundant and cheap fuel and electric

13 Historv of DeveloDment at The Geysers Geothermal Field

Pacific Gas and Electric power plant No. 1, The Geysers geothermal field, northern California; placed on line in 1960. (Geothermal Resources Council)

power, there was no incentive on the part of the electric quired surface ownership as well. Dick transferred the utility to offer more attractive purchase terms, especially leases to Geothermal Resources International (GRI) in as the life of the steam field could not be predicted with 1967, beginning a long and often acrimoniousrelationship any certainty. between the two parties. The first geothermal power plant (PG&E Unit 1) came In 1966, Union drilled its initial well (Ottoboni l), the on line in June 1960: the 12.5 MW turbine generator pre- first successful well not located in an area of thermal viously had been retired from PG&E service (Table 1). manifestations. Signal drilled three wells in 1967-68, of This initial success of the Magma-Thermal venture in- which one reportedly was successful. Three of four wells spired a geothermal leasing campaign by other companies drilled in 1%7-68 by GRI on the Dick property encoun- and individualsat The Geysers and vicinity. Magma Pow- tered stcam. These wells showed that the resource had er and its affiliates began to move farther afield, drilling greater areal extent than the zone of thermal manifesta- geothermal tests at Sulphur Bank Mine near Clear Lake in tions and extended to over 6,500 feet (2 km)in depth. In 1961. Wells were drilled by other entities at Calistoga in the space of 2 years, the productive area had been tripled 1960-61. None of these found steam; and because no in size and the number of successful operators had risen market was perceived for electric power from a hot-water to four. This number fell back to three in 1967 when a joint resource, these other projects were not commercially at- venture was established between Union and Magma- tractive. Thermal, with Union becoming the field operator for the Venture. The first well greater than 2,000 feet (600m) in depth at The Geysers was drilled in 1961 by Thermal Power. Along The scveral land parcels belonging to the federal or with this, the focus of drilling shifted to the northwest and state governments, or on which the federal or stategovern- southeast along Big Sulphur Creek, such that by late 1964 ment had retained the mineral rights, had not yet become wells were scattered and clustered along a 6 mile zone of available for geothermal lease. These included landsclose- the seek canyon. Wells had reached over 5,000 feet (1.5 ly intermingled within Union, Signal and/or GRI lease km)in depth by 1965. positions. The complex land picture became further com- PG&E Unit 2 (14 MW) was brought on line in 1963, plicated by companies applying for federal oil and gas leases or mining claims, taking geothermal leases from located in the same powerhouse as Unit 1, and the 28 MW or surface landowners whose rights to the geothermal re- Unit 3 was installed nearby in 1967. By that time, Union Oil Company (now Unocal) had amassed several thou- source were under legal challenge. sand acres of leases to private lands on the steeper hillsides Two oil companies,Occidental Petroleum and Shell Oil, above Big Sulphur Creek and in adjacent drainages. The had become involved in such leasing or claiming opera- M&T Corparation also had acquired a large leasehold tions, along with various private citizens and a mining extending farther to the east and west, surrounding and company (Cordero Mining) that was shortly to be ac- interfingering with the Magma-Thermal and Union land quired by Sun Oil Company. positions. The M&T leases were transferred to Signal Oil Exploratory drilling during the later 60s had proceeded and Gas Company. At about the same time, R.C. Dick had as far distant as Wilbur Springs, some 30 miles (50km) to acquired mercury leases south of Big Sulphur Creek; these the northeast. Both Magma Power and Cordero Mining he converted to geothermal leases, and ultimately he ac- drilled there without commercial success.

14 JamesB. Koenig

PG&E Unit 4 (also28 MW) became operational in 1968. cial Class I dumps, and sumps were leveled and filled. With Union as operator, the pace of drilling and field Roads were paved to minimize dust and erosion. Environ- development accelerated. PG&E in 1970 agreed to the mental protection became a way of life at The Geysers construction of up to six additional generation units (5,6, through the avoidance-and-codon methods stipulated 7,8,9and lo), each of 55 MW gross capacity. The Geysers in drilling and construction permits. was on its way to becoming one of the major geothermal At the metime that field activities were expanding fields of the world. vigorously and environmental issues were being grappled with the long-anticipated legal issues of resource nature ELECTRIC POWER - and ownership came to a head in the state and federal THE TUMULTUOUS YEARS court systems. When the legal dust had settled, geothermal resources were found not to be water resources, but The oil-price shocks of 1973 and 1974 provided both a were subject to reservation by the stateand federal govern- justification and a stimulus for geothermal development. In the previous year, Congress had passed and President ments under minerals reservation clauses in documents Nixon had signed the legislation authorizing the leasing giving surface title. Put into English, this meant that sever- of geothermal resources on federal lands. In the first al of the surface landowners did not hold geothermal federal lease sale in 1974, Shell had purchased some of the rights and therefore could not lease them to developers. most attractive parcels. Shell began drilling in the year Geothermal leases in these cases had to be obtained from following the lease. PG&E had entered into steam-pur- the federal or state govenunent that had made the reser- chase agreements with GRI and Signal. Sun, Geothermal vation. Surface landowners could not legally block access Kinetics, Inc., and McCulloch Oil Company all acquired to their properties by entities that had obtained these diverse lease positions and began preparations to drill. federal and state leases. However, some companies that Burmah Oil Company acquired Signal's holdings. And had tried unsuccessfully to obtain oil leases or mining Union continued to expand the productive boundaries of claims to federal lands in the 60s were allowed to convert the field through further step-out drilling. these into geothermal leases, despite attempts by others to Drilling depth now routinely reached 7,000or 8,000 feet obtain these lands in lease. (2.1 to 2.5 km).Shell's step-out discovery extended the As a result, the geothermal-ownership map of The field tothe southeast by nearly twomiles (3km).However, Geysers changed. But, as with the resolution of environ- structural or hydrologic boundaries were being recog- mental issues, development was spurred. In 1978 and nized on the west, southeast and northeast as a result of 1979,three electric utilitiesentered the scene as purchasers the extensive drilling campaigns. The field was seen to be of steam: Northern California Power Agency contracted at least 12 square miles (30 square km) in area. to buy steam from Shell. Sacramento Municipal Utility Environmental issues had surfaced in the late OS, when District entered into a steam-purchase contract with surface discharge of geothermal fluid was prohibited by Aminoil USA (successor-in-interest to Burmah). Califor- the Regional Water Quality Control Board. From 1968 nia Department of Water Resources contracted with MCR onward, all steam condensate and produccd water was Geothermal Corporation (McCulloch) for steam from its injected back into the geothermal reservoir. Bottle Rock leasehold. Not only did these agreements Now additional environmental issues emerged: preser- expand the market, but the purchase terms in two of these vation of fish and wildlife habitat; questions of slope contracts were based on energy delivered rather than stability and siltation of drainages; protection of rare or power generated, and pricing reflected the open market endangered species; noise control; visual esthetics; control price for fuel, Equally significant, these terms encouraged of accidental fluid spills; and, most telling of all, protection greater efficiency in the use of supplied steam, such that of air quality. Although the need for electric power was the average conversion rates in new power plants demonstrated, and the offset savings in oil usage was decreascd from about 18 to 20 pounds of steam per kWh becoming significant, geothermal wells and power plants to 14 or 15 pounds. alike were delayed through often drawn-out processes of Due to the compound incentive of increasing fuel prices permitting and environmental appeals. (the second "oil shock" of 1979), widened markets, and Monitoring of gas emissions, especially H2S, at drill rigs resolved issues of ownership, exploration and develop- and power plants led to the implementation of strict H2S ment boomed in the late 70s and early 80s. PG&E Unit 11 abatement measures. Power plants were sited to allow (106 MW) came on-line in 1975, followed in 1979 by Units maximum air dispersion of condensed steam, while min- 15 (55 MW) and 12 (106MW). This represented an average imizing the visual impact. Landslide-prone areas were growth of about 65 MW per year. Occidental Geothermal mapped and avoided, and steep hillsides were revege- began drilling on its leasehold acquired in the 1979 federal tated. Well-test discharges were controlled carefully and lease sale. Leasing and drilling extended far beyond The muffled effectively. Drilling residues were trucked to spe- Geysers, with exploratory wells drilled by several mm- History of Development at The Ceysers Geothermal Field

panies at distances of several miles (several km) to the west, noetheast, and southeast, Up to 10 drillmg rigs were in continuous operation. The original PG&E contract with the Magma-Themal venture had been based on proof of sufficient steam deliverability at wellhead and the price of oil and nuclear fuel. Subsequent contracts were written to allow the pro- jection of steam sufficiency on the basis of several productive wells. Ultimately, utilities become venture participants, putting risk money into drilling ventures designed to prove reserves on undeveloped acreage.

Pacific Gas and Electric power plant Unit 20, which went on line m 1985.8ig sulfur Creek Canyon is in the background. A bank of cooling towers is in the faregfound, and the power house is just behind the cooling towers. (Gmthmnal Resou~sCuunclO

NCPA, SMUD, and CDWR, as well as by PG&E, with steam supplied to these by Union, Aminoil (and its successor-in-interest, Phillips Petroleum Company), Grace Geothermal Corporation (successor to Shell Oil), and the MCR (McCullOch) group. Contracts for steam purchase Pacific Gas and Electric power plant Unit 14, on the western side were signed between Central California Power Agency of Big Sulphur Creek. The power plant went on line September 1980, and GRI on land acquired from Aminoil; and between the with a generating capacity of 114 MW (gross). Electrical transmission lines and steam transmission lines are in the foreground. (Geothermal CDWR and Geothermal Kinetics at the south end of The Resources Council) Geysers. CCPA had helped GRI to acquire the Aminoil properties through the provision of advance production payments. The decade of the opened with unparalleled confi- 80s However, unsettling events also had occurred. Litiga- dence: continued expansion, ever-increasing fuel prices tion never had ceased resource ownership and the and markets, and federal support all seemed assured. One over performance of obligations.One of particularly long dura- specific federal support action was the PURPA legislation tion involved R.C. Dick, GRI, and several other parties of 1979. The Public Utility Regulatory Policy Act required electric utilities to purchase electricity from specially regarding performance at the PG&E Unit 15 area. New qualified independent power producers at the utilities' suits began to affect operations in several leaseholds. avoided cost of new generation. One effect of this act was Union initiated a suit against PG&E, challenging several to help modify the distinction between explorer/devel- of the practices of their long-term relationship. By the end opers and electric utilities amss the geothermal industry, of 1990 this suit had not formally been settled. and to initiate similar changes, although of smaller mag- As a result of the legal action over performance brought nitude, at The Geysers. by NCPA against Grace, NCPA found itself essentially compelled to buy out Grace's interests. Thus, NCPA in ELECTRIC POWER -THE MATURE FIELD 1986 became the first electric utility to be in the compound role of field operator, power generator and franchised Between 1980 and 1986, over 1,OOO MW of new gcnera- tion were placed in operation at The Geysers, making it by utility. Grace had acquired the leases from Shell when that far the world's largest developed field. The rate of growth company decided to quit the geothermal business in 1982- had increased to an average of approximately 150 M W per 83. year. One of those plants, Oxy 1, (now Santa Fe Ceother- Starting in 1982 oil prices began to drop in combination mal) was constructed under the tenns of PURPA and with PG&E's Diablo Canyon nuclear plant coming on line, supplied 80 MW of electric power, rather than steam, to after a dozen years of delay, causing steam prices to begin PG&E at preferential prices. Other plants were built by a long, steep decline.

16 JamesB. Koenig

Ownership changes became more frequent and in- this and other steam-supply and plant-operation factors volved more participants. Among these, Sun relinquished CCPA's Coldwater Creek power plant was unable to ope- its position; Occidental sold out to Santa Fe International rate at rated capacity. Corporation; Natomas Company, which had acquired all With the departure of several of the large oil companies of Thermal Power, plus Magma Power's Geysers interest, (Shell, Sun, Phillips, etc.), the traditional separation be- was sold to Diamond Shamrock Corporation; DS in turn tween steam supplier and power generator had all but sold half of these interests to Union. Development pro- vanished. GGC (owned then by a subsidiary of Freeport grams were slowed, sometimes halted, as new owners Minerals Company) used the PURPA mechanism to am- evaluated and existing owners reevaluated their stra- struct two 20 MW power plants, selling electricity to tegies. PG&E. CDWR acquired MCR's Bottle Rock power plant, Even more ominous, Some steam-supply contracts but then was forced to shut it down because of operating were increasingly shaky Geothermal Kinetics could not cost and lack of well deliverability. GRI developed severe fulfill its 55 MW supply contact to CDWR, and soon went financial problems and entered receivership. Its debt- into bankruptcy, leaving CDWR with an unused turbine holding financiers in effect became the operators of the generator. PG&E first delayed and then canceled its plans Coldwater Creek wellfield. to expand its system by several hundred MW in response Most ominously, steam pressure was declining. This had to an unexpected overcapacity in power generation. This been observed as far back as the late Us, when the federal overcapacity in part reflected the enthusiastic response tax court had accepted the argument that steam was a under PURPA by independent power companies of all depletable resource for tax purposes. Development plans types- and operating permits had been predicated on forecasts of Several operators at The Geysers, including Unocal harmonic decline in steam pressure with time and on the (fomerly Union), Phillips' Geysers Geothermal Com- need for periodic makeup well drilling. Small pressure pany, and NCPA, were also having increased difficulty in sinks had been observed locally in well production and developing steam for existing or planned power plants. test data; these sinks now deepened and expanded. As Other utilities that had shown interest in entering the new plants came on line, presswe declines appeared to geothermal industry or in expanding their geothermal accelerate. This is discussed in technical detail in several facilities began to back away in response to reductions in papers of this volume. It is enough to say here that power forecast need or because of discouraging results in ex- production dropped significantlybelow nameplate capac- ploratory drilling. ity at several leaseholds and that the more inefficient The decreased stearn price along with ever-deeper drill- plants are being taken out of service. These include State ing at the field margins (typicallyto 9,OOO to 10,000 feet,or of California,Department of Water Resources' Bottle Rock, 2.7 to 3.0 km) placed a disincentive on further exploration. and PG&E Units 1 through 4 which will be decommis- The number of active drilling rigs was halved. Deep drill- sioned by the end of 1991. ing on the GIU property at the northwest end of The With steam prices at their low point for the past 15 , Geysers encountered increasingly gassy steam. Because of years, there is no economic justification for exploratory

I drilling outside of the production field or for deeper drilling within the field in search of new steam. There is scarcely any incentive for makeup drilling within the field to maintain steam supply. However, the situation is not bleak.

A GLIMPSE INTO THE FUTURE Present generation output at The Geysers is approximately 1,600 MW, of 2,042 MW (gross) of originally installed capacity. At least one operator, NCPA, now pro- duces power on a load-following basis rather than as base load. It is possible that load following will replace base loading for most operators, thereby reducing daily output and helping to extend field life. Concern over pressure declines has encouraged a greater degree of data sharing among operators. This has Air drilling of a steam production well in The Geysers. Note the steam discharge from the muffler. In the left center is the West Ford allowed more comprehensive field modeling, leading to a Flat power plant, 27 MW (net), owned by the Calpine Corporation. better understanding of field mechanisms. This may in (Geothermal Resources Council) turn lead to improved operating procedures. Steam reser-

17 History of Development at The Geysers Geothermal Field

ves still exist in undeveloped pockets. It remains to be The Geysers has produced electric power for over 30 determined if these should be drilled for immediate use or years and is likely to continue into the next century. Over retained for future pmsure maintenance. 600 wells have been drilled, of which perhaps half still im Injection of condensed steam is believed to help sup- in production. To date, almost 1.5 x 10" kWhof electricity port field pressure. Additional sources of water for injec- have been generated at The Geysers for the benefit of the tion arebeing evaluated. These include ponded rainwater, people of California. This has offsetthe equivalent of 200 treated sewerage, and peak-flow diversions from local million barrels of oil. Thernost recent power plant (20MW streams. About 30 percent of the total produced mass of Aidlin plant of Calpine Corporation) came on-line as re- steam presently is injected at The Geysers. More efficient cently as mid-1989. (less-water-consuming) cooling towers at power plants, This has been an enormous achievement, done mostly and the retrofitting of existing power plants to achieve a with private capital, often in'the face of indifference from lower steam-consumption rate also could provide more government agencies. With wise management, support in I water for injection, and possibly extend field life. the form of improved prices and publicly sponsored re- Improvements in gas extraction and recovery, and in search, and some degree of luck, The Geysers may equal corrosion control, may allow an increased use of the gassy its historic production over the next few decades. steam at the northwestern end of the field. Similarly, use of residual hot water, found locally at the field's eastern REFERENCES margin, in Iow-temperature binary-cycle generation, may help to extend the field life. Allen, E.T. and Day, A.L., 1927. Steam wells and other thermal activity at TheCeysers, California,Publication No. 378, published Finally, any significant increase in steam or clcctric by Camegie Institution of Washington, 100 p. power prices later in this decade may result in renewed Brewer, William H., Up and Down California in 1860-1864. The exploratory drilling beyond the present production boun- Journal of William H. Brewer, Francis P. Faquhar, (4.1,1930. dary or deeper drilling within the field. Publiished by the University of California Press.