John W. Lund, Gordon R. Bloomquist, Tonya L. Boyd, Joel Renner THE UNATED STATES OF AMERICA COUNTRY UPDATE John W. Lund 1, R. Gordon Bloomquist 2, Tonya L. Boyd 1, Joel Renner 3 1 Geo-Heat Center, Oregon Institute of Technology, Klamath Falls, OR 2 Washington State University Energy Program, Olympia, WA 3 Idaho National Engineering and Environmental Laboratory, Idaho Falls, ID E-mail: firstname.lastname@example.org Geothermal energy is used for electric power generation and direct utilization in the United States.
The present installed capacity (gross) for electric power generation is 2,534 MWe with about 2,000 MWe net delivering power to the grid producing approximately 17,840 GWh per year for a 80.4% gross capacity factor. Geothermal electric power plants are located in California, Nevada, Utah and Hawaii. The two largest concentrations of plants are at The Geysers in northern California and the Imperial Valley in southern California. The latest development at The Geysers, starting in 1998, is injecting recycled wastewater from two communities into the reservoir, which presently has recovered about 100 MWe of power generation. The second pipeline from the Santa Rosa area has just come on line. The direct utilization of geothermal energy includes the heating of pools and spas, greenhouses and aquaculture facilities, space heating and district heating, snow melting, agricultural drying, industrial applications and ground-source heat pumps. The installed capacity is 7,817 MWt and the annual energy use is about 31,200 TJ or 8,680 GWh. The largest application is ground-source (geothermal) heat pumps (69% of the energy use), and the next largest directuses are in space heating and agricultural drying. Direct utilization (without heat pumps) is increasing at about 2.6% per year; whereas electric power plant development is almost static, with only about 70 MWe added since 2000 (there were errors in the WGC2000 tabulation). A new 185-MWe plant being proposed for the Imperial Valley and about 100 MWe for Glass Mountain in northern California could be online by 20072008. Several new plants are proposed for Nevada totaling about 100 MWe and projects have been proposed in Idaho, New Mexico, Oregon and Utah. The total planned in the next 10 years is 632 MWe. The energy savings from electric power generation, direct-uses and ground-source heat pumps amounts to almost nine million tonnes of equivalent fuel oil per years and reduces air pollution by almost eight million tonnes of carbon annually (compared to fuel oil).
1. Introduction Geothermal resources capable of supporting electrical generation and/or direct use projects are found primarily in the Western United States (figure 1). However, geothermal heat pumps extend the utilization to all 50 states. The total identified potential for electrical production, estimated by the United States Geological Survey, stands at 22,990 MWe (Muffler, 1979). A recent evaluation of potential in just California and Nevada by GeothermEx, Inc. (Lovekin, 2004) places the most likely combined total for those two states at 6,200 MWe. This would be nearly triple the existing capacity.
Achieving this electric capacity potential will be dependent upon a number of factors including competing prices for energy and incentive programs that encourage development of renewable energy resources. Recently passed Renewable Portfolio Standards in a number of western states should have a significant impact on renewable development in general and could well result in increased interest in geothermal exploration and development. A production tax credit recently passed by Congress and signed into law in October 2004 provides for a 1.8 cent per kilowatt hour credit, greatly Раздел 1 Геотермальные и минеральные ресурсы, общие вопросы improves geothermal’s ability to compete with fossil fuel generation (Gawell, 2004).
WA MT ME ND MN OR ID VT NY SD WI NH MI CA MA CT NV RI IA NE PA WY NJ IL IN OH UT CO MD DE MO WV KS VA AZ NM NC OK TX AR TN SC GA MS AL LA FL Temperature Above 100oC (212oF) Temperature Below 100oC (212oF) Geopressured Resources Fig. 1. Geothermal Resource map of the United States In addition to these incentives programs, the United States Department of Energy (USDOE) continues to provide support for research and development of geothermal resources through cost sharing with industry and through research being conducted at a number of the national laboratories. Some ongoing efforts are directed at enhanced geothermal system, downhole diagnostics, enhanced evaporative cooling, mixed binary working fluids, corrosion resistant coatings and co-production of minerals. USDOE has recently cost shared the drilling of geothermal production wells through the Geothermal Resource Exploration and Definition (GRED) program. Three different solicitations have been offered to date. The USDOE is also funding a number of state programs aimed at removing barriers to geothermal development. Finally, USDOE continues to provide technical assistance to direct-use, and small-scale electrical project developers and users with their GeoPowering the West program (Hill, 2004) (www.eere.energy.gov/geothermal/deployment_gpw.html) through national laboratories and organizations such as the Geo-Heat Center at Oregon Institute of Technology (http://geoheat.oit.edu) and the Center for Distributed Generation and Thermal Distribution at Washington State University (www.energy.wsu.edu).
The United States continues to lead the world in installed geothermal power capacity as well as in electrical generation, and considering geothermal heat pumps, is one of the leaders in direct-use applications.
John W. Lund, Gordon R. Bloomquist, Tonya L. Boyd, Joel Renner Geothermal energy remains, however, a small contributor to the electric power capacity and generation in the United States. In 2004, geothermal plants constituted about 0.27 percent of the total operable power capacity, and those plants contributed an estimated 0.48 percent of the total generation due to their high load factor.
On a state level, geothermal electric generation is a major player in California and Nevada. The generation in California provides about 6% of the state’s energy consumption. It is a minor source of power in the states of Hawaii and Utah. However, it is significant on the Big Island of Hawaii where it now provides for approximately 25% of the power requirements. There has also been renewed interest and activity in Idaho, Utah, Oregon and New Mexico.
The most impressive geothermal growth in the United States occurred during the 1980s, with an average annual increase in capacity of about 11 percent. In contrast, from 1990-1998, it averaged only 0.14 percent due to a leveling off of new plant construction (Sifford and Bloomquist, 2000), and from 2000 to 2004 only approximately 70 MWe of new capacity was added. The period 2000-2004 also saw a reduction at The Geysers in California to an installed capacity of about 1,421 MWe, down from a total installed capacity of 1,875 MWe in 1990. However, only about 1,000 MWe are currently operating. Contributing to the capacity stagnation was the retirement and shut down of six units at The Geysers in California. These include the four original Pacific Gas and Electric (PG&E) units (78 MWe), both of the Central California Power Agency (CCPA) units (130 MWe), and the 55 MWe Bottle Rock plant. Some capacity at The Geysers has been restored due to the construction of two effluent pipelines that bring over 26 million tonnes of water per year to The Geysers for injection. The Lake County pipeline has allowed over 77 MW to be added (Dellinger, 2004) (GRC, 2003) and there are now plans to build as much as 100 MWe in new plants in what was previously abandoned areas of the Geysers. Capacity that will result from the completion of the Santa Rosa pipeline is yet to be determined as it was only completed in 2004, but estimates are that a total of about 100 MWe have already been added by the two lines.
Direct-use, other than geothermal heat pumps, has also remained fairly static with modest increases in space heating and agricultural drying. Even though the onion and garlic dehydration plant at Empire, Nevada (Empire Foods) has temporarily shut down due to competition from dried garlic imports from China, the plant at Brady’s Hot Springs (ConAgra Food Ingredients) has added a second line (4 m by 60 m continuous drier) that together can handle over twelve tonnes of wet onions per hour. A small district Раздел 1 Геотермальные и минеральные ресурсы, общие вопросы heating system has come online, I’SOT at Canby in northern California; existing greenhouses have been expanded and a new facility of 1.6 hectares added to the district heating system in Klamath Falls, Oregon, along with additional sidewalk and pavement snow melting systems in the downtown area. Geothermal heat pumps have been the largest growth area, mainly with installation in the mid-western and eastern states.
Precise numbers for these installations are hard to determine due to lack of any centralized data gathering; thus, estimates are conservative at 600,000 installed 12.0 kW equivalent units. Except for a few states, which have tax rebate programs for geothermal heat pumps, there is very little support for implementing direct-use projects. However, the USDOE geothermal program is attempting to revitalize direct-use and geothermal heat pump development in the United States.
Table 2 summarizes geothermal electric plant capacity and estimates for the future and table 5 summarizes direct-use capacity and utilization.
TABLE 2. UTILIZATION OF GEOTHERMAL ENERGY FOR ELECTRIC POWER GENERATION AS OF 31 DECEMBER 1) N = Not operating (temporary), R = Retired. Otherwise leave blank if presently operating.
2) 1F = Single Flash B = Binary (Rankine Cycle) 2F = Double Flash H = Hybrid (explain) 3F = Triple Flash O = Other (please specify) D = Dry Steam 3) Data for Locality Power Plant Year No. of Status1) Type of Total Annual Total Name Com- Units Unit2) Installed Energy under missioned Capacity Produced Constr. or MWe 2004 3) Planned GWh/yr MWe CALIFORNIA Geysers 1,421 7,784 Imperial Valley 500 4,569 Others 318 3,126 NEVADA 239 1,943 UTAH 26 200 HAWAII 30 218 Total 2,534 17,840 John W. Lund, Gordon R. Bloomquist, Tonya L. Boyd, Joel Renner TABLE 5. SUMMARY TABLE OF GEOTHERMAL DIRECT HEAT USES AS OF 31 DECEMBER 1) Installed Capacity (thermal power) (MWt) = Max. flow rate (kg/s) x [inlet temp. (oC) - outlet temp. (oC)] x 0. or = Max. flow rate (kg/s) x [inlet enthalpy (kJ/kg) - outlet enthalpy (kJ/kg)] x 0. 2) Annual Energy Use (TJ/yr) = Ave. flow rate (kg/s) x [inlet temp. (oC) - outlet temp. (oC)] x 0.1319 (TJ = 1012 J) or = Ave. flow rate (kg/s) x [inlet enthalpy (kJ/kg) - outlet enthalpy (kJ/kg) x 0. 3) Capacity Factor = [Annual Energy Use (TJ/yr)/Capacity (MWt)] x 0.03171 ( MW = 106 W) Note: the capacity factor must be less than or equal to 1.00 and is usually less, since projects do not operate at 100% capacity all year Note: please report all numbers to three significant figures.
Installed Capacity1) Annual Energy Use2) Capacity Factor3) Use (TJ/yr = 1012 J/yr) (MWt) Individual Space Heating4) 146 1335 0.District Heating 4) 84 788 0. Air Conditioning (Cooling) <1 15 0. Greenhouse Heating 97 766 0.Fish Farming 138 3012 0. Animal Farming Agricultural Drying5) 36 500 0. Industrial Process Heat6) 2 48 0. Snow Melting 2 18 0. Bathing and Swimming7) 112 2543 0. Other Uses (specify) Subtotal 617 9024 0. Geothermal Heat Pumps 7200 22,214 0. TOTAL 7817 31,238 0.4) Other than heat pumps 5) Includes drying or dehydration of grains, fruits and vegetables 6) Excludes agricultural drying and dehydration 7) Includes balneology 2. Production of electricity: all sources Table 1 presents operable electric production capacity and power generation in the United States from all sources for 1999-2003. For 2004, no data were available at the time of writing. All data in this table, except those footnoted, came from the USDOE Energy Information Administration (EIA) (website: www.eia.doe.gov).
Раздел 1 Геотермальные и минеральные ресурсы, общие вопросы TABLE 1. PRESENT AND PLANNED PRODUCTION OF ELECTRICITY (Installed capacity) Geothermal Fossil Fuels Hydro Nuclear Other Renewables Total (specify)Capac- Gross Capac- Gross Capac- Gross Capac- Gross Capac- Gross Capac- Gross ity Prod. ity Prod. ity Prod. ity Prod. ity Prod. ity Prod.
GWe TWh/yr GWe TWh/yr GWe TWh/yr GWe TWh/yr GWe TWh/yr GWe TWh/yr In operation in December 2003 2.5 17.8 730 2612 74 269 99.5 764 17.5 40 923.4 Under construction in December 2004 0 51 0 02 Funds committed, but not yet under construction in December 2004 0.6 3 0 0 0 3.Total projected use by 2010 6.3 45 810 2900 74 269 100 768 28 64 1018 Biomass, wind and solar Geothermal power production has stayed somewhat constant from 2000 to 2004, with steep declines in capacity slowed by reinjection activities at The Geysers and plant expansions elsewhere. This is discussed further below.
EIA data for geothermal energy are liberally estimated. We use our own estimates of operable geothermal capacity, and they are lower than EIA data. Discrepancies can be traced to plant status and load factors that vary each year. Capacity variations are due to both contractual issues and resource conditions.
3. Geothermal development by State 3.1 California California accounts for approximately 90 percent of the installed geothermal power capacity in the country. The major areas of development are The Geysers, Imperial Valley, Salton Sea, and Coso. Other areas with geothermal plants are Casa Diablo (Mono-Long Valley or Mammoth) and the Honey Lake Valley including Wendel and Amedee. Glass Mountain is scheduled for development but has been held up due to a number of lawsuits filed by opponents to the project. The locations of all of these areas are shown in Figure 2.
The Geysers There have been no new plants installed since 1989 when the 2x10 MWe J.W. Aidlin plant came on-line. The four original PG&E units were officially retired in 1992; all surface equipment for Units 1 through 4 has been dismantled. Supply wells have been redirected to other units. Unit 1 was designated a National Landmark in 1985 by the American Society of Mechanical Engineers. Plants no longer in service include PG&E Unit 15 (59 MWe, retired in 1989), DWR Bottle Rock plant (55 MWe, closed in 1990), and the CCPA Units 1&2 (130 MWe, retired in 1996). Table 2a gives data on the plants at The Geysers, including the rating and the actual output. Owing to a shortfall of steam, John W. Lund, Gordon R. Bloomquist, Tonya L. Boyd, Joel Renner GLASS MOUNTAIN * SURPRISE VALLEY * HONEY LAKE VALLEY THE GEYSERS CASA DIABLO San Francisco C A L I F O R N I A COSO Los Angeles SALTON SEA 200 km EAST MESA San Diego 0 100 miles HEBER Geothermal Plants Sites Major cities * Proposed Figure 2. Geothermal Power Plant Figure 2A. Geothermal Power Plant Areas Areas in California in the Salton Sea TABLE 2a. The Geysers Geothermal power Plants 1) N = Not operating (temporary), R = Retired. Otherwise leave blank if presently operating.
2) 1F = Single Flash B = Binary (Rankine Cycle) 2F = Double Flash H = Hybrid (explain) 3F = Triple Flash O = Other (please specify) D = Dry Steam Locality Power Plant Name Year No. of Status1) Type of Installed Annual Under Com- Units Unit2) Capacity Energy GWh Constr. or missioned MWe Planned MWe 1 Aidlin 1989 1 D 20 2 Bear Canyon 1988 1 D 22 3 Sonoma 1983 1 D 72 4 West Ford Flat 1988 1 D 29 5&6 McCabe 1971 2 D 106 7&8 Ridge Line 1972 2 D 106 9&10 Fumarole 1973 2 R D -- -11 Eagle Rock 1975 1 D 65 355 106 MW generator, new turbine installed 12 Cobb Creek 1979 1 D 106 13 Big Geysers 1980 1 D 78 426 133W generator, new turbine installed 14 Sulfur Springs 1980 1 D 65 355 109MW generator, new turbine installed 16 Quicksilver 1985 1 D 113 17 Lake View 1982 1 D 113 18 Socrates 1983 1 D 113 19 Callistoga 1984 1 D 80 20 Grant 1985 1 D 113 NCPA 1-2 1983 2 D 110 NCPA 3-4 1985, 86 2 D 110 TOTALS 23 1421MW 7784 GWh Раздел 1 Геотермальные и минеральные ресурсы, общие вопросы the difference between rated and actual power capacity is significant (1421 to 1020).
However, this shortfall is being reversed in several units by the southeast Geysers effluent recycling system and the new Santa Rosa pipeline as discussed below.
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