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89-596: Sonoma Valley is a valley located in southeastern Sonoma County , California , in the North Bay region of the San Francisco Bay Area . Known as the birthplace of the California wine industry, the valley is home to some of the earliest vineyards and wineries in the state, some of which survived the phylloxera epidemic of the 1870s and the impact of prohibition in the early 20th century. Today,

178-878: A turbine . These binary plants originated in the Soviet Union in the late 1960s and predominate in new plants. Binary plants have no emissions. An engineered geothermal system is a geothermal system that engineers have artificially created or improved. Engineered geothermal systems are used in a variety of geothermal reservoirs that have hot rocks but insufficient natural reservoir quality, for example, insufficient geofluid quantity or insufficient rock permeability or porosity, to operate as natural hydrothermal systems. Types of engineered geothermal systems include enhanced geothermal systems , closed-loop or advanced geothermal systems , and some superhot rock geothermal systems . Enhanced geothermal systems (EGS) actively inject water into wells to be heated and pumped back out. The water

267-636: A 508 MV capacity. The first geothermal power plant in the Tiwi region opened in 1979, while two other plants followed in 1980 and 1982. The Tiwi geothermal field is located about 450 km from Manila . The three geothermal power plants in the Tiwi region produce 330 MWe, putting the Philippines behind the United States and Mexico in geothermal growth. The Philippines has 7 geothermal fields and continues to exploit geothermal energy by creating

356-414: A broader floodplain may result. Deposition dominates over erosion. A typical river basin or drainage basin will incorporate each of these different types of valleys. Some sections of a stream or river valleys may have vertically incised their course to such an extent that the valley they occupy is best described as a gorge , ravine , or canyon . Rapid down-cutting may result from localized uplift of

445-533: A cirque glacier. During glacial periods, for example, the Pleistocene ice ages, it is in these locations that glaciers initially form and then, as the ice age proceeds, extend downhill through valleys that have previously been shaped by water rather than ice. Abrasion by rock material embedded within the moving glacial ice causes the widening and deepening of the valley to produce the characteristic U or trough shape with relatively steep, even vertical sides and

534-686: A marine sandstone called the Wilson Grove Formation . Gravels in the Petaluma Formation did not come from rocks located in Napa, but have been sourced to mountains east of San Jose, California. This does not mean rivers flowed northward from San Jose to Sonoma; rather, strike-slip movement along the Hayward-Sonoma Valley-Carneros fault system has dislocated present-day Sonoma County north and away from

623-594: A narrow valley with steep sides. Gill is used to describe a ravine containing a mountain stream in Cumbria and the Pennines . The term combe (also encountered as coombe ) is widespread in southern England and describes a short valley set into a hillside. Other terms for small valleys such as hope, dean, slade, slack and bottom are commonly encountered in place-names in various parts of England but are no longer in general use as synonyms for valley . The term vale

712-432: A relatively flat bottom. Interlocking spurs associated with the development of river valleys are preferentially eroded to produce truncated spurs , typical of glaciated mountain landscapes. The upper end of the trough below the ice-contributing cirques may be a trough-end . Valley steps (or 'rock steps') can result from differing erosion rates due to both the nature of the bedrock (hardness and jointing for example) and

801-442: A sedimentary basin, the geothermal gradient proved to be insufficient for electrical power generation. However, the system successfully produced approximately 11,000 MWh of thermal energy during its initial two years of operation." As with wind and solar energy, geothermal power has minimal operating costs; capital costs dominate. Drilling accounts for over half the costs, and not all wells produce exploitable resources. For example,

890-689: A significant share of the electrical power in Iceland , El Salvador , Kenya , the Philippines and New Zealand . Geothermal power is considered to be a renewable energy because heat extraction rates are insignificant compared to the Earth's heat content . The greenhouse gas emissions of geothermal electric stations are on average 45 grams of carbon dioxide per kilowatt-hour of electricity, or less than 5 percent of that of coal-fired plants. Geothermal electric plants were traditionally built on

979-465: A slower rate than that of the main valley floor; thus the difference in the two valleys' depth increases over time. The tributary valley, composed of more resistant rock, then hangs over the main valley. Trough-shaped valleys also form in regions of heavy topographic denudation . By contrast with glacial U-shaped valleys, there is less downward and sideways erosion. The severe downslope denudation results in gently sloping valley sides; their transition to

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1068-462: A small fraction of the emission intensity of fossil fuel plants. A few plants emit more pollutants than gas-fired power, at least in the first few years, such as some geothermal power in Turkey . Plants that experience high levels of acids and volatile chemicals are typically equipped with emission-control systems to reduce the exhaust. New emerging closed looped technologies developed by Eavor have

1157-672: A source of heat and/or electric power for millennia. Geothermal heating , using water from hot springs , for example, has been used for bathing since Paleolithic times and for space heating since Roman times. Geothermal power , (generation of electricity from geothermal energy), has been used since the 20th century. Unlike wind and solar energy, geothermal plants produce power at a constant rate, without regard to weather conditions. Geothermal resources are theoretically more than adequate to supply humanity's energy needs. Most extraction occurs in areas near tectonic plate boundaries . The cost of generating geothermal power decreased by 25% during

1246-409: A total of 270 PJ of geothermal heating in 2004. As of 2007, 28 GW of geothermal heating satisfied 0.07% of global primary energy consumption. Thermal efficiency is high since no energy conversion is needed, but capacity factors tend to be low (around 20%) since the heat is mostly needed in the winter. Even cold ground contains heat: below 6 metres (20 ft) the undisturbed ground temperature

1335-532: A typical well pair (one for extraction and one for injection) in Nevada can produce 4.5 megawatts (MW) and costs about $ 10 million to drill, with a 20% failure rate, making the average cost of a successful well $ 50 million. Drilling geothermal wells is more expensive than drilling oil and gas wells of comparable depth for several reasons: As of 2007 plant construction and well drilling cost about €2–5 million per MW of electrical capacity, while

1424-427: A valley between its sides is referred to as the valley floor. The valley floor is typically formed by river sediments and may have fluvial terraces . The development of a river valley is affected by the character of the bedrock over which the river or stream flows, the elevational difference between its top and bottom, and indeed the climate. Typically the flow will increase downstream and the gradient will decrease. In

1513-654: A valley of the coastal Miwok , Pomo and Wintun peoples, called the "Valley of the Moon" in their legends, the valley was selected by the Franciscan order of Spain as the site to build the Mission San Francisco Solano , the northernmost mission in their chain of twenty-one missions built in Alta California . Established in 1823 and named to honor St. Francis Solanus , Mission Solano

1602-510: A variety of transitional forms between V-, U- and plain valleys can form. The floor or bottom of these valleys can be broad or narrow, but all valleys have a shoulder. The broader a mountain valley, the lower its shoulders are located in most cases. An important exception is canyons where the shoulder almost is near the top of the valley's slope. In the Alps – e.g. the Tyrolean Inn valley –

1691-670: A watercourse only rarely. In areas of limestone bedrock , dry valleys may also result from drainage now taking place underground rather than at the surface. Rift valleys arise principally from earth movements , rather than erosion. Many different types of valleys are described by geographers, using terms that may be global in use or else applied only locally. Valleys may arise through several different processes. Most commonly, they arise from erosion over long periods by moving water and are known as river valleys. Typically small valleys containing streams feed into larger valleys which in turn feed into larger valleys again, eventually reaching

1780-405: Is a tributary valley that is higher than the main valley. They are most commonly associated with U-shaped valleys, where a tributary glacier flows into a glacier of larger volume. The main glacier erodes a deep U-shaped valley with nearly vertical sides, while the tributary glacier, with a smaller volume of ice, makes a shallower U-shaped valley. Since the surfaces of the glaciers were originally at

1869-456: Is approximately 100 billion times 2010 worldwide annual energy consumption. Earth's heat flows are not in equilibrium; the planet is cooling on geologic timescales. Anthropic heat extraction typically does not accelerate the cooling process. Wells can further be considered renewable because they return the extracted water to the borehole for reheating and re-extraction, albeit at a lower temperature. Replacing material use with energy has reduced

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1958-674: Is consistently at the Mean Annual Air Temperature that may be extracted with a ground source heat pump . Hydrothermal systems produce geothermal energy by accessing naturally-occurring hydrothermal reservoirs. Hydrothermal systems come in either vapor-dominated or liquid-dominated forms. Larderello and The Geysers are vapor-dominated. Vapor-dominated sites offer temperatures from 240 to 300 °C that produce superheated steam. Liquid-dominated reservoirs (LDRs) are more common with temperatures greater than 200 °C (392 °F) and are found near volcanoes in/around

2047-459: Is injected under high pressure to expand existing rock fissures to enable the water to flow freely. The technique was adapted from oil and gas fracking techniques. The geologic formations are deeper and no toxic chemicals are used, reducing the possibility of environmental damage. Instead proppants such as sand or ceramic particles are used to keep the cracks open and producing optimal flow rates. Drillers can employ directional drilling to expand

2136-487: Is not recoverable. In addition to the internal heat flows, the top layer of the surface to a depth of 10 m (33 ft) is heated by solar energy during the summer, and cools during the winter. Outside of the seasonal variations, the geothermal gradient of temperatures through the crust is 25–30 °C (77–86 °F) per km of depth in most of the world. The conductive heat flux averages 0.1 MW/km . These values are much higher near tectonic plate boundaries where

2225-501: Is only 50 meters (160 ft) deep while the main fjord is around 1,300 meters (4,300 ft) at the same point. Glaciated terrain is not the only site of hanging streams and valleys. Hanging valleys are also simply the product of varying rates of erosion of the main valley and the tributary valleys. The varying rates of erosion are associated with the composition of the adjacent rocks in the different valley locations. The tributary valleys are eroded and deepened by glaciers or erosion at

2314-631: Is residual heat from planetary accretion ; the remainder is attributed to past and current radioactive decay of naturally occurring isotopes . For example, a 5275 m deep borehole in United Downs Deep Geothermal Power Project in Cornwall , England, found granite with very high thorium content, whose radioactive decay is believed to power the high temperature of the rock. Earth's interior temperature and pressure are high enough to cause some rock to melt and

2403-488: Is the word cwm borrowed from Welsh . The word dale occurs widely in place names in the north of England and, to a lesser extent, in southern Scotland. As a generic name for a type of valley, the term typically refers to a wide valley, though there are many much smaller stream valleys within the Yorkshire Dales which are named "(specific name) Dale". Clough is a word in common use in northern England for

2492-592: Is to drill a well into a hot aquifer . An artificial hot water reservoir may be built by injecting water to hydraulically fracture bedrock. The systems in this last approach are called enhanced geothermal systems . 2010 estimates of the potential for electricity generation from geothermal energy vary sixfold, from 0.035 to 2 TW depending on the scale of investments. Upper estimates of geothermal resources assume wells as deep as 10 kilometres (6 mi), although 20th century wells rarely reached more than 3 kilometres (2 mi) deep. Wells of this depth are common in

2581-629: Is used in England and Wales to describe a wide river valley, usually with a particularly wide flood plain or flat valley bottom. In Southern England, vales commonly occur between the outcrops of different relatively erosion-resistant rock formations, where less resistant rock, often claystone has been eroded. An example is the Vale of White Horse in Oxfordshire. Some of the first human complex societies originated in river valleys, such as that of

2670-702: The Blue Wing Inn of 1840. The valley is located in southeastern Sonoma County between the Mayacamas Mountains and Sonoma Mountains . It stretches from San Pablo Bay in the south to the city of Santa Rosa in the north. Sonoma Creek flows down the valley to the bay. The area includes the incorporated city of Sonoma and part of the city of Santa Rosa, as well as numerous unincorporated communities, including Kenwood and Glen Ellen near Santa Rosa and, near Sonoma, El Verano , Boyes Hot Springs , Fetters Hot Springs, and Agua Caliente . Once

2759-601: The Energy Sector Management Assistance Program (ESMAP) report "Socioeconomic Impacts of Geothermal Energy Development" was published, highlighting the substantial socioeconomic benefits of geothermal energy development, which notably exceeds those of wind and solar by generating an estimated 34 jobs per megawatt across various sectors. The report details how geothermal projects contribute to skill development through practical on-the-job training and formal education, thereby strengthening

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2848-658: The Franciscan Complex along the Coast Range Thrust . The Jurassic-Cretaceous Franciscan Complex includes crumpled, uplifted terranes that have resulted from the subduction of the former oceanic Farallon Plate under the North American continent. During late Miocene-Pliocene time (~10 to ~4 million years) the area was attended by volcanism (Late Miocene Tolay Volcanics and Late Miocene - Pliocene Sonoma Volcanics ) which are interbedded with

2937-528: The Latin terms for 'valley, 'gorge' and 'ditch' respectively. The German term ' rille ' or Latin term 'rima' (signifying 'cleft') is used for certain other elongate depressions on the Moon. See also: Geothermic Geothermal energy is thermal energy extracted from the Earth's crust . It combines energy from the formation of the planet and from radioactive decay . Geothermal energy has been exploited as

3026-544: The Miwok tribes that lived in the valley, and the Pomo , it meant "valley of the moon" or "many moons". Settlers may have accidentally translated the words "many moons" into "valley of moons". Miwok legends say that the moon seemingly rose from this valley, or was "nestled" in the valley, or may have even sprung up multiple times in one night. In the native languages there is also a constantly recurring ending tso-noma , from tso ,

3115-504: The Nile , Tigris-Euphrates , Indus , Ganges , Yangtze , Yellow River , Mississippi , and arguably the Amazon . In prehistory , the rivers were used as a source of fresh water and food (fish and game), as well as a place to wash and a sewer. The proximity of water moderated temperature extremes and provided a source for irrigation , stimulating the development of agriculture . Most of

3204-654: The Philippine Institute of Volcanology and Seismology inspected the geothermal region in Tiwi, Albay . The first geothermal power plant in the Philippines was built in 1977, located in Tongonan, Leyte . The New Zealand government contracted with the Philippines to build the plant in 1972. The Tongonan Geothermal Field (TGF) added the Upper Mahiao, Matlibog, and South Sambaloran plants, which resulted in

3293-697: The Richter Scale occurred over the first 6 days of water injection. Geothermal power production has minimal land and freshwater requirements. Geothermal plants use 3.5 square kilometres (1.4 sq mi) per gigawatt of electrical production (not capacity) versus 32 square kilometres (12 sq mi) and 12 square kilometres (4.6 sq mi) for coal facilities and wind farms respectively. They use 20 litres (5.3 US gal) of freshwater per MW·h versus over 1,000 litres (260 US gal) per MW·h for nuclear, coal, or oil. The Philippines began geothermal research in 1962 when

3382-705: The Sonoma County Water Agency completed a comprehensive basin-wide groundwater study to characterize groundwater resources in the Sonoma Valley. The report can be obtained on the USGS publications website. Currently, a Basin Advisory Panel, composed of stakeholders from agriculture, environmental groups, domestic well owners, municipalities and government is working to develop a groundwater management plan to protect groundwater resources in

3471-624: The Tubbs Fire . The phrase "Valley of the Moon" was first recorded in an 1850 report by General Mariano Guadalupe Vallejo to the California Legislature. According to Jack London , who had a ranch there, the Native American word Sonoma means "valley of the moon". He used it for his book of the same name . But there are several other possible translations for Sonoma (see Sonoma County, California ). According to

3560-631: The break-even price was 0.04–0.10 € per kW·h. Enhanced geothermal systems tend to be on the high side of these ranges, with capital costs above $ 4 million per MW and break-even above $ 0.054 per kW·h. Between 2013 and 2020, private investments were the main source of funding for renewable energy , comprising approximately 75% of total financing. The mix between private and public funding varies among different renewable energy technologies, influenced by their market appeal and readiness. In 2020, geothermal energy received just 32% of its investment from private sources. In January 2024,

3649-668: The first civilizations developed from these river valley communities. Siting of settlements within valleys is influenced by many factors, including the need to avoid flooding and the location of river crossing points. Numerous elongate depressions have been identified on the surface of Mars , Venus , the Moon , and other planets and their satellites and are known as valles (singular: 'vallis'). Deeper valleys with steeper sides (akin to canyons) on certain of these bodies are known as chasmata (singular: 'chasma'). Long narrow depressions are referred to as fossae (singular: 'fossa'). These are

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3738-548: The 1980s and 1990s. Technological advances continued to reduce costs and thereby expand the amount of viable resources. In 2021, the US Department of Energy estimated that power from a plant "built today" costs about $ 0.05/kWh. In 2019, 13,900 megawatts (MW) of geothermal power was available worldwide. An additional 28 gigawatts provided heat for district heating, space heating, spas, industrial processes, desalination, and agricultural applications as of 2010. As of 2019

3827-462: The Geysers experienced reduced output because of local depletion. Heat and water, in uncertain proportions, were extracted faster than they were replenished. Reducing production and injecting additional water could allow these wells to recover their original capacity. Such strategies have been implemented at some sites. These sites continue to provide significant energy. The Wairakei power station

3916-471: The Pacific Ocean and in rift zones and hot spots. Flash plants are the common way to generate electricity from these sources. Steam from the well is sufficient to power the plant. Most wells generate 2–10 MW of electricity. Steam is separated from liquid via cyclone separators and drives electric generators. Condensed liquid returns down the well for reheating/reuse. As of 2013, the largest liquid system

4005-524: The Scandinavian ice sheet during the various ice ages advanced slightly uphill against the lie of the land. As a result, its meltwaters flowed parallel to the ice margin to reach the North Sea basin, forming huge, flat valleys known as Urstromtäler . Unlike the other forms of glacial valleys, these were formed by glacial meltwaters. Depending on the topography , the rock types , and the climate ,

4094-838: The US's first district heating system in Boise, Idaho was powered by geothermal energy. It was copied in Klamath Falls, Oregon , in 1900. The world's first known building to utilize geothermal energy as its primary heat source was the Hot Lake Hotel in Union County, Oregon , beginning in 1907. A geothermal well was used to heat greenhouses in Boise in 1926, and geysers were used to heat greenhouses in Iceland and Tuscany at about

4183-520: The Wairakei field. In Staufen im Breisgau , Germany, tectonic uplift occurred instead. A previously isolated anhydrite layer came in contact with water and turned it into gypsum, doubling its volume. Enhanced geothermal systems can trigger earthquakes as part of hydraulic fracturing . A project in Basel , Switzerland was suspended because more than 10,000 seismic events measuring up to 3.4 on

4272-511: The actual valley bottom is unclear. Trough-shaped valleys occur mainly in periglacial regions and in tropical regions of variable wetness. Both climates are dominated by heavy denudation. Box valleys have wide, relatively level floors and steep sides. They are common in periglacial areas and occur in mid-latitudes, but also occur in tropical and arid regions. Rift valleys, such as the Albertine Rift and Gregory Rift are formed by

4361-617: The commitment to advancing gender equality and social inclusion by offering job opportunities, education, and training to underrepresented groups, ensuring fair access to the benefits of geothermal development. Collectively, these efforts are instrumental in driving domestic economic growth, increasing fiscal revenues, and contributing to more stable and diverse national economies, while also offering significant social benefits such as better health, education, and community cohesion. Geothermal projects have several stages of development. Each phase has associated risks. Many projects are canceled during

4450-402: The crust is thinner. They may be further augmented by combinations of fluid circulation, either through magma conduits , hot springs , hydrothermal circulation . The thermal efficiency and profitability of electricity generation is particularly sensitive to temperature. Applications receive the greatest benefit from a high natural heat flux most easily from a hot spring . The next best option

4539-444: The development of the town and dispensed large ranches throughout the valley. California's first wineries were established here, including Buena Vista Winery (1857) and Gundlach Bundschu (1858). The other communities in the valley, such as Kenwood , Glen Ellen , Schellville , and Boyes Hot Springs , were founded later in the 19th century, some as resorts centered on the geothermic hot springs that still well up from deep within

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4628-547: The earth. Boyes Hot Springs and Agua Caliente were popular health retreats for tourists from San Francisco and points beyond until the middle of the 20th century. Today the Sonoma Mission Inn in Boyes Hot Springs remains as a main destination resort, and the wineries, the historic sites, and the area's natural beauty are the main tourist attractions. In October 2017, Sonoma Valley was badly affected by

4717-551: The earth; and noma , village; hence tsonoma , "earth village". Other sources say Sonoma comes from the Patwin tribes west of the Sacramento River , and their Wintu word for "nose". Per California Place Names, "the name is doubtless derived from a Patwin word for 'nose', which Padre Arroyo (Vocabularies, p. 22) gives as sonom ( Suisun )." Spaniards may have found an Indian chief with a prominent protuberance and applied

4806-479: The edges of tectonic plates where high-temperature geothermal resources approach the surface. The development of binary cycle power plants and improvements in drilling and extraction technology enable enhanced geothermal systems over a greater geographical range. Demonstration projects are operational in Landau-Pfalz , Germany, and Soultz-sous-Forêts , France, while an earlier effort in Basel , Switzerland,

4895-509: The expansion of the Earth 's crust due to tectonic activity beneath the Earth's surface. There are many terms used for different sorts of valleys. They include: Similar geographical features such as gullies , chines , and kloofs , are not usually referred to as valleys. The terms corrie , glen , and strath are all Anglicisations of Gaelic terms and are commonly encountered in place-names in Scotland and other areas where Gaelic

4984-443: The flow slower and both erosion and deposition may take place. More lateral erosion takes place in the middle section of a river's course, as strong currents on the outside of its curve erode the bank. Conversely, deposition may take place on the inside of curves where the current is much slacker, the process leading to the river assuming a meandering character. In the lower valley, gradients are lowest, meanders may be much broader and

5073-401: The fluids cool, dissolved cations precipitate out of solution, leading to the formation of calcium scale, a phenomenon known as calcite scaling. This calcite scaling has the potential to decrease flow rates and necessitate system downtime for maintenance purposes. Geothermal energy is considered to be sustainable because the heat extracted is so small compared to the Earth's heat content, which

5162-583: The hot springs there to supply public baths and underfloor heating . The admission fees for these baths probably represent the first commercial use of geothermal energy. The world's oldest geothermal district heating system, in Chaudes-Aigues , France, has been operating since the 15th century. The earliest industrial exploitation began in 1827 with the use of geyser steam to extract boric acid from volcanic mud in Larderello , Italy. In 1892,

5251-506: The human environmental footprint in many applications. Geothermal has the potential to allow further reductions. For example, Iceland has sufficient geothermal energy to eliminate fossil fuels for electricity production and to heat Reykjavik sidewalks and eliminate the need for gritting. However, local effects of heat extraction must be considered. Over the course of decades, individual wells draw down local temperatures and water levels. The three oldest sites, at Larderello, Wairakei , and

5340-549: The industry employed about one hundred thousand people. The adjective geothermal originates from the Greek roots γῆ ( gê ), meaning Earth, and θερμός ( thermós ), meaning hot. Hot springs have been used for bathing since at least Paleolithic times. The oldest known spa is at the site of the Huaqing Chi palace. In the first century CE, Romans conquered Aquae Sulis , now Bath, Somerset , England, and used

5429-427: The land surface or rejuvenation of the watercourse as a result for example of a reduction in the base level to which the river is eroded, e.g. lowered global sea level during an ice age . Such rejuvenation may also result in the production of river terraces . There are various forms of valleys associated with glaciation. True glacial valleys are those that have been cut by a glacier which may or may not still occupy

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5518-525: The late Miocene-Pliocene Petaluma Formation . The (~9 to 4 million year old) Petaluma Formation was a fresh-water river system flowing from east to west and through the volcanics. At that time, volcanic lava flows and river sands and gravels were actively deposited together, hence "interbedded lavas and gravels". The volcanoes may have been similar to island arcs . The Petaluma Formation is found in outcrop from Sears Point to Santa Rosa (through Sonoma Mountain) and as far west as Cotati where it interfingers with

5607-433: The local workforce and expanding employment opportunities. It also underscores the collaborative nature of geothermal development with local communities , which leads to improved infrastructure, skill-building programs, and revenue-sharing models, thereby enhancing access to reliable electricity and heat. These improvements have the potential to boost agricultural productivity and food security . The report further addresses

5696-794: The mountains in San Jose where the basin formed. The valley is drained by Sonoma Creek , whose headwaters rise in Sugarloaf Ridge State Park and discharge into the San Pablo Bay at the Napa Sonoma Marsh . Some of the principal tributaries to Sonoma Creek are Yulupa Creek , Graham Creek , Calabazas Creek , Bear Creek , Schell Creek and Carriger Creek . In spring 2006, the United States Geological Survey in conjunction with

5785-624: The nickname of Chief Nose to the village and the territory. The name may have applied originally to a nose-shaped geographic feature. The Sonoma Valley is part of the Coast Range Physiographic province . Basement rocks that make up the valley at great depth are the Great Valley Sequence shale, sandstone and conglomerate deposited in a continental slope- to abyssal plain environment via turbidite flows. The Cretaceous Great Valley Sequence overlies and contacts

5874-463: The ocean or perhaps an internal drainage basin . In polar areas and at high altitudes, valleys may be eroded by glaciers ; these typically have a U-shaped profile in cross-section, in contrast to river valleys, which tend to have a V-shaped profile. Other valleys may arise principally through tectonic processes such as rifting . All three processes can contribute to the development of a valley over geological time. The flat (or relatively flat) portion of

5963-436: The petroleum industry. Geothermal power is electrical power generated from geothermal energy. Dry steam, flash steam, and binary cycle power stations have been used for this purpose. As of 2010 geothermal electricity was generated in 26 countries. As of 2019, worldwide geothermal power capacity amounted to 15.4 gigawatts (GW), of which 23.86 percent or 3.68 GW were in the United States . Geothermal energy supplies

6052-507: The potential to reduce these emissions to zero. Water from geothermal sources may hold in solution trace amounts of toxic elements such as mercury , arsenic , boron , and antimony . These chemicals precipitate as the water cools, and can damage surroundings if released. The modern practice of returning geothermal fluids into the Earth to stimulate production has the side benefit of reducing this environmental impact. Construction can adversely affect land stability. Subsidence occurred in

6141-436: The power of the moving ice. In places, a rock basin may be excavated which may later be filled with water to form a ribbon lake or else by sediments. Such features are found in coastal areas as fjords . The shape of the valley which results from all of these influences may only become visible upon the recession of the glacier that forms it. A river or stream may remain in the valley; if it is smaller than one would expect given

6230-606: The reservoir size. Small-scale EGS have been installed in the Rhine Graben at Soultz-sous-Forêts in France and at Landau and Insheim in Germany. Closed-loop geothermal systems, sometimes colloquially referred to as Advanced Geothermal Systems (AGS), are engineered geothermal systems containing subsurface working fluid that is heated in the hot rock reservoir without direct contact with rock pores and fractures. Instead,

6319-446: The same elevation , the shallower valley appears to be 'hanging' above the main valley. Often, waterfalls form at or near the outlet of the upper valley. Hanging valleys also occur in fjord systems underwater. The branches of Sognefjord are much shallower than the main fjord. The mouth of Fjærlandsfjord is about 400 meters (1,300 ft) deep while the main fjord nearby is 1,200 meters (3,900 ft) deep. The mouth of Ikjefjord

6408-469: The same time. Charles Lieb developed the first downhole heat exchanger in 1930 to heat his house. Geyser steam and water began heating homes in Iceland in 1943. In the 20th century, geothermal energy came into use as a generating source. Prince Piero Ginori Conti tested the first geothermal power generator on 4 July 1904, at the Larderello steam field. It successfully lit four light bulbs. In 1911,

6497-550: The shoulders are quite low (100–200 meters above the bottom). Many villages are located here (esp. on the sunny side) because the climate is very mild: even in winter when the valley's floor is filled with fog, these villages are in sunshine . In some stress-tectonic regions of the Rocky Mountains or the Alps (e.g. Salzburg ), the side valleys are parallel to each other, and are hanging . Smaller streams flow into rivers as deep canyons or waterfalls . A hanging valley

6586-849: The size of its valley, it can be considered an example of a misfit stream . Other interesting glacially carved valleys include: A tunnel valley is a large, long, U-shaped valley originally cut under the glacial ice near the margin of continental ice sheets such as that now covering Antarctica and formerly covering portions of all continents during past glacial ages. Such valleys can be up to 100 km (62 mi) long, 4 km (2.5 mi) wide, and 400 m (1,300 ft) deep (its depth may vary along its length). Tunnel valleys were formed by subglacial water erosion . They once served as subglacial drainage pathways carrying large volumes of meltwater. Their cross-sections exhibit steep-sided flanks similar to fjord walls, and their flat bottoms are typical of subglacial glacial erosion. In northern Central Europe,

6675-537: The solid mantle to behave plastically. Parts of the mantle convect upward since it is lighter than the surrounding rock. Temperatures at the core–mantle boundary can reach over 4,000 °C (7,230 °F). The Earth's internal thermal energy flows to the surface by conduction at a rate of 44.2 terawatts (TW), and is replenished by radioactive decay of minerals at a rate of 30 TW. These power rates are more than double humanity's current energy consumption from all primary sources, but most of this energy flux

6764-435: The stages of reconnaissance and geophysical surveys, which are unsuitable for traditional lending. At later stages can often be equity-financed. A common issue encountered in geothermal systems arises when the system is situated in carbonate-rich formations. In such cases, the fluids extracting heat from the subsurface often dissolve fragments of the rock during their ascent towards the surface, where they subsequently cool. As

6853-536: The subsurface working fluid stays inside a closed loop of deeply buried pipes that conduct Earth's heat. The advantages of a deep, closed-loop geothermal circuit include: (1) no need for a geofluid, (2) no need for the hot rock to be permeable or porous, and (3) all the introduced working fluid can be recirculated with zero loss. Eavor , a Canadian-based geothermal startup, piloted their closed-loop system in shallow soft rock formations in Alberta, Canada. Situated within

6942-407: The upper valley, the stream will most effectively erode its bed through corrasion to produce a steep-sided V-shaped valley. The presence of more resistant rock bands, of geological faults , fractures , and folds may determine the course of the stream and result in a twisting course with interlocking spurs . In the middle valley, as numerous streams have coalesced, the valley is typically wider,

7031-407: The valley at the present day. Such valleys may also be known as glacial troughs. They typically have a U-shaped cross-section and are characteristic landforms of mountain areas where glaciation has occurred or continues to take place. The uppermost part of a glacial valley frequently consists of one or more 'armchair-shaped' hollows, or ' cirques ', excavated by the rotational movement downslope of

7120-588: The valley's wines are promoted by the U.S. federal government's Sonoma Valley and Carneros AVAs (or American Viticultural Areas ). Sonoma Valley offers a wide range of year-round festivals and events, including the Sonoma International Film Festival . Points of interest include the Quarryhill Botanic Garden , Mission San Francisco Solano , Jack London State Historic Park , Sonoma State Historic Park and

7209-719: The valley. Kroeber, A. L., Handbook of the Indians of California (New York 1976 - reprint of Bulletin 78 of the Bureau of American Ethnology of the Smithsonian Institution 1925) 38°22′N 122°30′W  /  38.367°N 122.500°W  / 38.367; -122.500 Valley At lower latitudes and altitudes, these glacially formed valleys may have been created or enlarged during ice ages but now are ice-free and occupied by streams or rivers. In desert areas, valleys may be entirely dry or carry

7298-538: The world's first commercial geothermal power plant was built there. It was the only industrial producer of geothermal power until New Zealand built a plant in 1958. In 2012, it produced some 594 megawatts. In 1960, Pacific Gas and Electric began operation of the first US geothermal power plant at The Geysers in California. The original turbine lasted for more than 30 years and produced 11  MW net power. An organic fluid based binary cycle power station

7387-565: Was Cerro Prieto in Mexico, which generates 750 MW of electricity from temperatures reaching 350 °C (662 °F). Lower-temperature LDRs (120–200 °C) require pumping. They are common in extensional terrains, where heating takes place via deep circulation along faults, such as in the Western US and Turkey. Water passes through a heat exchanger in a Rankine cycle binary plant. The water vaporizes an organic working fluid that drives

7476-844: Was commissioned in November 1958, and it attained its peak generation of 173 MW in 1965, but already the supply of high-pressure steam was faltering. In 1982 it was down-rated to intermediate pressure and the output to 157 MW. In 2005 two 8 MW isopentane systems were added, boosting output by about 14 MW. Detailed data were lost due to re-organisations. Fluids drawn from underground carry a mixture of gasses, notably carbon dioxide ( CO 2 ), hydrogen sulfide ( H 2 S ), methane ( CH 4 ) and ammonia ( NH 3 ). These pollutants contribute to global warming , acid rain and noxious smells if released. Existing geothermal electric plants emit an average of 122 kilograms (269 lb) of CO 2 per megawatt-hour (MW·h) of electricity,

7565-540: Was first demonstrated in 1967 in the USSR and later introduced to the US in 1981 . This technology allows the use of temperature resources as low as 81 °C. In 2006, a binary cycle plant in Chena Hot Springs, Alaska , came on-line, producing electricity from a record low temperature of 57 °C (135 °F). The Earth has an internal heat content of 10  joules (3·10   TWh ), About 20% of this

7654-621: Was laid out in the standard form of a Mexican town, centered around the historic plaza, which is still the town's focal point. Also known as "Valley of the Seven Moons" The raising of the first California Bear Flag and Vallejo's arrest in 1846 by a band of Americans claiming to act on the orders of Col. John C. Fremont was the initial act that founded the Bear Flag Republic . Vallejo later transferred his allegiance with US statehood (1850), and with his amassed land holdings guided

7743-414: Was once widespread. Strath signifies a wide valley between hills, the floor of which is either level or slopes gently. A glen is a river valley which is steeper and narrower than a strath. A corrie is a basin-shaped hollow in a mountain. Each of these terms also occurs in parts of the world formerly colonized by Britain . Corrie is used more widely by geographers as a synonym for (glacial) cirque , as

7832-634: Was shut down after it triggered earthquakes . Other demonstration projects are under construction in Australia , the United Kingdom , and the US. In Myanmar over 39 locations are capable of geothermal power production, some of which are near Yangon . Geothermal heating is the use of geothermal energy to heat buildings and water for human use. Humans have done this since the Paleolithic era. Approximately seventy countries made direct use of

7921-657: Was the sole California mission established under the rule of a newly independent Mexico . Within two generations of the Spaniards' arrival, however, the indigenous societies of the region were dispossessed of their land and decimated by diseases to which Europeans were resistant. Soon after the Sonoma mission was built, it was secularized by the Mexican government, and, under the orders of Lieutenant, later General Mariano Guadalupe Vallejo , el Pueblo de Sonoma (the town of Sonoma )

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