Geothermal Energy.
. Geothermal power is. Technologies in use include dry steam power stations, flash steam power stations and binary cycle power stations.
Geothermal electricity generation is currently used in 24 countries, while is in use in 70 countries. As of 2015, worldwide geothermal power capacity amounts to 12.8 (GW), of which 28 percent or 3,548 megawatts are installed in the.
International markets grew at an average annual rate of 5 percent over the three years to 2015, and global geothermal power capacity is expected to reach 14.5–17.6 GW by 2020. Based on current geologic knowledge and technology the GEA publicly discloses, the (GEA) estimates that only 6.9 percent of total global potential has been tapped so far, while the reported geothermal power potential to be in the range of 35 GW to 2. Countries generating more than 15 percent of their electricity from geothermal sources include, the,. Geothermal power is considered to be a, source of energy because the heat extraction is small compared with the. The of geothermal electric stations are on average 45 grams of per kilowatt-hour of electricity, or less than 5 percent of that of conventional coal-fired plants. As a source of renewable energy for both power and heating, geothermal has the potential to meet 3-5% of global demand by 2050.
With economic incentives, it is estimated that by 2100 it will be possible to meet 10% of global demand. Contents. History and development In the 20th century, demand for electricity led to the consideration of geothermal power as a generating source.
Tested the first geothermal power generator on 4 July 1904 in, Italy. It successfully lit four light bulbs. Later, in 1911, the world's first commercial geothermal power station was built there. Experimental generators were built in, Japan and, California, in the 1920s, but Italy was the world's only industrial producer of geothermal electricity until 1958. Global geothermal electric capacity.
Upper red line is installed capacity; lower green line is realized production. In 1958, New Zealand became the second major industrial producer of geothermal electricity when its was commissioned. Wairakei was the first station to use flash steam technology. Over the past 60 years, net fluid production has been in excess of 2.5 km 3. At Wairakei-Tauhara has been an issue in a number of formal hearings related to environmental consents for expanded development of the system as a source of renewable energy. In 1960, began operation of the first successful geothermal electric power station in the United States at The Geysers in California.
The original turbine lasted for more than 30 years and produced 11 net power. The binary cycle power station was first demonstrated in 1967 in the and later introduced to the United States in 1981, following the and significant changes in regulatory policies. This technology allows the use of much lower temperature resources than were previously recoverable. In 2006, a binary cycle station in, came on-line, producing electricity from a record low fluid temperature of 57 °C (135 °F). Geothermal electric stations have until recently been built exclusively where high temperature geothermal resources are available near the surface.
The development of and improvements in drilling and extraction technology may enable over a much greater geographical range. Demonstration projects are operational in, Germany, and, France, while an earlier effort in, Switzerland was shut down after it triggered earthquakes. Other demonstration projects are under construction in, the, and the. The of geothermal electric stations is low, around 7–10%, because geothermal fluids are at a low temperature compared with steam from boilers. By the laws of this low temperature limits the efficiency of in extracting useful energy during the generation of electricity. Exhaust heat is wasted, unless it can be used directly and locally, for example in greenhouses, timber mills, and district heating.
The efficiency of the system does not affect operational costs as it would for a coal or other fossil fuel plant, but it does factor into the viability of the station. In order to produce more energy than the pumps consume, electricity generation requires high temperature geothermal fields and specialized heat cycles.
Because geothermal power does not rely on variable sources of energy, unlike, for example, wind or solar, its can be quite large – up to 96% has been demonstrated. However the global average was 74.5% in 2008, according to the. Resources.
Enhanced geothermal system 1:Reservoir 2:Pump house 3:Heat exchanger 4:Turbine hall 5:Production well 6:Injection well 7:Hot water to district heating 8:Porous sediments 9:Observation well 10:Crystalline bedrock The Earth’s heat content is about. This heat naturally flows to the surface by conduction at a rate of 44.2 and is replenished by radioactive decay at a rate of 30 TW. These power rates are more than double humanity’s current energy consumption from primary sources, but most of this power is too diffuse (approximately 0.1 W/m 2 on average) to be recoverable. The effectively acts as a thick insulating blanket which must be pierced by fluid conduits (of, water or other) to release the heat underneath. Electricity generation requires high-temperature resources that can only come from deep underground. The heat must be carried to the surface by fluid circulation, either through, drilled water wells, or a combination of these.
This circulation sometimes exists naturally where the crust is thin: magma conduits bring heat close to the surface, and hot springs bring the heat to the surface. If no hot spring is available, a well must be drilled into a hot.
Away from tectonic plate boundaries the is 25–30 °C per kilometre (km) of depth in most of the world, so wells would have to be several kilometres deep to permit electricity generation. The quantity and quality of recoverable resources improves with drilling depth and proximity to tectonic plate boundaries. In ground that is hot but dry, or where water pressure is inadequate, injected fluid can stimulate production. Developers bore two holes into a candidate site, and fracture the rock between them with explosives or high-pressure water. Then they pump water or liquefied carbon dioxide down one borehole, and it comes up the other borehole as a gas.
This approach is called in Europe, or in North America. Much greater potential may be available from this approach than from conventional tapping of natural aquifers. Estimates of the electricity generating potential of geothermal energy vary from 35 to 2000 GW depending on the scale of investments. This does not include non-electric heat recovered by co-generation, geothermal heat pumps and other direct use. A 2006 report by (MIT) that included the potential of enhanced geothermal systems estimated that investing 1 billion US dollars in research and development over 15 years would allow the creation of 100 GW of electrical generating capacity by 2050 in the United States alone. The MIT report estimated that over 200 ×10 9 TJ (200 ZJ; 5.6 ×10 7 TWh) would be extractable, with the potential to increase this to over 2,000 ZJ with technology improvements – sufficient to provide all the world's present energy needs for several. At present, geothermal wells are rarely more than 3 km (1.9 mi) deep.
Upper estimates of geothermal resources assume wells as deep as 10 km (6.2 mi). Drilling near this depth is now possible in the petroleum industry, although it is an expensive process. The deepest research well in the world, the (KSDB-3), is 12.261 km (7.619 mi) deep.
This record has recently been imitated by commercial oil wells, such as 's Z-12 well in the Chayvo field,. Wells drilled to depths greater than 4 km (2.5 mi) generally incur drilling costs in the tens of millions of dollars. The technological challenges are to drill wide bores at low cost and to break larger volumes of rock. Geothermal power is considered to be sustainable because the heat extraction is small compared to the Earth's heat content, but extraction must still be monitored to avoid local depletion. Although geothermal sites are capable of providing heat for many decades, individual wells may cool down or run out of water.
Geothermal Energy Diagram
The three oldest sites, at Larderello, and the Geysers have all reduced production from their peaks. It is not clear whether these stations extracted energy faster than it was replenished from greater depths, or whether the aquifers supplying them are being depleted.
If production is reduced, and water is reinjected, these wells could theoretically recover their full potential. Such mitigation strategies have already been implemented at some sites. The long-term sustainability of geothermal energy has been demonstrated at the Lardarello field in Italy since 1913, at the Wairakei field in New Zealand since 1958, and at The Geysers field in California since 1960. Power station types.
Dry steam (left), flash steam (centre), and binary cycle (right) power stations. Geothermal power stations are similar to other steam turbine in that heat from a fuel source (in geothermal's case, the Earth's core) is used to heat water or another. The working fluid is then used to turn a turbine of a generator, thereby producing electricity.
The fluid is then cooled and returned to the heat source. Dry steam power stations Dry steam stations are the simplest and oldest design.
This type of power station is not found very often, because it requires a resource that produces dry steam, but is the most efficient, with the simplest facilities. In these sites, there may be liquid water present in the reservoir, but no water is produced to the surface, only steam. Dry Steam Power directly uses geothermal steam of 150 °C or greater to turn turbines. As the turbine rotates it powers a generator which then produces electricity and adds to the power field.
Then, the steam is emitted to a condenser. Here the steam turns back into a liquid which then cools the water. After the water is cooled it flows down a pipe that conducts the condensate back into deep wells, where it can be reheated and produced again. At in California, after the first thirty years of power production, the steam supply had depleted and generation was substantially reduced. To restore some of the former capacity, supplemental water injection was developed during the 1990s and 2000s, including utilization of effluent from nearby municipal sewage treatment facilities. Flash steam power stations Flash steam stations pull deep, high-pressure hot water into lower-pressure tanks and use the resulting flashed steam to drive turbines. They require fluid temperatures of at least 180 °C, usually more.
This is the most common type of station in operation today. Flash steam plants use geothermal reservoirs of water with temperatures greater than 360 °F (182 °C). The hot water flows up through wells in the ground under its own pressure. As it flows upward, the pressure decreases and some of the hot water boils into steam.
The steam is then separated from the water and used to power a turbine/generator. Any leftover water and condensed steam may be injected back into the reservoir, making this a potentially sustainable resource. Binary cycle power stations. Main article: Binary cycle power stations are the most recent development, and can accept fluid temperatures as low as 57 °C.
The moderately hot geothermal water is passed by a secondary fluid with a much lower boiling point than water. This causes the secondary fluid to flash vaporize, which then drives the turbines. This is the most common type of geothermal electricity station being constructed today.
Both and are used. The thermal efficiency of this type station is typically about 10–13%. Worldwide production. Geothermal Station, in Italy The International Geothermal Association (IGA) has reported that 10,715 (MW) of geothermal power in 24 countries is online, which is expected to generate 67,246 of electricity in 2010. This represents a 20% increase in geothermal power online capacity since 2005. IGA projected this would grow to 18,500 MW by 2015, due to the large number of projects that were under consideration, often in areas previously assumed to have little exploitable resource.
In 2010, the led the world in geothermal electricity production with 3,086 MW of installed capacity from 77 power stations; the largest group of geothermal in the world is located at, a geothermal field in. The Philippines follows the US as the second highest producer of geothermal power in the world, with 1,904 MW of capacity online; geothermal power makes up approximately 27% of the country's electricity generation. Said in The Climate Project Asia Pacific Summit that Indonesia could become a super power country in electricity production from geothermal energy.
India has announced a plan to develop the country's first geothermal power facility in Chhattisgarh. Canada is the only major country on the which has not yet developed geothermal power. The region of greatest potential is the, stretching from to the Yukon, where estimates of generating output have ranged from 1,550 MW to 5,000 MW. Utility-grade stations. A geothermal power station in,.
The largest group of geothermal in the world is located at, a geothermal field in,. As of 2004, five countries (, and ) generate more than 15% of their electricity from geothermal sources. Geothermal electricity is generated in the 24 countries listed in the table below. During 2005, contracts were placed for an additional 500 of electrical capacity in the United States, while there were also stations under construction in 11 other countries. Enhanced geothermal systems that are several kilometres in depth are operational in France and Germany and are being developed or evaluated in at least four other countries.
The 120- power station in southwest Iceland Fluids drawn from the deep earth carry a mixture of gases, notably ( CO 2), ( H 2S), ( CH 4), ( NH 3) and ( Rn). These pollutants contribute to, radiation and noxious smells if released. Existing geothermal electric stations, that fall within the of all total life cycle emissions studies reviewed by the, produce on average 45 kg of CO 2 equivalent emissions per megawatt-hour of generated electricity (kg CO 2eq/). For comparison, a coal-fired power plant emits 1,001 kg of CO 2 per megawatt-hour when not coupled with (CCS). Stations that experience high levels of acids and volatile chemicals are usually equipped with emission-control systems to reduce the exhaust. Geothermal stations could theoretically inject these gases back into the earth, as a form of carbon capture and storage. In addition to dissolved gases, hot water from geothermal sources may hold in solution trace amounts of toxic chemicals, such as, and salt.
These chemicals come out of solution as the water cools, and can cause environmental damage if released. The modern practice of injecting geothermal fluids back into the Earth to stimulate production has the side benefit of reducing this environmental risk. Station construction can adversely affect land stability. Has occurred in the in New Zealand.
Can trigger due to water injection. The project in, was suspended because more than 10,000 seismic events measuring up to 3.4 on the occurred over the first 6 days of water injection. The risk of geothermal drilling leading to has been experienced in.
Geothermal has minimal land and freshwater requirements. Geothermal stations use 404 square meters per versus 3,632 and 1,335 square meters for coal facilities and wind farms respectively. They use 20 litres of freshwater per MWh versus over 1000 litres per MWh for nuclear, coal, or oil. Geothermal power stations can also disrupt the natural cycles of geysers.
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For example, the geysers, which were uncapped geothermal wells, stopped erupting due to the development of the dual-flash station. Economics See also:. Geothermal power requires no fuel; it is therefore immune to fuel cost fluctuations.
However, tend to be high. Drilling accounts for over half the costs, and exploration of deep resources entails significant risks. A typical well doublet in Nevada can support 4.5 (MW) of electricity generation and costs about $10 million to drill, with a 20% failure rate. In total, electrical station construction and well drilling costs about 2–5 million € per MW of electrical capacity, while the is 0.04–0.10 € per kWh. Enhanced geothermal systems tend to be on the high side of these ranges, with capital costs above $4 million per MW and levelized costs above $0.054 per kWh in 2007. Geothermal power is highly scalable: a small power station can supply a rural village, though initial capital costs can be high. The most developed geothermal field is the Geysers in California.
In 2008, this field supported 15 stations, all owned by, with a total generating capacity of 725 MW. See also.
Geothermal Energy In The Philippines
What is geothermal power? Like coal, gas or nuclear power facilities, a geothermal power plant converts heat to electricity. It does this using high-temperature (300°F to 700°F) heat – known as geothermal energy – from the Earth, accessed by drilling hot water or dry steam wells in a process similar to drilling for oil.
The hot water or steam is piped to the surface and used to power turbines that generate electricity. According to the International Energy Agency (IEA), in 2017, global geothermal power generation was an estimated 84.8TW/h, while cumulative capacity reached 14GW. Is expected to rise to just over 17GW by 2023, with the biggest capacity additions expected in Indonesia, Kenya, Philippines and Turkey. It is estimated that, as a source of renewable energy for both power and heating, geothermal has the potential to meet 3-5% of global demand by 2050. Types of geothermal power plants Geothermal power plants, like their traditional counterparts, feature standard power-generating equipment including turbines, generators and transformers.
The first commercial geothermal station was built in Tuscany in 1911 and Italy was the world’s only industrial producer of geothermal electricity until 1958, when the Wairakei plant was commissioned in New Zealand. A geothermal power plant in Iceland. Image: Shutterstock There are three main types of geothermal power plants:. Dry steam plants utilise steam directly from a geothermal reservoir in order to power turbines and generate electricity. The first geothermal power plant ever built (in 1904 in Tuscany, Italy) was a dry steam plant. Flash steam plants are the most common type of geothermal power plants.
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They work by converting high-pressure hot water from deep inside the Earth into steam, which, when it cools, condenses to water and is injected back into the ground to be used again. Binary cycle power plants transfer the heat from geothermal hot water into another liquid. This then turns to steam used to drive a generator turbine.
Enhanced geothermal systems (EGS) explained Until recently, geothermal power stations had to be built in areas with naturally occurring high-temperature heat and water sources, and where the rock was suitable for drilling. However, enhanced geothermal systems (EGS) have the potential to extend use of geothermal resources.
The technique works by injecting water into rock systems, creating cracks to increase the rock’s permeability. This allows fluid to circulate in the fractured rock and transport heat to the surface, where electricity can be generated. The US Government’s Office of Energy Efficiency & Renewable Energy estimates that more than 100GWe of economically viable capacity may be available in the US, a 40-fold increase over present geothermal power generating capacity and 10% of current overall US electric capacity.
Inside the UK’s first deep geothermal power plant Work is beginning on what could become. Geothermal Engineering, the company behind the project, says Cornwall’s heat-producing granite rocks, which reach temperatures of up to 200°C (390°F), are suitable for geothermal energy. Two wells, one 2.8 miles (4.5km) and the 1.5 miles (2.5km) deep, will be drilled into granite near Redruth, Cornwall. The former hole will take seven months to finish and is thought to be the deepest yet drilled in the UK. Cold water will be pumped down to the hot rocks, brought to the surface as heated water and the steam used to drive turbines to produce electricity for as many as 3,000 homes.
During the geothermal energy process, hot water or steam is piped to the surface and used to power turbines that generate electricity. Image: Shutterstock According to Geothermal Engineering, geothermal power has the potential to deliver “up to 20%” of the UK’s electricity and heat energy needs “in a reliable and sustainable way”. Potential issues include whether the rocks are permeable enough to get the water through and sufficient volumes of heated water can be extracted to power the turbines.
Is geothermal a renewable energy source? Unlike renewable energy sources such as wind and solar farms, geothermal power plants are unaffected by the weather, meaning they can provide a stable supply of electricity (capacity factors range from 60% to 90%) and are therefore suitable for base load (continuous) electricity production. Geothermal power plants have average availabilities of 90% or higher, compared with around 75% for coal plants.
Geothermal energy is considered to be a renewable resource since energy can be extracted without burning fossil fuels such as coal, gas or oil, resulting in less harmful emissions. Also, geothermal power stations use the almost unlimited amount of heat generated by the Earth’s core and even in areas dependent on a reservoir of hot water, the volume extracted can be re-injected, making it a sustainable energy source.