A Geyser is an example of Geothermal energy. Hot springs, lava, and fumaroles are natural examples of geothermal energy. Geothermal power is currently more common in homes and businesses, using geothermal heat pumps to control the temperature in the building.
Here are some other examples of Geothermal energy:
- Geothermal Heated Homes: In Geothermally heated homes, an extensive coil system is filled with water and buried in the yard. The water moves through the coil system while the earth naturally keeps the temperature relatively stable, thus reducing the home’s cost.
- Geothermal Power Plants: Some power plants have used a venting system that allows steam from the earth to be used as a source of power. By harnessing this steam, the water powers the generators and thus create electricity.
- Hot springs: There are many natural hot springs located worldwide, and they happen when water heated geothermically emerges from the earth’s crust. Some hot springs are optimal and sought out because their temperature is perfect for a comfortable soak, while other springs are too hot to touch, causing severe scalding or even death for those who decide to take a dip.
- Heating buildings and Green Houses: If a lake is locally located, heating coils can be kept at the lake’s bottom. When antifreeze is added to the water in the reels, the water can stay at a constant temperature and then heat buildings and greenhouses.
- Geysers: Geysers are similar to hot springs in that it releases hot water from the earth’s crust. However, the water is so hot that it is projected into the air in a long column of steam and water. These remarkable wonders of the land can send thousands of liters of water vertically, hundreds of feet. Perhaps the most well-known geyser is Old Faithful in Yellowstone National Park in the United States. Named such due to its reliability, Old Faithful can and does erupt every 60-90 minutes. A few things have to be in play for geysers to occur: hot underground rocks, a subsurface water reservoir, groundwater source, and a vent or a broken point the water emerges through. While Old Faithful is the most world-famous, the phenomena of geysers are pretty rare. Only Chile, Island, New Zealand, Russia, and the U.S. have active geysers.
- Fumarole: As mentioned, for a geyser or hot springs to occur, they must vent through the steam and water. This vent is called a fumarole. These vents can be put to use to tap into the naturally occurring geothermal energy. When there are small cracks or long fissures on the earth’s surface, then fumaroles can form. Likewise, they might also appear on or near Laval flow surfaces and large deposits of pyroclastic flows. When there is a constant heat source like magma, these vents can be present for decades or sometimes centuries, or they could disappear in weeks or months. If they disappear quickly, it means that the volcanic deposit has cooled — the temperature ranges typically from 70-100°C.
Example of how Geothermal Energy Works
Once you delve below the earth’s crust, the ground is quite hot, and that heat is trapped underground. It is hotter the deeper you travel. The earth’s core is approximately 6,427km (4,000 miles) below the surface and is estimated to be 4200°C (7,600°F). Some of this heat was responsible for the formation process of the earth some four billion years ago. The heat that remains comes from the constant decomposition of natural radioactive materials underground. The earth’s core is so hot that rocks melt in their fury, thus creating magma. The liquid form of rocks has a lesser density than the solid stones around it, and therefore it is forced upward toward the surface. The magma is forced through the vents when the pressure is particularly intense, creating a volcanic eruption. However, this isn’t as common as it might sound, but instead can be the cause for heated nearby rocks, which, in turn, heats the water trapped within these rocks. When we apply heat to water, the molecules move, and this can create pressure, which, when it gets to the right temperature and pressure, forces the water up through the vents. The water collects into pools, which are what we refer to when we refer to hot springs. Or, if the water pressure is relatively high, then geysers are the result. The water that doesn’t make it to the surface but instead wells up underground is called geothermal reservoirs. Water is pumped into an ‘injection well’ o access the subsurface heat, filtered through the cracks in these hot rocks. The water is then brought back up via a ‘recover well,’ which uses the pressure from the steam from the heated water. The steam is then cultivated and becomes the power source of electric generators. The water from the reservoirs must be tapped to produce energy from these geothermal resources. There are three ways to do this.
Direct Geothermal Energy
This is generally a method used where geothermal reservoirs and hot springs are prevalent in the area. Vents are manually created by drilling into the geothermal reservoirs and then pumping the hot water directly into homes and buildings. A heat exchanger pumps the boiling water and transfers the heat from the hot water into the homes’ or buildings’ heating systems. The water returns to the geothermal reservoir, where it reheats and thus continues the cycle.
Geothermal Heat Pump
Geothermal heat pumps are also referred to as ground source heat pumps. This pump acts as a central cooling and heating system that transports the heat from the ground to its destination or from a home or building into the earth. It utilizes the heat from the earth in the winter and allows the heat to sink back into the ground during the summer months. Geothermal heat pumps work similarly to the standard heat pump. It, however, uses a high-pressure refrigerant to cultivate and transfer the earth’s heat into houses and then the heat from the houses into the ground. A geothermal heat pump and a traditional heat pump harness heat and release it externally into the atmosphere. A geothermal heat pump will relocate the heat through long loops of pipe filled with liquid buried underground to move and shift the heat in and out of housing and buildings. Electric compressors and heat exchangers will be installed in buildings using this heating method, which sucks up the heat from the piping and disperse it through the duct system of the building. This process reverses during hot summer months: the pipes suck heat away from the building and allow the ground to absorb it.
Geothermal Power Plant
Geothermal Power Plants harness the heat from underground and use it as a means of generating electricity. The types of geothermal power plants vary. Dry steam This method uses steam harnessed directly from the geothermic reservoirs. The steam is then transferred back to the geothermic power plants and pushes a turbine, triggering a generator and creating electricity. Flash Steam Using flash steam involves cultivating boiling water ranging from 148-371°C, by pulling it up from the geothermic reservoir via pipes that have been drilled down. Some of this water is converted into steam and sent to the turbines to power an electricity generator. This steam is then allowed to return to its water state when it cools and is directed back into the reservoir to continue the cycle after it reheats. Binary Cycle A binary cycle uses only moderately hot water, which is transferred through a heat exchanger. The energy or heat within the water is then used to heat certain liquids such as isobutene, which has a lower boiling point than water. Once it reaches its boiling point, this liquid converts to steam, directed to a turbine to make the blades spin, thus powering the generator that creates electricity. The amount of geothermic energy that can be useful depends on a few factors, such as the general temperature that the water ranges from, the location, the rocks underground, and the amount of water pumped into the site. If the stones prove not to be the right temperature (not hot enough or too quick to cool down), this is problematic for geothermal power stations.
What are the benefits of Using Geothermal Energy?
There are a few things that make this an optimal option for sourcing energy. First and foremost, it is clean energy. The water and heat can be harnessed without using fossil fuels or gas, oil, or coal sources. The extraction fields are relatively low regarding carbon dioxide output, only producing a sixth of what other relatively clean power plants produce (fueled by natural gas). Likewise, if there are any nitrous oxide or sulfur-bearing gases released, it is remarkably little. Another benefit is that this energy is in constant supply, any time, any day. While coal plants have an average availability of 75%, geothermal power plants have 90% availability. Finally, geothermal power is available locally, wherever there is heat to be harnessed. This eliminates the need for overseas oil drilling and retrieval, further removing a carbon footprint while limiting our demand for foreign oil.
Why is Geothermal Energy a Renewable Resource?
Geothermal energy is a renewable resource because of the cyclical nature of its cultivation and application. The earth’s core constantly generates heat, thus creating these geothermic reservoirs, requiring no human assistance. Furthermore, any water taken from these reservoirs is returned or reinjected for reheating, and the cycle repeats.
Where is Geothermal Energy Available?
While the hydrothermal reservoirs, the pools from which the hot water and steam are harnessed, are only located in the far western states of the U.S., for the most part, the earth’s energy can be accessed almost anywhere via the use of geothermal heat pumps. By applying direct-use methods, electricity can be generated anywhere. Technology, in the meantime, is edging toward utilizing other worldwide geothermal resources such as magma or hot, dry rock.
What are the Environmental Impacts of Using Geothermal Energy?
Geothermal energy and technology provide many solutions to our environmental problems regarding our electrical needs. Some advantages over conventional power generation methods include Low Emissions The only that geothermal flash plats release is extra steam into the atmosphere. There are no liquids or emissions at all discharged in geothermal plants. Because of this, the latter is thought to be the technology to dominate future energy production. Recycling Wastewater In Santa Rosa, California, treated wastewater is pumped to the Geysers power plants and reinjection fluid into the geothermal reservoir. Any water used from the pool containing salts and dissolved minerals is also used to reinject the reservoirs. The system of recycling used water will keep the reservoir functioning and relatively un-depleted through use.
Is It Possible to Deplete Geothermal Reservoirs?
When considering the longevity of geothermal reservoirs, we need only turn to the Larderello Field in Italy, which has had geothermal energy production since 1913. Likewise, the Wairakei Field in New Zealand has had this energy production in place since 1958, and the Geysers Field in California has been functional since 1960. A decline in pressure and production has been noted in some o the operating plants. As mentioned above, Santa Rosa in California utilizes used, treated wastewater to ensure the longevity of the reservoir. As a result, operators have reinjected water to maintain the pressure of the reservoir. This solution also allows for the productive reuse of treated wastewater.
How Much Does Geothermal Energy Cost Per Kilowatt-Hour (kWh)?
The cost of geothermal energy per kWh can vary depending on the time and the plant. However, for the Geysers in Santa Rosa, California, the power can range from $0.03-$0.035 per kilowatt-hour. However, a new plant built today would be more costly, about $0.05 per kWh, and might charge more when the electricity is used (such as peak, high-demand hours).
What Are the Different Types of Geothermal Power Plants
There are three types of geothermal power plants in use currently, diligently utilizing hydrothermal fluids to electricity. These methods are flash steam, dry steam, and the binary cycle. How the conversion is used or the type used is selected during development depends on the water’s temperature and whether the substance used is in steam or liquid form.