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GEOTHERMAL ENERGY
1.INTRODUCTION
Geothermal energy use the internal heat from the earth.
The internal Earth is divided into three layers the heat increase at the same time we deepen so there is a big thermal gradient and a heat flow to the exterior. This flow is used to obtain energy.
It is a clean and renewable energy
2.THEORICAL BASICS
TYPES
There are two types of geothermal deposits:
-Dry deposits:
+It is an area on the Earth with hot materials or stones in dry. +It is injected water for a recovered drill and its get hot +The heat is used by means of a heat exchanger and the water is rejected.
-Hot water deposit:
+These sites can form a source ( used as thermal baths ) or be underground ( serve to capture the heat From inside the Earth ) .
+There are four types depending the temperature of water:
High Temperature (150-400 degrees): Steam is produced at the surface and through the turbine generates electricity. Several conditions are required for
the possible existence of a geothermal field occurs: an upper layer comprising a cover impermeable rock, aquifer, or reservoir, of high permeability; fractured soil allowing convective fluid flow, and therefore the heat transfer from the source to the surface, and a heat source magmatic
Medium Temperature (70-150 degrees): The steam-electric conversion is performed with a lower yield, and be exploited by means of a volatile fluid. These sources allow small power plants explode, but the best use can be made by urban heat delivery systems for use in heating and cooling
Low temperature (50-70 degrees):is usable in wider areas than earlier, in all sedimentary basins. Is due to the geothermal gradient.Very low temperature (20-50 degrees) :This energy is used for domestic, urban and agricultural needs, such as geothermal HVAC (geothermal heat pump).
How it works
Geothermal energy use the heat from the internal Earth’s heat to produce energy,how?
-First we drill the zone (near tectonic zone) to get the heat we use injection well.
-After that the water goes from the Earth’s surface up this water moves the turbine which convert it into energy
-Finally, water returns by recovery well and the process re-start.
Facilities
There are two types or facilities depending of the system of catchment used in the extraction of geothermal energy:
Horizontal:
-Near to the surface (1-2 meters)
-Depends of the variation of the ambient temperature.
-It occupies lots of space
-It is used for little power because vertical facilities have more power.
Vertical
-Perforations between 50 and 200 meters (far to the surface)
- Don’t depends of the variation of the external temperature
-It has a biggest cost
-It occupies less space than horizontal
3.ADVANTAGES It’s a source that would avoid dependence on foreign
energy. No noise Cheap energy, because it is not subject to
international prices.
No destruction. The land to build geothermal plant is smaller than the other plants need so no forest clearance is needed, or builds storage tanks.
Minimal residues, mostly takes advantage causing less environmental impact caused by the oil and coal.
Big savings, both economic and energy. Ecological The emission of CO2 is lower than would be issued for
the same energy by combustion.
4.DISADVANTAGES Letal emission, emission of sulfuric acid which is
detected by the smell of rotten eggs, which in large quantities not smell, and it is letal.
Thermal pollution, is produced by pouring hot water into rivers and streams and the generation of greenhouse gases called.
In certain places, not all areas of the world have a usable energy source, the temperature may not be sufficient or quantities of water.
Can’t carry, as primary energy. Exhaustible. Contamination of nearby waters with substances such
as arsenic, ammonia… Deteroration of the landscape, for the construction of
plants, soil excavations… Environmental impact.
5.WHERE THEY ARE
The principal geothermal plants are distributed principally by the zone of 1. USA, Raft River: It was the first geothermal plant in the world with binary cycle2. ICELAND, Nesvavellir: It is one of the biggest geothermal plant in the world.3. RUSSIA, Mutnovski: It is the biggest in Russia, it has more than 90 wells.
6.ENVIRONMENTAL IMPACT
It has bad environmental impact. It is cause by:-Water Quality and UseGeothermal power plants can have impacts on the water quality and consumption, Hot water pumped from underground reservoirs often contains high levels of sulfur, salt, and other minerals.
Air EmissionsIt is an open system and that suppose a problem because it emit hydrogen sulfide, carbon dioxide and others dangerous gases. Hydrogen sulfide is the most common type of emission. In the atmosphere it changes into sulfur dioxide which form small acid particulates that can be absorbed by body and cause diseases, sulfur dioxide also cause acid rainThis air emission cause too global warming, a problem which all the world is involve to solve.Land UseThe amount of land required for the installation of a geothermal plant is too big, and it cause alterations in the landscape.
7.COSTAccording to studies, an economically competitive geothermal power plant can cost as low as $3400 per kilowatt installed. The cost is high at firsty because the initial construction costs of a geothermal facility represent two thirds or more of total costs. Geothermal power does not need outside fuel to operate geothermal on a constant source of free fuel. Factors:• Size of the plant• Power plant technology• Knowledge of the resource• Temperature of the resource• Chemistry of the geothermal water• Resource depth and permeability• Environmental policies• Tax incentives• Markets• Financing options and cost• Time delays
8.MISCELLANEOUS
