Welcome to one of renewable source of energy– geothermal power plants.
Unlike other power plants that rely on coal or other fossil fuels to create electricity for homes and businesses, geothermal power plants use superheated fluids from the earth’s geothermal resources to generate electricity.
The natural heat of the earth creates geothermal resources. This heat comes from molten rock, called magma, located at the earth’s core deep below the geothermal resource. Over thousands of years, rainwater reeps through cracks in the earth’s surface and collects in underground reservoirs. The magma heats the water until it becomes a superheated fluid.
To reach the superheated fluid, wells are drilled 5,000 to 10,000 feet below the surface of the earth. These wells, called production wells, bring the superheatad fluid to the earth’s surface where it can be used to generate electricity for homes and businesses.
This geothermal power plant ( in below video ) uses crystallizer-reactor clarifier technology. A process that turns the geothermal superheated fluid into steam while removing solids from it. The steam is used to drive a turbine and generate electricity. All remaining geothermal fluids are injected back into the reservoir for reuse.
Under its own pressure, superheated fluid from the geothermal resource flows naturally to the surface through production wells. As the liquid flows foward the surface, the pressure decreases causing a small portion of the fluid still within the well to separate or “flash” into steam.
At the surface, the superheated fluid and steam mixture flows through surface pipelines and into a wellhead separator. Inside the separator, the pressure of the superheated fluid is reduced. This causes a large amount of the superheated fluid to rapidly vaporize and flash into high-pressure steam. The geothermal fluid that is not flashed into steam in the wellhead separator flows to a second vessel called a standard–pressure crystallizer where an additional amount of standard-pressure steam is produced.
The flash process continues in the low-pressure crystallizer. The remaining fluid is again flashed, this time at a lower pressure to produce low-pressure steam.
All of the low-pressure, standard-pressure, and high-pressure steam is delivered to a turbine. The fluid that is not flashed into steam flows into the reactor clarifier system and is then returned to the geothermal reservoir through injection wells.
Turbines are the primary piece of equipment used to transform geothermal energy into mechanical energy. Pressurized steam created from the geothermal superheated fluid flows through pipelines to large steam turbine. The force and energy in the steam is used to spin the turbine blades. The turbine turn a shaft directly connected to an electrical generator. An electrical charge is created when magnets rotate within the generator. Large copper bars carry the electrical charge to a step-up transformer outside the plant. Within the transformer, the voltage is increased before the power is sent to the power lines that carry it to homes and businesses.
Geothermal energy is a sustainable resource because with proper management, a geothermal resource can remain a renewable source of energy. Water trapped deep within the earth will naturally replace the superheated fluid that is drawn from the geothermal resource through surface wells. However, it is possible to deplete the geothermal resource by removing fluid faster than it can be naturally replaced. To help prevent this, the steam used in the geothermal power plant passes through a condenser that turns it back into fluid. At this stage, it’s possible to recover minerals from the geothermal fluid before it’s injected back into the earth. This condensed fluid, along with the fluid that did not flash to steam, is injected back into the undergound reservoir. Magma naturally reheats the fluid so it can be used again.
Read more: http://www.geothermalenergy.org/
( Picture courtesy of www.power-technology.com )
John L Featherstone geothermal power plant (formerly Hudson Ranch I) is located in Salton Sea field, California, US. EnergySource inaugurated the geothermal power plant in March 2012.
The plant uses a Crystalliser reactor clarifier process, which is an advanced method for turning the geothermal superheated liquid into steam while removing solids. The process helps achieve thermal gains and recover minerals effectively. The brine handling system in the plant prevents mineral build-up, so minimises corrosion.
In addition, the plant is equipped with a new type of process vessel, which accepts the solid-laden brine waste streams, and an integrated process that directs the brine flow streams in order to minimise air contact.
The John L Featherstone plant is a three-stage flash geothermal plant with an installed capacity of 49.9MW. It is the first new stand-alone geothermal plant in over 20 years in the Salton Sea area. Construction began in May 2010.
The $400m geothermal power plant provides electricity for approximately 50,000 houses. It created more than 200 jobs during construction. It has also created 55 full-time jobs during the operational phase.
John L Featherstone plant has three production wells each 7,500ft in depth, four injection wells, and geothermal reservoirs. The plant also has a 50MW Fuji turbine.