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Geothermal power Earth‘s power harvested
Geothermal power • Geothermal power is energy generated by heat stored • • • beneath the Earth's surface. The first geothermal generator was tested on 4 July 1904, at the Larderello dry steam field in Italy. The largest group of geothermal power plants in the world is located in The Geysers, a geothermal field in California. As of 2007, geothermal power supplies less than 1% of the world's energy.
Contents • 1 Electricity generation • • • – Dry Steam Power Plants – Flash steam Power Plants – Binary-cycle Power Plants 2 Geothermal energy usage 3 Advantages 4 Disadvantages
Electricity generation • There are three different types of power plants – dry steam – flash – binary
Dry Steam Power Plants – – A dry steam power plant uses dry steam. Dry steam is steam that contains no water droplets. Typically above 235°C Dry steam plants are used where there is plenty of steam available that is not mixed with water. – Dry steam plants are the simplest and most economical of geothermal plants.
Flash steam Power Plants – A Flash steam power plant uses hot water. – Typically above 182 °C – The high pressure underground keeps the water in the liquid state, although it is well above the boiling point of water at normal sea level atmospheric pressure. – As the water is pumped from the reservoir to the power plant, the drop in pressure causes the water to convert, or "flash", into steam to power the turbine. – Flash steam plants are the most common type of geothermal power generation plants in operation today.
Binary-cycle Power Plants – The water used in binary-cycle power plants is cooler than that of flash steam plants. – From 107 to 182 °C – The hot fluid from geothermal reservoirs is passed through a heat exchanger which transfers heat to a separate pipe containing fluids with a much lower boiling point (ios-butane or iso-pentane) which are vaporized to power the turbine. – The advantage to binary-cycle power plants is their lower cost and increased efficiency.
Geothermal energy usage • Iceland – The Svartsengi Power-Plant , The Nesjavellir Power-Plant, The Krafla Power-Plant • United States – there were 75 new geothermal power projects underway in 12 states as of May 2007 and are currently present in Alaska, California, Hawaii, Nevada, and Utah • New Zealand – Kawerau geothermal power station is a 90 -megawatt geothermal power plant now under construction
Advantages • It‘s clean and safe for the surrounding environment. • It is also sustainable because the hot water used in the • geothermal process can be re-injected into the ground to produce more steam. From an economic view, geothermal energy is extremely price competitive in some areas and reduces reliance on fossil fuels and their inherent price unpredictability.
Disadvantages • Construction of the power plants can adversely affect • land stability in the surrounding region. Dry steam and flash steam power plants also emit low levels of carbon dioxide, nitric oxide, and sulfur, although at roughly 5% of the levels emitted by fossil fuel power plants.
We thank you! • Made by : – Adascalitei Victor – Coman Andrei – Oaida Adrian • Coordinated by : – Schnabel Dieter