5 Responses

1. Water, heated to steam builds pressure that drives a turbine and turns a generator to make electricity.

2. Three different types of power plants – dry steam, flash, and binary – are used to generate electricity from geothermal energy, depending on temperature, depth, and quality of the water and steam in the area.[4] In all cases the condensed steam and remaining geothermal fluid is injected back into the ground to pick up more heat. In some locations, the natural supply of water producing steam from the hot underground magma deposits has been exhausted and processed waste water is injected to replenish the supply. Most geothermal fields have more fluid recharge than heat, so re-injection can cool the resource, unless it is carefully managed.

   Dry Steam Power Plants

   A dry steam power plant uses dry steam, typically above 235°C (455°F), to directly power its turbines. Dry steam is steam that contains no water droplets. All of the molecules are in a gaseous, as opposed to liquid, state.[5] Dry steam plants are used where there is plenty of steam available that is not mixed with water.[6] This is the oldest type of geothermal power plant and is still in use today. Dry steam plants are the simplest and most economical of geothermal plants. However, they emit small amounts of excess steam and gases.[4] The geothermal plants at The Geysers are dry steam plants.

   Flash steam

   Flash steam power plants use hot water above 182 °C (360 °F) from geothermal reservoirs. 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. Any water not flashed into steam is injected back into the reservoir for reuse.[4] Flash steam plants, like dry steam plants, emit small amounts of gases and steam.[7]

   Flash steam plants are the most common type of geothermal power generation plants in operation today. An example of an area using the flash steam operation is the CalEnergy Navy I flash geothermal power plant at the Coso geothermal field.

   Binary-cycle

   The water used in binary-cycle power plants is cooler than that of flash steam plants, from 107 to 182 °C (225-360 °F)[7]. 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.[4] These fluids, usually Iso-butane or Iso-pentane, are vaporized to power the turbine.[8]. The advantage to binary-cycle power plants is their lower cost and increased efficiency. These plants also do not emit any excess gas and, because they use fluids with a lower boiling point than water, are able to utilize lower temperature reservoirs, which are much more common. Most geothermal power plants planned for construction are binary-cycle.[8]

   I hope this helps

   ME!

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3. two main ways

   tap steam directly to run a turbine

   draw hot water and pump in cold to draw heat from rock.

4. Steam from a geothermal field passes through a heat exchanger and demineralized water is heated through the heat exchanger. The heated water flows to a steam turbine which drives an alternator.Steam condensate then flows to a storage tank. The water from the condensate tank is agin recycled back to the heat exchanger and is superheated for another cycle of driving a steam turbine.

5. Very good answers, since your asking a science question you might want to look up the Conservation of Energy and 2 law of thermodynamics. They explain “how” energy if converted from heat to mechanical.