• What is geothermal energy? Simply put, it is energy from the Earth. Geo refers to the solid part of the Earth and thermal refers to heat energy. Anywhere the Earth's surface is in close proximity to magma or volcanic activity under or near the Earth's surface, we can harness the energy.

• Geothermal Energy produces no pollution. There are virtually no greenhouse gases given off. There is no pollution.

• 3. You cannot transport geothermal energy. I used to live in the coal region of Pennsylvania. For years coal trucks used to drive by our front door hauling Anthracite coal to home and industries.
• 4. There may be geothermal gases. Geothermal steam and hot water do contain naturally occurring traces of hydrogen sulfide (a gas that smells like rotten eggs) and other gases and chemicals that can be harmful in high concentrations.

• Geothermal energy has been used for thousands   of years in some countries for cooking and heating.
• How it works

• Hot rocks underground heat water to   produce steam.

   

  We drill holes down to the hot region, steam comes up, is purified   and used to drive turbines, which drive electric generators.
•   Advantages  
   
  • Geothermal energy does not produce any pollution,   and does not contribute to the greenhouse effect.
• Once you've built a geothermal power station, the   energy is almost free.
    It may need a little energy to run a pump, but this can be taken   from the energy being generated.
• The big problem is that there are not many places where   you can build a geothermal power station.
    You need hot rocks of a suitable type, at a depth where we can drill   down to them.
    The type of rock above is also important, it must be of a type that   we can easily drill through.
• Hazardous gases and minerals may come up from underground,   and can be difficult to safely dispose of.

• Is it renewable?

   

  Geothermal energy is renewable.  
    The energy keeps on coming, as long as we don't pump too much cold water   down and cool the rocks too much

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• Geothermal Electricity Production

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  This geothermal power plant generates electricity for the Imperial Valley in California.

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  Geothermal power plants use steam produced from reservoirs of hot water found a few miles or more below the Earth's surface to produce electricity. The steam rotates a turbine that activates a generator, which produces electricity.

• Geothermal Basics

        

  What Is Geothermal Energy?

   

  The word geothermal comes from the Greek words geo (earth) and therme (heat). So, geothermal energy is heat from within the Earth. We can recover this heat as steam or hot water and use it to heat buildings or generate electricity.  

  Geothermal energy is a renewable energy source because the heat is continuously produced inside the Earth.
• Geothermal energy is generated in the Earth's core. Temperatures hotter than the sun's surface are continuously produced inside the Earth by the slow decay of radioactive particles, a process that happens in all rocks. The Earth has a number of different layers:

• Where Geothermal Energy is Found

        
    
  The ring of fire goes around the edges of the Pacific. The map shows that volcanic activity occurs around the Pacific rim.
  Source: National Energy Education Development Project (Public Domain)
   
   

  Naturally occurring large areas of hydrothermal resources are called geothermal reservoirs. Most geothermal reservoirs are deep underground with no visible clues showing above ground. But geothermal energy sometimes finds its way to the surface in the form of:

    
   
  • Volcanoes and fumaroles (holes where volcanic gases are released)
   
  • Hot springs
   
  • Geysers

• U.S. Geothermal Is Mostly in the West

   

  Most of the geothermal reservoirs in the United States are located in the western States and Hawaii.
• Electricity generation power plants require water or steam at very high temperature (300° to 700°F). Geothermal power plants are generally built where geothermal reservoirs are located within a mile or two of the surface.

• The United States Is the Leader in Geothermal Power Generation

   

  The United States leads the world in electricity generation with geothermal power.  In 2009, U.S. geothermal power plants produced 15 billion kilowatt-hours (kWh), or 0.4% of total U.S. electricity generation.  In 2009, five States had geothermal power plants:
• Geothermal power plants use hydrothermal resources that have two common ingredients: water (hydro) and heat (thermal). Geothermal plants require high temperature (300°F to 700°F) hydrothermal resources that may come from either dry steam wells or hot water wells.
• high-pressure hot water from deep inside the Earth and convert it to steam to drive the generator turbines.   When the steam cools, it condenses to water and is injected back into the ground to be used over and over again. Most geothermal power plants are flash steam plants.

• Geothermal Power Plants Have Low Emission Levels

   

  Geothermal power plants do not burn fuel to generate electricity, so their emission levels are very low. They release less than 1% of the carbon dioxide emissions of a fossil fuel plant. Geothermal plants use scrubber systems to clean the air of hydrogen sulfide that is naturally found in the steam and hot water.

   

  Geothermal plants emit 97% less acid rain-causing sulfur compounds than are emitted by fossil fuel plants. After the steam and water from a geothermal reservoir have been used, they are injected back into the Earth.

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•      

  Method	Cents/kW-h	Limitations and Externalities
  Wind Currently supplies approximately 1.4% of the global electricity demand. Wind is considered to be about 30% reliable.	4.0 - 6.0 Cents/kW-h	Wind is currently the only cost-effective alternative energy method, but has a number of problems. Wind farms are highly subject to lightning strikes, have high mechanical fatigue failure, are limited in size by hub stress, do not function well, if at all, under conditions of heavy rain, icing conditions or very cold climates, and are noisy and cannot be insulated for sound reduction due to their size and subsequent loss of wind velocity and power.
  Geothermal Currently supplies approximately 0.23% of the global electricity demand. Geothermal is considered 90-95% reliable.	4.5 - 30 Cents/kW-h	New low temperature conversion of heat to electricity is likely to make geothermal substantially more plausible (more shallow drilling possible) and less expensive. Generally, the bigger the plant, the less the cost and cost also depends upon the depth to be drilled and the temperature at the depth. The higher the temperature, the lower the cost per kwh. Cost may also be affect by where the drilling is to take place as concerns distance from the grid and another factor may be the permeability of the rock.
  Hydro Currently supplies around 19.9% of the global electricity demand. Hydro is considered to be 60% reliable.	5.1 - 11.3 Cents/kW-h	Hydro is currently the only source of renewable energy making substantive contributions to global energy demand. Hydro plants, however, can (obviously) only be built in a limited number of places, and can significantly damage aquatic ecosystems.
  Solar Currently supplies approximately 0.8% of the global electricity demand.	15 - 30 Cents/kW-h	Solar power has been expensive, but soon is expected to drop to as low as 3.5 cents/kW-h. Once the silicon shortage is remedied through alternative materials, a solar energy revolution is expected.
• Tide
  
  2 - 5 Cents/kW-h Blue Energy's tidal fence, engineered and ready for implementation, would provide a land bridge (road) while also generating electricity. Environmental impact is low. Tides are highly predictable.

• Estimates of the electricity generating potential of geothermal energy vary from 35 to 2,000 GW.^[2] Current worldwide installed capacity is 10,715 megawatts (MW), with the largest capacity in the United States (3,086 MW),^[3] Philippines, and Indonesia.

• Like many   renewable resources, geothermal resources need relatively high initial   investments to access the heat, hot water and steam. But the geothermal   "fuel" cost is predictable and stable. Fossil fuel supplies will increase   in cost as reserves are exhausted. Fossil fuel supplies   can be interrupted political disputes abroad. Renewable geothermal   energy is a better long term investment.
• Examples are   the huge costs of global climate change; the health effects from ground   level pollution of the air; future effects of pollution of water and   land; military expenditures to protect petroleum sources and supply   routes; and costs of safely storing radioactive waste for generations.   Geothermal energy can already compete with the direct costs of conventional   fuels in some locations and is a clean, indigenous, renewable resource   without hidden external costs.

• Future Of Geothermal Energy

   

    The future of geothermal energy depends on three factors: it's demand, supply and it's competitiveness among other renewable resources in terms of cost, availability, reliability etc..  Demand for geothermal energy is going to increase and increase with the increase in the population and extinction of other non-renewable sources. Moreover, today government also support the resources which are cleaner and do not spoil the environment.  Supply of geothermal energy is limited and confined to certain areas only.

• Enhanced geothermal systems (EGS), also sometimes called engineered geothermal systems, offer great potential for more than 100 GW of geothermal power which 40 times more than present geothermal power.
• ultimately geothermal global resources amount to 50,000 times the energy of all oil and gas resources in the world.
• Enhanced Geothermal Systems (EGS) – Often categorized under the antiquated term
  ‘Hot Dry Rock,’ EGS is thought by several experts to refer to any resource that requires artificial stimulation. This includes resources that have to be fully engineered, or ones that produce hydrothermal fluid, but sub-commercially. Regarding the latter, one expert states that, ‘As we go further, there might be projects that require more and more stimulation.’ Although EGS technology is still young and many aspects remain unproven, several projects are currently underway. If EGS technology proves commercially successful, it is expected to allow significantly increased extension of and production from existing fields, as well as utilization of geothermal energy in previously implausible locations.

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• Engineered geothermal systems (EGS) are based on a related principle, but they work even in parts of the world that are not volcanically active, by drilling thousands of metres underground to mimic the design of natural steam or hot-water reservoirs. Wells are bored and pathways are created inside hot rocks, into which cold water is injected. The water heats up as it circulates and is then brought back to the surface, where the heat is extracted to generate electricity. Because the Earth gets hotter the deeper you drill, EGS could expand the reach of geothermal power enormously and provide access to a virtually inexhaustible energy resource.

• According to the government, geothermal has the  potential to supply the United States with 20% of our electricity needs.
• The  capital cost of geothermal development is expensive, however; 2/3rds are drilling  costs. Yet as we overcome some of these technology challenges and make the process  more standardized it is believed that geothermal can supply up to 20% of the United  States electricity needs by 2050. But innovation and investment in initial steps  need to happen now.