NAME- RAHUL SINHA. CLASS- B.Tech(ME-147) SECTION-M4901. ROLL. NO.- B38. SUBJECT- GENERAL PRESENTATION. SUBMITTED TO- Mr. VISHANT. TOPIC –GEOTHERMAL ENERGY

What is geothermal energy? Geothermal energy- energy that

comes from the ground; power extracted from heat stored in the earth› Geo: earth› Thermal: heat

Direct Small scale uses Heating homes Hot springs Greenhouse heating Food dehydration

plants Agriculture

› Crop drying› Milk pasteurization

Electrical Dry steam Flash steam Binary cycle

Earth’s core heat Water → steam → drive electrical

generators Turbines Area specific

› Geothermal energy is localized

Each uses the heat from underground in some manner to generate energy

Different combinations of water temperatures create different effects

How Geothermal Energy Works

Used for bathing in Paleolithic times

Ancient Romans used it as a central heating system for bathing and heating homes and floors

1892: America’s first district heating system was put into place

Example of a Power Plant in Larderello Today

1926: a deep geothermal well was used to heat greenhouses.

1960: Pacific Gas and Electric has first successful geothermal electric power plant in US at The Geysers› Turbine lasted more than 30 years

To get the steam and water out of the earth, a hole is drilled using a drilling rig. We call this hole a well and it is about 27cm wide and can go down over 2.5km into the earth. It is very expensive to drill a well and it can cost up to $8 million dollars.

When the well is being drilled, a special drilling mud is used to stop the well collapsing. A metal pipe is then put in to stop it collapsing when the well is in use. Inside this pipe is another pipe called the liner. The steam and water travel up this liner.

At the top of this well is a master valve used to control the flow and then a pipeline carries the water and the steam to the power station.

At the Mighty River Kawerau Power Station there is about 8km of pipeline. The pipe has to be thick and welded together so it can stand the pressure from the hot steam and water. Bolted on to the pipelines are valves. These are like very big versions of taps we have at home. They are used to turn off the steam and water or to slow it down. The pipelines are also covered with insulation to stop the heat escaping and also to stop peoplefrom burning themselves. The pipes heat up to about 180oC.

Water is not used so it has to be separated from the steam. This is done by the separator which sends the water to a re-

injection well that puts the water back deep into the ground This means the water can be reheated and used again. The

steam is sent to the power station. The steam is sent to the turbine and as it passes through the turbine blades, it makes the turbine spin. The turbine causes the generator to spin and this is what produces the electricity.

What happens to the steam? Once it comes out of the turbine, it goes to the condenser. The condenser’s job is to turn the steam back into water so it can be re-injected back into the ground. Because the condenser needs to cool the steam to turn it back to water, water is used for cooling. The condensed water is then sent to the cooling tower to cool even more. The water needed for cooling is then used again - recycled –and the rest is put back into the ground.

It is renewableIt doesn’t cause pollutionOwners of buildings using geothermal have cut 25 to 50 percent off their utility bills. No cooling towers, rooftop units, or individual room air conditioning units are needed, so buildings and schools using geothermal systems look better. There’s no fire hazard and no outside equipment that could potentially hurt kids Geothermal systems are quieter, more reliable, more efficient, and more compact compared to regular heating and cooling systems.Daniel Boone high school saved $33,000 by using geothermal energy.Geothermal energy costs dropped from $.10 - .16 per kilowatt hour to $.5 - .8 per kilowatt hour. The earth under our feet stays the same temperature year round, whether it’s blazing hot in summer or freezing cold in winter. In summer the earth is cooler than the air, and in winter it’s warmer. Geothermal heat pumps cleverly put that fact to good use. They use the earth to warm buildings in the winter and keep them cool in the summer. They work so well TVA helps Valley businesses and school systems install them in their buildings.

• 100% renewable Earth’s core is always going to be heated As long as there is a way to extract the

energy from the heat, the energy will always be available

Geothermal energy does not produce any pollution, and does not contribute to the greenhouse effect. The power stations do not take up much room, so

there is not much impact on the environment. No fuel is needed. 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.

Sometimes a geothermal site may "run out of steam", perhaps for decades.

Hazardous gases and minerals may come up from underground, and can be difficult to safely dispose of.

Remarkable difference of environmental effects compared to fossil fuels› Leaves almost no

footprints Most hardware used

to extract geothermal energy is underground› Minimal use of

surface

(http://www.geothermal.nau.edu/about/enviroment.shtmlNorthern Arizona University. 2009 Oct 27)

Easy to operate Open up economy Much more efficient

use of land

Power Source

Land Requirement (ac/mW)

Geothermal 1-8

Nuclear 5-10

Coal 19

Fluids drawn from the deep earth carry a mixture of gases

Pollutants contribute to global warming and acid rain

Construction of Plants can adversely affect land stability

Sources may hold trace amounts of toxic chemicals/mineral deposits

Loud Noises Initial start up cost

(expensive)

Operation Noise Level (dBa)

Air drilling  85–120

Mud drilling  80

Discharging wells after drilling (to remove drilling debris)

Up to 120

Well testing 70–110

Diesel engines (to operate compressors and provide electricity)

45–55

Heavy machinery (e.g., for earth moving during construction)

Up to 90

Not everyone agrees that geothermal energy is a solution to our energy crisis

Too costly Noise Use of fresh water Land surveying The technology is not quite there Some people just believe that our fossil

fuels will “never” run out› Don’t believe that fossil fuels are finite

Overall, geothermal appears to be a sound solution to energy needs

Geothermal energy has the ability to expand

Few environmental effects Very cost efficient Geothermal is RENEWABLE

ASK.COM GEOTHERMAL EDUCATION SOCIETY. GOOGLE.COM WIKEPEDIA.ORG WWW.GEOHEAT.OIT.EDU http://www.darvill.clara.net/altenerg/fossil.htm http://www.umich.edu/~gs265/society/fossilfuels.htm www.worldenergy.org/wec-geis/publications/reports/ser/

geo/geo.asp http://lsa.colorado.edu/summarystreet/texts/

geothermal.htm