By,N Venkata Srinath,1st Yr MS Power Systems.

GeothermalHeat in the interior of the earthGreek originated.

Geo-earth and thermal-heat.Temperature rise 20-30°/Km .

Geothermal effects can be visualized asHot gassesHot springGeysers

-A spring that discharges hot water and steamVolcano

Technologies AquacultureSpasDesalinationGeothermal heat pump/District heating IndustryPower Generation

AquacultureGeothermal aquaculture, the ‘farming’ of water-dwelling

creatures.Uses natural warm water to speed the growth of fish.Europe, USA, China and Japan.Catfish, Tilapia, Eels and Alligators.

SpasA health resort near a spring.A place of business with equipment and facilities for

exercising and improving physical fitness.

DesalinationGeothermal desalination is a proven process under

development for the production of fresh water using heat energy.

It requires less maintenance than reverse osmosis membranes.

 In 1998 Douglas Firestone Aquagenesis from Nevada has began working with evaporation/condensation air loop water desalination.

Geothermal heat pump/District heatingA geothermal heat pump or ground source heat

pump (GSHP) is a central heating.The first successful commercial project was installed in

the Common wealth Building (Portland, Oregon) in 1946.

IndustryGeothermal energy is used by industries like food

processing for pasteurizing , timber, leather manufactures, paper and dying .

Power generationGeothermal power is the power extracted form the heat

stored in the earth.

Types of technologies for locating geothermal reservoirs MagnetotelluricElectric Vacuum

How geothermal is an alternative/renewableAlternative: Instead of fossil fuels, we are using earth’s

heat to generate steam.Renewable: The rate at which its heat is reducing is less

than the rate it is increasing due to radioactive decomposition.

Different types of power generationsFlash steam plants.Dry steam plants.Binary power plants.Hybrid power plants.

Flash steam plantsSuitable for the reservoirs which cannot generate the

steam 150°c.Most geothermal power plants operating today are ‘Flash

steam’ power plants.Hot water from production wells is passed through one or

two separators where, released from the pressure of the deep reservoir, part of it flashes (explosively boils) to steam.

Dry steam plantReservoirs which can generate steam of temperature 180-

350°c.This geothermal reservoirs produce mostly steam and very

little water.Here, the steam shoots directly into the turbine.

Binary power plants.The geothermal water is passed through one side of a heat

exchanger.

where the heat is transferred to a second liquid, called a working fluid, in an adjacent separate pipe loop.

The working fluid boils to vapour (like steam) powers the turbine generator.

The geothermal water passes only through the heat exchanger and is immediately recycled back into the reservoir.

Binary power plants are generally more expensive to build than steam-driven plants.

Advantages:The working fluid (usually isobutene or

isopentane) boils and vapour’s at a lower temperature than does water.

The binary system uses the reservoir water more efficiently.

Binary power plants have virtually no emissions.

Hybrid power plant In Hybrid power plants, flash and binary processes are

combined.An example of such a hybrid system is in Hawaii, where a plant

provides about 25% of the electricity used on the Big Island.

World 1st geothermal plant(Dry steam power plant) was built in 1904 at Larderello in Tuscany Italy which can give supply for 5 bulb.

1911 250kw power plant was built in devil valley which was destroyed in world war II.

Rebuilt and expanded, still serving today.

DisadvantagesGeothermal heat is extracted from deep

within the earths surface, and this is the main disadvantage concerning finding a suitable location.

To lay pipe lines, it has to dig for several feet's.

Too expansive to bore.

Indian Scenario In India 1970 MNRE has started Hot Spring Committee .Other survey committees are NGRI, GSI. In India total potential is 6000 – 10,000MWThere are 340 potential cites.

The most promising provinces are    i)The Himalaya,  ii) Sohana,  iii) Cambay,   iv)  Son-Narmada-Tapi (SONATA) and v) The Godavari.

India’s first Geothermal plant was installed at Parbati Valley Manikaran (Himachal Pradesh) in 1992.

India has collaborated with Iceland for Geothermal Technology in 2007.

NTPC combined with Mitsubishi(Japan) in 2009 to built a 25MW power plant in Gujarat.

MNRE planned to built a 1MW power plant at puga (Ladakh district, J&K)

Tattapani region (Madhya Pradesh) where the installation of a 20MWe binary plant has been planned.

References Magnetotelluric Dept, NGRI, Hyderabad.http://mnes.nic.in/http://www.clean-energy-ideas.com/http://www.digtheheat.com/geothermal/http://en.wikipedia.org/