Seminar

GEOTHERMAL ENERGY

‘energy within earth’

AKHIL KUMAR6-EE-005

EEE

WHAT IS GEOTHERMAL ENERGY?

Word geothermal comes from greek words-Geo (earth) & Thermal (heat)

A renewable energy source because the water is replenished by rainfall and the heat is continuously produced inside the earth.

Geothermal is number three of the renewable energy sources in world electrictity production after hydro and biomass. It is followed by wind and solar energy

HOW IT IS PRODUCED? Geothermal energy is generated in the

earth's core, about 4,000 miles below the surface. 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.

Different layers are shown in adjacent fig.

earth's crust is broken into pieces called plates.

The temperature of the rocks and water get hotter and hotter as you go deeper underground.

DIFFERENT GEOTHERMAL ENERGY SOURCES

Hydrothermal convective Reservoirs: • Vapour -dominated (dry steam fields)• Liquid-dominated system(wet steam fields)• Hot water fields

Petro-thermal or Hot dry rocks

Molten magma.

Valcanoes .

WHERE GEOTHERMAL ENERGY IS FOUND?

Geothermal energy can sometimes find its way to the surface in the form of: volcanoes and

fumaroles (holes where volcanic gases are released)

hot springs and geysers.

Most of the geothermal activity in the world occurs in an area called the Ring of Fire.

TYPES OF GEOTHERMAL POWER PLANTS Dry steam plants - use steam piped directly from a

geothermal reservoir to turn the generator turbines. The first geothermal power plant was built in 1904 in Tuscany, Italy at a place where natural steam was erupting from the earth.

Flash steam plants - take 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 plants.

Binary power plants - transfer the heat from geothermal hot water to another liquid. The heat causes the second liquid to turn to steam which is used to drive a generator turbine.

DRY STEAM PLANT

FLASH STEAM PLANT

BINARY CYCLE STEAM PLANT

GEOTHERMAL POWER PLANTS

Geothermal power is generated in over 20 countries around the world including Iceland, United States, Italy, Germany, Turkey, France, The Netherlands, Lithuania, New Zealand, Mexico, Nicaragua, Costa Rica, Russia, Philippines, Indonesia, People's Republic of China, Japan and Saint Kitts and Nevis. Chevron Corporation is the world's largest producer of geothermal energy.

USES OF GEOTHERMAL ENERGY Direct use and district

heating systems which use hot water from springs or reservoirs near the surface.

Geothermal heat pumps use stable ground or water temperatures near the earth's surface to control building temperatures above ground.

Electricity generation in a power plant requires water or steam at very high temperature (300 to 700 degrees Fahrenheit). Geothermal power plants are generally built where geothermal reservoirs are located within a mile or two of the surface.

Geothermal

provinces

of India

ADVANTAGES The heat source requires no purchase of fuel.

Emissions of undesirable substances are small.

Reduces reliance on fossil fuels and their inherent price unpredictability.

Useful minerals, such as zinc and silica, can be extracted from underground water.

Geothermal energy is “homegrown” . This will create jobs, a better global trading position.

DISADVANTAGES The geothermal fluid is corrosive, and worse, and thus

limits the efficiency of heat engines in extracting useful energy as in the generation of electricity.

Extracting large amount of water can cause land subsidence, and this can lead to an increase in seismic activity.

There is the fear of noise pollution during the drilling of wells.

Brine can salinate soil if the water is not injected back into the reserve after the heat is extracted.

END OF PRESENTATION

THANK YOU