GEOTHERMAL ENERGY

Umashankar MaliSem-IBranch-ME

3 1 / 10 / 2011

VNS institute of technology, Bhopal

Introduction

Geo=Earth

Thermal=Heat

Introduction

Geothermal Energy is heat (thermal) derived from earth (geo)

Contained in rock and fluid in the earths crust

Source of geothermal energy is radioactive decay

Geothermal energy

Geothermal power is generated wherever water comes in contact with hot rocks below the earth’s surface.

The rocks give off heat that makes the water hot enough to turn in to steam.

Power companies can drill wells and pump the hot water or steam to the surface, where it can be used to generate energy.

in areas where no underground water or steam exists naturally, engineers can pump water into the ground to be heated by hot rocks.

Bolivia, Iceland, New Zealand, and the united states have developed geothermal power plants.

Types and Application of Geothermal Energy

1.Direct use Involves using the heat in water directly

Temperature: 38°C-149°C

e.g. heating of buildings, industrial processes, greenhouses , aquaculture and resource

Types and Application of Geothermal Energy

2. Ground-source heat pumps use the earth or groundwater as a heat source in

winter and sink in summer

Temperatures: 4˚C to 38˚C

Heat pump transfers heat from the soil to the house in winter and from the house to the soil in summer

Types and Application of Geothermal Energy

3.Power generation geothermal power plant taps the natural supplies of

heat energy that have accumulated inside the earth.

Schematic energy of Geo-Thermal energy power plant

Geothermal energy plant

Indian Scenario

Puga Valley (J&K) Godavari Basin Manikara (Himachal

Pradesh) Bakreshwar (West Bengal) Tuwa (Gujarat) Jalgaon (Maharashtra)

Heated water may give out after a while-hotspot moves or aquifer pressure drops.

Geo thermal hot spots are sparsely distributed. Geothermal energy is quite low grade because

the temperature of steam is only between 150 to 200 c(at 100 psi).

salts in water can corrode equipment, shorten lifespan.

Limited to geographic areas where geothermal heating naturally occurs.

Demerits of Geothermal Energy

Merits of Geothermal Energy

Power source during construction Renewable as long as water is heated naturally Much lower greenhouse gas emissions than

fossil fuels Meet the needs of electricity demand in

limited area An experimental unit as a pilot plant for a

larger size installation.