Energy Resources: Geothermal Energy

Almost___ is generated by geothermal energy.

45%

Comes from the Greek word “geo” means earth and “therme” means heat.

This heat comes from the decay of radioactive elements and the residual heat produced when planet is formed.

Covers all techniques used to recover the heat in the Earth’s subsurface, particularly in

aquifers.

The rock reservoir that contain groundwater

Aquifer

a body of permeable rock which can contain or transmit groundwater.

Geothermal Energy

This heat tends to increase as you get deeper to the ground.

Geothermal gradient

Average value of gradient is 30C per 100

meters.

Geothermal Power Plant

•Binary Cycle

•Dry Steam

•Flash Steam

Binary Cycle

the hot water from the underground is pumped through a heat exchanger which heats a second liquid that transforms into steam

Dry Steam Power Plant

hot steam from underground is piped directly into turbine which power the generator

Flash Steam Power Plant

Hot water from underground is pumped into a cooler temparature flash tank. The sudden change in temparature creates steam which power the generator

geothermal power plants, wells are drilled for about 1 to 2 miles deep

beneath the Earth’s surface to pump steam or hot water to the surface. As the hot

water rises towards the surface, the pressure drops causing the hot water to turn into

steam.

The kinetic energy of the steam powers the turbine to spin. This converts kinetic

energy (steam) to mechanical energy (turbine). The turbine is connected to a generator

that converts mechanical energy to electricity.

The electricity that produced in generator will flow to step up transformers

raising the voltage so it can travel long distances. The electricity will then flow to pole

transformers to power lines until it reaches your home.

The steam that is used to spin the turbine will undergo cooling in the cooling

tower to condense the steam back to water. The water will be injected back to the

Earth’s surface in an injection well. The process continues to sustain the supply of

electricity.