With passage of time demand for renewable energy sources is rising and we are also trying to find alternatives of non-renewable sources. Geothermal energy is also famous type of renewable energy sources and is gathered from heat that comes from the earth. Earth is great source of heat at certain points where it combines with water and is very easy to extract. Many reservoirs of heat have been discovered and hundreds of others are waiting to discover.
In other terms heat is also known as thermal energy which helps in determining temperature of matters. This energy originates from earth’s crust formation and radioactive decay of minerals. The difference in temperature between core of earth and surface of earth drives conduction of thermal energy if form of heat from core to the surface of earth. From ancient times this heat is being used for purpose of space heating and hot water bathing but today it is used solely for purpose of electricity generation.
This energy is cost effective, environment friendly, sustainable and reliable renewable source but geothermal walls within the earth release greenhouse gases at very low rate. Therefore we can say that its contribution to global warming is detectable as compared to gas emitted from fossil fuels and biofuels etc.
How geothermal energy is captured and works?
Most widely used method for capturing geothermal energy is to tap into naturally occurring hydrothermal convection systems. In these systems cooler water seeps into the crust of earth, get heated there and then rises to the surface in form of heat or thermal energy. The point from where this heat comes out is very simple to capture and use it as driving force to run electrical generators. In geothermal power plants holes are drilled on surface of earth to capture heat effectively, three basic designs are used in these plants to pull hot water and steam from core of the earth and return warm water to prolong life of these sources.
In first design, heat moves towards the condenser from turbine where heat condenses into water. In second approach extremely hot water is flashed into steam to drive turbine and in the last design hot water pass through heat exchanger. In this exchanger hot water heats other liquids and convert it into stream to run turbine. These three designs are famously known as dry steam system, flash steam system and binary steam system.
Direct use of geothermal energy:
It is not necessary to use any of the design to capture heat and use it to run turbines, geothermal springs can be used directly as well. Heat is used directly to heat greenhouses, to dry out fish and de-ice roads, for improving oil recovery, and to heat fish farms and spas etc.
Ground source heat pumps are also used to tap energy and provide it to building. These pumps enjoy benefit of constant temperature round the year. Here air or anti freezing liquid is pumped in underground pipes of building. In summers liquid moves heat out of the building and in winters is provide heat to the building from ground.
Pros and cons of using geothermal energy:
As compared to other renewable sources of energy, fewer cons are associated with geothermal energy. We are going to discuss them here
- This energy is environment friendly, negligible greenhouse gases release from wall of core of earth
- This is a great renewable source of energy which not only provide heat to buildings but also make them cool in summers
- This energy has partially unlimited potential.
- This is a reliable and sustainable source of energy
- Construction of geothermal power plants can affect the stability of the land
- Commercial geothermal power project is expensive
- It is available from certain regions on the planet