Wind Power

GEOTHERMAL ENERGY

Geothermal energy is an alternative energy source, although it is not resourceful enough to replace more than a minor amount of the future’s energy needs. Geothermal energy is obtained from the internal heat of the planet and can be used to generate steam to run a steam turbine. This in turn generates electricity, which is a very useful form of energy.
 
There are many Geothermal hotspots which are volcanic features found all around the world. Basically a hotspot is an area of reduced thickness in the mantle which transmits excess internal heat from the interior of the earth to the outer crust. These hotspots are well known for their unique effects on the surface, such as the volcanic islands of Hawaii, the mineral deposits and geysers in Yellowstone National Park, or the hot springs in Iceland. These geothermal hotspots can easily be used to generate electricity.
Advantages
• Does not create any pollution.
• The cost of the land is usually less expensive than constructions on land for oil, gas, coal, or nuclear power plants.
• Geothermal plants take up very little room
• Low running costs

 
Disadvantages
• Geothermal heat is only available from deep within the earths surface, and this is the main disadvantage concerning finding a suitable build location
• Land surveys may take several years to complete
• Often prospective land cannot support a geothermal energy plant.
• Suitable hot spots within the earths crust are only most common around dangerous landscapes such as volcanos and fault lines
• Unfeasibility of Geothermal energy plants next to a volcanos
• Geothermal sites can stop producing energy as part of a natural process
• Harmful gases can escape from deep within the earth
• Disposing of escaped gases can be very tricky to do safely
 
Main Components of a Geothermal Energy Plant

• The Well – This is the source of the steam which will be converted into energy
• Headers and pipes – These connect the wellheads to the power plant.
• The steam then goes to the turbine.
• Turbines – The turbine with generator turns the motion into electricity
• Condenser – This unit condenses the steam. Most plants use direct contact condensers that use the condensed water itself as the cooling media.
• Cooling towers - These cool the hot condensate for use in the condensers and for plant cooling.
• Reinjection Wells – These return the excess condensate back to the underground thermal reservoirs.
• NCG & H2S removers - Hydrogen Sulphide seperates in the condenser. Steam ejectors suck out these gases so that the vacuum is maintained in the condenser.
• Ground or water pipes incorporating either an open- or closed-loop system

Continued in Part 5 - TIDAL ENERGY