Advantages and Disadvantages of Geothermal Energy




The heat from our planet is referred to as geothermal energy.


The heat from our planet is sustainable and it is clean.


Geothermal energy resources range from very shallow ground just below our feet through to hot rock and hot water that is located well below the surface of the Earth, quite a few miles down.


Even farther down you can find magma which is a molten rock. This magma has particularly high temperatures.


You’ll find, if you care to test it, that almost everywhere around our planet the uppermost ten feet or so maintains a relatively consistent temperature. This temperature ranges between 50 and 60 degrees Fahrenheit (10-16 Centigrade).


As a way of heating and cooling buildings, geothermal heat pumps are able to tap into this source.


The heat pump system is made up of the heat pump, ductwork to deliver the air, in addition to a heat exchanger which are pipes linked together and positioned near the “target” building in shallow ground.


During the winter months, heat is removed from the heat exchanger by the heat pump. After this, it is pumped into the interior delivery system.


In the summer, heat that is removed from inside the building can be utilized as a way of providing hot water inside the building. The hot water is entirely free, besides the cost of the water, of course.


Hot natural water that can be found near to the Earth’s surface – geothermal water reservoirs – can be used in direct fashion to produce heat for a variety of applications.


These geothermal reservoirs can be used to heat buildings, for greenhouse plant production, to dry crops, to heat water at fish farms, for pasteurizing milk, and for many other large-scale industrial applications.



So, what are the advantages of geothermal energy?


How about the disadvantages of geothermal energy?


Let’s find out now.





Advantages of Geothermal Energy



1  Geothermal energy comes from a renewable resource

Natural resources are responsible for the creation of geothermal reservoirs. In turn, these reservoirs are, likewise, naturally replenished. As such, geothermal energy is entirely renewable as an energy source.


Energy supplies from geothermal reservoirs will persist for a few billion years from now.



2  Geothermal energy is environmentally friendly

While there are some aspects of harvesting and harnessing geothermal energy that are somewhat polluting in nature, the pollution is minor in comparison to harvesting and harnessing fossil fuels such as oil and coal.


Geothermal power plants have a minimal carbon footprint and the development of resources for geothermal energy harvesting is seen as beneficial in terms of fighting against global warming.


A typical geothermal power plant emits approximately 122kg of carbon dioxide per megawatt-hour (MWh) of electricity generation.


Compare that to a typical coal power plant and it’s 1/8th (one eighth) of the amount of carbon emission.



3  Geothermal energy production has huge potential

Around 15 terawatts (TW) of energy is required annually to provide enough energy around the world.


However, 15 terawatts is far less than the amount of energy that you will find inside the Earth’s crust.


That’s not to say that all geothermal reservoirs are profitable, though.


On an annual basis, the estimate is that we can harvest anything between 0.035 and 2 TW from geothermal power plant production.


Currently, geothermal power plants worldwide provide around 10,715 megawatts (MW) of electricity. This amount is much less than the current capacity of installed geothermal heating which stands at 28,000 MW.



4  Geothermal energy is ideal for heating and for cooling

To turn power turbines as a way of generating electricity by using geothermal energy resources, the water temperature needs to be above 300 Fahrenheit (150 Centigrade).


Geothermal heat pumps can also be used to tap into heat sinks/ sources.


Geothermal heat pumps work in a very similar fashion to electrical heat pumps.


Around six feet (two meters) or so below the surface of the ground, seasonal changes in temperatures which tend to greatly impact air temperatures remain relatively consistent.


As such, using a geothermal heat pump to tap this source makes for an excellent heat sink or heat source.


Very many homeowners now utilize this method to heat and to cool their homes.



5  Geothermal energy is reliable

Geothermal power plants are easy to predict with respect to the amount of power output.


On the other hand, with respect to solar and to wind, the prevailing weather conditions determine the amount of power production to a huge degree,


As such, geothermal power plants can be used to meet demands for base load energy consumption.






Disadvantages of Geothermal Energy



1  Geothermal energy has issues of sustainability

Over thousands of years, rainwater ameliorates into the Earth’s surface, then into geothermal reservoirs.


The fluid within geothermal reservoirs can become depleted should the fluid be removed more quickly than it is replaced. And for geothermal energy – power – to be sustainable, these reservoirs must be properly managed.


While geothermal energy is sustainable, it is reliable, and it is also environmentally friendly, there are heavy upfront costs and these costs mean we are unable to realize the full potential.


Thus, the amount of geothermal power we will use in future will depend upon technological advancements, on politics (the mount of subsidies), and on energy prices in general.


For now, it’s a scenario that is very difficult to predict.



2  Geothermal energy comes with “some” environmental issues

Below the Earth’s surface, there is a large amount of greenhouse gases. Near to geothermal power plants, the emissions of greenhouse gases have a tendency to be far higher than normal.


Emissions of silica and sulfur dioxide are commonplace near geothermal plants, while geothermal reservoirs may consist of various toxic heavy metals, inclusive of boron, arsenic and mercury.


Nevertheless, any pollution that is associated with geothermal energy is almost insignificant in comparison to pollution associated with fossil fuels.



3  Geothermal energy is expensive

On a commercial scale, projects involving geothermal power are costly.


Exploring and drilling of new reservoirs is a costly business.


For a geothermal power plant that has a capacity of one megawatt (MW), the price is typically between $2 million and $7 million U.S.


As such, the majority of geothermal resources are not cost-effective in terms of utilization. Well, at least not with our current level of technology, with the amount of government subsidies, and with the current price of energy.


Geothermal heating and cooling systems also have sizable upfront costs.


Nevertheless, over a period of many years, there’s every chance that geothermal heating and cooling systems will save money. As such, they are long-term investments.


A ground source heat pump costs anything between $3,000 and $10,000. Payback for these pumps will occur over a ten- to 20-year period.



4  Geothermal energy production is location specific

There are some countries such as Iceland and the Philippines (both countries meet almost a third of their entire electricity demands using geothermal energy) that have been blessed with excellent geothermal resources. 


The majority of countries, however, have not been so blessed. 


Should geothermal energy be transported over long distances as hot water, and not as electricity, there will, of course, be a significant amount of energy loss. 



5  Instability of the planet’s surface (earthquakes)

When geothermal power plants are constructed it can impact the surrounding land’s stability. 


Hydraulic fracturing can occur, which leads to earthquakes. Hydraulic fracturing is a particular problem in the development of enhanced geothermal system (EGS) power plants.