What Are the advantages of Geothermal Energy?
Many advantages of geothermal energy have made this energy source one of the most talked about and promising alternative energy sources. I have come across many people wanting to know the major advantages and drawbacks of geothermal energy, which is considered to be a key element in future energy supply based on renewable sources. Here in this article I am going to discuss the basic geothermal energy facts like ‘what is geothermal energy’, how does geothermal energy work, ‘what are the major advantages of geothermal energy’ and what its major drawbacks are.
What is geothermal energy?
Geothermal energy is defined as the energy that emanates from the heat in the core of the earth. ‘Geothermal’ literally means ‘Earth’s heat, which is estimated to be 5,500 degrees centigrade at the Earth’s core – about as hot as the surface of the sun. Geothermal energy is a clean, renewable resource that can be tapped by many countries around the world located in geologically favorable places.
How does geothermal energy work?
The earth’s center which lies almost 4,000 miles beneath its’ surface is so hot that it is molten. Heat from the earth’s core radiates outwards and heats up the outer layers of rock called the ‘mantle’. When the rocks in the outermost shell of the earth made of the earth’s crust and upper part of the mantle melts at extremely high temperatures, this molten rock is called ‘Magma’. The temperature of magma usually falls somewhere between 700 and 1300 degrees Celsius. Magma (molten rock) may come quite close to the surface of the earth. When magma comes close to the surface it transfers heat to the ground water found trapped in porous rock or water running along fractured rock surfaces and fault lines. A usable form of geothermal energy is thus created under the earth’s surface. Some of this super heated water rises back to the surface of the earth where it emerges as hot springs or even geysers and steam vents. Sometimes the hot water becomes trapped below the surface as a geothermal reservoir. By drilling boreholes into these geothermal reservoirs the hot water and steam are piped up which can then be used directly to heat our homes and businesses or to generate electricity. Many countries have developed various methods of tapping into these geothermal energy sources.
Advantages and major drawbacks of Geothermal Energy
There are many advantages of using geothermal energy either directly or indirectly, the most important among which are explained below. The advantages of geothermal energy listed here are based on utilization of the energy source in two main ways – for generating Electricity and for heating and cooling purposes. Although the advantages of geothermal energy greatly outweigh its disadvantages, especially when compared with fossil fuels, geothermal energy still has its few drawbacks like any other form of power generation technology, some of which are mentioned here.
Advantages of Geothermal Energy – Eco Friendly
One of the biggest advantages of geothermal energy is that it is considered relatively clean and does not cause significant amounts of pollution when compared with fossil fuel alternatives such as coal, oil and gas. Most systems only emit water vapor, although some emit very small amounts of sulphur dioxide, nitrous oxides, and particulates. The carbon footprint of a geothermal power plant is minimal and power generation from it is almost 100% emission free. However, there are a few polluting aspects of geothermal energy which are mentioned below but they are minor compared to the pollution associated with coal power and fossil fuels.
Advantages of Geothermal Energy – Renewable energy source
Geothermal energy is considered a sustainable and renewable energy source. The Earth is continuously radiating heat out from its core. The constant flow of heat from the earth’s core ensures an inexhaustible and essentially limitless supply of energy for billions of years to come. Once the hot water or steam trapped below the surface of the earth in the geothermal reservoirs is utilized, it can be pumped back into the ground. It is a resource that can sustain its own consumption rate unlike conventional energy sources such as coal and fossil fuels, which will be eventually used up. For all these reasons geothermal energy is called a renewable energy source.
Advantages of Geothermal Energy – Huge potential
The future is almost here for geothermal energy. Geothermal power projects around the globe continue to gain momentum and expand. As of January 2016, the global market of geothermal power is at about 13,300 MW of operating capacity spread across 24 countries and based on current data, the global geothermal industry is expected to reach about 18,400 MW by 2021.
Although not used fully due to factors such as location and high initial costs, geothermal energy will turn out to be the cheapest source of power generation in the years to come when fossil fuels would start to diminish due to our increased reliance on them. Even though there are geographical limitations when it comes to geothermal energy technologies, this power source has massive potential. Upper estimates show a worldwide potential of this energy source is 2 TeraWatts (TW). A recent study by the Geothermal Energy Association (GEA) estimated that just 6.5% of global geothermal energy potential, has been tapped so far. From taking advantage of the potential areas across the US that have the possibility to serve as the greatest sources of geothermal power to harnessing the energy from temperature changes at different depths in the ocean, researchers are moving forward to make widespread use of geothermal energy a real possibility in our lives.
Advantages of Geothermal Energy – Stable and predictable supply
Unlike solar and wind power geothermal power is a reliable source of supply as it is available all year long and we can predict the power output of a geothermal plant with remarkable accuracy. Solar panels can only produce electricity during the day and wind turbines only produce power when there is enough wind. One of the major advantages of geothermal energy is that it is constantly produced and the energy supply is non-fluctuating. The benefit of constant supply makes geothermal based power plants excellent for meeting the base-load energy demand which means geothermal plants can produce electricity or heat at near to its full capacity for 365 days in a year.
Advantages of Geothermal Energy – Can be used directly
Geothermal energy systems are adaptable to many different conditions. Apart from generating electricity, the hot water in geothermal reservoirs, which produces heat and steam, can be directly used to heat or cool homes and businesses efficiently, grow crops, dehydrate foods, warm fish ponds, melt ice on roads and sidewalks or for other multiple purposes. The direct use of geothermal energy can be done by the usage of geothermal springs for the purpose of heating, melting sidewalks during winter. Another schematic approach to trap this energy is by using ground-source heat pumps that supply heating and cooling to the houses. Today geothermal heat pumps are used in about 45 states in US and around the world, to heat and cool homes, buildings and businesses.
Advantages of Geothermal Energy – Lesser land requirement
Another among the major advantages of geothermal energy is that the land required to build a geothermal facility is much less compared to all the power generating technologies in use today. A geothermal power plant needs about 1.4 square miles of land to produce one GigaWatt of electrical power while coal facilities require 12 square miles of land and wind farms need 4.6 square miles to yield the same amount of power.
Advantages of Geothermal Energy – Cost effective
Electricity generated by geothermal plants is considered to be one of the cheapest power sources in use today. Although the initial cost of geothermal power plants is considerably high when taking into account the investment required for exploration and drilling wells, once functional the operating costs of geothermal power stations are considered to be very low as no fuel is used to generate the power and the energy generated from the plants is cheaper by up to 80 percent than conventional fossil fuel plants.
Homeowners typically achieve energy savings up to 25% to 50% over conventional systems of cooling and heating by using geothermal energy. Although the initial expense for building the home system is quite high, the savings on energy bills on heating and cooling will more than cover the initial investment within few years.
Geothermal plants can release small amounts of greenhouse gases such as hydrogen sulphide and carbon dioxide. The water in the underground reservoirs can also pick up traces of toxic elements such as arsenic, mercury and selenium, which can be leaked to water sources if the geothermal system is not properly insulated.
Disadvantages of geothermal energy – High upfront cost
The biggest disadvantage of geothermal energy is high upfront costs. A large proportion of this cost is associated with surveying for the proper area to build such a plant and exploration and drilling of geothermal energy resources. Geothermal power plant construction and well drilling currently cost about $2-5 million per generated MW of electricity. Geothermal energy is currently being harnessed in a small number of countries of the world. The main reason for this is that geothermal power plants are currently cost-effective only in areas near tectonic plate boundaries. But the recent technological advances should significantly expand the range of viable geothermal resources in years to come.
Disadvantages of geothermal energy – Location specific source
Another major drawback of geothermal energy production is that you just can’t set up a geothermal power station anywhere you want. It is only suitable for regions which have hot rocks below the earth and can produce hot water and steam over a long period of time. The type of rocks present also matters a lot because some rocks are too strong to drill through. These rocks must also occur at reasonable depths to make drilling down to them a feasible option. A suitable location for drilling should be positioned near an area with big amount of water, because extracting geothermal energy requires a large amount of water.
Disadvantages of geothermal energy – Possibility of local depletion
Although geothermal energy is considered a sustainable and renewable energy source and the geothermal sites are capable of providing heat for many decades, eventually specific locations may get out of steam as a result of low temperature or of over-hydration which is injected to cool off the rocks, making the site unable to produce enough energy. Extensive initial research is, therefore, needed for selecting proper site before setting up the geothermal plant. Extraction of energy from geothermal reservoirs also needs to be monitored carefully to avoid such local depletion of geothermal resources.
On going through many advantages of geothermal energy described in this post it is obvious that geothermal energy may seem to be a great idea on the surface to many of us. It is true that being a cheap and clean renewable and sustainable energy source, geothermal power has unquestionable advantages over extremely polluting and unsustainable fossil fuels. But it also suffers from few disadvantages mentioned above, which is why it is not being utilized everywhere to its full capability. But taking given examples of major countries like US, Philippines, Indonesia, Mexico, New Zealand, Italy, Iceland, Kenya and Japan, which have had great success with this source of energy, one can highly recommend for putting more focus in harnessing this Earth-friendly resource in a safe and cost-effective manner.