Humanity is likely to suffer from an energy crisis in the near future. Therefore, any source of energy that we can lay hands on is gold. However, there’s yet another issue, which we have to keep in mind. It is sustainability. Since conventional energy accounts for high carbon emissions, we need to look for more renewable sources of energy. Countries worldwide are mostly focusing on wind and solar energy. Although these two have high availability, they too have limitations. They are not that reliable. Therefore, at times like these, if we can tap into any other source of energy, it might prove revolutionary. Geothermal energy could prove one such source. However, right now, it’s utility is not that certain.
The Good, The Bad and The Ugly about Geothermal energy
The temperature rises one degree Celsius for every 30-50 meters you go down the earth’s surface. This heat is brought to the near-surface by thermal conduction and by intrusion into the earth’s crust of molten magma originating from great depth.This heat energy is called geothermal energy.
We can define Geothermal energy as a sort of renewable energy derived from the heat that is there deep in the earth’s crust. Humans are using this clean and sustainable energy for thousands of years in some countries. However, so far they have utilized it mostly for cooking and heating. As groundwater heats, geothermal energy generates in the form of hot water and steam which we can use for direct heating of homes and greenhouses.
Production of electricity
People in antiquity harnessed Geothermal resources as an energy source. Therefore, now too we can utilize it as an energy source. Geothermal electricity generation technologies consist of three methods. First method is the dry steam method. It uses steam as it comes from the underground source to drive the turbines, flash steam method. This makes use of the underground hot water (360 degrees F) pumps to the surface where it flashes to steam and drives the turbines. The second is a binary method that makes use of hot underground water. It runs the water through a heat exchanger where it heats a fluid with a lower boiling point that flashes to steam and drives the turbine.
Electric power plants driven by geothermal energy provide over 44 billion kilowatt-hours (kWh) of electricity worldwide per year with United states, Philippines and Indonesia producing the majority. Currently only 24 countries have geothermal power stations.
Can this be better?
The amount of geothermal energy stored deep in the earth is much greater than the amount of energy that humans use. The efficiency amounts to only 10-23%. But that energy is not easily accessible. The efficiency of engines that convert heat to energy is limited due to thermodynamic laws. The heat that is rejected by the power plant. It goes to waste when exhausted into the environment. However, we can use this heat in greenhouses, mills and also in local houses. On the other hand, their engines are not the theoretical perfect engines, either. Since geothermal energy is an independent resource its efficiency can be much larger if used in a proper way.
A major drawback to geothermal energy is finding a suitable build location. An ideal site for drilling a well in order to trap geothermal energy must provide hot rocks in the layer of the Earth’s crust that would heat the water pumped into the well at suitable level. Such a project may only be useful to provide electricity or heat to the local area only if the area is remote. After finding the location its quite uncertain to say whether the geothermal area is active or not. The location may remain active constantly for several years and then stop for a few months. Hence not all locations are completely reliable.
Geothermal power requires no fuel (except for pumps). Therefore, it is immune to fuel cost fluctuation. However, the capital costs are significant. Drilling accounts for over half the costs, and exploration of deep resources entails significant risks. A typical well doublet (extraction and injection wells) in Nevada can support 4.5 megawatts (MW) and costs about $10 million to drill, with a 20% failure rate.
Another arguable disadvantage of converting to geothermal energy is a high installation cost. Combined with current state and federal incentives, geothermal installation costs are extremely competitive with conventional fossil fuel systems. The development of geothermal reservoirs is often unfeasible because they are too far from major population centers. This adds to the cost of transmitting electricity, which is higher over long distances.
Can this be avoided?
Almost all other energy sources have some limitations based on locations. It is not only the case with geothermal energy sources. Geothermal is a renewable energy resource deriving energy from the heat of the earth’s core and volcanic-thermal activity. The Earth’s core will continue to produce massive amounts of heat for millions of years which can be harnessed by humans. The installation costs are though high, but one can easily offset them with savings on utility bills. Possible rebates from your local electric company could also prove beneficial. Moreover, the cost of geothermal electricity is also 50% of what it was in 1980.
Hazardous Materials and Earthquakes
The ugly part of geothermal energy is the hazardous gasses and minerals such as mercury, hydrogen sulphide, ammonia and arsenic come upon the surface along with hot water. These materials, which could cause environmental pollution, are not easy to deal with. It’s another disadvantage is the possibility of natural earthquakes which may cause damage to the power plant and also local residents.
Why are we so critical?
The several geothermal power plants in existence use hot spots on the earth, where the temperature is much higher than the 150 0F. Geothermal power in the long run could be very cheap, but the initial cost of installing the power will definitely be high.
Harnessing geothermal energy requires a small piece of land and freshwater. But this energy can be along with with dangerous risk of carrying a mixture of gases such as carbon dioxide, hydrogen sulphide, methane and ammonia which can add to global warming, air pollution, and acid rain. Various poisonous minerals like arsenic and mercury also come to the surface, thus polluting underwater and soil.
Reasons for the popularity of geothermal energy
Let us now look at some of the reasons to look at geothermal energy as a viable alternative.
1. Renewable Source
This form of energy utilizes steam and hot water, which is trapped under the surface of the Earth. The heat is generated at Earth’s core and is considered as limitless source of energy. Additionally the amount of heat that is extracted is very negligible in comparison to heat present in core of the planet making it renewable energy source.
2. Clean Power Plants
In these power plants there is minimal environmental impact with plants divided into three categories, i.e. binary, flash and dry steam geothermal plants. In dry steam plants as the name suggests, steam is sent to power plant through pipes into the generator. Flash steam power plants turn hot water from geothermal reservoirs into steam, which then is used to run the turbines. The water is sent back into reservoir, which makes it a very sustainable means of generating power. In binary plants, hot water boils one type of organic compound, which vaporizes when heated and turns the turbine.
3. Different Applications
Farmers make good use of such energy with Italian farmers using it for heating water and use in winter crops. Greenhouses are also humidified and heated with this energy and there is one plant for food dehydration, which dries fifteen million pounds of garlic and onions every year using geothermal energy. Other places where this thermal energy is made use of include swimming pools, commercial building and in fish farms to keep the water heated.
4. Base Load Stability
It is a very stable form of energy with plant availability ranging from 95 to 99% while in comparison coal plants have about 75% operational ability. The heat source is constant while other alternative energy mediums are not so stable. As for example, wind turbines will not work if there is no wind and similarly on cloudy days, solar power generation dips.
5. Clean Energy Form
Geothermal energy does not generate waste as other forms of energy sources do. In the energy production process there is no use of fossil fuels or coal and the power plants are powered by using steam. In power plants such as the binary plants, the water is injected back into the reservoir thus there is zero emission. In addition to it, there is nothing required to be transported from a different location to the power plant for generation of energy since the power source is right underneath the plant itself.
Is Geothermal Energy the future of clean energy?
The difference between world’s energy demand and supply is growing everyday. Along with this, the existing sources of electricity are depleting faster than ever as the global economy get more dependent on fossil fuels than ever. There is not only an economic side of this story. Rather, on a bad note, the use of fossil fuels has endangered the world with twin threats of climate change and global warming. This situation has also prompted many to search and switch over to green sources of electricity. But the rate at which this is happening is far from satisfactory. There are many technological, policy-level and budgetary challenges that have so far prevented the full growth of renewable energy sector.
The idea of tapping geothermal energy for meeting the electricity demand of the world is also facing similar challenges. As, little has been done so far even when many have claimed that the geothermal energy can alone supply electricity for the entire world. Not only this, it would be cheap, non-radioactive and emission-free electricity.
Is it really that serious?
Yes. This can be judged from the fact that most of the world’s politics revolves around energy as countries try to push themselves on an advantage position with respect to the others. Wars have been fought on this issue in recent times. Many have even alleged that the major inspiration behind the US’s bombing of Iraq post 9/11 was the vast oil reserves of this turbulent nation.
As far as the issue of geothermal energy is concerned, scientific facts speak in its favor. Most of the earth is made up of heat and different types of rocks are differently heated as one go to different layers of the earth. The heat only grows as one go deeper below the surface. Scientists have proposed to capture a portion of earth’s heat and convert it into electricity. Such electricity would be carbon-neutral and inexhaustible. With little efforts, they say, geothermal energy can supply electricity for the whole world.
Developments in Geothermal Energy
1. Utah’s 10MW geothermal power plant ready to function
Raser Technologies has constructed the first geothermal power plant in Utah in over 20-years. Constructed in just six-month time, the power plant can provide 10MW of electricity to the city. It has been constructed along the largest geothermal hotbed discovered in last 25-years.
2. Canadian university harnesses geothermal energy for heat and power
The University of Ontario Institute of Technology in Canada has started this ambitious $4 million project for capturing geothermal energy to meet all the power demands on campus. 375 boreholes at the cost of $10,000 each have been dug in the campus area for this. It can produce 8 MW electricity which can be supplied to about 1000 homes in and around the campus of the university.
3. Acconia crafts zero-emission headquarters using solar and geothermal energy
Solar and thermal energy development firm Acconia has constructed geothermal and solar energy-based zero-emission new headquarter. The building is completely powered by multiple green sources like sunlight, solar thermal power, geothermal energy and biodiesel. The entire building walls from outside and the roof top is covered with photovoltaic cells. They generate solar power which is transferred to a central unit. The central unit also receive power generated by tapping the geothermal energy.
The Bottom line:
Since geothermal energy is a renewable source of energy, it will soon become popular and much cheaper. But the geothermal areas are limited therefore this energy source will not be beneficial worldwide.