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Geothermal energy - Some points to consider

The announcement made in April 2002, to inform that Velupillai Prabhakaran was to hold his maiden national and international press conference in Mallavi, Vanni to mark the so-called Prabha-Ranil peace accord was itself some sort of a headline news to many local and foreign media. However, it was ironic that Udaya Gammanpila and myself to have visited Vavuniya, on the very day that Prabhakaran had his famous press conference at which he was subtly unfolding his grand plan for a Tamil Eelam.

Having travelled along Medawachchiya-Trincomalee road, we reached Kinniya on the following morning, where the world famous Hot-wells are located. At first sight, we were very happy to notice the presence of large and active crowds in the vicinity of the Hot-wells.

However, our happiness quickly evaporated when we saw that LTTE agents were charging a gate fee from the visitors to visit the Hot-wells, a natural resource in our own country. When we looked around further, to our dismay, we observed that the sacred Bo tree which was there for many years has been cut down and old statues venerated by Buddhists being destroyed. It was evident that ethnic and religious cleansing was effectively taking place there, under the pretext of so-called peace. What we saw around us, catalyzed me to swear to myself that before long we should liberate not only our natural resources and our national heritage around the area, but the entire country and the people from the clutches of Velupillai Prabhakaran. We are happy now to see that our country being fully liberated and are proud for the contribution we have made to preserve its unitary character, once again.

On our return, Udaya who is always inquisitive and eager to learn, wanted to know the physical theory behind the Hot-wells in Kinniya. I explained to him about the high temperature molten metal core inside the earth and as to how it causes water bodies which warms up in certain areas of the earth. I enlightened him about the oceanic heat patch identified from Mulathivu to Verugal area and also about the technology called Ocean Thermal Energy Conversion or OTEC to convert Geothermal to Electricity energy. I can still remember, during our University days, two decades ago as to how our Power System Professors were arguing on this particular subjects - prospects of Geothermal Energy as our alternate energy. It is noted that now many countries in the world, specially the USA are generously funding the research and development work on tapping this enormous energy source.

Once, I heard that the US Ex Vice President Al Gore, quoting the Massachusetts Institutes of Technology, having said that in 2006, it had been estimated that technically extractable quantity of US Geothermal resource was about 2000 times the annual consumption of the primary energy source of the USA. It was a clear manifestation of the fact that if they had succeeded, there would not have been any energy problem in USA for two millennia.

It is true that Geothermal potential is so high and effectively unlimited. Two experts in this field, Bruce Green and Gerald Nix says that "the energy contents of domestic Geothermal resources which runs to a depth of three kilometers is estimated to be three million quads - equivalent to 30,000 year supply of energy at current rate in the USA. According to the UN world energy assessment report the Geothermal resource is approximately 280,000 times the annual consumption of primary energy in the world. So, whatever way it is being accounted, it would be the largest energy reserve the entire human beings have and is larger than the combined resource potential of fossil fuel and renewable resources such as solar and wind.

In order to understand Geothermal energy we should understand the inside of the earth. According to the Geologists, the inner core of our earth is made up of iron and its temperature is estimated to be between 8000 to 120000F which is as same as the temperature at the surface of the sun and the outer core comprises of molten metal of which the temperature is between 6700 - 80000F. Therefore, the enormous heat so generated inside the earth is naturally transmitted to the earth mantel and to the outer crust by convention and conduction.

It is widely assumed that this outer crust runs to an average depth of 30 kilometers and the crust itself generates heat causing its contained radio active metal to decay. The Geologists are of the opinion that within a depth of 10 kilometers of the outer crust of the earth there contain 60,000 times as much energy as all the petroleum and natural gas resources in the world.

This enormous inside heat sometimes comes out to the earth surface through the earth fault lines or weak earth structures and as a result we could naturally find very hot geological areas and hot water bodies like in Kinniya-Trincomalee.

Geologists have already identified two kinds of geological heat areas. One is in and around the areas where earth tectonic plates meet each other.

It is believed that the earth's other crust is made out of floating tectonic plates and the inner heat could come out along their boundaries. The scientists also have identified what they call the ring of fire, a hot zone around the Pacific Ocean from New Zealand - Indonesia - China - Japan - Alaska - North America and to South America lying parallel to the boundaries of tectonic plates. The other kind of heat areas are the earth's Hot-Spots.

They are available around the world and may have come to being due to volcanic activities or other geological activities. The scientists are now able to clearly map out these Hot regions and their energy potential. Although, Sri Lanka does not possess any of the above Hot-Zones it has high temperature gradient area around it.

One explanation given for the existence of these Hot-Spots is that some asteroid or space motor had caused earth core heat to surface in earth's crust.

It is like that when some space matter which is large enough to make waves collide with the earth curst the shock waves so created could travel through earth's core to the diametrically opposite side of the earth.

This pushes the melted metal core and other heated metals to move towards the other side of the earth causing Hot-Spots. Whatever the explanation attributed for the existence of Hot-Spots, they are warm enough to generate heat and electricity. The next question is to know as to how we could tap this valuable energy source.

This mechanism could be described as follows: After having identified the Hot Zone, sometimes several kilometers deep into the earth, wells are drilled. For this purpose generally there are twin wells where one is used to pump down the cool water and the other to pump back the heated water which is being heated when it goes through Hot Rocks or Hot Zones inside the earth. Thereafter, the heated water or liquid is used to drive the turbine which propelled the generator and produce electricity.

This general mechanism has now been enhanced and is called Enhanced Geothermal System or EGS. When we use the same technique to convert oceanic heat into electricity we called it Ocean Thermal Energy Conversion or OTEC.

Generally, some industrialized countries with Geothermal potential are using this energy for their heating and cooling purposes. New Zealand was the first country to introduce thermal energy - the Wivekei power station in New Zealand produces 180 mega watts of electricity using Geothermal energy. In California - USA, 22 Geothermal plants are now in operation making it, perhaps the largest Geothermal installation in the world. Japan, Iceland, Australia, France and Germany etc, are the other countries which use Geothermal energy for generating electricity for heating and cooling purposes.

Geothermal energy has many advantages. Firstly, as it does not emit carbon dioxide it is basically considered to be clean energy.

Secondly, its constant supply of energy, unlike wind or solar which are heavily dependent on weather and time conditions could be used as a major base load energy source like coal or oil without any pollution.

Thirdly, if Research and Development could enhance the utility value of the Geothermal energy, it could simply replace fossil fuel as our main source of energy as it's potential is estimated to be so large. Due to these encouraging factors, the so-called industrialized countries are now aggressively taking steps to use Geothermal energy as a major option.

However, when going into these options, countries have to overcome many constraints of which its cost problem being the worst. It has been estimated that to drill a single hole to a depth of three kilometers it costs 5 million US$ or more and it is similar to drilling an oil well. It is a random process where sometimes one may not be successful in producing heat. Could scientists be able to overcome the uncertainty associated with its drilling process and lower the high cost involved? Some are optimistic like Ex US Vice President Al Gore, who is already using Geothermal energy for heating and cooling facilities in his house.

They use ground heat to produce heating, cooling and hot water to their house. Would it be an alternative energy source to our country as well. Although, we do not have Hot-Spots and Hot regions which could produce substantial energy, we also should research into the available Geothermal potential in Sri Lanka. Our Geologists and our Geological Survey and Mines Bureau, has identified 10 high gradient temperature locations which could produce Geothermal energy.

However, we need more attention, investment and research into this new field.

(The writer is the Minister of Environment and Natural Resources)

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