Sunday, April 6, 2014

Geothermal Energy and Mongolia

By Paul Sullivan,

Georgetown University

The earth gets more amazing the more one learns about it. For example, the earth is a massive source of heat. That heat is partially from the left over heat from its creation. Now, isn’t that amazing? Most of it, about 80 percent, is from radioactive decay of isotopes of thorium, uranium and potassium. When radioactive isotopes decay they throw off heat. Most of this is happening in the earth’s crust, which is kind of a radioactive thermal blanket for the world. Don’t worry we are not being zapped by lots of neutrons from this all day. The crust also works as a barrier to the radiation, hence we get heat.

Traveling from the center of the earth to where we are standing (or sitting reading this) we can see extreme temperatures and extreme temperature changes. Without getting too technical, the earth is made up of the inner core, which is molten iron-nickel, the mantle and the crust. The inner core is solid due to pressure-temperature combinations and what it is made of. The outer core is liquid. The entire core is about 3,500 kilometers thick. If we could travel from the innermost point of the core to its outermost point we would go from 7,500 degrees Celsius to about 3,700 degrees Celsius. Above the core is the mantle, which is about 2,800 kilometers. The mantle’s temperature goes from about 3,700 degrees Celsius near to its “edge” with core to about 870 degrees Celsius as it gets nearer to the crust.

As we travel further to the surface things are getting cooler, although these sorts of temperatures are hotter than most of us could imagine. The crust is the next stop on this trip to the surface of the earth from its core. The crust is about six-12 kilometers thick under the oceans. It can be as much as 20-90 kilometers thick under the continents. As we travel from the deepest part of the crust to the surface, the temperatures get cooler. Another interesting fact, the soil and rocks of the crust acts as insulators to solar heating radiation, which we will see later in the article, for example, dig deep enough in the hot sands of a desert in the summer and you will reach cool sands.

The crust is a complex place. It is not like the even crust of a piece of bread or the uniform shell of an egg. It has moving parts, the continental plates, that mostly slowly drift about and sometimes collide with each other. There are many fault lines, which are places where earthquakes are more likely to happen than in other areas. Some of the more famous of these would be the San Andreas Fault that goes across California. Mongolia has the Bulgan fault line, which was the location of a massive 8.2 earthquake in 1905. The results of this earthquake can be seen even today with a fissure that goes on for hundreds of kilometers. The Amur Plate, the Eurasian Plate and the Indo-Chinese Plate combine around and through Mongolia.

From 1905 to 1967, there was a series of very strong earthquakes in Mongolia. Earthquakes are a fairly normal part of things in some parts of Mongolia, especially near the Russian and Chinese borders and near the area where the fault line go up and across the center of the country. There are many faults running east-west at various angles across the country. It is part of the Baykal rift system. There has been seismic activity especially in the Gobi-Altay and Mongolian-Altay mountain systems. The northwest near the Russian border has been especially active at times. Mongolia is a seismically active place, but not like those areas near the so-called “Ring of Fire” in the Pacific Basin, Japan, Chile, or Indonesia.

There are many places where Mongolia’s geological structure can be to its benefit. Many of these can be found in the hot springs, warm springs and other geothermal zones that can be found in the northern central part of the country and in the northwest.

Some of these springs may be used to produce electricity for the villages and towns near to them. If the waters are very hot, then flash steam geothermal plants can be set up. By drilling down to where it is much hotter than at the surface, the hot water could be used to produce steam, which in turn can turn a turbine, which turns a generator, which produces electricity. If the ground is not so hot, then a binary geothermal system could be set up. The less hot water is taken up from deep in the ground and its warmth is used to boil something like methanol or ammonia, which boils at a lower temperature than water. The ammonia or methanol steam then turns the turbine, which turns the generator, which produces electricity. If producing electricity near warm and hot springs seems odd to some, it does happen in some areas of the world where tourism sites produce electricity from the same temperatures that keep the tourists coming for mineral, warm and hot baths for health and relaxation.

It need not be the case that this can be done at hot springs or even warm springs. In places in Mongolia where the hotter rocks are near the surface at hundreds to even thousands of feet down, injection pipes can bring cool water from the surface to the hotter rocks. The water can be used in flash steam geothermal systems when the rock is very hot. Where the rocks are not that hot, the injected cool water can be brought back up as warmer water to be used in binary geothermal systems that boil off the methane, ammonia and the like.

Wherever there is water and hot rocks within economic reach to produce electricity this can be done. However, it is best to do this near places where the electricity is needed. It would be too costly and too much electricity would be lost if the geothermal generated electricity needed to go over very large distances to where it will be used.

I am certain that there are many places in Mongolia that could develop either the flash system or the binary systems for geothermal energy. It is a matter of finding the best and most economically and technically possible areas and getting the infrastructure set up. A lot less CO2 is produced from geothermal energy. There is surely a lot less air pollution produced from geothermal electricity generation compared to generating electricity with coal.

There are many other economic uses for the hot rocks, warm rocks, and warm springs that are in Mongolia. These include the greater development of health spas, warm swimming pools, melting snow on roads and other important places, hot water for houses and other buildings, keeping animals warm, greenhouse warming, even during some cold times (Iceland does this), food processing, curing concrete blocks and other construction material, cloth and yarn drying for factories, and hundreds, if not thousands, of other uses constrained only by one’s imagination and the technical and economic feasibility of the projects.

Many of these applications could be used to help develop tourism and industry in the country. Geothermal energy could be used to replace energy produced by coal, oil and other fossil fuels. There are many examples in the world of large buildings, houses, and even large parts of cities that are heated and cooled with geothermal energy. There are a growing number of places that are using geothermal energy to produce electricity. Some minerals and oil companies are using geothermal energy to help recover more of their product from underground than would otherwise be possible. Some mining and other companies are producing some of their electricity, and some of their heating and cooling from geothermal.

Geothermal has some other fascinating applications. One of them is for geothermal heat pumps. These can be developed just about anywhere they are needed. If one were to dig down into the ground about two-three meters here in Washington the soil would be a constant 50-60 degrees year round in most places.
In Mongolia one may have to dig a bit deeper than two to five meters. In Minnesota, way in the north of my country, depths of three to four meters may be needed in some places because of how deep frost levels can be in that cold state. However, at two to three meters, the temperatures in many parts of the state are in the 10 degrees Celsius level or thereabout all year round. The depth one would need to dig depends on the latitude in the world one is at, whether there is permafrost or not, frost levels for a good part of the year, and whether one is near hot rocks, hot springs or other sources of heat, such as some mineral mines.

However, normally there will be a depth that a building developer or home builder (apartment builder) can dig to find this sweet spot for constant temperature underground. Why do I call it the sweet spot? Because if you set up pipes with certain liquids in certain ways in the ground, and cover them over properly, you can readily pump that 10-15 degree Celsius temperature into the building, home or apartment building.

Let us say it is 10 degrees Celsius. Each place will have some differences from other places, so let’s simplify this. Let’s put the piping system down, cover it up with soil after connecting it to the heat pump and the fan systems which are inside the building, not outside like many cooling systems. During the warmer summer days, constant 10 degrees Celsius liquid is pumped to the fans and the fans bring that cool air into the building via a heat exchanger, a device that conducts the temperature from one medium to another. Bigger buildings will need larger more powerful piping and fans systems, but I am sure you get the picture.

That 10 degrees Celsius liquid and the air resulting from the heat exchanger and fans will naturally cool the building. If more cooling is needed on some days, then a normal cooling system can be used in conjunction with the geothermal system. But think of all of the electricity and more that will be saved. Now think about how much energy would be saved if the buildings are well-insulated and designed for energy efficiency with the geothermal-conventional system. It is a lot in most areas. Some estimates state that typically a geothermal heat pump system can save 30-40 percent over the average conventional system. The energy is from the earth, not just from an electric air conditioner.

Now, let’s turn things around. It is now the coldest part of the Mongolian winter. Homes, gers, apartment complexes, office buildings and more, need to be heated. If there is a building or a home with the geothermal system 10 degrees Celsius air is being pumped into the building. This 10 degrees Celsius is a lot warmer than the outside air. The home or other building would want to be warmer than this, but think of how much energy is saved, and pollution not produced, by brining the home or building initially up to this temperature using the earth. After this, warmer air than the air temperature outside is brought in, then the other conventional heating systems can kick in to make up the difference to make a comfortable home or building. With good insulation in the walls, triple-pane glass windows, tight building of doors and other openings, and more, a huge amount of energy — and money — could be saved. Using this for individual gers would be difficult, but as groups in villages or large families, this may be possible, if they are to remain stationary. This sort of system is not for families who move about. Other forms would need to be considered for those families.

Given that many people in Mongolia are of low or modest incomes, many would likely not be able to afford the digging and drilling and fairly expensive systems heat pumps involve. However, as these systems become more common in the country, and in the world, costs could be driven down by rising learning curves, as well as having economies of scale in the production of the pipes and other systems. The Mongolian government may also want to look into some national projects on this as a use for its newfound wealth. But this needs to be done properly and carefully, and with the best devices and experts involved.

For now, the pipes and the heat pump systems will have to be imported. Installation, at first, will have to be done by outside experts, while at the same time training Mongolians to do this. That sort of offset would be great for any technology being developed in the country. Mongolians could also find jobs in this from step one.

Can I see in 10, 20, and 30 years a viable energy industry being developed by Mongolians educated outside and inside of the country? Yes. Can I see geothermal as an important part of this development of Mongolian skills and jobs in energy? Yes. Can I see Mongolians adapting these technologies to their economic, cultural, and weather environments? Yes. Can I see them exporting these adaptations to similar and other parts of the world? Yes.

In energy, as with any other industry a country first learns, then adapts, then develops in its own way — optimally. If Mongolia is really going to develop, it needs to move forward with its own people and its own ideas eventually, rather than just relying on outside ideas and people. The chances are there. Doing this right is vital for the future of the country.
So do we have another reason to be thankful for the wonders of this earth?
Yes.

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