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The Warsaw Voice » Other » November 19, 2008
Technology
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Heat from the Earth's Core
November 19, 2008   
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Geothermal energy is practically inexhaustible. It is used around the world to produce heat as well as electricity. But the geothermal waters in Poland are too cold to be used for anything but heating.

"Poland has a lot of potential for the use of geothermal water sources, but only in certain regions," says Dr. Eleonora Solik-Heliasz from the Department of Geology and Geophysics of the Central Mining Institute (GIG) in Katowice, southern Poland. Geothermal water sources are chiefly available in the Warsaw, Łódź and Szczecin regions. The rock structures dating back to the Mesozoic era which form them contain high-temperature water deposits from a depth of at least 1,000 meters. High-temperature water is defined as being above 40 degrees Celsius, but can sometimes reach 60 or 80 degrees.

The heat is on
Geothermal sources began to be exploited in Poland 10 years ago as an ecological source of heat. There are currently four large installations of this type with a combined output of 75 MW, and the construction of more is planned.

"The fundamental factor is not only the temperature, but also the scale of water deposits," says Solik-Heliasz. The determining factor in the decision to exploit a source is the amount available. The temperature is the second most important factor.

Rock formations at great depths have high temperatures, but often do not contain enough water to permit the extraction of a sufficient amount of heat. If the quantity is too low, the whole technology becomes unprofitable. The main problem is therefore to find a site with enough water deposits, and only then determine if the temperature is high enough, experts say.

In Poland, such water deposits are available in areas around Warsaw, Łódź and Szczecin as well as near the southern town of Nowy Targ, not far from the popular mountain resort of Zakopane. There, a number of geothermal installations are already in operation.

How it is done
Hot water is extracted to the surface, where it gives off its energy in heating systems, and is then pumped back underground. First, two wells of a sufficient depth are dug. The first pumps the hot water up to the surface, where it is transferred to a system of receivers and heat exchangers, where the heat is recovered. During this process, the water cools and is then transported to the other well, located at a distance of one to three kilometers from the first. Here, it is pumped back to the same depth as it was extracted from.

Why is the extracted water pumped back inside? "It has to be put somewhere," says Solik-Heliasz. "Often, water extracted from such depths is salty, making it impossible to just pump it into rivers without polluting the environment. This explains why it is pumped back down through another well. We call this a doublet: we have one well for extraction and one for disposal."

There are two ways of dealing with the extracted water. If the temperature is high enough, the water can be pumped directly into heat exchangers and used for heating buildings. If it is not, it is first directed into heat pumps, which raise the temperature. It is easier to heat it up to the correct temperature than to start from scratch, which is an obvious advantage over traditional heating installations.

Does this technology require special installations or can existing ones be used? It all depends on the temperature of the extracted water. If the temperature is high enough, which is quite rare, the water can be pumped directly into traditional high-temperature heating systems installed in buildings and working at around 90 degrees Celsius. But geothermal energy is best used in more modern low-temperature heating installations, where the required temperature is only around 60 degrees Celsius.

Everything depends on the well's efficiency. For example, a few geothermal wells in the Zakopane area are enough to supply most of the town with heating. According to data published by consulting company Frost & Sullivan in July, around 90 percent of hotels and a growing number of households in Zakopane use geothermal heating. It is estimated that in the Podhale region, thanks to the high efficiency of the underground sources, geothermal heating is 40 percent cheaper than the gas equivalent.

Geothermal installations
The number of geothermal installations in Poland is continually rising. Seven new projects are under way in the Nowy Targ area alone. In the country as a whole, the best known installations already operating are in Mszczonów near Warsaw, Pyrzyce near Szczecin, and Uniejów near Bełchatów. Talks are in progress with the authorities of the Silesia province to build an installation near Jaworze.

The Ministry of Education and Higher Education has commissioned Solik-Heliasz to conduct a study that resulted in an Atlas of Geothermal Resources in the Upper Silesia Region. It will be published at the end of this year and will contain thorough information about the possibilities of extracting geothermal energy and building balneotherapy centers in selected municipalities and districts in Silesia province.

In 2005-2007 workers at the Central Mining Institute in Katowice conducted a study entitled "Geothermal Waters of the Upper Silesian Region: Utilitarian Energy Extraction." Its object was the analysis of how to best harness geothermal energy in order to make geothermal heating installations at a low cost and risk. According to the study, the optimal sites for such projects in Silesia are areas around the cities of Jastrzębie Zdrój, Rybnik, and Czechowice. The obtainable water efficiency in these areas is about 10 cubic meters per hour, with the possibility of raising it through various methods, the institute says.

Renewable energy
Geothermal energy is one of the most important renewable energy sources alongside biomass, solar power and wind power. As such it has enormous benefits for the environment, experts say. It is a clean energy as its extraction does not involve carbon emissions or the release of any other noxious substances into the atmosphere. In regions where geothermal energy is in use, there is already a noticeable difference in air quality. Zakopane, for instance, has already recorded a decrease in carbon dioxide emissions. The wells also have no detrimental effects on the environment. There are already dozens of thousands of such wells around Poland, which were drilled in the past decades for various reasons, usually the search for mining deposits. Some of them could be reused for geothermal energy extraction, which would be good for the environment and help lower the costs involved.

No drawbacks, just benefits
According to experts, geothermal energy has only benefits: it does not emit pollutants, counters global warming, prevents localized pollution such as acid rain, does not generate waste disposal or land reclamation costs, carries no risk of disaster or contamination, and helps save on the use of fossil fuels.

Geothermal energy will never be the main source for heating needs, experts say, nor will it ever fully replace coal, oil and natural gas. But it is perfectly suited for satisfying local needs as well as those of the leisure and tourism industry. Water extracted from the depths of the earth is often brine, which not only contains energy in the form of heat but also has numerous health benefits. This can be a boon for health tourism-or at least the sector which goes by the name of balneotherapy and is concerned with analyzing the medical benefits of hot water extracted from deep underground and its therapeutic use in the treatment of various diseases.

Experts say that Poland's geothermal potential is 150 times greater than the country's energy needs. The lack of widespread use is therefore due to the high cost of building the necessary installations, the greatest of which lies in drilling wells. Costs are borne for the most part by municipalities. However, a growing number of installations are being built by private investors. In one such project, a private company is building a recreation center heated by geothermal energy in Białka Tatrzańska in the mountains. Similar spas are already in use in Cieplice, Duszniki Zdrój, Lądek Zdrój, Ustroń, Konstancin, and Ciechocinek.

Studies show that the cost of geothermal energy extraction is constantly falling. In 2005, the cost of extraction was 50-150 euros/MWh. By 2010, it is estimated to fall to 40-100 euros/MWh, and then stabilize at 40-80 euros/MWh by 2020. This should boost interest in geothermal technology, experts say.

Further cost economies could result from the reuse of existing wells, for example those in the vicinity of coal mines, experts say. But this is a tricky matter that mostly depends on the technical condition of those wells. "We try to use them as often as possible," says Solik-Heliasz, "but this must be preceded by geophysical testing to determine if the well is suitable for our needs. We can only move forward on the basis of such a study."

The greatest potential for this exists in Silesia where there are many coal mines, both functioning and abandoned, which must constantly pump out water. These costs are borne by the state budget. The extracted water could be used for heating, even just for the needs of the mine itself, but potentially for those of the adjacent housing.

In April Solik-Heliasz and her team worked on the technological aspects of a project for the use of the hot water deposits in an abandoned mine to heat the buildings of the new Silesian Museum, which is being constructed in Katowice. This is the first use of this technology in Poland and was singled out for praise in the Polish Ecological Pantheon contest in the "Institutions helping fund projects to protect the environment" category at the POLEKO International Trade Fair for Environmental Protection in the western city of Poznań.

Geothermal energy should be looked at in a wider perspective, experts say. Today's high investment costs will bring benefits in the future by positively influencing local budgetary incomes, fiscal policies and tourism. They will also enhance the development of rural areas and benefit local infrastructure and business by highlighting the regions' environmental awareness and innovation.

Julia Pawłowska


Thinking Big
The Central Mining Institute (GIG) in the southern city of Katowice is a research and development center that is overseen by the Ministry of the Economy. It is tasked with doing research for the mining industry as well as private companies, state and local institutions, and foreign partners.

GIG's main concerns are mining, environmental engineering, quality issues as well as education and training. Its experts deal with the problems of waste disposal and recycling, conduct energy surveys, draw up plans for modernizing the energy infrastructure, monitor the environment, and run numerous programs promoting ecology aimed at municipalities and regions.

GIG is also active in education, providing postgraduate studies, specialized training courses and seminars, and works with higher education institutions such as the Warsaw School of Economics (SGH) and the Jagiellonian University in Cracow.
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