Meyer and Kozlowski PYRZYCE - FIRST GEOTHERMAL HEATING SYSTEM IN POLAND Prof. Dr. Civil Eng. Zygmunt MEYER Civil Eng. Jan Investment Company "EKO-INWEST" S.A. (Joint Stock Company) 4; 70-780 Szczecin. POLAND Key words: district heating, geothermal water, Pyrzyce, ABSTRACT The North West part of Poland (Szczecin Region) has good for using geothermal water for heating purpose. The geothermal aqufier is placed 1500 - 2000 m below the surface and the temperature of geothermal water varies C to 90" C. In Pyrzyce there has been undertaken a large project of a town heating system based on a geothermal heating plant. The original concept was to use a coal fired heating plant. The project assumes two doublets (four geothermal wells) which supplies about 360 of geothermal water with temperature about C. The peak power of the geothermal plant is about 50 what ensures heat for the whole town of Pyrzyce (about 16 thousand citizens) and for foreseen development of the county. The geothermal loop includes: heat exchangers, heat pumps (absorption) and low temperature gas boilers. About 2/3 of the annual heat demand will be covered by geothermal heat. The implementation of the project is well advanced, about 2/3 of all the works (including wells) have been Fig. Isotherms of geothermal waters strata and its depth in already finished. The main contractor is the "EKO-INWEST" S.A., Szczecin Suubasin Company from Szczecin. For example, the main heat exchangers - plate type have a surface INTRODUCTION covered with palladium or titanium just as the main pump pushing The intensified degradation of the human natural environment water from well or heat pumps. There is another danger, awakes a growing anxiety. The problem is seen more and more considering geothermal heating plants, microbiological clearly inside a local society in the country scale as well as in a corrosion. Salt and hot geothermal water can be a good global scale. The alternative sources of energy in the Szczecin environment for bacteria growth. The bacteria injected into bedrock Region are the following ones: water-power and wind power plants, can silt it up (stick up) the flow impossible. Therefore one N-gas in area, straw and wooden cuttings, biogas as a should avoid contact of geothermal water with atmospheric air. product of organic waste recovery and sludge treatment, solar energy and geothermal energy. There are very good conditions for using geothermal waters for heating in the Szczecin GEOTHERMAL HEATING PLANT IN PYRZYCE Geothermal water occurs there at the depth from 1600 m to 2200 m We have several examples of of geothermal energy in and with temperature of C to C. Europe. As in the Szczecin neighbourhood, there exist geothermal These strata consist of grey sandstone with high porosity and heating plants in Neubrandenburg (Germany), in Southern Sweden thickness up to 200 meters (these are so called lias formations). in Lund, and in Northern Denmark in Thisted. In the Federal Each square km of the terrain contains at depth about cubic Republic of Germany, in Land four new meters of geothermal water. The corresponding energy may be geothermal power plants are under construction. It has been compared to about 160 thousand tons of coal. Szczecin city itself years since the pilot station of the Polish Academy of Sciences came covers an area of about 400 square kms. In addition such an energy on line. It is called in near is renewable. Zakopane and takes about 8 of geothermal water. Bore-holes assigned for geothermal waters utilization should be The first, full scale geothermal heating plant in Poland is the plant characterized by high discharge rates Q. The increase in discharge in Pyrzyce near Szczecin. The town Pyrzyce lies in the north- can be achieved by enlarging bore-holes diameter at the filter zone western part of Poland, some 32 km south of Szczecin. Both the ( SO called: broaching). Geothermal boreholes have diameters even town and commune of Pyrzyce are situated inside the catchment up to 50 cm. In the area of usually the maximum area of Lake. Lake is a main source of supply, of discharge of a single bore-hole does not exceed 200 The drinking water for Szczecin City. Szczecin City is inhabited by discharge seems to be underrated (determined with a Safely factor), 400,000 The water intake is located directly in the reservoir. since for instance, in geothermal heating plant in Lund (Sweden) up Pyrzyce commune with its fertile soils is knowns for intensive to 500 are taken from a single well. Limiting the discharge agricultural production. The town is inhabited by about 16,000 from a single well to 200 causes that, depending on local people and the commune some 26,000 A district heating system conditions, the thermal power obtained varies it between 7 and 10 does not exist in town. Buildings are heated by individual coal fired boilers. They consume some 38 000 tons of As mentioned before, geothermal water from the Szczecin Basin coal per year. nower of this plant was estimated at SO to is very aggressive because the mineralization is high (high content of meet the actual heat demands of the town. reserve also salts 112 mg )). Therefore the exists that would a development of all the commune by installation in a well where geothermal water flows must be made of developing an industry tc The peak power special materials. meets the heat demand for 20.000 inhabitants. 2269 Meyer and The geothermal heating plant is based upon 4 wells (2 production - drilling projects and geological supervision provided by and 2 injection), each of about m deep. Geothermal water is Przedsigbicrstwo "POLGEOL" from lifted to the earth surface by means of a pump, then flows to heat - drillings were made by Przedsigbiorstwo i exchangers, heat pumps and again down to the injection well where from it is injected into the same geological layer from where it was earlier - project is supplied by OLSEN" from Thisted in taken. The period of time needed for water to again enter the Denmark. production well is equal to 30 years. The discharge of a single well The rest of the construction works are delivered by Polish is about 200 h. Water temperature in the bedrock equals companies after competitive bidding.. whereas the temperature of cooled (injected) water equals The total cost of the geothermal heating plant and town district 26°C. The distance between wells is 1700 m. The geothermal water heating system in is USD. The plant itself costs is strongly aggressive, as it has very high salt content and other about USD. minerals, about 120 Therefore pumps used to the water on must be of special construction, while heat exchangers are covered with and titanium. High salt and other minerals ECONOMICAL. ASPECTS OF GEOTHERMAL HEATING content causes strong corrosion, so a proper choice of materials and PLANT devices is of great importance. All pumps, which operate in Apart from environmental protection aspects one should consider production wells and are all the time submerged in hot water the total costs of construction of a plant and production cost of (without cooling), and pipelines as well as exchangers and heat warm water for a longer period of exploitation, 30 years. pumps are made of such materials that can resist the corrosion Comparison of capital costs and unit heat production costs in caused by the brine. various heating plants is shown in Table For comparison purposes Another interesting solution used in Pyrzyce are pumps with it was assumed that the plant is of power of 50 and produces varying discharge. In summer time when heat demand it town 500,000 GJ of heat per year 33 of production for peak decreases, the constant discharge of geothermal water, 200 demand power). Time of exploitation was chosen for 30 years. h is too much. The injected water would have the temperature Increase of raw materials prices was assumed to be 30 higher than assumed (26 The cheaper solution is to decrease 1995). In addition, for geothermal heating plant it was assumed that the brine discharge and cooling it while injecting to the nominal peak power would have been achieved by means of gas burning. It temperature of 26 "C. Absorption pumps, 10 each, are of was assumed that the additional gas burning would cost 20 of gas lithium cadmium type. In such way, about 110 000 is heating plant which means USD. It comes Table 1 that recovered from the geothermal heat, which covers about 84 of for the conditions of the Szczecin Region, the capital cost of coal the annual heat demand. fired plant with installation, for flue gas purification, significantly In the future, when an industry constantly consuming a large exceeds erection costs of a geothermal heating plant. The cost of amount of heat through all the year is developed, the efficiency wilt production of 1 of heat in geothermal heating plant is about 4 be higher. The heat demand in the town heating system is covered times lower than in traditional heating plants. It was announced in in the following manner: main exchangers 2x8 MW, absorption heat Poland that higher heat prices that will charge to the consumers. It pumps combined with high temperature gas boilers 2x10 low means that prices will have temperature gas boilers 2x10 MW. The scheme of installation for to take into account mentioned in Table 1 costs of heat production the geothermal heating plant in Pyrzyce is shown in Figure and additionally costs of operating and maintaining of the heating Pyrzyce town, at the moment, does not have any heat distribution network. Moreover if means that the price will have to exceed network.