Geothermal Conditions for the Usage of Heat Pumps in Eastern Siberia
Total Page:16
File Type:pdf, Size:1020Kb
Proceedings World Geothermal Congress 2005 Antalya, Turkey, 24-29 April 2005 Geothermal Conditions for the Usage of Heat Pumps in Eastern Siberia Raisa Dorofeeva1, Sergey Popov2 and Valery Stennikov2 1-Institute of the Earth Crust, Russian Academy of Sciences, Siberian Branch; 2-Energy Systems Institute, Russian Academy of Sciences, Siberian Branch Keywords: Temperature, geothermal regime, heat flow, INTRODUCTION heat pump A large fuel and energy base of the country has been set up in the Irkutsk Region (East Siberia). It mines about 5% of ABSTRACT the country’s coal, produces over 6% of the electrical power, The area under consideration is located in Central Asia and and processes about 5 % raw oil. includes a complicated combination of geological structures of different ages and different types: the Precambrian (Є) Despite the fact that the Irkutsk Region has unique reserves Siberian platform, Sayan-Baikal (PR+PZ) and Transbaikal of hydrocarbons, with regard to the usage of quality fuel (MZ) folded areas and Cenozoic (KZ) Baikal Rift Zone. (gas, black oil) it is considerably inferior in the balance of boiler-furnace combustible to other (in particular European) At depth of 1 km in the south of the Siberian platform the regions of the Russian Federation (less than 10 % against measured temperatures vary from 14-29 оС. The calculated 65-70 %). It has a negative affect for the exploitation costs, temperature at the depth of 5 km reaches between 40-118 and is the reason of high pollution of the environment. оС. On abnormal sites it exceeds 100 оС. The region annually emits about 20 million tons of СО2. In the Baikal Rift Zone at the depth of 1 km the rift Over 80 % of this value is contributed by power stations of depressions are outlined by 20 оС isotherm. Within those JSC “Irkutskenergo”, and their departmental and municipal о contours the temperature reaches as much as 37-56 С in the boiler-houses. The dynamics of СО2 emissions from power Tunka, 33-55 оС - in the Selenga, and 22-66 оС - in the stations of JSC “Irkutskenergo” is listed in Table I. Barguzin depressions. At the depth of 5 km the rift zone is marked by 60 оС isotherm, while rift depressions are The main priorities in order to cut pollutants on the whole о outlined by 70 -100 С isotherms. Within those borders there and CO2 in particular in the Irkutsk Region are the is a probable increase of the temperatures up to 120-150 оС following: in the Tunka and Barguzin depressions, i.e. rift depressions are much stronger heated as opposed to their folding 1. Operation of existing and building of new electrical framing. power plants in order to increase the overall efficiency of the electrical power sector in economy of the Region. Despite the low-temperature geothermal regime on the south of the Siberian Platform, the possibility of using GHP 2. Providing gas to the consumers. (Geothermal Heat Pumps) to supply heat to different consumers is being studied. Household, communal or 3. Wide usage of power sources on the basis of renewal industrial loads (up to 1-5 MWt) of thermal power are power resources. considered as consumers. The major requirements include the availability of a stable current of low potential thermal 4. Usage of other progressive know-how (technologies) energy, located very close to the consumer. aimed at decreasing fuel consumption and respectively cutting of СО2 emission. The use of the thermal energy from surface and/or underground water will decrease the consumption of the The GHP systems are one of the progressive paths to an organic fuel for heating and hot water supply, which will effective utilization of small power engineering for a thermal significantly improve the ecological characteristics of the energy supply to small consumers. environment of Eastern Siberia. Table I. Main technical-economic indices of JSC “Irkutskenergo”operation (given in rounded numbers) Years Indices 1990 1996 2000 2001 2002 Electric power production, billion, 66.00 54.8 53.1 54.4 56.4 kW.h Production of heat, mln. Gcal 43.6 36.1 32.2 30.5 28.3 Heat consumption, million tons of c.e. 11.6 7.1 6.8 6.2 6.3 Emission of green house gases, 33.2 20.4 19.9 17.6 17.8 million tons 1 List Dorofeeva, Popov and Stennikov Fig. 1. The scheme of the relief of the area of the Baikal region Baikal and Eastern-Sayan uplands, Middle Siberian plateau 1. PHYSICAL-GEOGRAPHIC INFORMATION 2. STRUCTURAL-GEOLOGICAL AND The complex geologic structure, hydrogeological conditions, GEODYNAMIC CHARACTERISTICS OF THE severe climate over the vast area covering Lake Baikal and REGION adjacent Sayan-Baikal folded area as well as the southern The southern part of the Eastern Siberia is comprised of part of the Siberian platform significantly affect the three areas of tectonic activization from different ages: the formation of the geothermal field. Paleozoic - the southern part of the Siberian platform or the Irkutsk amphitheater; The Mesozoic - the Transbaikal area The main physical-geographic factors influencing the of moderate mountain folding and the Cenozoic - the Sayan- distribution of the temperature in upper horizons include the Baikal area of intensive mountain folding which is mainly relief, sedimentation evolution and climate. occupied by the Baikal Rift Zone. Relief. The Baikal upland, southeastern part of the Eastern The western part of the considered region contains the Sayan upland and southern part of the Middle-Siberian Irkutsk amphitheater (the south of the Siberian platform), highland are located within the area under consideration. having a two-level structure: the crystalline Archean- (Fig.1). Proterozoic basement, overlapped by the sedimentary cover, which mainly contains the Proterozoic formations. The Late Climate. The climate in the Baikal region is sharply Paleozoic and Early Mesozoic basic volcanic rocks and continental. Only on the shores of Lake Baikal the interstratal trap intrusions are abundant on some sites of the continental character of the climate slightly decreases due to amphitheater. The thickness of the sedimentary cover the heat effect of the lake’s water mass. Sharp variations in reaches as much as 3-5 km in the PreBaikal and Sayan seasonal and day temperature are found. It is hot in the marginal troughs and in the Sayan-Enisei depression and summer, but the winter is frosty with very little snow. The decreases to 2.5-2.0 km and less on large positive structural o average annual air temperature is lower than – 4 C in the units of the basement north and –1 oC, -2 oC in the south. 3. DEEP STRUCTURE OF THE REGION The duration of the period without any frost over the major part of the area does not exceed 100 days. The maximum The gravimetric and seismic data show that the earth's crust duration of the period without any frost amounts to 120 in the Rift Zone differs from the crust of adjacent regions in days, and is found on the shores of Lake Baikal. big variations in the thickness. Within the rift zone the thickness of the crust varies from 35 km (the deepest part of The water temperature in Lake Baikal, which is the greatest the Baikal depression) up to 50 km (mountain framing of the accumulator of fresh water in the world, shows seasonal Tunka depression). Sharp changes (by 8-10 km) frequently changes only in the uppermost layer up to the depth of 200- occur on small (15-20 km) distances. The earth's crust tends 250 meters. The underlying layers from 250 m to the bottom to thin out under large depressions as compared with areas demonstrate a slightly slow decrease of temperature. directly adjoining mountain ridges (Zorin, 1971, Puzyrev et al., 1974). 2 Dorofeeva, Popov and Stennikov The thickness of the earth's crust in southern areas of the rocks, occurring under beds of constantly flowing rivers and Siberian platform varies from 38-41 km. The reflecting under large water reservoirs. border, which can be conventionally considered as Conrad’s interface is found at the depth of 19-20 km. The thickness of Thus, temperature conditions of upper horizons of the the so-called “granite layer”, the roof of which is the earth’s crust result from the depth of the occurrence of the crystalline basement of the platform amounts to about 15-17 neutral layer, presence or absence of permafrost rocks, the km. This layer most likely, consists of acid magmatic permafrost rock thickness, intensity of the water exchange, formations (granites, granodiorites) and metamorphic rocks dissection of the relief and slope exposition. It should be (granite-gneisses and related rocks). “The basalt” layer, noted that when we determined the values of the geothermal occurring in the lower part of the earth’s crust is 20 km thick parameters the zone of climatic influence was mostly and is composed probably of rocks similar in composition to excluded from calculations or corresponding corrections gabbro and diorites. were added. The deepest borehole on the southwest shore of Lake Baikal As far as the western shore of Lake Baikal is concerned, the is the Listvinichnoe-2 borehole (L-2). The borehole L-2 is borehole located in the Listvinichnoe settlement, near the located in Listvyanka settlement, on the western shore of source of the Angara River was thoroughly studied. It was Lake Baikal, on the right bank of the Angara River source. 1163 m deep and penetrated the Archean crystalline rocks, The range of measured temperature in this borehole exceeds which are regionally metamorphosed in conditions of the 1000 meters (coordinates 51-50 N, 104-53 E, altitude 562, granulite facies and are subjected to the affect of date of temperature measurement is 1967) metamorphic processes magmatization and granitization (Table 3).