Geothermal Conditions for the Usage of Heat Pumps in Eastern Siberia

Proceedings World Geothermal Congress 2005 Antalya, Turkey, 24-29 April 2005

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). Table 3 shows the measured temperatures in 4.1. TEMPERATURE OF ROCKS FROM THE borehole L-2 marked by red. NEUTRAL FIELD In the upper part of the L-2 borehole one can observe the The layer of seasonal temperature variations for the area temperature decrease by almost 1oC to the depth of 30-35 m under study, where permafrost does not appear, is 10-20 m o as compared with the temperature at the depth of 5 m. It is on average and the temperature at this depth is close to 0 C. most likely that up to this depth the cooling effect of Lake However, in the permafrost zone the depth of neutral layer Baikal and cold surface water penetrating the borehole occurrence increases to 30-60 m. So, the temperature at its through the fissure zone still have the impact. From the bottom decreases (Table 2). depth of 35 meters there is a gradual increase in the temperature, which amounts to 29 oC at the hole’s bottom In the zone of the continuous occurrence of permafrost rocks (Fig 2a). In the range from 0 to 260 m there are 4 points of one can observe local taliks, found mainly in the tectonic actual temperature measurement. When extrapolating the dislocations, particularly in those which, lead the thermal diagram on the present surface the temperature is underground water to the surface, as well as in well filtered close to 3 oC (Fig. 2 b).

Table 2. Temperature of rocks at the depth of the neutral layer

Area with Depth of Tempera- Depth of permafrost rock Area characteristics Sites occurrence of the ture, neutral layer occurrence zero isotherm, m oС Island Sporadic islands South-west shore of Less than 10-25 m, occurrence with the thickness Lake Baikal, basin of frequently is not 5-10 0 of 50 m Selenga River available

Central part of the

Big and Small Khamar-Daban, north-east shore of

Lake Baikal, eastern 25-50, part of Ulan-Burgasy, Khorinsk and in cases 10-20 -1, –0 Transitional Thickness of Tsagan-Khurtai 30-70 from island to frozen ground is Ridges, Tugnui continuous 50-100 m, taliks on depression

slopes of the South-east offshoots southern exposition of the Eastern Sayan 10-15 -1,-3 and under large and Khamar-Daban, 60-120 reservoirs central and west parts of the Barguzin ridges, North-Eastern part of Uda depression

3 Dorofeeva, Popov and Stennikov

Table 3. Geothermal parameters of borehole L-2

Borehole Geothermal parameters Depth interval of Temperature, оС measured Geothermal Rock heat Heat flow, temperature, m 150 m 1000 m gradient,10-3 conductivity, mW/m2 оС/m W/mK

L-2 22.4 (23.7) 2.23 50-54 35-1163 6.34 25.68

Fig. 2. Thermal diagrams of borehole L-2A- total, B – for depth 30-260 m

The lowest values of the geothermal gradients are common corrections to the above value resulting from recent to the lower section of the sequence (below 800 m). This glaciations of Lake Baikal shores, the cooling effect of the section contains predominant granitization gneisses. The lake’s water and difference in surface temperature in the off- average geothermal gradient of this horizon is 21.6 mK/m. shore zone. Our calculations indicate that the average The upper part of the sequence contains granitized and normalized value of the measured heat flow in L-2 borehole migmatized rocks of the granulite facies (magmatites, amounts to 50 mW/m2. However, if corrections due to the agmatites, skarns, pegmatites, granites). The geothermal effect of the relief and contrast of the heat conductivity are gradient in this section changes on average up to 22.6 entered the heat flow increases up to 53 mW/m2. mK/m. 4.2. TEMPERATURES AT THE DEPTH OF 150 AND Variations of gradient are due to changes in heat-physical 1000 M features of rocks and the degree of the jointing. At depth of 1 km in the south of the Siberian platform the о The data by E.A. Lyubomova (1968) show that the heat flow measured temperatures vary from 14 up to 29 С (Fig. 3). 2 The calculated temperatures at the depth of 5 km reach as in the L-2 borehole reaches as high as 67 mW/m . This value о includes both the actual heat flow equal to 47±5 and much as 40-118 С. On abnormal sites they exceed 80-100 оС (Lysak, Dorofeeva, 1997).

4 Dorofeeva, Popov and Stennikov

Fig. 3. Temperature in southern part of East Siberia on depth 1 km. Isotherms: (оС): 1 – real; 2 – forecast.

The distribution of the heat flow and depth temperatures is 4.3. HEAT FLOW caused mainly by geological-structural features of the sedimentary cover and related heterogeneities in the heat- In southern regions of the Siberian platform the physical section as well as heat transfer in the Angara-Lena determinations in 64 deep boreholes demonstrate the artesian basin. In recharging areas of this basin (i.e. on variations of the heat flow from 21 up to 60 mW/m2. Its average value is 38 ± 4 mW/m2. A rather intensive removal marginal uplifts) the heat flow and temperatures are much 2 lower as compared to the centers of discharging of brines on of heat (45 ± 6mW /m ) is observed in arched parts of salt domes (Lysak, 1968). Rather low values of the regional anticlinal structures and the saline domes complicated by heat flow indicate tectonic stability in the southern areas of tectonic dislocations. A low heat flow is common to the Nepsky arch (28 ± 5 mW/m2) and marginal uplifts (24 ± 4 the Siberian platform which can be counted on as a steady 2 geothermal regime. mW/m ).

In the Baikal Rift Zone at the depth of 1 km the rift In the Baikal Rift Zone (BRZ) the heat flow is rather non- о uniform, as its values vary from 15-20 up to 100-200 depressions are outlined by 20 С isotherm. Within those 2 contours the temperature reach as much as 37-56 оС in the mW/m and higher. Moreover, this range of values is Tunka, 33-55 оС - in the Selenga, and 22-66 оС - in the common to the Baikal depression. It almost always exceeds 50 mW/m2. An abnormally increased removal of the heat Barguzin depressions. At the depth of 5 km the rift zone is 2 marked by 60 оС isotherm, while rift depressions are (more than 100-200 mW/m ) occurs only on separate sites - outlined by 70 and 100 оС isotherms. Within those borders in zones of faults, being usually elongated along the shore of the lake. Extreme values of the heat flow (more than 200- there is a probable increase of the temperatures up to 120- 2 150 оС in the Tunka and Barguzin depressions, i.e. rift 3000 mW/m ) are found in local centers of discharge of depressions are much stronger heated as opposed to their fissure hydrotherms at the bottom of the lake. The average folding framing. value of the heat flow, except for extreme values, is equal to 71 ± 21 mW/m2 (Golubev, 1993).

5 List Dorofeeva, Popov and Stennikov

The determinations in 29 boreholes drilled in the folding Totally 73% of all heated buildings in the region have the framing of rift depressions show the average heat flow of 40 central heating. In big cities this value constitutes about 87% mW/m2. The lowered values of the heat flow here are due to while in districts 40%. With regard to the living-space these the redistribution of heat and removal of the convective values are about 70, 86 and 36%, respectively. share of flow into floor depressions. In total 64 % of the population of the Region are supplied 5. CURRENT STATE OF ENERGY CONSUMPTION with hot water, in cities this value is reaches 82 %, while in AND ITS OUTLOOK outlying districts its about 29 %. The power system of JSC “Irkutskenergo” supplies over 95 The calculated temperature of the room air is accepted to be % of central electrical power. The basic consumers of +20 oС. Specific consumption of heat for hot water supply in electric power in the Irkutsk Region are the large industrial accordance with russian standards is 629 kcal/h per person, plants (66 %) and wholesale consumers-sellers (9.5 %). The which corresponds to the temperature of hot water (55oС), aluminum plants (Bratsk and Irkutsk) are greatest consumers temperatures of cold water in winter (5 oС) and in summer of electric power (47.5 %) (Fig.4). (15 oС) as well as the duration of water delivery during the year, which is equal to 350 days.

The comparison of the specific annual heat consumption per 1 m2 of the heated floor space in cities and districts demonstrates that often for areas with low outside air temperature this specific index appears to be less than for southern areas with less cold climate. For example for Slyudyanka it is 0.648 Gcal/m2 year, for Irkutsk 0.593. This apparent mismatch is compensated by building houses in the northern areas using heat-resistant constructions and material.

The total amount of heat consumption by the housing- communal sector of the region without regard for heat losses in grids and by customers appears to be about 25700 thousand Gcal per year. About 87 % is necessary for heating, and about 13% is required for the hot water supply. The large cities consumed 65% of the total heat consumption. About 69 % of heat is consumed from grids of centralized heat supply and about 31% is consumed from heating stoves.

The share of heating in the centralized heat supply makes up about 80%. The centralized heat supply of cities has the similar portion in the total heat consumption. The total heat consumption of the centralized heat supply from thermoelectric power station (including the boilers of JSC "Irkutskenergo”) constitutes a little bit over 10,000 thousand Fig. 4. Principal scheme of electric power grids of the Gcal (45%)annually. Energy from electric boilers made up Irkutsk Region. 4,370 thousand Gcal (19.5%); and that from boiler-house working on the organic combustible it almost 8,000 thousand The basis of municipal thermal energetic in the Region are Gcal (about 35.5%). the small boilers constructed in 1950-1960’s and heat supply systems, which were put into operation predominantly The heating season lasts from 8 months in the south up to 10 in1960-1970’s. Those boilers and heat supply systems have and more months in the north. Table 4. gives the outside air not been completely substituted by newer ones. temperature during the heating period for the areas located close to Irkutsk city. The actual efficiency of boilers is 50-60 %. However, documentation states that the efficiency of the boilers should The maximal temperature of the supplied heat carrier in the make up 75-80 %. heating system is taken as 95oС, and the returned one is 70˚С. These temperatures are maintained at calculated and In accordance with acting standards three categories of lower temperatures of outside air. At higher temperatures of buildings are distinguished in terms of heat consumption: 1- the outside air they will decrease. 2-storey, 3-4-storey, 5 and more storey. The heating season starts at the temperature of the outdoor The analysis of the statistical information demonstrates that air equal to + 8 oС. In the summer the heating is switched 84 % of the population of the region lives in urban off. The temperature of hot water given for household settlements - cities and settlements of urban type (SUT), 16 requirements should not be lower than 55 oС. % of people live in rural areas.

6 Dorofeeva, Popov and Stennikov

Table 4. Duration of outside air temperature for the heating period -40 and Temperature, ˚С -35 -30 -25 -20 -15 -10 -5 0 +8 lower Duration, hours 7 58 172 458 864 1730 2600 3300 4320 5780

The main features, which are to be considered when The specific consumption of water per person in the Irkutsk reconstructing the heat supply are the following: Region is 307 l/day; 2.737 million m3 of water passes through the centralized water supply system per day (that in 1. relatively high temperature 95 oС for applying calculation per inhabitant makes 1.5 м3 of water per day). non-traditional heat sources including GHP heating systems; There are totally 82 cities and settlements of urban types in the Irkutsk Region. About 2098 thousand people live there. 2. small surface of heating instruments to provide the There are 33 administrative districts (with the population of demanded heat emission at low temperatures of 576 thousand people). heat carrier; REFERENCES 3. one-pipe heating system which does not permit individual regulation; Golubev V.A., Klerkx I., Kipfer R. // Heat flow, hydrothermal vents and static stability of discharging 4. lack of automatics and the regulation restrict the thermal water in Lake Baikal (South-Eastern Siberia) // opportunities of system reconstruction; BCREDP Elf Aquitaine. - 1993. - V. 17, № 1. - Р. 53- 65. 5. combining of heating systems and systems of hot water supply provide specific features for Lysak S.V. Geothermics of the Baikal region // Geology and implementation of new engineering solutions; Geophysics. – 1968. - № 9. – P. 16-21.

6. open system, independent scheme require special Lysak S.V., Dorofeeva R.P. Geothermal regime of upper approaches and solutions. horizons of the earth’s crust in south areas of the Eastern Siberia // Doklady of Academy of Sciences. – The constructing of heat supply systems in the Irkutsk 1997. - V. 352, № 3. - P. 405-409. Region in many respects differs from other countries, which it is necessary to consider when reconstructing systems. Lyubimova E.A. Thermal regime of the Earth and Moon. M.: Nauka - 1968. – 279 p. 6. WATER SUPPLY AND WATER DELIVERY 3 Pyzerev N.N., Mandel’baum M.M., Krylov S.V. et al. Deep The water resources making up 175-180 km are available structure of the Baikal rift using the data on explosion annually in the area of the Irkutsk regions. 135-140 km3 is 3 seismology // Geology and Geophysics. – 1974. - № 5. brought from outside the Region and 310 km flows out. – P. 155-167. Less than 1 % (approximately 1.5 billion m3) of those 3 resources is used in industry. It includes 316 million m for Zorin Yu. A. Recent structure and isostasy of the Baikal Rift 3 household-communal needs, 1175 million м for Zone and adjacent areas. M.: Nauka. - 1971. – 168 p. manufacturing, 4 million м3 for irrigation, 45.5 million m3 for water supply of the agriculture.