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Low enthalpy geothermal energy utilisation schemes for greenhouse and district heating at Traianoupolis Evros, Greece
Geothermics 32 (2003) 69–78 www.elsevier.com/locate/geothermics
Low enthalpy geothermal energy utilisation schemes for greenhouse and district heating at Traianoupolis Evros, Greece Constantine Karytsasa,*, Dimitrios Mendrinosa, Johann Goldbrunnerb a
Geothermal Department, Centre for Renewable Energy Sources, 19th km Marathon Ave, Pikermi-Attica, Greece b Technical University of Graz, Rechsbauer Strasse 12, 8010 Graz, Austria Received 15 May 2002; accepted 7 August 2002
Abstract A socio-economic study has been made of the possible use of low enthalpy geothermal resources for district and greenhouse heating in the Traianoupolis Evros region. The thermal energy potential of the Aristino-Traianoupolis geothermal field has been estimated at 10.8 MWth (discharge temperature of 25 C). Geothermal wellhead water temperatures range from 53 to 92 C, from 300 m deep wells yielding over 250 m3/h. Our conclusions show, amongst the different scenarios examined and on the basis of a market study, that utilisation of this geothermal energy capacity for district heating of nearby villages, and/or greenhouse heating directed at serving local vegetable markets, would be an attractive investment. # 2002 CNR. Published by Elsevier Science Ltd. All rights reserved. Keywords: Geothermal investments; District heating; Greenhouses; Greece
1. Introduction This study demonstrates the positive technical and financial aspects of utilising geothermal energy in a form that has a direct impact on a region by increasing its per capita income and at the same time, improving the standard of living of its inhabitants. An additional benefit of such a project is the reduction in the environmental * Corresponding author. Tel.: +30-1-0660-3375; fax: +30-1-0660-3301. E-mail address: [email protected] (C. Karytsas). 0375-6505/03/$30.00 # 2002 CNR. Published by Elsevier Science Ltd. All rights reserved. PII: S0375-6505(02)00051-2
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effects that may accompany the utilisation of conventional fuels. The study has been financed by the European programme ‘‘Energy Planning at a Regional and Urban Level of DG XVII’’ (XVII/4.1040/93-022) (Karytsas et al., 1996).
2. Context This technical and economic feasibility study focuses on a proposal to utilise a new, environmentally clean, thermal energy source (i.e. geothermal energy) for district and greenhouse heating in the region of Traianoupolis Evros (see Fig. 1). The latter region was chosen for this study on the basis of the following: The region is one of the coldest in Greece (average minimum outside temperature of 7 C during the winter period, National Meteorological Survey, 1993), resulting in a relatively high level of energy consumption for house heating (49,392 degree-hours when the desired internal air temperature is equal to 20 C). The geothermal field lies between the villages of Aristino, Aetochori and Loutros, Karytsas 1991; Karytsas et al., 1996 (see Fig. 1). Since this is a rural region there is a need for economic development and improvements to the standard of living of the population in the area.
Fig. 1. Map of the study area. The geothermal field is located between the villages of Aetochori, Aristino and Loutros, approximately 3–5 km E and NE of the airport of Alexandroupoli.
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3. Geological background The Traianoupolis region belongs to the Circum Rhodope Belt, which is considered the most central geotectonic belt of the Greek geotectonic zones. The Alpine formations of the Circum Rhodope Belt consist of Permo-Triassic and Jurassic rocks, which have been trangressively placed on the old crystalline core of the Rhodope Belt Massive (see Fig. 1). All Alpine formations are meta-sediments metamorphosed up to the greenschist metamorphose stage. The meta-Alpine sediments of the region are characterised by a Molassic clastic series (Eocene-Oligocene) consisting of conglomerates, clayish marls, nummulitic marly limestones, and sandstones (Lalechos, 1986). The volcanic formations of the region are rhyolites, andesites, and dacites of Eocene-Oligocene age (coeval with the active plutonism that occurred in the main Rhodope Massive to the west) (see Fig. 2). The geological formations in the study region are, from the youngest to the oldest, as follows: Lower terrace system (Pleistocene): Terrestrial red sand-to-clayey sand with alternations of bedded pebbles and gravels or dispersed, without clayey cover. They are located 20 to 30 m above the present riverbank level. Occasionally cross-bedding may be encountered. These formations are very thin and are scarcely encountered. Sediments of the Oligocene: Sandstones, clays, clayey marls, and marly limestones, encountered at the formation base.
Fig. 2. Schematic geological cross-section of the study area.
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Sandy-marly pyroclastics (Priabonian/Oligocene): The pyroclastics are tuffs to tuffites of intermediate volcanism, in banks, beds or partly unbedded, as ignimbrites, agglomerate or lapilli, altered, with sheet-like silicates (sericite, chlorite and illite), dispersed ferrous hydroxides and pyrite. In the stratigraphical sense these pyroclastics serve as a key horizon, the base of the Priabonian, pinpointing the transitive horizon between Priabonian and Oligocene. Dacites/Dacitoid andesites (Priabonian): Light brown, compact to porous in volcanic domes, dykes and beds of submarine extrusions and as pillow lavas. Propylitization, sericitization and recrystallization of the ground mass to secondary quartz and albite. Characteristic alteration to NNW–SSE, NNE– SSW tectonic directions with kaolinization, silicification and mineralization. Andesites (Lutetian-Priabonian-Oligocene): Dark-coloured, compact, in domes, dykes and pipes. Holocrystalline to subcrystalline groundmass. Columnar jointing.
4. Results According to the present study the geothermal field of Aristino-Traianoupolis could yield a total thermal power of over 10 MWth (discharge temperature of 25 C) from four productive boreholes with temperatures from 53 to 92 C, with a total proven aggregate yield of 257 m3/h (see Table 1) (Karytsas et al., 1996). The chemistry of the fluid is presented in Table 2. Since the area is in the vicinity of a protected RAMSAR Treaty zone (Evros River Delta), it is highly recommended indeed that geothermal fluid reinjection be adopted. 4.1. Greenhouse heating Utilising the entire geothermal capacity, together with a fuel-fired back-up system (designed to cover peak thermal demands and eventual breakdown of the geothermal system), approximately 70,000 m2 of glass geothermal greenhouses for tomato Table 1 Characteristics of the boreholes and their geothermal power potentiala Well
Depth (m)
Diameter (mm)
Static water level (m)
Flow rate (m3/h)
Temperature ( C)
Ko E P Evros-III
118 48 42 252
168.3 360 380 168.3
11.3
17 110 90 40
82 54 53 92
8.5
Total a
Water discharge temperature T=25 C.
257
Thermal power potential (kW) 1100 3700 2900 3100 10,800
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crops could be installed, or, alternatively, 55,000 m2 glass geothermal greenhouses for cucumber crops (see Tables 3 and 4). Of course, intermediate scenarios of different cultivation types or cover materials can also be envisaged, provided that the total energy demand equals the optimal geothermal field capacity. However, the economic feasibility and market study applied to the wider region of Evros Prefecture concludes that a total of 35,000 m2 of glass tomato-crop geothermal greenhouses and 25,000 m2 of glass cucumber-crop geothermal greenhouses could be developed together most profitably, covering the domestic market requirements of the Prefecture of Evros. Development of these geothermal greenhouses will lead to a savings of 2325 tonnes of oil equivalent (TOE) per year (1 TOE is equal to 8,000,000 kcal), will provide at least 60 new jobs, will reduce CO2 emissions by 7440 tons annually and will provide the owners with an energy savings of US $930,000 (per year) relative to diesel oil per year. 4.2. District heating The geothermal district heating study concludes that the heating demands of all three municipalities of the region (Aristino, Anthia and Loutros) can be met entirely Table 2 Geothermal fluid chemistry Well Koa pH TDS, ppm Chemical species Na K Ca Mg Cl HCO3 SO4 NO3 B Cu SiO2 Fe Zn Al Li Mn Sr NH4 F PO4 a b
7.8 10,070 mg/l 2977 163.5 636.6 16.8 5571 109.8 528.6 2.5
84.7 0.2 1.1 0 3.8 1.7 14.3 5.1 2.8 0.2
Source: Centre for Renewable Energy Sources (CRES). Source: Geotek ltd—Greece.
Well Evros-IIIb 5
mg/l 2003 87.8 880 20.5 4500 27 776 <0.06 <0.005 <10 50 712
7.5
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by a geothermal district heating system. The total heating demand of the 1049 dwellings is 9.98 MWth and the annual energy savings achieved with this system amounts to 1847 TOE/year and an annual reduction of 5910 tons of CO2) (see Table 5).
5. Evaluation of investments The most likely scenarios, in that they are the most feasible direct utilisation schemes in the region, are summarised in Table 6 and described below.
Table 3 Annual energy savings (TOE/1000 m2) Crop type
Optimum temperature ( C)
Cover material
Annual energy demand (106 kcal/1000 m2)
Annual energy savings (TOEa/1000 m2)
Crop A (tomatoes)
14
Glass PVC
231 285
29 36
Crop B (mixed crop)
16
Glass PVC
313 387
39 48
Crop C (cucumber)
18
Glass PVC
403 506
51 63
a
1 TOE=8,000,000 kcal.
Table 4 Total area of greenhouses according to borehole characteristics Crop type
Optimum temperature ( C)
Crop A (tomatoes)
Cover material
Back-up system
Total greenhouse area (1000 m2)
Glass
Without With Without With
40 70 35 60
Without With Without With
35 60 30 55
Without With Without With
35 55 30 45
14 PVC
Crop B (mixed crop)
Glass 16 PVC
Crop C (cucumber)
Glass 18 PVC
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5.1. Scenario 1: district heating only This scenario is based on a more socially oriented and government-funded policy, giving emphasis to district heating and with no agricultural uses of the geothermal energy. On the basis of this scenario, heating of the 1049 dwellings, in Aristino, Anthia and Loutros, will require 9.98 MWth or 94.3% of the available total geothermal power. If this scenario is developed, a total of 1847 TOE/year will be saved, leading to a reduction in CO2 emissions of 5910 tons annually. The municipalities may also benefit by approximately US $300,000 per year through net cash flow, in that the resulting district heating cost would correspond to 40% of current oil prices (i.e. 1 TOE=US $160, or E160). The total initial investment cost for this first scenario is estimated to be in the order of US $3,400,000, of which US $600,000 are for the primary geothermal loop and the remaining US $2,800,000 for the secondary district heating system (Table 7). Based on this more socially oriented scenario, 75% of this initial investment, or US $2,550,000, would come from governmental funding to the municipalities and 25% or US $850,000, from municipalities, own sources (Table 7). Hence, the amount that the municipalities would have to amortise is US $850,000 (Table 7).
Table 5 Annual energy consumption, energy savings and reduction in CO2 emissions Municipalities (annually)
Aristino
Anthia
Loutros
Total
Number of dwellings Total thermal demand (MWth) Energy consumption (109 kcal) Energy savings (TOE) Reduction in CO2 emissions (ton) Energy savings (000 US $)a
198 1.90 2.8 352 1126 140.8
373 3.53 5.2 655 2096 262
478 4.55 6.7 840 2688 336
1049 9.98 14.7 1847 5910 738.8
a
1 TOE=US $400, or E400.
Table 6 Scenarios for geothermal energy exploitation in the study area District heating (number of dwellings)
Greenhouses (1000 m2)
Annual energy savings TOE
Annual reduction in CO2 emissions (ton)
Scenario 1
1049
None
1847
5910
Scenario 2
571
Tomato (35) or cucumber (25)
2018
6458
Scenario 3
0
Tomato (35) and cucumber (25)
2325
7440
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5.2. Scenario 2: 50% district heating and 50% agricultural applications In the case of an intermediate socio-economic development, where equal weight is given to improving the standard of living and to the agricultural development of the area, then an intermediate scenario may be adopted (Scenario 2). Therefore, heating of the village of Anthia (571 buildings in Anthia and Aristino; 5.43 MWth or 51.3% of the geothermal power available) is accompanied by the development of 35,000 m2 of glass tomato-crop geothermal greenhouses or, equivalently approximately 25,000 m2 of glass cucumber-crop geothermal greenhouses (5.15 MWth or 48.7% of the geothermal power available). With this scenario the savings are 2018 TOE per year, which will lead to a reduction in CO2 emissions of 6458 tons annually. The total initial investment cost for this scenario (Case 2) is estimated to be in the order of US $3,600,000, of which US $600,000 are for the primary geothermal loop, equally distributed among the district heating and greenhouse applications, as shown in Table 7. Of the remainder, US $1,600,000 are allocated to the secondary district heating system and US $1,400,000 are for the greenhouse construction and their secondary heating loop (Table 7). Based on this scenario, 75% of the initial investment for district heating, or US $1,425,000, would come from governmental funding to the municipalities, and 25%, or US $475,000, from the municipalities, own sources (Table 7). For the remaining US $1,700,000 corresponding to the greenhouses, 30%, or US $510,000, will be derived from government regional development grants and 70%, or US $1,190,000, from the greenhouse owners’ own sources (Table 7). Therefore, in this scenario a total of US $1,935,000 (or 53.8%) will come from government funds or grants and US $1,665,000 (or 46.2%) from the municipalities’ own sources or private funds. Hence, the initial investment that the municipalities have to amortise for district heating is US $475,000, while the greenhouse owners have to amortise US $1,190,000 (Table 7). It has however been estimated that the net cash flow from the provision of geothermal heat will correspond to US $600,000/year for the greenhouses and US $150,000/year for district heating.
Table 7 Financial breakdown (capital costs, funding, profits) per scenario Amounts in US $ (or E) Primary loop District heating Greenhouses Total Govern. funding Own funds Annual profits
Scenario 1 District heating 600,000 2,800,000 – 3,400,000 2,550,000 850,000 300,000
Scenario 2
Scenario 3 Greenhouses
District heating
Greenhouses
300,000 1,600,000 – 1,900,000 1,425,000 475,000 150,000
300,000 – 1,400,000 1,700,000 510,000 1,190,000 600,000
600,000 – 2,400,000 3,000,000 900,000 2,100,000 1,250,000
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5.3. Scenario 3: agricultural applications only A more vigorous developmental policy is that in which the entire geothermal power available is devoted to greenhouse heating to meet at least the domestic market requirements of the Prefecture of Evros (Scenario 3). This scenario provides the user with clear revenue profits of at least US $1,250,000 per year. The total initial investment cost for this third scenario is estimated to be in the order of US $3,000,000, of which US $600,000 would be allocated to the primary geothermal loop and the remaining US $2,400,000 to the greenhouse construction and their secondary heating loop, as shown in Table 7. Based on this scenario, 30% of the initial investment, or US $900,000, would come from government development grants and 70%, or US $2,100,000, from private sources (see Table 7). Hence, the amount that the greenhouse owners have to amortise is US $2,100,000 (Table 7). 5.4. Results The economic analysis, in terms of Net Present Value (NPV), Internal Rate of Return (IRR) and Simple Payback, based on 5% cost of money and a 25-year lifespan of the investment, is summarised in Table 8. Assuming a 25-year lifespan of the investment, 5% cost of money, and 5% and 2.5% of initial capital investment, annual operation and maintenance costs for the district heating and the greenhouses, respectively, the cost of energy delivered to the customers has been estimated at US $0.024 per kWh for scenario 1 (district heating) and 0.013 per kWh for scenario 3 (greenhouse heating). When government support is subtracted from the capital costs these figures drop yo US $0.013 per kWh and US $0.010 per kWh, respectively. It is however evident that geothermal district heating in the area is marginally profitable with no government support, but becomes an attractive investment when government funds are taken into consideration. On the other hand, greenhouse heating with geothermal energy is a very attractive investment with or without government funding. Table 8 Investment appraisal per scenario Government support
NPV US $ (or E)
IRR (%)
Simple payback years
Energy costs US $/kWh (or E)
Scenario 1 District heating
No Yes
+828,000 +3,378,000
7.3 35.2
12 3
0.024 0.013
Scenario 2 District heating
No Yes
+214,000 +1,639,000
6.1 31.5
13 4
0.025 0.014
Scenario 2 Greenhouses
No Yes
+6,756,000 +7,266,000
35.2 50.4
3 2
0.017 0.014
Scenario 2 Greenhouses
No Yes
+14,617,000 +15,517,000
41.6 59.5
3 2
0.013 0.010
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6. Recent developments Geothermal energy has been utilised in the region for the past 3 years for domestic hot water production and space heating in the hotel of the Traianoupolis spa complex, 5 km east of the airport on the main highway. The geothermal heating system comprises one production and one reinjection well, a plate heat exchanger and buried polypropylene transmission piping for the primary geothermal loop, as well as buried polypropylene transmission piping, sub-floor heating and flow regulating valves for the district heating of the six buildings forming the spa hotel. The total energy requirement, amounting to 1 MWth approximately, is covered by the geothermal fluids produced from one of the wells listed in Table 1.
References Karytsas, C. 1991. The technical and economic context of low temperature geothermal energy development in Greece. In: Seminaire pour la Formation a la Geothermie Applique´, BRGM-IFE-AFME, December 1991, Meaux, France, p. 9. Karytsas, C., Kanavakis, G., Zarkadoula, M., Choustoulakis, P., Peroglou, G., 1996. Technical and Financial Feasibility Study for District Heating and Greenhouse Heating with Geothermal Energy at Aristino Evros. CRES—DG-XVII, Contract No: XVII/4.1040/93-022. Lalechos, I., 1986. Correlation and observations in Molassic sediments in onshore and offshore areas of Northern Greece. Mineral Wealth 42, 7–34. National Meteorological Survey, 1993. Climatological Data from Alexandroupolis Airport.
Low enthalpy geothermal energy utilisation schemes for greenhouse and district heating at Traianoupolis Evros, Greece Constantine Karytsasa,*, Dimitrios Mendrinosa, Johann Goldbrunnerb a
Geothermal Department, Centre for Renewable Energy Sources, 19th km Marathon Ave, Pikermi-Attica, Greece b Technical University of Graz, Rechsbauer Strasse 12, 8010 Graz, Austria Received 15 May 2002; accepted 7 August 2002
Abstract A socio-economic study has been made of the possible use of low enthalpy geothermal resources for district and greenhouse heating in the Traianoupolis Evros region. The thermal energy potential of the Aristino-Traianoupolis geothermal field has been estimated at 10.8 MWth (discharge temperature of 25 C). Geothermal wellhead water temperatures range from 53 to 92 C, from 300 m deep wells yielding over 250 m3/h. Our conclusions show, amongst the different scenarios examined and on the basis of a market study, that utilisation of this geothermal energy capacity for district heating of nearby villages, and/or greenhouse heating directed at serving local vegetable markets, would be an attractive investment. # 2002 CNR. Published by Elsevier Science Ltd. All rights reserved. Keywords: Geothermal investments; District heating; Greenhouses; Greece
1. Introduction This study demonstrates the positive technical and financial aspects of utilising geothermal energy in a form that has a direct impact on a region by increasing its per capita income and at the same time, improving the standard of living of its inhabitants. An additional benefit of such a project is the reduction in the environmental * Corresponding author. Tel.: +30-1-0660-3375; fax: +30-1-0660-3301. E-mail address: [email protected] (C. Karytsas). 0375-6505/03/$30.00 # 2002 CNR. Published by Elsevier Science Ltd. All rights reserved. PII: S0375-6505(02)00051-2
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effects that may accompany the utilisation of conventional fuels. The study has been financed by the European programme ‘‘Energy Planning at a Regional and Urban Level of DG XVII’’ (XVII/4.1040/93-022) (Karytsas et al., 1996).
2. Context This technical and economic feasibility study focuses on a proposal to utilise a new, environmentally clean, thermal energy source (i.e. geothermal energy) for district and greenhouse heating in the region of Traianoupolis Evros (see Fig. 1). The latter region was chosen for this study on the basis of the following: The region is one of the coldest in Greece (average minimum outside temperature of 7 C during the winter period, National Meteorological Survey, 1993), resulting in a relatively high level of energy consumption for house heating (49,392 degree-hours when the desired internal air temperature is equal to 20 C). The geothermal field lies between the villages of Aristino, Aetochori and Loutros, Karytsas 1991; Karytsas et al., 1996 (see Fig. 1). Since this is a rural region there is a need for economic development and improvements to the standard of living of the population in the area.
Fig. 1. Map of the study area. The geothermal field is located between the villages of Aetochori, Aristino and Loutros, approximately 3–5 km E and NE of the airport of Alexandroupoli.
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3. Geological background The Traianoupolis region belongs to the Circum Rhodope Belt, which is considered the most central geotectonic belt of the Greek geotectonic zones. The Alpine formations of the Circum Rhodope Belt consist of Permo-Triassic and Jurassic rocks, which have been trangressively placed on the old crystalline core of the Rhodope Belt Massive (see Fig. 1). All Alpine formations are meta-sediments metamorphosed up to the greenschist metamorphose stage. The meta-Alpine sediments of the region are characterised by a Molassic clastic series (Eocene-Oligocene) consisting of conglomerates, clayish marls, nummulitic marly limestones, and sandstones (Lalechos, 1986). The volcanic formations of the region are rhyolites, andesites, and dacites of Eocene-Oligocene age (coeval with the active plutonism that occurred in the main Rhodope Massive to the west) (see Fig. 2). The geological formations in the study region are, from the youngest to the oldest, as follows: Lower terrace system (Pleistocene): Terrestrial red sand-to-clayey sand with alternations of bedded pebbles and gravels or dispersed, without clayey cover. They are located 20 to 30 m above the present riverbank level. Occasionally cross-bedding may be encountered. These formations are very thin and are scarcely encountered. Sediments of the Oligocene: Sandstones, clays, clayey marls, and marly limestones, encountered at the formation base.
Fig. 2. Schematic geological cross-section of the study area.
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Sandy-marly pyroclastics (Priabonian/Oligocene): The pyroclastics are tuffs to tuffites of intermediate volcanism, in banks, beds or partly unbedded, as ignimbrites, agglomerate or lapilli, altered, with sheet-like silicates (sericite, chlorite and illite), dispersed ferrous hydroxides and pyrite. In the stratigraphical sense these pyroclastics serve as a key horizon, the base of the Priabonian, pinpointing the transitive horizon between Priabonian and Oligocene. Dacites/Dacitoid andesites (Priabonian): Light brown, compact to porous in volcanic domes, dykes and beds of submarine extrusions and as pillow lavas. Propylitization, sericitization and recrystallization of the ground mass to secondary quartz and albite. Characteristic alteration to NNW–SSE, NNE– SSW tectonic directions with kaolinization, silicification and mineralization. Andesites (Lutetian-Priabonian-Oligocene): Dark-coloured, compact, in domes, dykes and pipes. Holocrystalline to subcrystalline groundmass. Columnar jointing.
4. Results According to the present study the geothermal field of Aristino-Traianoupolis could yield a total thermal power of over 10 MWth (discharge temperature of 25 C) from four productive boreholes with temperatures from 53 to 92 C, with a total proven aggregate yield of 257 m3/h (see Table 1) (Karytsas et al., 1996). The chemistry of the fluid is presented in Table 2. Since the area is in the vicinity of a protected RAMSAR Treaty zone (Evros River Delta), it is highly recommended indeed that geothermal fluid reinjection be adopted. 4.1. Greenhouse heating Utilising the entire geothermal capacity, together with a fuel-fired back-up system (designed to cover peak thermal demands and eventual breakdown of the geothermal system), approximately 70,000 m2 of glass geothermal greenhouses for tomato Table 1 Characteristics of the boreholes and their geothermal power potentiala Well
Depth (m)
Diameter (mm)
Static water level (m)
Flow rate (m3/h)
Temperature ( C)
Ko E P Evros-III
118 48 42 252
168.3 360 380 168.3
11.3
17 110 90 40
82 54 53 92
8.5
Total a
Water discharge temperature T=25 C.
257
Thermal power potential (kW) 1100 3700 2900 3100 10,800
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crops could be installed, or, alternatively, 55,000 m2 glass geothermal greenhouses for cucumber crops (see Tables 3 and 4). Of course, intermediate scenarios of different cultivation types or cover materials can also be envisaged, provided that the total energy demand equals the optimal geothermal field capacity. However, the economic feasibility and market study applied to the wider region of Evros Prefecture concludes that a total of 35,000 m2 of glass tomato-crop geothermal greenhouses and 25,000 m2 of glass cucumber-crop geothermal greenhouses could be developed together most profitably, covering the domestic market requirements of the Prefecture of Evros. Development of these geothermal greenhouses will lead to a savings of 2325 tonnes of oil equivalent (TOE) per year (1 TOE is equal to 8,000,000 kcal), will provide at least 60 new jobs, will reduce CO2 emissions by 7440 tons annually and will provide the owners with an energy savings of US $930,000 (per year) relative to diesel oil per year. 4.2. District heating The geothermal district heating study concludes that the heating demands of all three municipalities of the region (Aristino, Anthia and Loutros) can be met entirely Table 2 Geothermal fluid chemistry Well Koa pH TDS, ppm Chemical species Na K Ca Mg Cl HCO3 SO4 NO3 B Cu SiO2 Fe Zn Al Li Mn Sr NH4 F PO4 a b
7.8 10,070 mg/l 2977 163.5 636.6 16.8 5571 109.8 528.6 2.5
84.7 0.2 1.1 0 3.8 1.7 14.3 5.1 2.8 0.2
Source: Centre for Renewable Energy Sources (CRES). Source: Geotek ltd—Greece.
Well Evros-IIIb 5
mg/l 2003 87.8 880 20.5 4500 27 776 <0.06 <0.005 <10 50 712
7.5
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by a geothermal district heating system. The total heating demand of the 1049 dwellings is 9.98 MWth and the annual energy savings achieved with this system amounts to 1847 TOE/year and an annual reduction of 5910 tons of CO2) (see Table 5).
5. Evaluation of investments The most likely scenarios, in that they are the most feasible direct utilisation schemes in the region, are summarised in Table 6 and described below.
Table 3 Annual energy savings (TOE/1000 m2) Crop type
Optimum temperature ( C)
Cover material
Annual energy demand (106 kcal/1000 m2)
Annual energy savings (TOEa/1000 m2)
Crop A (tomatoes)
14
Glass PVC
231 285
29 36
Crop B (mixed crop)
16
Glass PVC
313 387
39 48
Crop C (cucumber)
18
Glass PVC
403 506
51 63
a
1 TOE=8,000,000 kcal.
Table 4 Total area of greenhouses according to borehole characteristics Crop type
Optimum temperature ( C)
Crop A (tomatoes)
Cover material
Back-up system
Total greenhouse area (1000 m2)
Glass
Without With Without With
40 70 35 60
Without With Without With
35 60 30 55
Without With Without With
35 55 30 45
14 PVC
Crop B (mixed crop)
Glass 16 PVC
Crop C (cucumber)
Glass 18 PVC
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5.1. Scenario 1: district heating only This scenario is based on a more socially oriented and government-funded policy, giving emphasis to district heating and with no agricultural uses of the geothermal energy. On the basis of this scenario, heating of the 1049 dwellings, in Aristino, Anthia and Loutros, will require 9.98 MWth or 94.3% of the available total geothermal power. If this scenario is developed, a total of 1847 TOE/year will be saved, leading to a reduction in CO2 emissions of 5910 tons annually. The municipalities may also benefit by approximately US $300,000 per year through net cash flow, in that the resulting district heating cost would correspond to 40% of current oil prices (i.e. 1 TOE=US $160, or E160). The total initial investment cost for this first scenario is estimated to be in the order of US $3,400,000, of which US $600,000 are for the primary geothermal loop and the remaining US $2,800,000 for the secondary district heating system (Table 7). Based on this more socially oriented scenario, 75% of this initial investment, or US $2,550,000, would come from governmental funding to the municipalities and 25% or US $850,000, from municipalities, own sources (Table 7). Hence, the amount that the municipalities would have to amortise is US $850,000 (Table 7).
Table 5 Annual energy consumption, energy savings and reduction in CO2 emissions Municipalities (annually)
Aristino
Anthia
Loutros
Total
Number of dwellings Total thermal demand (MWth) Energy consumption (109 kcal) Energy savings (TOE) Reduction in CO2 emissions (ton) Energy savings (000 US $)a
198 1.90 2.8 352 1126 140.8
373 3.53 5.2 655 2096 262
478 4.55 6.7 840 2688 336
1049 9.98 14.7 1847 5910 738.8
a
1 TOE=US $400, or E400.
Table 6 Scenarios for geothermal energy exploitation in the study area District heating (number of dwellings)
Greenhouses (1000 m2)
Annual energy savings TOE
Annual reduction in CO2 emissions (ton)
Scenario 1
1049
None
1847
5910
Scenario 2
571
Tomato (35) or cucumber (25)
2018
6458
Scenario 3
0
Tomato (35) and cucumber (25)
2325
7440
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5.2. Scenario 2: 50% district heating and 50% agricultural applications In the case of an intermediate socio-economic development, where equal weight is given to improving the standard of living and to the agricultural development of the area, then an intermediate scenario may be adopted (Scenario 2). Therefore, heating of the village of Anthia (571 buildings in Anthia and Aristino; 5.43 MWth or 51.3% of the geothermal power available) is accompanied by the development of 35,000 m2 of glass tomato-crop geothermal greenhouses or, equivalently approximately 25,000 m2 of glass cucumber-crop geothermal greenhouses (5.15 MWth or 48.7% of the geothermal power available). With this scenario the savings are 2018 TOE per year, which will lead to a reduction in CO2 emissions of 6458 tons annually. The total initial investment cost for this scenario (Case 2) is estimated to be in the order of US $3,600,000, of which US $600,000 are for the primary geothermal loop, equally distributed among the district heating and greenhouse applications, as shown in Table 7. Of the remainder, US $1,600,000 are allocated to the secondary district heating system and US $1,400,000 are for the greenhouse construction and their secondary heating loop (Table 7). Based on this scenario, 75% of the initial investment for district heating, or US $1,425,000, would come from governmental funding to the municipalities, and 25%, or US $475,000, from the municipalities, own sources (Table 7). For the remaining US $1,700,000 corresponding to the greenhouses, 30%, or US $510,000, will be derived from government regional development grants and 70%, or US $1,190,000, from the greenhouse owners’ own sources (Table 7). Therefore, in this scenario a total of US $1,935,000 (or 53.8%) will come from government funds or grants and US $1,665,000 (or 46.2%) from the municipalities’ own sources or private funds. Hence, the initial investment that the municipalities have to amortise for district heating is US $475,000, while the greenhouse owners have to amortise US $1,190,000 (Table 7). It has however been estimated that the net cash flow from the provision of geothermal heat will correspond to US $600,000/year for the greenhouses and US $150,000/year for district heating.
Table 7 Financial breakdown (capital costs, funding, profits) per scenario Amounts in US $ (or E) Primary loop District heating Greenhouses Total Govern. funding Own funds Annual profits
Scenario 1 District heating 600,000 2,800,000 – 3,400,000 2,550,000 850,000 300,000
Scenario 2
Scenario 3 Greenhouses
District heating
Greenhouses
300,000 1,600,000 – 1,900,000 1,425,000 475,000 150,000
300,000 – 1,400,000 1,700,000 510,000 1,190,000 600,000
600,000 – 2,400,000 3,000,000 900,000 2,100,000 1,250,000
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5.3. Scenario 3: agricultural applications only A more vigorous developmental policy is that in which the entire geothermal power available is devoted to greenhouse heating to meet at least the domestic market requirements of the Prefecture of Evros (Scenario 3). This scenario provides the user with clear revenue profits of at least US $1,250,000 per year. The total initial investment cost for this third scenario is estimated to be in the order of US $3,000,000, of which US $600,000 would be allocated to the primary geothermal loop and the remaining US $2,400,000 to the greenhouse construction and their secondary heating loop, as shown in Table 7. Based on this scenario, 30% of the initial investment, or US $900,000, would come from government development grants and 70%, or US $2,100,000, from private sources (see Table 7). Hence, the amount that the greenhouse owners have to amortise is US $2,100,000 (Table 7). 5.4. Results The economic analysis, in terms of Net Present Value (NPV), Internal Rate of Return (IRR) and Simple Payback, based on 5% cost of money and a 25-year lifespan of the investment, is summarised in Table 8. Assuming a 25-year lifespan of the investment, 5% cost of money, and 5% and 2.5% of initial capital investment, annual operation and maintenance costs for the district heating and the greenhouses, respectively, the cost of energy delivered to the customers has been estimated at US $0.024 per kWh for scenario 1 (district heating) and 0.013 per kWh for scenario 3 (greenhouse heating). When government support is subtracted from the capital costs these figures drop yo US $0.013 per kWh and US $0.010 per kWh, respectively. It is however evident that geothermal district heating in the area is marginally profitable with no government support, but becomes an attractive investment when government funds are taken into consideration. On the other hand, greenhouse heating with geothermal energy is a very attractive investment with or without government funding. Table 8 Investment appraisal per scenario Government support
NPV US $ (or E)
IRR (%)
Simple payback years
Energy costs US $/kWh (or E)
Scenario 1 District heating
No Yes
+828,000 +3,378,000
7.3 35.2
12 3
0.024 0.013
Scenario 2 District heating
No Yes
+214,000 +1,639,000
6.1 31.5
13 4
0.025 0.014
Scenario 2 Greenhouses
No Yes
+6,756,000 +7,266,000
35.2 50.4
3 2
0.017 0.014
Scenario 2 Greenhouses
No Yes
+14,617,000 +15,517,000
41.6 59.5
3 2
0.013 0.010
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6. Recent developments Geothermal energy has been utilised in the region for the past 3 years for domestic hot water production and space heating in the hotel of the Traianoupolis spa complex, 5 km east of the airport on the main highway. The geothermal heating system comprises one production and one reinjection well, a plate heat exchanger and buried polypropylene transmission piping for the primary geothermal loop, as well as buried polypropylene transmission piping, sub-floor heating and flow regulating valves for the district heating of the six buildings forming the spa hotel. The total energy requirement, amounting to 1 MWth approximately, is covered by the geothermal fluids produced from one of the wells listed in Table 1.
References Karytsas, C. 1991. The technical and economic context of low temperature geothermal energy development in Greece. In: Seminaire pour la Formation a la Geothermie Applique´, BRGM-IFE-AFME, December 1991, Meaux, France, p. 9. Karytsas, C., Kanavakis, G., Zarkadoula, M., Choustoulakis, P., Peroglou, G., 1996. Technical and Financial Feasibility Study for District Heating and Greenhouse Heating with Geothermal Energy at Aristino Evros. CRES—DG-XVII, Contract No: XVII/4.1040/93-022. Lalechos, I., 1986. Correlation and observations in Molassic sediments in onshore and offshore areas of Northern Greece. Mineral Wealth 42, 7–34. National Meteorological Survey, 1993. Climatological Data from Alexandroupolis Airport.