Slovenia - State of the art of country and local
situation
Table of contents
1. Geothermal resources
Geothermal potential
Low-enthalpy geothermal potential
Low-enthalpy geothermal reserves
Location of geothermal reserves
Hidrogeological consideration ( lithology)
2. Geothermal exploitation installations
Locations of exploitation places
3. Hybrid geothermal installations
4. Case study
4.1.Geographical overview of the region
Characteristics of the relief
Climate
Temperature
Solar radiation
Hydrography
Vegetation
Pedology
Geology
Hidrogeology
Landuse
Territorial administrative units
Economy
4.2 Technology
Power plant description (Flash steam plants, Dry steam plants, Binary plants)
4.3 Biomass energy
Solar radiation
Biomass potential distribution
Biomass sources
Biomass installations and their characteristic parameters
Biomass production thermal/electrical
Energetic technical potential (TJ/year) per source of biomass
Calorific power (Kcal/mc)
Uses
4.4 Biogas energy
Biogas installations and their characteristic parameters
Uses
List of figures
Figure 1- Geothermal resources potential areas in Slovenia
Figure 2- Location of low enthalpy geothermal reserves in Slovenia
Figure 3- Location of geothermal reserves in Pannonian Basin from Slovenia
Figure4 - Administrative map of geothermal resource Celje
Figure 5- Administrative map of geothermal resource Rogatec
Figure 6 - Administrative map of geothermal resource Šoštanj
Figure 7- Administrative map of geothermal resource Planina-Lasko- Zagorje
Figure 8 -Administrative map of geothermal resource Krsko –Brezice region
Figure 9 - Administrative structure of Ljubljana basin
Figure10 - Geological formations of Slovenia
Figure 11- Hydrogeological map of Slovenia
Figure 12- Thermal gradient in slovenia
Figure 13 - Map of Velenje Basin on Salek Valley , Slovenia
Figure14- Rainfall by month from year 1961-1990 I Slovenia (mm)
Figure 15 - Average temperature 1961-2003 in slovenia
Figure 16 -The hydrographical map of Velenje Basin
Figure 17- Pedological map of Slovenia
Figure 18 - Map with average soil depth in Slovenia
Figure 19 - Geological map of Slovenia
Figure 20 - Geological formation of Velenje Basin
Figure 21- The map of topoliska with Spa inscribed
Figure 22- Temperature in depth of 1000 m in Slovenia
Figure 23- Temperature in depth of 4000 m in Slovenia
Figure 24 -Producing wells in Topolšica Valley
Figure 25 -Land use in municipality of Sostanj
Figure 26 - Land use in municipality of Velenje
Figure 27- Territorial adminsitrative units of case study
Figure 28- Average monthy solar radiation per day in case study zone
Figure 29 - Annual global solar radiation in slovenia
Figure 30 -The daily sunshine duration in Slovenia
Figure 31- The scheme of photovoltaic system
Figure 32- Biomass potential distribution in Slovenia
1. Geothermal resources
Geothermal potential
Slovenia's geothermal potential is shown in the map below (Fig.1)
Figure 1 – Geothermal resources potential areas in Slovenia
In North East Slovenia (Pannonian basin) we have two aquifers: Thermal 1 and Thermal 2 (high
temperature source). Thermal 1 is low enthalpy aquifer in a surface of 1372 km2 with the temperatures
up to 150°C. The depth of this aquifer increases eastward.
In Rogatec-Celje-Šoštanj region are larger deposits of geothermal water with temperatures between
20°C and 80°C. Estimated depth of aquifer is 1000 – 3000 m.
Planina-Laško-Zagorje region has temperatures between 20°C and 45°C. Depth of tertiary layers is up
to 1500 m.
Geothermal potential in Krško-Brežice region is 0,5x1018 J. Maximum energy, which was estimated
according to the thickness of the aquifer (400 m) is 11,2 GJ/m2. Temperatures are between 20°C and
65°C.
Ljubljana basin is not so interesting for utilization because of very low temperatures between 20°C and
30°C.
(source: Nina Langerholc, The comparison of geothermal potential and use in Slovenia and in Iceland
– diploma work, University of Ljubljana, Faculty of Arts, 2008)
Low-enthalpy geothermal potential
Low-enthalpy geothermal reserves
Slovenia's low enthalpy geothermal reserves is shown in the map below (Fig.2)
Figure 2– Location of low enthalpy geothermal reserves in Slovenia
Location of geothermal reserves
Geothermal reserves in Slovenia are located in Pannonian basin, Rogatec-Celje-Šoštanj region
Planina-Laško-Zagorje region, Krško-Brežice region and Ljubjana basin.
-
Pannonian basin – NE Slovenia
Location of geothermal reserves in Pannonian basin in Slovenia are showing in Figure 3.
Figure 3- Location of geothermal reserves in Pannonian Basin from Slovenia (
-
Rogatec-Celje-Šoštanj region (Fig.4, Fig.5, Fig.6)
source: T-jam, http://en.t-jam.eu/)
Figure 4 - Administrative map of geothermal resource Celje
Figure 5- Administrative map of geothermal resource Rogatec
Figure 6 – Administrative map of geothermal resource Sostanj
(source: Nina Langerholc, The comparison of geothermal potential and use in Slovenia and in Iceland
– diploma work, University of Ljubljana, Faculty of Arts, 2008)
-
Planina-Laško-Zagorje region (Fig.7)
(vir: http://www.grajman.si/slike/zemljevid.jpg)
Fig.7- Administrative map of geothermal resource Planina -Lasko-Zagorje
-
Krško-Brežice region (Fig.8)
(vir: http://www.grajman.si/slike/zemljevid.jpg)
Fig.8 – Administrative map of geothermal resource from Krsko –Brezice region
-
Ljubljana basin (Fig.9)
Fig.9 – Administrative structure of Ljubljana Basin
(source: Nina Langerholc, The comparison of geothermal potential and use in Slovenia and in Iceland
– diploma work, University of Ljubljana, Faculty of Arts, 2008)
Hidrogeological considerations (lithology)
Geological formations of Slovenia is showing in the map below. (Fig.9)
Aluvij
Ploščasti apnenec (ladinij)
Peščen prod
Ploščati apnenec, dolomit (anizij)
Konglomerat, peščenjak, glina – ivniške plasti
Vijoličasti kremenov peščenjak
Tonalit
Drobnozrnat gnajs s prehodi v blestik, filter
Temen filitoidni skrilavec, vložki apnenca
Biotitov granit in grandioru
Sivi apnenec in dolomit
Svetlo sivi in rožnati apnenec
Ploščati grušč
Diabaz
Zelenkasti in vijoličasti filitoidni skrilavec
Meja pojezerij
Figure 10-Geological formations of Slovenia
(source: http://www.academia.si/uploads/clanek/71/image001.jpg)
Hidrogeological map of Slovenia is showing in Fig.11.
Fig.11- Hidrogeological map of Slovenia
(source: http://www.geo-zs.si/podrocje.aspx?id=129)
Surface (sqkm) of regions with geothermal resources in Slovenia are:
-
Pannonian basin – 1400 km2
Rogatec-Celje-Šoštanj region – 450 km2
Planina-Laško-Zagorje region – 380 km2
Krško-Brežice region – 550 km2
Ljubljana basin – 600 km2
(source: Nina Langerholc, The comparison of geothermal potential and use in Slovenia and in Iceland
– diploma work, University of Ljubljana, Faculty of Arts, 2008)
Depth of the aquifers of the same regions in Slovenia are:
-
Pannonian basin – NE Slovenia
Rogatec-Celje-Šoštanj region
Planina-Laško-Zagorje region
Krško-Brežice region
Ljubljana basin
depth up to 1500 m
depth up to 1400 m
depth between 500 and 1500 m
depth up to 400 m
depth up to 500 m
(source: Nina Langerholc, The comparison of geothermal potential and use in Slovenia and in Iceland
– diploma work, University of Ljubljana, Faculty of Arts, 2008)
Number of drilled wells for geothermal resources in Slovenia are 103 wells.
The well with maximum depth is in Korovci (Pannonian basin) is 2178 m, drilled in 2009.
(source: Seznam vrtin.pdf)
Temperatures of wellhead of the regions with geothermal resources in Slovenia are :
-
Pannonian basin: T=40 – 80°C
Rogatec-Celje-Šoštanj region: T=20 – 50°C
Planina-Laško-Zagorje region: T=20 – 45°C
Krško-Brežice region: T=15 – 65°C
Ljubljana basin: T=18 – 30°C
(source: Nina Langerholc, The comparison of geothermal potential and use in Slovenia and in Iceland
– diploma work, University of Ljubljana, Faculty of Arts, 2008)
Thermal gradient is showing in Fig.12
Figure 12- Thermal gradient in Slovenia
(vir: http://gcs.gi-zrmk.si/Svetovanje/Clanki/Grobovsek/PT391.htm)
Chemistry
In Slovenia we have several types of hydro chemical facies of thermal and thermo mineral water. In
Pannonian basin there is the evolutionary water type that occurs in gravels, sands and sandstones.
Chemical composition of water is changing with distance from the recharge area and depth. In the
shallower parts water is dominantly Ca-Mg-HCO3, which evolves into Na-HCO3 water type through
transitional water types (Ca-Mg-Na-HCO3, Mg-Na-Ca-HCO3, Mg-Na-HCO3, Na-Ca-HCO3, Na-MgCa-HCO3, Na-Ca-Mg-HCO3). Chemical composition changes due to weathering of sodium plagioclase
and significant water-rock interaction. Evolutionary water in the distal parts of Pannonian sedimentary
basin and its basement, where limited or no recharge of meteorical water is observed, is mixed with
connate pore water of Na-Cl water type. Oil and gas is present in traces. Mixed water are of Na-HCO3Cl or Na-Cl-HCO3 water type.
(source: Andrej Lapajne, Origin and chemical composition of thermal and thermo mineral waters in
Slovenia, Geological Survey of Slovenia, Ljubljana, 2006)
Exploitable reserves (for 20 years) MW/day
Theoretical potential for electricity generation in Slovenia is 50 – 70 MW, which means theoretical 438
GWh electricity generation per year.
(source: Nina Langerholc, The comparison of geothermal potential and use in Slovenia and in Iceland
– diploma work, University of Ljubljana, Faculty of Arts, 2008)
Flow rate (l/s)
-
Pannonian basin - >100 l/s
Rogatec-Celje-Šoštanj region - >250 l/s
Planina-Laško-Zagorje region - >150 l/s
Krško-Brežice region - >240 l/s
Ljubljana basin - >150 l/s
(source: Nina Langerholc, The comparison of geothermal potential and use in Slovenia and in Iceland
– diploma work, University of Ljubljana, Faculty of Arts, 2008)
2. Geothermal exploitation installations
Locations of exploitation places
Total installed power 48,62 MWt, of which 3,94 MWt geothermal heat pumps.
(source: Nina Langerholc, The comparison of geothermal potential and use in Slovenia and in Iceland
– diploma work, University of Ljubljana, Faculty of Arts, 2008)
Uses
Pannonian basin
Thermal water is of excellent quality and is not difficult to use (only slightly aggressive and does not
damage the pipelines). It is used primarily for swimming pool water, balneology, hotel and residential
heating and hot water. It is assumed that the possibility of extending the capabilities of the spatial
features are big, it will be necessary to change the way of exploitation of thermal water, since the
current amount of drawings already exceed the capacity of renewable aquifer. As a solution, therefore,
the limited withdrawal or return of used thermal water back into the aquifer, so called reinjection.
Rogatec-Celje-Šoštanj region
Geothermal water is used in the spa in Rogaška Slatina. Proposed use is in complementary agricultural
activities (greenhouses), for heating, for production processes in small businesses.
Estimated temperature of geothermal aquifer in Šalek valley is high and allows varied use: heating,
heating of swimming pools, balneology, use in industrial processes, greenhouses. According to the
characteristics and development potential of the area would be the most suitable expansion of tourist
facilities in Topolšica and the simultaneous introduction of heating with geothermal water. The water
could be use after that use as domestic hot water or for melting snow. Water could be pumped back in
the aquifer after use to prevent excessive depletion. In addition tourism opportunities the great potential
for the use of geothermal water is in the industry and trade.
Planina-Laško-Zagorje region
Geothermal water is used mostly in spas (Laško, Rimske Toplice, Podčetrtek). Because the estimated
temperature geothermal potential of aquifer is quite high, it would be possible to extend the use for the
purposes of balneology and swimming pools, while it would be possible to simultaneously heating in
urban areas. As the interface use we could include industrial applications.
Krško-Brežice region
Geothermal energy is used for spa Terme Čatež. At sufficiently high temperature could be used for
geothermal heating. According to the trend of increasing number of land with vegetables would be best
geothermal use for greenhouses. Since the proportion of covered shelters for vegetables is growing,
new capacities would be equipped with geothermal heating source instead of conventional heating. In
the western extension of the Krško basin is located Dolenjske Spa. Nearby Novo Mesto we have
Šmarješke Spa, where they use water for swimming and individual heating. According to the water
temperature in the area would be reasonable to use it for fish farming or in greenhouses.
Ljubljana basin
In terms of geothermal water temperature conditions, the greatest potential for exploitation is at the
Ljubljana Marshes. Water there could be used for room heating and not only on individual needs but as
district heating systems. In case of insufficient water temperature could be geothermal hot water heated
by conventional energy sources.
(source: Nina Langerholc, The comparison of geothermal potential and use in Slovenia and in Iceland
– diploma work, University of Ljubljana, Faculty of Arts, 2008)
Concerning to Geothermal exploitation installations, in this moment there is no hybrid geothermal
installations in Slovenia.
3 . Hybrid geothermal installations
To date no hybrid geothermal installations are located in Slovenia .
4.Case study - Šalek valley
4.1 Geographical overview of the region
Geographical position
Šalek valley (also Velenje basin- Fig.13) is a valley in the northern part of Slovenia, in the northeastern
pre-alpine foothills. The valley lies between the Kamnik-Savinja Alps to the west, the Pohorje
Mountain Range to the east, and the Sava Hills to the south. It has a northwest-southeast orientation
and is approximately 8 km long and 2 km wide. It contains a number of rivers and lakes. The Paka
River runs through Velenje, with a number of tributaries from the northwest: Trebušnica Creek,
Veriželj Creek and Slatina Creek.
(source: http://en.wikipedia.org/wiki/Šalek_Valley)
Fig.13-Map of Velenje Basin on Salek valley , Slovenia
(source: http://www.gis.si/egw/GOS_T08_P01/img/Saleska1.png)
Characteristics of the relief
Especially on the north, the valley is closed in by a chain of high mountains, from northeast to
northwest: Paški Kozjak hills with its peaks Basališče (1273 m) and Špik (1063 m), and Smodivnik
(923 m), Stropnica (860 m), Vodemlja (780 m), Ljubela (778 m), Graška Gora Hill (Graška gora, 800
m), the Krištan Mountain Pasture (654 m), Big Peak (Veliki vrh) and Stakne Peak (Staknetov vrh, 1223
m). The highest peaks rise beyond these: Uršlja Gora hill (Uršlja gora, 1696 m), also named Plešivec,
and Smrekovec (1569 m). The northern border of the valley meets the Karavanke mountain range, and
this northern area of the valley therefore has the fewest road connections.
The southern part of the valley is less mountainous, and is surrounded by lower mountains and hills
such as Wine Mountain (Vinska gora) to the northeast. The southern edge along the Ložnica Hills arose
along the geologically important Šoštanj Fault, allowing the valley road access towards the east. The
town of Velenje is also located at the end of this eastern opening.
Because of mining in the vicinity of Velenje, subsidence results in water flooding the resulting basins
and creating lakes. The largest lake is Lake Velenje (Velenjsko jezero) and nearby Lake Družmirje
(Družmirsko jezero) and Lake Škale (Škalsko jezero), approaching the Paka to the south at the western
end of the valley, where the town of Šoštanj is located.
The Šalek valley is situated at an altitude of between 355 and 390 meters and gradually declined from
north to south. In the village Šalek the upper Paka valley opens up from the narrow part into the open
valley. The valley is gradually expanding and has the widest range in area of Lake Dužmirje. Below
Šoštanj the wide valley narrows again to canyon.
(source: http://en.wikipedia.org/wiki/Šalek_Valley)
Climate
Šalek valley has a temperate continental climate. Summers are moderately warm, winters are cold.
Against the cold winds from the north is protected by the hilly outskirts of the Kamnik-Savinja Alps
and the Karavanke mountain range, which prevents abnormal situations and mitigates pronounced
influence of western air circulation.
(source: Rok Dolinšek, Environmental pollution and its landscape impacts on the Šalek valley –
diploma work, University in Ljubljana, Faculty of Arts, 2010 )
Precipitations
Rainfall is fairly evenly distributed throughout the year. Characteristic of rainfall is very high
variability in annual plurals. Average fall in Šalek valley is around 1250 mm of rainfall per year per
sqm, in Slovenia on average according to the latest data 1570 mm (Fig.14).
(source: Rok Dolinšek, Environmental pollution and its landscape impacts on the Šalek valley –
diploma work, University in Ljubljana, Faculty of Arts, 2010 )
Figure 14 – Rainfall by month from year 1961-1990 in Slovenia (mm)
Figure above shows average rainfall by month in mm from year 1961 to 1990.
(source: Rok Dolinšek, Environmental pollution and its landscape impacts on the Šalek valley – diploma work, University
in Ljubljana, Faculty of Arts, 2010 )
Temperature
Average temperature in January in Velenje is -1°C and in July 18,8°C. Average annual temperature in
Velenje is 9,2°C. (Fig.15)
Figure15- Average temperature 1961-2003 in Slovenia
The figure above shows annual temperatures from year 1961 to 2003 in Velenje, Celje and Šmartno.
Dotted line is trend line for Velenje.
(source: Rok Dolinšek, Environmental pollution and its landscape impacts on the Šalek valley –
diploma work, University in Ljubljana, Faculty of Arts, 2010 )
Solar radiation
According to the Metheorological Institute of Slovenia intensity of solar radiation achieves an average
1390 kWh/sqm-yr.
(source: Edis Mustafić, Analysis of renewable energy sources potentials in Pomurje and the Šalek
valley – diploma work, University of Maribor, Faculty of energy technology, 2011)
Hydrography
The hydrographical map of Velenje Basin is showing in Figure 16.
Figure 16 – The hydrographical map of Velenje Basin
The main river in the river Paka, which flows along the southern edge of the Šalek valley. Paka is a
torrential river with snow-rain regime with the lowest flow in August and highest in the spring.
The climate change is also reflected in the reduction of the annual flow of river Paka in Šoštanj. On
average, approximately 0,2 m3/s of water flows through the sewers. This purified water fows into Paka
river below Šoštanj. Paka river is too abundant water source, its self-cleaning abilities are poor.
(source: Rok Dolinšek, Environmental pollution and its landscape impacts on the Šalek valley –
diploma work, University in Ljubljana, Faculty of Arts, 2010 )
Vegetation
Grasslands are dominated on the plains and in the valleys of streams. On Quaternary river alluvium
along Paka river due to the small slope the fields are dominated. In the hilly outskirts the forests are
dominated. On shady slopes we also have forests dominating, on sunny slopes there are fields, orchards
and vineyards.
On shady slopes the lowland forest is dominated, it mostly includes oaks and hornbeams. In the band
between 350 and 700 m as a result of human activity predominates mixed beech forest. Higher focused
are extensive areas of forest, mostly spruce and fir trees, as a result of selective dilution of deciduous
trees.
(source: Rok Dolinšek, Environmental pollution and its landscape impacts on the Šalek valley –
diploma work, University in Ljubljana, Faculty of Arts, 2010 )
Pedology
Figure 17 represent pedological map of Slovenia.
Figure 17 – Pedological map of Slovenia
(source: http://www2.arnes.si/~gljsentvid10/temperatura_tal_dif_enacba_tjs.html)
Solids in Šalek valley are varied. In the hilly outskirts, built of limestone and dolomite are brown
carbonate soils. On Quaternary river alluvium along Paka river are brown alluvial soils. On the
southern outskirts of the predominantly silicate rock, there was formed distinct brown soil.
(source:Rok Dolinšek, Environmental pollution and its landscape impacts on the Šalek valley –
diploma work, University in Ljubljana, Faculty of Arts, 2010 )
The following map show the deep of soil in Slovenia (Fig.18).
Figure 18 – Map with average soil depth in Slovenia
(source: http://www2.arnes.si/~gljsentvid10/temperatura_tal_dif_enacba_tjs.html)
Geology
The geological map of Slovenia is showing in Figure below (Fig.19).
Figure 19 – Geological map of Slovenia
(source: http://www.georis.si/)
In view of the geological formation extends Šalek valley in the late Pliocene, when the central part
between Smrekovec neotectonic fracture and thermal breakthrough Šoštanj-Topolšica-Dobrna-Rogaška
Slatina drafted. Tectonic line passing through the center of Velenje fracture and have northwestsoutheast direction. Territory north of Smrekovec fracture lifted, while the south of the territory was
drafting. Geological drafting lasted for over two million years, so the bottom of the valley is at a depth
of 1100 to 1200 m. Enclosed part flooded and water started to dispose sediments such as silt and clay
on the bottom. Following the withdrawal of water in Tertiary rivers disposed the basin with gravel and
sand.
In some places between the layers in coal deposit, which is 8,3 km long and up to 2,5 km wide. It is at
a depth of between 200 to 500 m, reflecting the fact that the drafting was steady and slow. The average
thickness is 60 m, maximum thickness measures over 100 m. Lignite coal is relatively young, it dates
back to the late Tertiary or early Pliocene – 2,5 million years. In the northern part of the Šalek valley
underlying carbonate rocks, mainly Triassic dolomite and some limestone, south of the river Velunja
the granite and tonalite. The southern part consists of sedimentary rocks. Sandy marls, sandstones and
andesite tuffs are dominating.
(source: Rok Dolinšek, Environmental pollution and its landscape impacts on the Šalek valley –
diploma work, University in Ljubljana, Faculty of Arts, 2010 )
Aluvij
Ploščasti apnenec (ladinij)
Peščen prod
Ploščati apnenec, dolomit (anizij)
Konglomerat, peščenjak, glina – ivniške plasti
Vijoličasti kremenov peščenjak
Tonalit
Drobnozrnat gnajs s prehodi v blestik, filter
Temen filitoidni skrilavec, vložki apnenca
Biotitov granit in grandioru
Sivi apnenec in dolomit
Svetlo sivi in rožnati apnenec
Ploščati grušč
Diabaz
Zelenkasti in vijoličasti filitoidni skrilavec
Meja pojezerij
Figure 20 – Geological formation of Velenje Basin
(source: Zdravko Praunseis, Geothermal energy in Šallek valley, 2013)
The Šalek Valley formed in the late Cenozoic era, during the Pliocene epoch of the Neogene period.
(Fig.20) Faults started to appear at this time due to epirogenic movement, vertically lifting and
lowering the surface. Ridges formed and the ground sank, and lignite deposits started to form between
the sand and loam. These brown coal deposits represent the great majority of the mineral wealth of this
area. Besides the Ljubljana Marshes the Šalek Valley is one of the tectonically youngest basins in
Slovenia.
(source: http://en.wikipedia.org/wiki/Šalek_Valley)
Hidrogeology – overview
Aquifers – overview (age of the intercepted strata)
Potential aquifer Šalek valley – Triassic carbonate rocks. Geothermal reservoir – aquifer in the
sedimentary basin. Aquifer Topolšica – aquifer with hot springs and aquifer in the sedimentary basin.
The aquifer is on the north side bounded by subvertical Smrekovec fracture, at which the Triassic
carbonate rocks are in contact with oligomiocen tonalite and Perms roks.
(source: Zdravko Praunseis, Geothermal energy in Šallek valley, 2013)
Spatial distribution of wells
The figure below shows Topolšica with Spa inscribed
Figure 21 – The map of Topolšica with Spa inscribed
Depth of the aquifers
Estimated depth of the potential aquifer is 2000 to 3000 m.
(source: Zdravko Praunseis, Geothermal energy in Šallek valley, 2013)
Aquifer thickness
Thermal water comes from a depth of at least 800 to 1000 m.
(source: Zdravko Praunseis, Geothermal energy in Šallek valley, 2013)
Temperature gradient (oC/km)is showing in Fig. 22 and Fig.23 .
(source: http://www.mladinska.com)
Figure 22 - Temperatures in depth of 1000 m in Slovenia
(source: http://www.mladinska.com)
Figure 23 - Temperatures in depth of 4000 m in Slovenia
Lithology
Dolomite, dolomitized limestone, limestone.
(source: Zdravko Praunseis, Geothermal energy in Šallek valley, 2013)
Depth of the drilling (m)
Toplica spring – 375 m.
Topolšica well – 374,81 m.
(source: Zdravko Praunseis, Geothermal energy in Šallek valley, 2013)
Flow rate (l/s)
Toplica spring – between 20 and 60 l/s depends on water situation
Topolšica well – 10 l/s, maximum permissible current withdrawal 20 l/s
(source: Zdravko Praunseis, Geothermal energy in Šallek valley, 2013)
Temperature of the fluid
Toplica spring – 27-35°C
Topolšica well – 31,9°C
(source: Zdravko Praunseis, Geothermal energy in Šallek valley, 2013)
The chemistry of the fluid
Ca-Mg-HCO3
Water contains cations: sodium, potassium, calcium, magnesium, strontium, iron and anions: chloride,
fluoride, iodide, nitrate, sulfate, bicarbonate.
(source: Zdravko Praunseis, Geothermal energy in Šallek valley, 2013)
Number of producing and shut in wells is showing in figure below (Fig.24)
EXISTING WELL
DESTROYED WELL
WELL TO CAPTURE WATER
HORIZONTAL PROJECTION OF THE WELL
DRINKING WATER SUPPLY
SPRING
PUMPING STATION
THERMAL SPRING TOPLICA
OUTFLOW FROM A THERMAL SPRING
Figure 24 – Producing wells in
Topolšica Valley( source: Topolšica Spa)
Landuse
Landuse in municipality of Šoštanj is shown on the figure below.(Fig.21)
Figure 25-Land use in municipality of Šoštanj
Where the brown color are fields, yellow – permanent crops, light green – grassland, green –
overgrowing, dark green – forest, red – built areas, blue – water surfaces, grey – other.
Landuse in municipality of Velenje is shown on the figure below.(Fig.22)
Figure 26 -Land use of municipality of Velenje
Where the brown color are fields, yellow – permanent crops, light green – grassland, green –
overgrowing, dark green – forest, red – built areas, blue – water surfaces, grey – other.
(source: Rok Dolinšek, Environmental pollution and its landscape impacts on the Šalek valley –
diploma work, University in Ljubljana, Faculty of Arts, 2010 )
Territorial administrative units
Territorial administrative units of zone is showing blow(Fig.23)
Figure 27 – Territorial administrative units of case study
The black line shows municipality border and the red line shows the border of Šalek valley. We have
two municipalities, namely the municipality of Velenje, which had a population of 33.226 in year 2008
and municipality of Šoštanj with a population of 8.420 in 2008. In total, therefore, in both
municipalities, covering Šalek valley, lived 41.646 people in 2008.
(source: Rok Dolinšek, Environmental pollution and its landscape impacts on the Šalek valley –
diploma work, University in Ljubljana, Faculty of Arts, 2010 )
Economy
1. Coal industry and energy technology
TEŠ (Thermal power plant Šoštanj – located in municipality of Šoštanj) with installed power of 809
MW produces approximately a third of all electricity in Slovenia. For an average annual production of
4 TWh of electricity, they burn more than 4 million tons of lignite, which is emerged in the Velenje
lignite mine (located in municipality of Velenje), which is one of the largest in Europe. Coal basin
covers approximately 21 km2. Industrial development of Šalek valley is therefore based on the
development of lignite mine Velenje. Lignite is used solely for the electricity generation in TEŠ.
2. Industry
In addition to energy technology is industry or electrical industry also very important. The most
important industrial group in Šalek valley is Gorenje. The importance of both activities witnessed by
the information on the proportion of staff. In the municipality of Velenje the percent of employment in
industry and mining is beyond two-thirds of the total active population, in municipality of Šoštanj three
quarters of total active population.
3.Agriculture
Most of the arable land is at the middle and at the lower flow of river Velunja all the way to Lake
Družmirje, but some of them can also be found nort of Škale and Velenje Lake. There is a lot of
farming. Orchards and vineyards are blossomed on the sunny slopes of the higher areas. In addition to
agriculture, forestry is also important.
(source: Rok Dolinšek, Environmental pollution and its landscape impacts on the Šalek valley –
diploma work, University in Ljubljana, Faculty of Arts, 2010 )
4.2 Technology
Maximum total annual volume of abstraction of groundwater from the spring Toplice and well is
473.000 m3/year, with an average annual flow 15 l/s.
(source: Zdravko Praunseis, Geothermal energy in Šallek valley, 2013)
4.3 Biomass energy
Solar energy
Solar energy potential (Intensity of solar radiation (kWh/sqm-yr)
According to the Metheorological Institute of Slovenia intensity of solar radiation achieves an average
1390 kWh/sqm-yr. Intensity of solar radiation in Šalek valley per month: January – 1,51 kWh/sqm,
February – 2,44 kWh/sqm, March – 3,51 kWh/sqm, April – 4,24 kWh/sqm, May – 5,16 kWh/sqm,
June – 5,32 kWh/sqm, July – 5,39 kWh/sqm, August – 4,81 kWh/sqm, September – 3,56 kWh/sqm,
October – 2,24 kWh/sqm, November – 1,47 kWh/sqm, December – 1,17 kWh/sqm.
Figure 28 - Average monthly solar radiation per day in case study zone
The figure shows average monthly solar radiation per day in Šalek valley (blue line).
The map below shows annual global solar radiation in MJ/sqm.
Figure 29 - Annual global solar radiation in Slovenia
(source: Edis Mustafić, Analysis of renewable energy sources potentials in Pomurje and the Šalek
valley – diploma work, University of Maribor, Faculty of energy technology, 2011)
The coverage degree of solar energy during the year (%)
In Slovenia we utilize only about 28 GWh, which is only 3 % of the estimated technical potential.
Figure 30 shows the course of daily sunshine duration in hours in January (blue line), April (green
line), July (red line), October (yellow line) in Ljubljana. It is similar everywhere in Slovenia.
Figure 30 - The daily sunshine duration in Slovenia
In the winter, when the need for heating energy is the greatest, unfortunately we get only about 10 –
15% of the total annual solar energy.
(source: Edis Mustafić, Analysis of renewable energy sources potentials in Pomurje and the
Šalek valley – diploma work, University of Maribor, Faculty of energy technology, 2011)
Types of plants (open circuit, closed circuit)
Regarding the use of photovoltaic systems can be divided into smaller independent systems (DC),
independent systems with inverter (DC-AC) and solar power plants, which are connected to the
network.
Independent systems (DC) – Electricity produced from the modules is stored in rechargeable batteries
for times when solar radiation is too weak to operate the system at night or in bad weather. Batteries
from overcharging and excessive before emptying are protected by a solar regulator. Users working in
the DC battery voltage, typically 12 or 24 V.
Independent systems with inverter (DC-AC) – With DC-AC photovoltaic systems DC battery voltage
converts with the help of inverters in AC voltage (230 V). This enables the use of conventional electric
machines which operate in electricity grid.
Photovoltaic power systems are connected to the electricity grid. In such systems, the modules are
connected to the electricity grid through inverters.
(source: Toni Radanovič, Comparison of tracking and stationary photovoltaic systems –
diploma work, University of Maribor, Faculty of energy technology, 2011)
Technologies and equipment for recovery of solar radiation (photovoltaic systems)
Use of solar energy to thermal systems use a solar collectors, where water and air are warmed for hot
water and heating. Solar panels take up of solar energy, provided that they are placed at an angle of 25°
to 45° and facing in the direction of south or southwest. The main part of the collector is absorber,
which is usually made of metal. Its main purpose is to absorb solar energy through a special layer and
then transfers the heat from this layer to the water or air that weight through it. Collectors are usually
linked together in a system of solar panels on the roof or somewhere close to the building.
(source: Toni Radanovič, Comparison of tracking and stationary photovoltaic systems – diploma work,
University of Maribor, Faculty of energy technology, 2011)
According to technology developments collectors are classified into four generations:
Flat solar panels Flat solar panels are usually made up of copper and aluminum piping, covered with
absorber plate. Pipes are arranged in parallel in height or width and connected at both ends. Heating
liquid in the pipes absorbs heat through absorption panels. This is usually covered with glass with low
iron content, which allows higher transparency. That type of collector can be quite effective if they
provided favorable climatic conditions: outdoor temperature at least 18°C and a high degree of
exposure to the sun. therefore, in areas with plenty of sunshine and warm climate throughout the year
usually represent a valid alternative. In such a situation a well-designed and manufactured solar panel
reaches at least 45-60 % efficiency.
- Vacuum pipe collectors
Vacuum pipe collector is built on the basis of two concentric glass pipes mounted to the one in the
second. The space between them is a vacuum. The outer surface of the inner pipe is coated with a heat
absorbing material and containing a heating fluid. A heat transfer fluid is heated in the manner is
relatively economical, vacuum pipe insulation provides low heat losses. It has a higher efficiency than
flat plate collector, no matter on time of year and weather conditions.
- U-pipe solar collector
U-pipe solar collector is type of vacuum pipe collector. To absorb solar energy still uses the principle
of double glass pipe with many disadvantages of this design. Instead of heating the liquid directly into
the inner glass pipe has this type of device a metal tube in a U shape, filled with liquid heating and
implanted into the inner glass pipe. Metal foil, which is in thermal contact with the inner surface of a
glass pipe, while the metal U-pipe, the heat is transferred to the glass walls of the liquid in the U-pipe.
Withstand the water pressure from the public piping and fixtures can be operated in closed-loop
system.
-
Advanced solar panels (source: http://www.bioplanet.si/tipi-soncnih-kolektorjev.htm)
Technologies and equipment for recovery of solar radiation (photovoltaic systems) are showing in
Figure 31.
Figure 31 - The scheme of Photovoltaic system
where the numbers are: 1 – module, 2 – overvoltage protection, 3 – regulator, 4 – junction fuse box, 5 –
accumulator, 6 – inverter.
(source: Photovoltaic systems in buildings, OPET Slovenia, 2002)
Network connectivity
Power inverters are links between a series of photovoltaic modules and AC systems. Direct current,
produced by the modules the inverters convert in alternating current and the voltage and frequency
adjust to the network structure. Inverters can convert 12 V to 220 V as well as 24 or 48 V.
(source: Toni Radanovič, Comparison of tracking and stationary photovoltaic systems – diploma work,
University of Maribor, Faculty of energy technology, 2011)
Uses
Solar energy is being used to produce electricity and hot water, same in all countries.
Biomass potential distribution
Figure below (Fig.32) show biomass potential distribution in Slovenia.
Figure 32 - Biomass potential distribution in Slovenia
The map above shows wood stock in m3/ha.
Wood biomass in Šalek valley:
Area (ha)
Forest area (ha)
Percentage of forest (%)
Private forest (in the proportion of the forest) (%)
Maximum disforest (m3/year)
Percentage of houses heated with wood (%)
17909
10573
59,13
83,28
46123
11,11.
Biomass sources
The group of wood biomass includes: wood from forests, wood from abandonment land, wood from
agricultural and urban areas, scrap wood from primary and secondary wood processing, disused
(uncontaminated) wood.
Biomass installations and their characteristic parameters
Biomass production thermal/electrical
Energetic technical potential (TJ/year) per source of biomass
-
Calorific power (Kcal/mc)
Uses
Biomass is used for heat and electricity production, same in all countries.
4.4 Biogas energy
Biogas installations and their characteristic parameters
Utilization of biogas in Šalek valley is negligible, as these potentials. Most likely could be used as a
source of fermentation of biological waste in sewage treatment, pyrolysis, gasification and landfill gas.
Those things would require large financial investments, but are because of the proximity of thermal
power plant currently economically not meaningful.
(source: Edis Mustafić, Analysis of renewable energy sources potentials in Pomurje and the Šalek
valley – diploma work, University of Maribor, Faculty of energy technology, 2011)
Regardless of what is written above, there is installation for biogas production on the Central sewage
treatment of Šalek valley.
Uses
-The Central sewage treatment facility in Šalek valley, managed by the utility company of the
municipality of Velenje, the sludge stabilization process used mesic stabilization in two-stage
anaerobic digester heated
-The process of anaerobic decomposition of organic matter at a temperature of 37°C. Biogas produced
contains 67% of methane. It is used as a fuel in cogeneration device or in the oven.
Thus, by its own generated energy covers about a third of the need for power and the need for the entire
heat.
(source: Sinenergija, Kssena, 2009)