Energy Security for Slovakia - Energy policy based on renewables



1. Why the energy security must be the key political issue


From the energy production and consumption point of view Slovakia is probably in the most vulnerable position among the EU member states. Practically all oil and gas and large amount of coal are imported from Russia. Especially the oil and gas deliveries seem to be risky business for the future. Most EU countries diversified their suppliers so that problems with one of them can be somehow compensated by another one. Also the pipeline connections (interconnections between MS) allow most of the EU MS to diversify their oil ad gas suppliers. This is not the case of Slovakia - 98% of oil and 98 % of gas are flowing through Ukraine - the rest is domestic production. Political contacts to Russia were traditionally very good and deliveries were considered reliable. But the recent politically and economically motivated problems between Russia and oil and gas transit countries - Ukraine or Belorussia showed that Slovak energy security became a hot issue for the government. Despite the fact that Slovakia does have long term contracts with Russian suppliers of oil and gas, in case of problems with transit countries the only solution would be to use stored oil and gas and that is only short term measure.


Political stability in Russia and good relationships between EU and Russia seems to be crucial in securing the oil and gas deliveries. In the short term perspective Russia needs EU maybe more than is the opposite because of huge revenues from export to the EU and no possibility to substitute this dependency with other export markets in the meantime. The situation is rapidly changing and Russia is building its strategic partnership with China and other fast developing Asian economies. Construction of new oil and gas pipelines between Russia and these - from EU perspective competing markets - is from Russian perspective logical step towards diversifying of their export markets. All this would not be a big problem if there would be enough resources to cover ever increasing energy consumption in China and other emerging economies building ties to Russia. But this is not the case. In maximally five years time when the pipelines especially to China will be developed and when production of Russian oil and gas will culminate the situation for the most depending countries like Slovakia will be critical.


Future energy security must be seen also from the perspective of upcoming peak oil. Recent Russian oil data show that the rate of export is slowing down where ever increasing domestic consumption is playing big role. The tightness and future problems with gas deliveries to Europe have been mention several times by Russian experts. This new situation must be judged by the EU very seriously. The MS (especially those first on the line) should be prepared for the worst situation when Russian deliveries will be declining or maybe stopped for long time e.g. from political reasons.


The key question is: are we prepared for the worst case scenario? The answer at least for Slovakia is no. INFORSE is trying to come up with the solution which can partially overcome the problems (short term measures) and also with the solution (long term measures) which can solve the problems with oil and gas for ever.


2. Scenarios


Following scenarios are dealing only with oil and gas shortages, provided that the electricity production is primarily not depending on Russian resources. Unfortunately nuclear fuel which provides 50 % of electricity (rest is hydro, coal and natural gas) in Slovakia is also imported from Russia. Nevertheless, for this case it is estimated that the nuclear fuel will not be an imminent problem and that it can be substituted by other suppliers or even the electricity can be imported from abroad.


On the other hand natural gas used primarily for heating purposes and oil used for transportation can not be substituted easily by other suppliers. Thus the scenarios are based on finding alternatives to these fuels and contrary to the official - alternatives based on renewables.



2.1. Scenario Nr. 1 : Natural Gas Problem


Situation picture:


Priority problem:

Heating buildings and warm water preparation = 90% of natural gas consumed in Slovakia.


Solutions and Renewable energy options:


Following renewable energy sources can be used in Slovakia for heating and warm water preparation:

1. Biomass

2. Solar energy

3. Geothermal (heat pumps)


Note: Electricity produced from renewables and used for electrical heating is not considered as the option because it is considered for providing the energy for renewable energy heating facilities e.g. heat pumps.



Solutions can be defined for:



2.1.1. Municipal level solutions:


Option 1:  Biomass + Solar

Substitution of natural gas firing boilers by the biomass burning boilers with solar collectors used for water storage preheating.


Description: most of the recent heating facilities also in bigger cities can be retrofitted for wood chips or pellets burning. Technology for biomass burning is available. Problems with covering large demand for the technology (new orders) in short period of time will arise. Problems with biomass fuel can be solved from short term perspective due to the large forest area (50% of Slovakia covered by forests). The amount of biomass fuel needed will be reduced by the utilization of newly installed solar collectors on the roofs of heating facilities with preheated warm water storage.


Option 2: Geothermal

Substitution of natural gas firing boilers by the geothermal heat or heat pumps utilisation.


Description: potential for geothermal heating is available in large parts of Slovakia and has not been used yet. Especially several smaller municipalities are the main target users. Technology is available. Problem with growing electricity consumption, when developed on large scale, needs to be addressed. Generally this option should be accompanied by the large scale wind energy development which is not properly used yet and which should cover all extra electricity needs mentioned here.



2.1.2. Single family houses solutions:


Option 1: Biomass+Solar

Small biomass (wood logs) furnaces are just starting to be discovered by the public. It is primarily the ever increasing natural gas prices which forced the small users to cut off the natural gas pipelines (district heating systems) and use own biomass small boilers. Technology is not a problem and price is reasonable. No further incentives are needed especially in rural areas where this development is going on even without external crisis.


Solar collectors - self building program: Due to the fact that people especially in rural areas still prefer cheap and even do-it-yourself solutions it would be appropriate to use solar collectors build by the people themselves. Simple water heating solar collectors can be build cheaply, easily and quickly. The know-how and the information to spread the message around is needed. The equipment needed for construction can be borrowed and passed around the groups of people participating at self building program.



2.1.3. Industrial level solutions:


It is assumed that during the crisis the industrial level of activity will be reduced so the need for the fuel change and retrofitting of own heating facilities will be left upon the decision of owners. Nevertheless solutions described above can be applied in this sector as well.



2.2. Scenario Nr. 2 : Oil Problem


Situation picture:


Priority problem:

Providing fuel for transportation.



Solutions and Renewable energy options:


Following renewable energy sources can be used in Slovakia for substitution of oil:

1. Biofuels (biogas, biodiesel)

2. Wind, hydro and PV (electricity)





Solutions can be defined for:


Provided that key transport services in case of emergency like medical, fire or police will always be met by the government first and their share on total fuel consumption is small.



2.2.1. Public transportation:


Option 1: RE electricity


Slovakia has a very good network of public transportation lines build during communist regime. Unfortunately majority of vehicles (buses) are running on diesel fuel. The key problem thus would be to shift passengers from busses to trolleybuses in cities and to use rail for intercity travel.


Cities: new trolleys can be built relatively easily, busses are already being retrofitted to dual diesel/electricity use.


Intercity travel (commuting): rail network should be further developed instead of being reduced in the meantime. This solution should be supported anyway and taking its historical development in account should not be the big problem for developed country like Slovakia.



Option 2: Biofuels


Biofuels which can from technical point of view easily substitute oil (ethanol, biodiesel) are used in limited way by now. But their share is growing - all this as the result of EU legislation.


Nevertheless biogas (purified to clean methane gas) produced from organic waste is not used at all in Slovakia and should have a priority here. Upgraded biogas has the same properties as natural gas. Therefore it can be used with the same car engines and vehicle configuration as natural gas. Retrofitting of diesel powered busses to natural gas is being enforced by the municipalities in the meantime. Biogas instead of natural gas (methane) should have the priority in case of crisis situation. Beside biogas plants build at waste water treatment facilities which are quite frequently used in Slovakia, the huge unused potential does exists in industrial sewage treatment plants and agricultural farms (manure).


Biodiesel in form of domestically produced raw plant oil burned in retrofitted diesel engines busses should be also supported.



2.2.2 Transportation of goods :


Rail should be the primary way of goods transportation. Trucks should be either put on rail or should be retrofitted to biofuels (biogas, biodiesel). Above mentioned Options Nr. 2 should be used appropriately in this sector.



2.2.3 Private transportation:


Option Nr. 1 Biofuels


Private transportation and use of cars is growing in Slovakia. Recently used cars are least prepared for retrofitting to alternative fuels. Nevertheless use of biofuels should be enforced. Two options are viable:


1. Biogas produced from municipal waste. In several European cities (most successful project in Goteborg) cars are running on biogas (methane after purification of biogas) produced from organic waste. This solution is technologically viable and should be promoted by the municipalities in connection with waste management.


2. Biodiesel in form of raw plant oil used in retrofitted diesel engines. Raw plant oil has the best input/output energy ratio and should have the priority over biodiesel produced by means of esterification  (e.g. from rape seed). Import of biodiesel from developing countries should be forbidden until environmental and social acceptance criteria in producer countries will be met.



3. Potential of RE Souces in Slovakia


Above mentioned solutions to the crisis scenarios are based on technologies (available on the market) which require considerable increase of utilization of renewable energy sources in Slovakia. Key question is if this increase can be achieved in reasonable period of time and if the potential of these sources can cover the demand?


Despite the fact that substituting of fossil fuels by renewables can be linked to several specific difficulties like utilizing RE in big cities or substituting natural gas in centralized heating systems this is considered to be technical problem which can be solved when needed. Financial requirements for RE technologies are sometimes higher than in case of cross-subsidised fossil fuels and thus can create a limitation. Nevertheless for the purpose of this study we estimated the potential of RE which are cost competitive on EU market today (wind, biomass, hydro, geothermal, thermal solar).


Short term measures - Biomass


Biomass can be utilised in different ways. According to the domestic experience the heat production seems to be the most cost effective at present. Nevertheless biogas utilisation with combined heat and power production and biofuels for transportation (biodiesel) are becoming more and more competitive on Slovak market even without subsidies. All these technologies are available in Slovakia and can be introduced in short period of time. Energy plantation can also be considered because of relatively huge land area available which is not supposed to be used for food production. According to the government it will be reforested.


As the biomass resource we assume waste wood, straw, manure from agricultural farms and a land area available for energy plantation.



Wood and straw potential can be estimated from recent numbers of wood and grain production. For the estimate of energy plantation we used Slovak experience with experimental plantation of Salix viminalis. Weight gain up to 15 t/ha/yr of dry matter can be expected (30 t/ha/yr fresh matter) with the density 10 000 cuttings per ha.


Wood, straw and energy plantation potential for Slovakia.


Mil. ton/yr.


Fuel wood + waste wood from forestry (fresh)



Straw (1/3 out of 3 mil. tonnes of grain production per year)



Straw from rape seed production (40.000 ha * 4 t/ha) dry



Energy plantation (400.000 ha) dry matter of Salix viminalis







Energy content used for this estimate:

fresh wood - 10 GJ/ton

dry wood – 15 GJ/ton

straw – 14,2 GJ/ton

rape seed straw - 18 GJ/t



For the estimation of biogas potential we can use the numbers of animals (cattle, pigs and poultry) and derive biogas production in m3. From this the heat and power production can be estimated according to domestic experiences with this technology.


Biogas potential for Slovakia.


Total stock

Annual manure production

Annual electricity production

Annual heat production

Cattle (500 kg)

1 mil.

10 mil. Ton

300 mil. KWh

2 PJ

Pigs  (150 kg)

2 mil.

6 mil. Ton

180 mil. kWh

1,2 PJ


12 mil.

0,36 mil. Ton

12 mil. kWh

0,08 PJ




492 mil. kWh

3,3 PJ


Data are based on results from biogas facility in Batka. Inputs for this facility are following:


Average manure production: 149,3 t/day

Average biogas production: 2587,5 m3/d  (63,5 % CH4)

Average power production: 4485,9 kWh/d

Average heat production: 29,1 GJ/d.





Geothermal energy is used in Slovakia for several decades. Present utilisation is around 1,2 PJ per year. Main use is for heating purposes (swimming pools, agriculture). Just recently geothermal energy was introduced for heating apartment houses and also for power production. The total potential for this source is almost inexhaustible and theoretically could cover all our energy needs. However for the purpose of this study only governmental estimate of „practically available potential“ is used. According to this source the utilisation of 22,68 PJ/yr. until the year 2010 can be achieved. It should be noted that huge potential of geothermal energy could be used by means of heat pumps.


Geothermal potential for the heat production - 22,68 PJ/year.





Solar energy can cover all our energy needs. Utilisation of solar collectors and passive solar energy use are the most cost effective ways and are becoming more and more popular in Slovakia. These technologies can substitute huge part of our needs for heating and warm water preparation. Despite some financial restrains today, photovoltaic can also be considered as the important source of electricity in the short term.





Taking into account average typical performance of solar collector for heat production of 350 kWh/yr/m2 or 1,26 GJ/yr/m2 we can estimate that using 10 m2 per person or utilising 50 mil. m2 of solar collector area we can achieve the heat production of 63,0 PJ per year. Despite the fact that such an area seems to be very large it should be noticed that for the energy needs combination with e.g. heat pumps (geothermal energy) is also available what can lead to the reduction of collector area. Nevertheless 10 m2 per person can be achieved by the utilisation of roofs of the recent buildings. Constructing large solar collector fields for centralised heating systems could be considered as an alternative to placing of collectors on roofs.


Solar thermal potential for the heat production - 63 PJ/year.





Electricity produced by photovoltaics is becoming widely accepted as the major source of power in the future. Nevertheless here it is considered as the additional source to the easy and fast achievable potential like wind and biogas. It is assumed that price advantage of these sources will lead to the full utilisation of their potential as estimated above. For the Slovak electricity needs it is estimated that 15 TWh/year should be covered by photovoltaics. Size of 100 mil. m2 seems to be sufficient for the production of this amount of electricity. This PV area is based on the average power production of typical PVs on the market today. For the average solar irradiation in Slovakia a typical PV system can produce 150 kWh per year per m2.


Total solar potential for power production – 15 TWh/yr.





Wind power is not utilised in Slovakia yet. First larger wind mills - four 600 MW turbines are in planning stage. This technology, which is already cost competitive in some EU countries, is delayed in Slovakia mainly due to the low feed in tariffs. In case that governmental policy will change we can estimate the wind potential with the means of following methodology.    

1.     Assessing the land (square kilometres) available for wind turbines sitting. Only areas with average annual wind speeds more than 5-5,5 metres per second (m/sec) at a height of ten metres above ground are taken into account. This average speed is recognised as feasible for the exploitation of win energy at today’s generating costs.

2.     Estimating the number of wind turbines per square kilometre.

3.     Multiplying number of turbines by average annual power production. Power production by average 600 kW turbine at 6m/sec average wind speed is taken as 1 GWh/yr.


The total available land resource for Slovakia was estimated by the ministry of economy at 257 km2 in 43 regions (wind velocity higher than 5 m/sec). It should be mentioned that further improvements in the technology will extent the potential for utilising wind speeds of less than 5 m/sec. and the potential area can be considerably larger. Nevertheless for the purpose of this study 257 km2 were taken into account. According to the sitting experience up to 25 turbines can be placed in area of 1 km2. The distance from each other will be at least 200 meters.

Theoretical annual power production from 25 turbines (600 MW each) or 1 km2 will be 25 GWh/year. This gives the theoretical potential of 6,4 TWh/yr. for the whole potential area (257 km2).


Total wind potential for power production – 6,4 TWh/yr.



Medium and long term measure - HYDRO

Recent hydropower production is around 3,8 TWh/yr and can be increased considerably. According to the governmental estimate the total potential for electricity production in hydro power plant is 6,61 TWh/year according to some other sources this could be up to 7,38 TWh/yr. Despite the fact that there will be hardly 100 % utilisation of this potential (in some countries it is more than 90 %) we consider production of 6,61 TWh/yr. as the upper bound here.


Important feature of Slovak hydropower production is its utilisation of large pump hydro power plants. Their total capacity today represents 1015 MW and 600 MW is in planning. Due to the excellent geographical conditions the potential for pump hydro is much larger and according to the previous estimates it can reach up to 10.000 MW. This can be used in future as the important energy storage what is of crucial importance if RE like PV or wind is to be used on broader scale. 


Total hydro potential for power production – 6,61 TWh/yr.



4. Conclusion


To summarise the potentials for renewables in Slovakia we can conclude that wind, hydro, biomass, geothermal and solar energy can cover all our energy needs in the in case of any disruptions of fossil fuel deliveries in the future. It should be noticed that potentials of hydro and biomass are suggested to be fully utilised (technical potential) and higher gains most likely cannot be expected in the future. Potential for wind is based on recent possibilities and future increase of power production is likely due to the improvements in technology. Wind together with geothermal and solar energy can easily produce more than what is estimated here.


Total potential of RE in Slovakia.


Annual power production in TWh

Annual heat production in PJ




Biomass : Wood, straw, energy plantation









Solar thermal









RE Potential - TOTAL



Annual Slovak power consumption in 2005



Annual Slovak power consumption in 2005




(*) where industry share is 147,9 PJ

individual heating (households) share - 62 PJ

centralised heating systems share - 104,3 PJ