Small Hydro Power Plants in Croatia

Zarko Janic

Abstract: This paper provides information about small hydro power plants in Croatia. The MAHE program (National Program of Small Hydro Power Plants Construction) has been described. Hydrological potential, costs and the prospects of small hydro plants in Croatia have been also described.

Keywords: Small hydro power plants, MAHE

1. Introduction

The hydro power plants can be categorized in many ways – type of the turbine, size etc. Small hydro power plants are plants with an installed power smaller than the limit. The limit varies from state to state, in Croatia small plants are those from 10 kW to 5000 kW (5 MW) of installed power. In the European union and in the most countries of the world the limit is 10MW. Small hydro power plants can also be categorized in several ways but in this paper this issues will not be discussed. The first power plants and the first steps in the electrification of the world started mostly with small hydro power plants something more than a 100 years ago. Nowadays, the same processes are happening in remote parts of Africa, South America and Asia. [1] Programs for the energy efficiency and usage of renewable energy sources were started in 1997, by the Croatian government, among them the National Program of Small Hydro Power Plants Construction called MAHE. [1]

2. Small hydro power plants in the world

Among the renewable sources of energy in the world, hydro power plants produce the most electric energy.Among the hydro power plants, small hydro power plats make about 7% of installed power (approx. 50 GW). The potential for the total installable power is estimated to be about 180 GW, which is about 6% of the estimated total installable power in hydro power plants (for this statistics small hydro power plants were considered those with an installed power less than 10 MW).

Table 1 [3]Continent No. of small

hydro plantsInstalled power (MW)

Africa 165 1048,27Asia 45720 29877,489Australia an Oceania

73 157,98

Europe (without Russia and Turkey)

17328 2398,42

North and Central America

615 4113,25

South America 438 1175,19Total 64339 48770,599

Small hydro power plants are increasing its importance in the power systems of the developed countries. There is a very large number of plants built all over the world and because of the good experiences in building and working the interest for them is increasing. Most of the small hydro power plants are private property and the

numbers in table 1 show their popularity. There were more than 60000 small power plants in the world in 2002. – the statistics are based on approximately 66% of the countries.In Europe the countries with most small hydro plants and the most installed power are shown in table 2.

Table 2 [3]

CountryInstalled power

(MW)

No. of small hydro power plants

Austria 670 1720Czech rep. 200 1200France 1972 1717Germany 1300 6000Italy 2000 1510Norway 950 550Spain 1540 *Sweden 1050 1615Switzerland 750 1000

* - Data not available

3. Small hydro power plants in Croatia

There are 31 operating small power plants in Croatia with the total of about 73MW of installed power. Nine plants are private property, two are industrial plants and the rest is owned by the Croatian Electric Utility (some of which plants of biological minimum on the dams of large hydro plants) – see Appendix A. There are few more plants constructed and not in use for some time which could be used again. The first step in planning and building small hydro power plants in Croatia was in 1981. when Elektroprojekt published the “Plan for Development of Small Hydro Power Plants in Croatia until 2000” [4]. The next document made was “Methodology and Guidelines for Design and Construction of Small Hydro Plants in Croatia” [5] in 1982 which set criteria and guidelines for the next elaborates. The “Register of Small Streams” [6], the “Register of Small Hydro Power Plants – Stage I.” [7] and the “Register of Small

Hydro Power Plants – Stage II.A” [8] then followed. [1]

4. Croatian hydro potential

The Register of Small Streams (KMVS), which was made in 1985, gave the first assessment of possible locations on 134 streams. From those 63 streams have been judged as suitable for small hydro power plants. On those 63 streams 699 locations were identified. All of them were categorized in 4 categories – see table 3. The total installed power on those 699 locations could be about 177 MW (natural gross power of 135 MW), and the technically usable annual production of 567,7 GWh (natural gross potential of 1180 GWh). The first category is the most interesting for investors but they are mostly in areas of protected environment, although they can be very well incorporated with the environment their future is uncertain. Because of the small net head, very high flow and, consequently, a small installed power and small amount of energy, the fourth category can be eliminated.

Table 3 [2]

1

No. of locations 108Average net head 16,62mMaximum flow 8,04m3/sAverage installed pover 791,3 kWAverage annual production 3564 MWh

2

No. of locations 244Average net head 5,33mMaximum flow 9,81m3/sAverage installed pover 247,35 kWAverage annual production 1115 MWh

3

No. of locations 231Average net head 3,11mMaximum flow 6,69m3/sAverage installed pover 95,47 kWAverage annual production 430 MWh

4

No. of locations 116Average net head 0,998mMaximum flow 13,08m3/sAverage installed pover 73,53 kWAverage annual production 346 MWh

The table 4 shows that less than 3% of the locations would have an installed power between 5 and 1,5 MW but more important is that its installed power would be nearly 1/3 of the total installed power.Table 4 [2]Installed power (kW)

No. of locations

Total installed power (kW)

5000-1500 20 (3%) 50232 (29%)1500-1000 17 (2%) 21723 (12%)1000-500 42 (6%) 28768 (16%)500-100 296 (42%) 55667 (31%)Under 100 324 (47%) 20765 (12%)TOTAL 699 177155

It was planed that the Register of Small Hydro Power Plants (KMHE) would be made in two stages. The first stage gave the designs for plants on 13 streams. 50 possible locations were identified (see Appendix B) and 10 of the possible locations were studied more thoroughly giving basic principles for constructing plants (guidelines for the type of structures, hydro mechanical equipment etc.). The selected 13 streams are Bregana, Brzaja, Buticnica, Cabranka, Jadro, Krupica, Krusa, Ljuta, Orljava, Ovrlja, Ruda Velika, Rumin Veliki and Zrnovnica. It was planed that the Stage II would study all the other streams but it was not carried out according to the plan, so only 4 streams have been studied – Cuckov Jarak, Kupcina, Slapnica and Vitunjcica. In those 4 streams 17 possible locations were identified – see Appendix C.

5. Pilot program

In 1998 the pilot program has been started. The program included 50 locations from the first stage of the Register of small hydro power plants, 17 from the second (II.A) stage and more 10 as a result of interest of investors in some locations. This way the program wanted to encourage building of small hydro power plants. The main goal of the pilot program was to test the procedure of planning, engineering and

building small hydro power plants. The more accurate Croatian potential of small hydro power plants would be one of the results as well. [3]Based on the contact with the institutions the environmental protection and cultural heritage protection restrictions were identified as the more restricting. One of the main reasons is the current approach so that all the restrictions are made for the whole stream and not for specific locations. [3]

Table 5 [3]Location

1. Butisnica 12. Butisnica 23. Cetina - Cikotina lada4. Cetina - Vinalic5. Jadro 26. Jadro 27. Kupcina 28. Kupcina 39. Kupcina 410. Kupcina 511. Kupcina 712. Ljuta 213. Mirna – bridge14. Orljava 115. Orljava 216. Orljava 317. Orljava 418. Orljava 4-119. Orljava 520. Orljava 621. Orljava 722. Orljava 823. Ovrlja 124. Pantana 125. Ruda Velika 126. Ruda Velika 227. Vitunjcica 128. Vitunjcica 229. Vitunjcica 330. Zrmanja Vrelo 1

As a result of space-planning 33 locations have been eliminated. Two projects (Krupa 3 and 4) have been joint into one project so 41 project went to the next level (2 projects were added later on). Based on the cultural heritage and environmental protection more 13 projects have been eliminated,

leaving 30 locations in the pilot programs – table 5. [3]

6. Finances

According to the regulations in the energy sector “Besides the Croatian Electric Utility (HEP), persons, companies and other legal persons can also produce and distribute electric power.” so it is a possibility for investors because of the easy construction and maintenance as well as the good rate of return. [9]One of the key issues is the construction cost. The four categories from the previous chapter give four categories of construction costs. The coefficient of the profitability (Cp) gives an approximate picture of the construction cost. [10]

Ctot – total costPmax – maximum installed power

These are the estimations of the construction costs per installed power for the four categories. [10]

1. Cp 2500 US$/kW2. 2500 US$/kW Cp 4500 US$/kW3. 4500 US$/kW Cp 6000 US$/kW4. 6000 US$/kW Cp

The percentages of specific parts of the total cost are shown in table 6.

Table 6 [2]Preparation and construction 40-70%Hydro-mechanical equipment 1-2%Electric and machinery equipment 20-40%Connection with the electric system Up to 20%Other (studies, project, buy offs etc.) 5-10%

The Croatian Electric Utility guarantees the buying of the entire production of

electric energy. The price is set by the regulations. For plants whose installed power is under 500kW is 75% of the average price of electric energy and for plants with an installed power grater than 500kW is 65% of the average price of electric energy for buyers [2]. Calculations for a pilot project (Krupa-3), done by MAHE, show that the project is profitable.The MAHE program suggests that because most of the locations are located in rural undeveloped areas and areas of special state care (occupied areas or areas on the first line during the war), the local government should encourage such programs to gain advantages for the local community (through taxes, concessions etc.). Such facilitations should be introducing the possibility of power plants in urban plans, permission for the building etc even prior to the interest of investors.

7. Environmental impact

Small hydro plants, as all other types of plants, have environmental impacts. Because of their small size, if constructed taking into account all factors, they can have a really small impact or even improve it. The basic impacts on the environment are the change in the parameters of water (percentage of oxygen in the water, decrease of speed of the flow, level of the water, possible decrees of biodiversity etc.). The most important is to estimate correctly the biological minimum. If it is not calculated correctly it can result in extinction of plants and animals, especially in the zone between the intake and the exhaust. There are a lot of endemic and rare species in Croatia, which makes these calculations even more important. For example Switzerland the Mattheyes equation is used for calculating the biological minimum [10].

Vmin – biological minimum (l/s)V347 – water flow in 347 days in year (l/s)

There is always the possibility of the contamination by various types of oil and other liquids used during construction and use of the plant. Knowing that the most profitable locations in Croatia are those in National parks and other areas of protected environment, the standards for these plants should be set high and the authorities should strictly control their appliance. Because of the small size of small hydro power plant accumulation lake, it should not have a big impact on the level of underground water, which can have a significant impact on the surrounding vegetation. Level of noise produced by the equipment, nowadays, is considerably under the recommended levels so no noise contamination should be experienced.There are a lot of possible good impacts. First of all is the decrease of the possibility of floods. Small hydro plants as one of the renewable types of plants do not use fossil fuels. For example a 5 MW plant using fossil fuels uses 1400 toe (tons of oil equivalent) per year. It also produces about 16000t of carbon dioxide (CO2) and 1100t of sulfur dioxide (SO2). The structure itself (the dam and the powerhouse) can be a degradation of the environment but not necessarily. The powerhouse can be built underground or well integrated in the environment. The dam can also be well integrated in the surrounding environment. Special attention should be given to road construction, used during building of the structure and for later maintenance. The accumulation lake can be attractive for fishing, tourism, recreation etc. One of Croatian’s priorities is tourism. Nowadays the continental part (and the whole non-coastal part) of Croatia is not yet valorized enough as a tourist destination so small hydro power plants can be a possible

location for development of recreation or fishing tourism.

8. Conclusion

The legislation was not discussed in the paper, the main reason is a lack of experience and consequently the necessary time for gaining all approvals is hard to estimate - it should be 4-5 years. For example in Switzerland it is 1-3 years, in Austria from 3 months (theoretical minimum) to several years. [2]The register of small hydro power plants has not been carried out completely so some of the water streams are not yet considered and possible locations are not yet identified. Because of the approach to restrictions, which apply to the whole stream, it is nearly impossible to build a small hydro power plant [3].The possibility of integrating small hydro power plants in the water supply system has not yet been studied in Croatia. Turbines can be installed in the closed systems with a fall. For example in Czech republic and Slovakia there is more than 3,3MW of installed power on 22 locations in the potable water supply system. [3]External costs are not yet included in the price of electric energy. It would give an advantage to small hydro power plants as they do not emit any harmful gases or particles. Studies show that because most of locations are in rural area, small hydro power plant would give an increase of stability of electric energy supply and in some cases a decrease of loses in electric energy transmission [3].Regulations on the use of renewable energy sources are in the procedure and the draft version provides a system of bonuses for among others small hydro power plants by annual bonuses depending on the annual energy production. [11] The Croatian government is preparing a decision on the minimal share of

renewable sources of energy for all distributors in Croatia. It should be 4,5% of energy, which cannot be less than 300MW [12]. Maybe those regulations will actualize the building of small hydro power plants in Croatia.References[1] Austrian National Committee on Large Dams: Austrian hydro power professionals 2nd edition[2] Basic, Hubert et al.: MAHE: National Program of Small Hydro Power Plants Construction, Energy institute Hrvoje Pozar, Zagreb, 1998.[3] Basic, Hubert: New Approach to Planning Small Hydro Power Plants Construction, Faculty of Electric Engineering and Computing, doctor’s dissertation, Zagreb 2003[4] Plan for Development of Small Hydro Power Plants in Croatia until 2000, Elktroprojekt inzenjering, Zagreb, 1981[5] Methodology and Guidelines for Design and Construction of Small Hydro Plants in Croatia, Elektroprojekt inzenjering, Zagreb, 1982[6] Register of Small Streams, Elektroprojekt inzenjering, 1989.[7] Register of Small Hydro Power Plants – Stage I., Elektroprojekt inzenjering, 1993.[8] Register of Small Hydro Power Plants – Stage II.A, Elektroprojekt inzenjering, 1993.[9] Croatian Electric Utility: Small Hydro-Power Plants, Croatian Electric Utility, Zagreb, 1993.[10] Labudovic, Boris et al.: Renewable energy sources, Energetika marketing, Zagreb, 2002.[11] Regulations on the Use of Renuwable Energy Sources, draft version no. 19, August 19 2003[12] Decision on Minimal Share of Renewable Sources of Energy, without Large Hydro Power Plants, in the Structure of Electric Energy of the Companies Involved in Electric Energy Distribution, draft version

Zarko Janic was born in Pula, Croatia, in 1980. He is a student at the Department of Power Systems of the Faculty of Electrical Engineering and Computing in Zagreb, Croatia. He has been among the 10% of the most successful students of the Faculty throughout his studies. He is the winner of the Josip Loncar Award in 2002 and 2003, and the Hrvoje Pozar Award in 2003. He is a member of DOOR – Society for Sustainable Development Design and of DOOR working group for the project MojaEnergija (MyEnergy).

Contact:Zarko Janiczarko.janic@pu.htnet.hrGinzkeyeva 1, 52100 Pula, Croatia

DOOR – Society for Sustainable Development Design,Unska 3, 10000 Zagreb, Croatia

Appendix A

Operating small hydro power plant in Croatia [5]

NameInstalled power

(MW)Average annual production

(GWh)HE Mreznica 2 0,004 *HE Mreznica 2 0,006 0,042HE Cabranka 2 0,008 *HE Kupa 2 0,01 *HE Finvest II 2 0,03 0,13HE Kupcina 6 2 0,045 0,6HE Orljava 7 2 0,065 *HE Pamucna industrija Duga Resa 1 1,16 3,87

HE Tvornica cementa “10. kolovoza” Majdan 1 1,2 3,5

HE Finvest I 2 1 3,17HE Roski slap 2 1,4 5,583HE Krcic 3 0,3 2HE Gojak 3 0,32 *HE Varazdin 3 0,585 3,8HE Vinodol 3 0,4 *HE Senj 3 0,64 *HE Orlovac 3 0,8 0,6CHE Lepenica 3 1,1 0,5HE Cakovec 3 1,44 9,03HE Zavrelje 3 1,47 4HE Dubrava 3 1,8 11,3HE Zeleni Vir 3 1,8 8HE Ozalj II 3 2,2 10HE Zakucac 3 2,4 3,2HE Ozalj I 3 3,3 14,1CHE Fuzine 3 4 4,5HE Kraljevec 3 4,77 23,666CHE Busko Blato 3 4,8 0HE Jaruga 3 5,6 35HE Golubic 3 6,54 20,1HE Miljacka 3 24 115TOTAL 73,193 281,691

1 – Industrial power plant2 – Private property3 – owned by Croatian Electric Utility* – data not available

Appendix B

Possible 50 locations from the Register of Small Hydro Power Plants – Stage I. [1]

StreamInstalled power

(kW)Annual production

(kWh)Installed stream

flow (m3/s)Net head

(m)Bregana-1 43 267294 0,5 10,90Bregana-2 49 304813 0,5 12,43Bregana-3 33 209176 0,5 8,53Bregana-4 49 313190 0,5 12,90Bregana-5 45 302603 0,5 11,53Bregana-6 55 374435 0,5 13,95Bregana-7 129 823048 1,6 10,27Brzaja-1 63 339102 0,3 26,78Brzaja-2 70 374177 0,3 29,55Brzaja-3 39 226650 0,3 16,44Brzaja-4 37 216723 0,3 15,72Butisnica-1 473 2783439 2,8 21,52Butisnica-2 84 553607 2,8 3,84Cabranka-1 185+45 1330538 0,7 + 0,3 35 + 21Cabranka-2 207 989007 1,8 14,62Cabranka-3 220 1051919 1,8 15,55Cabranka-4 233 1200605 1,8 16,46Cabranka-5 232 1196229 1,8 16,40Cabranka-6 216 1114535 1,8 15,28Cabranka-7 399 1841314 3,3 15,41Cabranka-8 1378 6355581 3,3 53,19Cabranka-9 402 1853263 3,3 15,51Cabranka-10 469 2165127 3,3 18,12Jadro-1 192 996421 6,87 3,57Jadro-2 200 1035712 4,81 5,30Krupa-1 542 2413805 2,8 24,67Krupa-2 1070 4003032 8,6 15,86Krupa-3 1592 6039890 10,0 2,03Krupa-4 1084 4126804 10,0 13,81Krupa-5 1435 5506079 10,0 18,28Krupica-1 1380 5534534 10,0 17,59Krupica-2 1406 5513359 23,0 7,79Ljuta 2206 8245366 7,5 37,48Orljava-1 132 684139 2,5 6,74Orljava-2 75 389902 2,5 3,83Orljava-3 98 512402 2,6 4,82Orljava-4 90 461321 3,1 3,68Orljava-5 156 804902 4,7 4,23Orljava-6 251 1298774 5,4 5,92Orljava-7 217 1121439 7,9 3,50Orljava-8 159 823719 8,1 2,50Ovrlja 72 418272 1,03 8,91Ruda Velika-1 702 4484196 10,0 8,95Ruda Velika-2 415 2558540 17,0 3,11Ruda Velika-3 149 1306123 5,0 3,80Rumin Veliki 364 1555486 8,7 5,33Zrnovnica-1 325 1619318 1,8 23,03Zrnovnica-2 332 1651662 1,8 23,49Zrnovnica-3 129 644071 1,8 9,16Zrnovnica-4 77 383911 1,8 5,46

Appendix C

Possible 17 locations from the Register of Small Hydro Power Plants – Stage II.A [1]

StreamInstalled power

(kW)Annual production

(kWh)Installed stream

flow (m3/s)Net head

(m)Cuckov Jarak 190 115740 0,3 73,30Kupcina-1 98 608400 0,2 57,80Kupcina-2 23 136800 1,0 2,60Kupcina-3 26 157300 1,3 2,30Kupcina-4 65 399400 2,3 3,30Kupcina-5 37 232600 2,6 1,70Kupcina-6 60 369400 2,6 2,70Kupcina-7 37 246300 2,6 1,8Slapnica-1 50 296800 0,4 14,10Slapnica-2 45 269400 0,4 12,80Slapnica-3 40 239400 0,5 9,10Slapnica-4 66 400000 0,8 9,50Slapnica-5 86 526300 0,8 12,50Slapnica-6 109 648900 0,9 13,70Vitunjcica-1 56 276600 3,3 2,00Vitunjcica-2 56 271600 3,6 1,80Vitunjcica-3 56 306400 4,3 1,70