# An Improved Techno-Economic Approach to Determination of More Precise Installed Parameter for Small Hydropower Plants

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## Abstract

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## 1. Introduction

^{2}, which is one of the highest values in Europe. Due to the topographical characteristics of the terrain, intertwined with watercourses, Montenegro’s theoretical hydro potential is rated to 9.8 TWh annually [37]. As Montenegro is classified as one of the European countries with a very rich water potential, it is indisputable that the government must use this potential as the strongest benefit for economic and social development. With adoption of the Energy Law in 2003, as well as the signing of the Agreement on the formation of the Energy Community in 2005, the transformation of the energy sector in Montenegro began [38]. The process of the new SHPPs development campaign in Montenegro began with the adoption of the Small Hydropower Development Strategy in 2006 [39]. During 2010 and 2011, flow on 65 small watercourses was measured under the project named the Registry of Small Rivers and Potential Locations of SHPPs at Municipality Level for Central and Northern Montenegro, and relevant flow duration curves (FDCs) were obtained [40]. This Registry was enhanced during 2018 and 2019 [41]. The Energy Development Strategy of Montenegro until 2030 [42], as well as the National Action Plan for Renewable Energy Sources by 2020 [43], are the planning dynamics of the development of SHPPs.

## 2. Materials and Methods

_{avA}is the average annual flow, Q

_{avD}is the average daily flow, and N

_{D}is the number of days in one year. Secondly, average perennial flow is determined as the arithmetic mean of the average annual flows available for a given period,

_{av}is the average perennial flow and N

_{y}is the the number of years.

_{i}for each watercourse initially ranges from 1.0 to 2.5 [47]. In addition to hydrological data, the collection and unification of suitable types of hydraulic turbines from well-known world manufacturers was carried out, considering and adapting their energy characteristics to the diversity and specifics of mountain rivers. For the obtained values of design flow, a net head, pipeline diameter, installed capacity, and annual electricity production were calculated for the chosen type of the turbine [48]. This procedure gives 16 variants for each watercourse with K

_{i}step of ΔK

_{i}= 0.1 or 608 alternatives of observed parameters (capacity, annual electricity production, income, NPV, IRR, and PB) in total. The analysis of economic parameters was based on regionally current prices, as well as for the European small hydropower market. Then, appropriate mathematical models were made, and in-house software was developed [49,50]. For any value of design flow, the software makes an optimization procedure whose output are net head and diameter of the pipeline. Based on these calculations, the design flow which gives both the highest electricity production, the highest gross income and the best economic parameters has been determined. Administrative provisions often impose external constraints on the design, which may lead to deviations from the optimum sizing of the plant [51]. Such administrative impacts are beyond the scope of the present paper.

_{h}is the hydraulic power, ρ is the mass density, g is the gravitational acceleration, Q

_{d}is the design flow, H

_{n}is the net head, η

_{t}is the turbine efficiency, η

_{g}is the generator efficiency, and η

_{tr}is the transformer efficiency. According to the rules for calculating the purchase price of energy from the SHPPs [52], the incentive energy prices are determined depending on the capacity at the plant’s threshold in the manner defined in Table 1. It should be noted that SHPPs with capacity below 1 MW and above 8 MW have a constant values of incentive price.

_{d}= K

_{i}·Q

_{av}= (1.0 ÷ 2.5)·Q

_{av}, capacity, annual energy production, gross income, NPV, IRR, and PB are calculated for every design flow, where Q

_{av}is averaged perennial flow. Annual energy production is calculated with flow that changes according to FDC, taking into account decreasing turbine efficiency with decreasing flow through the turbine, as well as ecological flow and cut-off flow of the chosen turbine. Cut-off flow or technical minimum of the turbine is the minimum flow rate on which turbine is able to work with sufficient efficiency. Pelton, Cross-flow, and Francis turbines are used as a solution for hydro energy utilization for all rivers with cut-off flow of Q

_{cut-off}= {0.1Q

_{d}; 0.1Q

_{d}; 0.3Q

_{d}}, respectively [53]. The annual gross income of the small power plant is calculated from the generated energy and the incentive energy prices. Based on this approach, investigated rivers can be divided into two groups according to the capacity range (Table 2).

_{i}with a step of 0.1 belong to the proposed range. Group I fits with the range of the incentive price, but this is not the case with Group II, which intersects between different ranges of the incentive price. Group I has 16 SHPPs and Group II has 22 SHPPs. Finally, the initial range of SHPP installed parameter is narrowed for both groups of rivers.

## 3. Results

_{i}. It can be observed that for all 16 watercourses the value of K

_{i}= 2.5 gives the maximum annual electricity production and the maximum income. This is not the case for NPV and IRR. Some watercourses give the value K

_{i}= 2.5, but most offer different ones. In some cases, the same value for K

_{i}is obtained for NPV and IRR, while in some, different values are obtained. Therefore, it can be noticed that if the annual production and annual income are considered as a decision parameter, a practically unambiguous value of K

_{i}= 2.5 is obtained for the considered group of power plants below 1 MW. The situation is completely different if economic parameters are considered as decision criteria. The SHPP installed parameter for the maximum value of NPV is in the range of K

_{i}= (1.3 ÷ 2.5) where only one watercourse has K

_{i}= 1.3, and if it was excluded from consideration then the range of the SHPP installed parameter would further be narrowed to K

_{i}= (1.6 ÷ 2.5). If the IRR is observed, then the SHPP installed parameter is in the range of K

_{i}= (1.6 ÷ 2.5). Thus, the economic parameters of NPV and IRR for a group of power plants with an installed capacity below 1 MW give, it can be said, the same range of the SHPP installed parameter. Payback period corresponds to maximum value of IRR and its range is very wide, i.e., PB = (5.4 ÷ 16.0) years. For Group I, the range of K

_{i}is narrowed from initially K

_{i}= (1.0 ÷ 2.5) to K

_{i}= (1.6 ÷ 2.5) Maximum IRR and NPV is obtained for the Umski SHPP, and they are IRR = 18.94% and NPV = 1466.40 kEUR.

_{i}= 2.5 obtained from all parameters, which means that for this plant’s maximum value of K

_{i}gives the best performance regarding both the technical and economical view. Hridska SHPP started with a capacity of 412.8 kW for K

_{i}= 1.0 and finished with 999.8 kW for K

_{i}= 2.5 having, for all capacities, a constant incentive price (Table 1). Due to this fact, annual electricity production and annual income exhibit permanent and similar rising behavior (Figure 2a). Figure 2b shows the change in NPV, IRR, and PB as a function of K

_{i}. NPV and IRR continuously increase from minimum to maximum value, with NPV having a slightly sharper growth. On the other hand, as expected, PB decreases with the increase in these parameters. The total investment is 1.37 mEUR, and the payback period is PB = 8.7 years.

_{i}= 1.8 is due to the increase in pipeline diameter from DN500 to DN600. With Hridska SHPP, there is no doubt that the value K

_{i}= 2.5 is chosen for the SHPP installed parameter.

_{i}for Jasičje SHPP. The maximum value of annual production and income was obtained for K

_{i}= 2.5 (Figure 3a). This SHPP started with capacity of 323.8 kW for K

_{i}= 1.0 and finished with capacity of 807.2 kW for K

_{i}= 2.5. The total investment for this value of K

_{i}is 1.65 mEUR. Maximum values of NPV (657 kEUR) and IRR (12.34%) are obtained for the same value of the SHPP installed parameter, K

_{i}= 1.9 (Figure 3b). The total investment in this case is 1.46 mEUR and the payback period is 8.2 years. For K

_{i}= 2.0, the diameter increases from DN600 to DN700, which leads to an increase in investment and a decrease in the economic parameters of NPV and IRR. On the other hand, this increase in diameter leads to an increase in annual electricity production and annual income. The difference in annual income obtained for K

_{i}= 2.5 and K

_{i}= 1.9 is around 13 kEUR, and difference in total investment is 190 kEUR. It is obvious here that the value of SHPP installed parameter K

_{i}= 1.9 should be chosen as the best choice for the case investigated.

_{i}for Bukovičko SHPP. This SHPP started with capacity of 285.8 kW for K

_{i}= 1.0 and finished with 716.1 kW for K

_{i}= 2.5. The annual electricity production and income permanently rise up to K

_{i}= 2.5 with a total investment of 1.36 mEUR and a payback period of 9.66 years. On the other hand, maximum values of NPV (378.2 kEUR) and IRR (11.3%) are obtained for K

_{i}= 1.8 and K

_{i}= 1.6, respectively (Figure 4b). Total investment for maximum NPV is 1.15 mEUR and 1.10 mEUR for maximum IRR, and corresponding payback periods are 8.94 and 8.89 years, respectively. The difference in income is 14.3 kEUR compared with income obtained for maximum NPV, and 20.7 kEUR compared with income obtained for maximum IRR. The difference in investment between highest income and maximum NPV is 210 kEUR and between highest income and maximum IRR is 260 kEUR. The difference in investment is more than ten times higher than difference in income, which means that SHPP installed parameters obtained for maximum NPV and IRR are more preferable as optimal solution for Bukovičko SHPP. Keeping in mind that SHPP installed parameter obtained for maximum IRR gives the lower investment and payback period, compared to SHPP installed parameter obtained for maximum NPV, the self-imposed conclusion is that in this particular case the optimal value of SHPP installed parameter is K

_{i}= 1.6.

_{i}. SHPP installed parameter, which for each considered case gives the maximum annual electricity production, has the value K

_{i}= 2.5. Therefore, if maximum annual electricity production was the only parameter under consideration, the maximum value of K

_{i}would always be chosen. If the maximum annual income is observed, then the value of the SHPP installed parameter ranges from K

_{i}= {1.5 ÷ 2.5}, where only three SHPP K

_{i}< 2.0. For the 19 considered SHPPs belonging to the Group II, range of SHPP installed parameter is K

_{i}= {2.0 ÷ 2.5}. It is obvious that higher values of SHPP installed parameters give a higher annual revenue. The situation is quite different when it comes to IRR and NPV for Group II. For both parameters, the range K

_{i}is narrowed, but from the upper limit, and is K

_{i}= {1.0 ÷ 2.1} which can be seen from Table 7. This appears due to the specific price policy in Montenegro, which decreases the incentive price when an SHPP installed capacity becomes higher than 1MW (Table 1). The payback period is also wide, and ranges from 4.3 years for the Trnovačka SHPP to 13.5 years for the Bukovica 1 SHPP. Maximum IRR and NPV is obtained for Trnovačka SHPP and they are IRR = 24.45% and NPV = 2892.4 kEUR.

_{i}= 1.5) and the maximum for annual electricity production (K

_{i}= 2.5); Bistrica Lipovska SHPP, where the SHPP installed parameter is the same for electricity production and income (K

_{i}= 2.5), as well as for IRR and NPV (K

_{i}= 1.3); Vrelo SHPP where the values of the SHPP installed parameter are the same for income and NPV (K

_{i}= 1.9) and different for production (K

_{i}= 2.5) and IRR (K

_{i}= 1.6); and Stožernica SHPP where different values of K

_{i}are obtained for all considered parameters (Table 8).

_{i}.

_{i}= 1.0 and finished with 1606.0 kW for K

_{i}= 2.5. The annual electricity production permanently rises up to K

_{i}= 2.5 with maximum value of 4.643 GWh/year, but it should be noted that annual electricity production is practically the same for K

_{i}= 2.4 and equal to 4.641 GWh/year. The maximum value of annual income is obtained for K

_{i}= 1.5 (Figure 5a), as for this value of SHPP, the installed capacity is below 1 MW (956.4 kW), and for the next value of K

_{i}= 1.6, the installed capacity is 1012.4 kW, which imposes a decrease in incentive price according to Table 1, and an according drop in annual income. Increase in pipeline diameter from DN800 to DN900 for K

_{i}= 1.7 recovers annual income, which rises after that, but not enough to achieve the value obtained for K

_{i}= 1.5. The maximum values of NPV (1580.9 kEUR) and IRR (14.37%) are obtained also for K

_{i}= 1.5 (Figure 5b). Total investment is 2.35 mEUR with the payback period of 7.2 years. There is no doubt that K

_{i}= 1.5 is the optimal solution for Kaludarska SHPP.

_{i}= 1.0 and finished with 1890.0 kW for K

_{i}= 2.5. From Figure 6a, it can be seen that the transition from one equation for calculating the incentive price to another occurs for K

_{i}= 1.4, when changing installed capacity from 986 kW for K

_{i}= 1.3 to 1052 kW for K

_{i}= 1.4. Due to that, the annual income decreases from 457.3 kEUR for K

_{i}= 1.3 to 437.5 kEUR for K

_{i}= 1.4. Unlike the previously considered case (Kaludarska SHPP), Bistrica Lipovska SHPP has a rapid recovery of annual income for K

_{i}= 1.5, due to the transition from pipeline diameter from DN1100 to DN1200, and its further growth up to a maximum value of 496.7 kEUR for K

_{i}= 2.5.

_{i}= 1.3, namely NPV = 2237.1 kEUR and IRR = 18.65%. Payback period that corresponds to maximum IRR is PB = 5.6 years. Total investment for K

_{i}= 1.3 is 1.91 mEUR and total investment for K

_{i}= 2.5 is 2.71 mEUR, with difference in investment of 800 kEUR. The difference in annual income between K

_{i}= 2.5 and K

_{i}= 1.3 is 39.4 kEUR, which means that the invested funds are 20.3 times higher than the income that can be realized if K

_{i}= 2.5 is chosen as the optimal value. In this particular case of Bistrica Lipovska SHPP, it is obvious that the optimal value of SHPP installed parameter is K

_{i}= 1.3.

_{i}= 1.0 and finished with 1268.1 kW for K

_{i}= 2.5. As in all previous cases, maximum annual electricity production is obtained for K

_{i}= 2.5. Annual income has similar behavior as for Kaludarska SHPP; it has maximum for K

_{i}= 1.9, and after that has sharp drop for K

_{i}= 2.0 due to crossing the border of 1 MW of plant installed capacity. Maximum NPV = 2069.6 kEUR is also obtained for K

_{i}= 1.9, and for this plant NPV and annual income give the same optimal value of SHPP installed parameter. On the other hand, maximum IRR = 20.93% is obtained for K

_{i}= 1.6, but with a very close value of 20.11% for K

_{i}= 1.9. Payback period is 4.97 years for K

_{i}= 1.6 and 5.17 years for K

_{i}= 1.9. Consequently, it could be concluded that K

_{i}= 1.9 is the optimal value for Vrelo SHPP.

_{i}= 1.0 and finished with 1667.5 kW for K

_{i}= 2.5. The maximum annual electricity production is obtained for K

_{i}= 2.5, while annual income has one extreme for K

_{i}= 1.4 (capacity 944.8 kW), dropping after that for K

_{i}= 1.5 (capacity 1004.5 kW), due to crossing the border of 1 MW, and finally rising with practically constant value of around 447 kEUR for K

_{i}= (2.2 ÷ 2.5). A maximum value of 447.7 kEUR is obtained for K

_{i}= 2.3. This annual income is higher than income obtained for K

_{i}= 1.4 for 7.4 kEUR, and the difference in investment for K

_{i}= 2.3 and K

_{i}= 1.4 is 560 kEUR. It is clear that K

_{i}= 1.4 is more favorable as an optimal solution. This is confirmed in Figure 8b. A maximum value of NPV = 2055.5 kEUR is also obtained for K

_{i}= 1.4, with a permanent drop after this value of SHPP installed parameter. IRR has maximum value of 18.07% for K

_{i}= 1.2, but is very close to the value obtained for K

_{i}= 1.4, which is 17.77%. There is no doubt that the optimal solution for Stožernica SHPP is K

_{i}= 1.4.

## 4. Conclusions

_{i}= (1.0 ÷ 2.5) is adopted and for each value, with step of ΔK

_{i}= 0.1, the main techno-economic parameters of every plant are calculated with 608 alternatives in total. According to these parameters, optimal and more accurate values of SHPP installed parameters are defined by narrowing its range.

- 1.
- Annual electricity production and annual income give the highest examined value of K
_{i}= 2.5 as the optimal solution for all considered plants. - 2.
- The economic parameters NPV and IRR narrowed the initial value of SHPP installed parameter range to K
_{i}= (1.6 ÷ 2.5). - 3.
- By studying a few typical examples, it can be noticed that NPV and IRR have more influence on the choice of SHPP installed parameter compared to annual electricity production and income.

- 4.
- Annual electricity production for any case gives chosen upper limit of K
_{i}= 2.5 as the optimal solution. - 5.
- The highest annual income gives the range of SHPP installed parameter range of K
_{i}= (2.0 ÷ 2.5). - 6.
- NPV and IRR also narrow the range of the K
_{i}, but from the upper limit, and for this group of plants it is K_{i}= (1.0 ÷ 2.1). - 7.
- Examination of several typical examples shows that NPV and IRR are more influential parameters for choosing K
_{i}compared to annual electricity production and income. - 8.
- Due to higher and constant incentive price, the SHPP installed parameter which gives capacity below 1 MW can always be chosen as the optimal solution.

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Conflicts of Interest

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**Figure 1.**Locations where SHPPs are envisaged [39].

**Figure 2.**(

**a**) Annual electricity production and income—Hridska SHPP; (

**b**) NPV, IRR, and PB—Hridska SHPP.

**Figure 3.**(

**a**) Annual electricity production and income—Jasičje SHPP; (

**b**) NPV, IRR, and PB—Jasičje SHPP.

**Figure 4.**(

**a**) Annual electricity production and income—Bukovičko SHPP; (

**b**) NPV, IRR, and PB—Bukovičko SHPP.

**Figure 5.**(

**a**) Annual electricity production and income—Kaludarska SHPP; (

**b**) NPV, IRR, and PB—Kaludarska SHPP.

**Figure 6.**(

**a**) Annual electricity production and income—Bistrica Lipovska SHPP; (

**b**) NPV, IRR, and PB—Bistrica Lipovska SHPP.

**Figure 8.**(

**a**) Annual electricity production and income—Stožernica SHPP; (

**b**) NPV, IRR, and PB—Stožernica SHPP.

**Table 1.**Electricity prices depending on the capacity of the power plant [52].

Hydro Power Plant Capacity (MW) | Incentive Price (cEUR/kWh) |
---|---|

P_{SHPP} < 1 MW | 10.44 |

1 ≤ P_{SHPP} $<$3 MW | 10.44 − 0.7·P_{SHPP} |

3 ≤ P_{SHPP} $<$5 MW | 8.87 − 0.24·P_{SHPP} |

5 ≤ P_{SHPP} $<$8 MW | 8.35 − 0.18·P_{SHPP} |

8 ≤ P_{SHPP} $\le $ 10 MW | 6.8 |

River Group | Capacity Range | Remark |
---|---|---|

I | P_{SHPP} < 1 MW | fits with incentive price range |

II | 0.4 MW ≤ P_{SHPP} ≤ 2.4 MW |

**Table 3.**Maximum annual production and income and corresponding SHPP installed parameter for SHPPs below 1 MW—Group I, (*—constructed plants).

No | SHPP Name | Annual Electricity Production (GWh) | Annual Income (kEUR) | K_{i} for Max Electricity Production | K_{i} for Max Income | Current K_{i} for (*) |
---|---|---|---|---|---|---|

1 | Jasičje | 2.53 | 264.4 | 2.5 | 2.5 | |

2 | Štitarička 1 | 2.65 | 276.6 | 2.5 | 2.5 | |

3 | Bijela 1 | 2.12 | 221.7 | 2.5 | 2.5 | |

4 | Mišnića * | 0.77 | 81.3 | 2.5 | 2.5 | 1.0 |

5 | Slatina | 0.90 | 94.2 | 2.5 | 2.5 | |

6 | Šeremet * | 2.25 | 235.5 | 2.5 | 2.5 | 2.3 |

7 | Bukovičko | 1.97 | 205.8 | 2.5 | 2.5 | |

8 | Rupočajski | 2.34 | 244.8 | 2.5 | 2.5 | |

9 | Lazanska | 2.09 | 218.7 | 2.5 | 2.5 | |

10 | Kozička | 2.42 | 253.1 | 2.5 | 2.5 | |

11 | Bukeljka | 1.98 | 207.1 | 2.5 | 2.5 | |

12 | Rmuš * | 1.59 | 166.8 | 2.5 | 2.5 | 1.8 |

13 | Spaljevići * | 2.35 | 246.2 | 2.5 | 2.5 | 1.7 |

14 | Umski * | 3.01 | 314.4 | 2.5 | 2.5 | 1.1 |

15 | Javorski | 2.74 | 286.7 | 2.5 | 2.5 | |

16 | Hridska * | 2.18 | 228.0 | 2.5 | 2.5 | 1.5 |

**Table 4.**Internal rate of return, net present value, payback period, and corresponding SHPP installed parameter for SHPPs below 1 MW—Group I.

No | SHPP Name | IRR (%) | NPV (kEUR) | PB for Max IRR (year) | K_{i} for Max IRR (%) | K_{i} for Max NPV |
---|---|---|---|---|---|---|

1 | Jasičje | 12.35 | 656.9 | 8.2 | 1.9 | 1.9 |

2 | Štitarička 1 | 10.18 | 399.4 | 9.7 | 2.0 | 2.1 |

3 | Bijela 1 | 8.78 | 118.2 | 11.6 | 2.0 | 2.0 |

4 | Mišnića | 5.37 | 163.9 | 16.0 | 1.9 | 1.8 |

5 | Slatina | 7.09 | 58.8 | 13.6 | 1.9 | 1.8 |

6 | Šeremet | 14.11 | 745.3 | 7.3 | 1.8 | 2.1 |

7 | Bukovičko | 11.30 | 378.2 | 8.9 | 1.6 | 1.8 |

8 | Rupočajski | 15.42 | 876.4 | 6.7 | 1.9 | 2.5 |

9 | Lazanska | 7.67 | 58.2 | 12.8 | 2.5 | 2.5 |

10 | Kozička | 6.07 | 377.1 | 14.8 | 1.8 | 1.3 |

11 | Bukeljka | 6.51 | 247.4 | 14.2 | 2.5 | 1.6 |

12 | Rmuš | 6.38 | 225.1 | 14.4 | 2.5 | 2.5 |

13 | Spaljevići | 10.19 | 369.2 | 9.7 | 2.5 | 2.5 |

14 | Umski | 18.94 | 1466.4 | 5.4 | 1.7 | 2.3 |

15 | Javorski | 14.05 | 958.1 | 7.3 | 2.5 | 2.5 |

16 | Hridska | 11.63 | 507.9 | 8.7 | 2.5 | 2.5 |

SHPP Name | K_{i} for Max Electricity Production and Max Income | K_{i} for Max IRR (%) | K_{i} for Max NPV | PB for Max IRR (year) |
---|---|---|---|---|

Hridska | 2.5 | 2.5 | 2.5 | 8.7 |

Jasičje | 2.5 | 1.9 | 1.9 | 8.2 |

Bukovičko | 2.5 | 1.6 | 1.8 | 8.9 |

**Table 6.**Maximum annual production and income and corresponding SHPP installed parameter for SHPPs from 0.4 MW to 2.4 MW—Group II, (*—constructed plants).

No | SHHP Name | Annual Electricity Production (GWh) | Annual Income (kEUR) | K_{i} for Max Electricity Production | K_{i} for Max Income | Current K_{i} for (*) |
---|---|---|---|---|---|---|

1 | Kaludarska | 4.64 | 435.2 | 2.5 | 1.5 | |

2 | Stožernica | 4.81 | 447.7 | 2.5 | 2.3 | |

3 | Vrelo * | 3.89 | 402.7 | 2.5 | 1.9 | 1.3 |

4 | Skrbuša | 4.46 | 417.6 | 2.5 | 2.5 | |

5 | Radmanska | 3.76 | 359.6 | 2.5 | 1.7 | |

6 | Bistrica Lipovska * | 5.44 | 496.7 | 2.5 | 2.5 | 1.3 |

7 | Pecka * | 3.32 | 331.7 | 2.5 | 2.1 | 2.0 |

8 | Trnovačka | 5.97 | 534.2 | 2.5 | 2.4 | |

9 | Hotska | 4.50 | 412.7 | 2.5 | 2.5 | |

10 | Jasenička | 4.72 | 429.6 | 2.5 | 2.4 | |

11 | Bukovica 2 | 6.35 | 559.9 | 2.5 | 2.5 | |

12 | Požnja | 4.95 | 454.2 | 2.5 | 2.5 | |

13 | Ljevak * | 4.65 | 433.0 | 2.5 | 2.5 | 1.0 |

14 | Koložun | 3.90 | 357.7 | 2.5 | 2.5 | |

15 | Rzački | 3.21 | 322.9 | 2.5 | 2.0 | |

16 | Meteška | 2.59 | 255.8 | 2.5 | 2.0 | |

17 | Bjelojevićka | 3.23 | 321.3 | 2.5 | 2.0 | |

18 | Crnja | 2.65 | 258.4 | 2.5 | 2.1 | |

19 | Bukovica 1 | 2.78 | 282.7 | 2.5 | 2.3 | |

20 | Vinicka | 2.73 | 276.7 | 2.5 | 2.0 | |

21 | Paljevinska * | 2.28 | 230.5 | 2.5 | 2.3 | 1.4 |

22 | Štitska * | 2.78 | 264.9 | 2.5 | 2.5 | 2.0 |

**Table 7.**Internal rate of return, net present value, payback period, and corresponding SHPP installed parameter for SHPPs from 0.4 MW to 2.4 MW—Group II.

No | SHHP Name | IRR (%) | NPV (kEUR) | PB for Max IRR (year) | K_{i} for Max IRR | K_{i} for Max NPV |
---|---|---|---|---|---|---|

1 | Kaludarska | 14.37 | 1580.9 | 7.2 | 1.5 | 1.5 |

2 | Stožernica | 18.07 | 2055.5 | 5.7 | 1.2 | 1.4 |

3 | Vrelo | 20.93 | 2069.6 | 5.0 | 1.6 | 1.9 |

4 | Skrbuša | 20.80 | 2185.6 | 5.0 | 1.5 | 1.6 |

5 | Radmanska | 15.80 | 1421.5 | 6.5 | 1.2 | 1.7 |

6 | Bistrica Lipovska | 18.65 | 2237.1 | 5.6 | 1.3 | 1.3 |

7 | Pecka | 11.99 | 808.8 | 8.4 | 1.7 | 2.1 |

8 | Trnovačka | 24.45 | 2892.4 | 4.3 | 1.1 | 1.7 |

9 | Hotska | 13.85 | 1342.6 | 7.4 | 1.3 | 1.3 |

10 | Jasenička | 15.69 | 16555 | 6.6 | 1.2 | 1.2 |

11 | Bukovica 2 | 11.01 | 961.2 | 9.0 | 1.0 | 1.0 |

12 | Požnja | 19.91 | 2161.6 | 5.2 | 1.2 | 1.3 |

13 | Ljevak | 19.65 | 2097.6 | 5.3 | 1.5 | 1.5 |

14 | Koložun | 13.90 | 1041.2 | 7.4 | 1.3 | 1.3 |

15 | Rzački | 17.80 | 1436.4 | 5.8 | 1.7 | 2.0 |

16 | Meteška | 9.85 | 316.9 | 9.9 | 2.0 | 2.0 |

17 | Bjelojevićka | 16.08 | 1292.3 | 6.4 | 1.7 | 2.0 |

18 | Crnja | 8.27 | 55.5 | 12.1 | 2.1 | 2.1 |

19 | Bukovica 1 | 7.07 | 192.2 | 13.5 | 1.5 | 1.5 |

20 | Vinicka | 13.05 | 792.3 | 7.8 | 1.5 | 1.8 |

21 | Paljevinska | 13.05 | 125.7 | 11.6 | 1.5 | 1.5 |

22 | Štitska | 12.31 | 679.1 | 8.2 | 1.9 | 1.9 |

SHPP Name | K_{i} for Max Electricity Production | K_{i} for Max Income | K_{i} for Max IRR (%) | K_{i} for Max NPV | PB for Max IRR (year) |
---|---|---|---|---|---|

Kaludarska | 2.5 | 1.5 | 1.5 | 1.5 | 7.2 |

Bistrica Lipovska | 2.5 | 2.5 | 1.3 | 1.3 | 5.6 |

Vrelo | 2.5 | 1.9 | 1.6 | 1.9 | 5.0 |

Stožernica | 2.5 | 2.3 | 1.2 | 1.4 | 5.7 |

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**MDPI and ACS Style**

Vilotijević, V.; Karadžić, U.; Vujadinović, R.; Kovijanić, V.; Božić, I. An Improved Techno-Economic Approach to Determination of More Precise Installed Parameter for Small Hydropower Plants. *Water* **2021**, *13*, 2419.
https://doi.org/10.3390/w13172419

**AMA Style**

Vilotijević V, Karadžić U, Vujadinović R, Kovijanić V, Božić I. An Improved Techno-Economic Approach to Determination of More Precise Installed Parameter for Small Hydropower Plants. *Water*. 2021; 13(17):2419.
https://doi.org/10.3390/w13172419

**Chicago/Turabian Style**

Vilotijević, Vidosava, Uroš Karadžić, Radoje Vujadinović, Vuko Kovijanić, and Ivan Božić. 2021. "An Improved Techno-Economic Approach to Determination of More Precise Installed Parameter for Small Hydropower Plants" *Water* 13, no. 17: 2419.
https://doi.org/10.3390/w13172419