HIDROENERGIA 2006 7th – 9th June 2006 Grieff – Scotland United Kingdom
SUCCESSFUL IMPLEMENTATION OF SMALL HYDROPOWER IN MAXIMAZING THE BENEFITS OF OPTIMAL MULTIPURPOSE RESERVOIR USE Prof.dr Sreten Škuletić Faculty of Electrical Engineering, University of Montenegro
Milica Vujović Electric Power Industry of Montenegro, National Dispatching Center
GENERATION CAPACITY - 868 MW - 658 MW (or 75.6%) in hydro PP, and - 210 MW (or 24.4%) in thermal PP Power System of Montenegro consists of:
- 2 big hydro power plants: - HPP"Perucica", P = 307 MW[(5x38) + (2x58.5)], - HPP"Piva", P = 342 MW (3x114)
only one thermal power plant: TPP"Pljevlja" with P = 1x210 MW.
7 very old SHPP Total P= 9 MW, and W= 21 GWh/yr. and 2
SMALL HYDRP POWER PLANTS - SHPP
1. SHPP »Glava Zete«
2. SHPP »Slap Zete«
SHPP »Rijeka Mušovića« 1,26 MW
SHPP »Lijeva Rijeka«
SHPP »Rijeka Crnojevića« 0,555 MW
_________________________________ - Installed power: - Gross production:
9,025 MW 21 GWh/year 3
Production in 2005. SHPPs 1%
TPP “Pljevlja” 32%
HPP “Piva” 30%
HPP “Perućica” 37%
THE AVERAGE ANNUAL PRODUCTION FROM ALL POWER PLANTS IS: ∼ 3.000 GWh/YEAR
THE AVERAGE ANNUAL CONSUMPTION IS: more than 4.500 GWh/YEAR AVERAGE YEARLY SHORTAGE OF ELECTRICITY IS > 30%, WITH THE TREND TO INCREASE IN THE FUTURE 6
HYDRO POWER POTENTIAL NATURAL FLOW •
USED HYDRO POTENTIAL
1.800 GWh/god. (~ 27%)
OPTIMAL USE OF WATER COURSES -DIVERTED:
USED HYDRO POTENTENTIAL (~17%)
MAIN GOAL: Analysis of the possibilities to maximize the benefits of optimal usage of an existing reservoir, built previously for other purposes, by building a SHPP. It will use the available water and head, and for the purpose of generating electricity, it will use: - all existing constructed structures, - existing conditions and - available discharge in accordance with the need of other users, considering the predetermined minimum technical flow of water.
The various possible technical variants are analyzed and discussed, and the optimal solution is proposed and explained. 8
EXISTING CONSTRUCTED STRUCTURES AND CONDITIONS
The reservoir of the „Otilovići” dam was built in 1980. on the Ćehotina River: - arch concrete dam has height of 59.0 m, - the reservoir has total water volume of 18x106 m3,
- useful water volume of 13x106 m3. The dam and the reservoir are primary intended to provide storage capacity for the cooling water for the TPP „Pljevlja” (210 MW), which is located approximately 8 km far from the dam. Steel pipe with diameter of 800 mm conveys water from the reservoir to the cooling tower.
The water from the reservoir is also used 9 as drinking water for Pljevlja city.
Mean annual flow in profile of „Otilovići” dam is 4.68 m3/sec. Water needed for TPP and water supply for Pljevlja city now is 0.53 m3/sec only. Adding one more generator in TPP (210 MW) has been planned. It would result in increasing cooling water consumption, which is going to be doubled (0.64 m3/sec). Until 2010. water needs of the city Pljevlja are going to increase by about 0.04 m3/sec. Considering that, future needs are going to be about 0.89 m3/sec. Additionally, estimated quantity of water in order to provide ecology minimum in riverbed is about 0.8 m3/sec. 11
Taking into consideration all mentioned, after fulfilling all predicted functions, it is obvious that the reservoir stores more than enough water, and that there is a possibility of multipurpose usage of the available water from the existing reservoir. This offers very good possibility to maximize the benefits of the available water, i.e. for optimal reservoir use, considering that the rest of water could be used for some other purposes, for example
for electricity generation in SHPP.
MAIN ANALYZED TECHNICAL VARIANTS
Taking into account the fact that existing constructed structures and conditions offer a good possibility for electricity generation in SHPP, a number of various technical variants and solutions have been analyzed. Several solutions, which were abandoned for various reasons, are explained in the paper. 13
The best solution is described in detail. For proposed solution the main parameters and elements of a new SHPP are determined and selected: - installed flow (considering all other
users, technical, energy, economic, ecology and financial parameters,...),
- dimension of penstock, - working regime, - number and type of turbines, - characteristics of main other parts, - and so on... 14
PROPOSED SOLUTION Based on comparing and processing possible variants, optimal solution for a new SHPP was selected. Technical solution was conditioned by uninterrupted operation of “Otilovići” reservoir. Dimensions and disposition of main parts of SHPP are determined according to the optimal parameters, presented in the paper, such as: - Intake, - Penstock, - Disposition of the plant, - Powerhouse, - Connection to the power grid, - Electricity generation in the new SHPP, - Profitability of accepted solution...
Disposition of the SHPP „Otilovici“
Penstock of the SHPP „Otilovici“
Profitability of accepted solution: Total electricity generation in new SHPP would be between 11.6 GWh/year and 11.92 GWh/year, depending on the observed case. Economic analysis for accepted solution was performed in the paper regarding: - structure and dynamics of investment, - operational costs, - period of capital investment return, - price of building one MW of installed capacity and - price of generating one kWh in the proposed SHPP.
It is obvious that building the new SHPP wouldnâ€™t require any additional expropriation costs, because purchase and compensation were paid before construction of the dam. The capital investment return is expected after 8 years of operation. Financial actuality rate is significantly exceeding marginal border of profitability. Therefore, realization of this project would provide economical generation of electricity and achieving sure and attractive income. Considering situation and conditions in this region, very unstable price of electricity and its still social character, more detailed analysis hasnâ€™t been possible. But, it should be done. 19
CONCLUSIONS (1) The reservoir of the „Otilovići“ dam, previously built to provide cooling water for TPP „Pljevlja“ and water for Pljevlja city, could be a very good example of optimal multipurpose reservoir use. Considering hydrology conditions in Ćehotina River basin, as well as dimensions of the existing reservoir, it is obvious that there is a significant quantity of water which could be used for electricity generation in SHPP. 20
After detailed technical, energy and economic analyses the optimal solution is proposed and described. It fulfills all prerequisites and uses existing costructed structures. The economic and financial discussions point out that new SHPP would be a profitable project. 21
Thank you for your attention! 22