Feasibility Study of Pumped Storage System for Application in Amhara Region, Ethiopia

Mastewal Alemu Tilahun (ID: 850614-A186)

Master of Science Thesis 2009

Department of Energy Technology Division of Heat and Power Technology Royal Institute of Technology Stockholm, Sweden

Master of Science Thesis: EGI-2012-015MSC EKV875

Feasibility Study of Pumped Storage System for Application in Amhara Region, Ethiopia

Name of the student: Mastewal Alemu Tilahun Approved: Examiner Supervisor Name of the Examiner: Name of the supervisor(s); Prof. Torsten Fransson 1.Babak Rezapoor (KTH) 2.Prof.S.P.Chary Supervisor at Bahir Dar University 3. Mr. Assefa Ayalew Co-Supervisor at Bahir Dar University

Commissioner Contact person

ABSTRACT

In these days environmental issues are critical. Environmental concerns mainly rise from energy productions. Fortunately Ethiopia is trying to use renewable energy sources as a means for electrical power production and it is a great start for a long, tiresome green energy journey. The basic job to be done in green energy sectors is to maximize the capacity of renewable technologies to fulfil the best efficiency. Intermittent nature of the energy production and their inefficiency to meet peak load demands are the basic problems in renewable energy sectors.

Ethiopia‟s electrical power production is mainly dependent on hydropower; according to latest data from EEPCO hydro covers 88% of the total production. There are two major nature of this power plant; since the working medium is water it is mainly dependent on the nature of the seasons and secondly it rarely meets peak load demands. After the erection of the power plant the energy production is not time dependent; it can produce power continuously; but the consumption is time dependent which is defined as peak hours and off-peak hours. There is excess load in time of off-peak hours and scarcity in peak hours. So this work can help to maximize the capacity of the water for production by using technological advancements to produce lot of energy in almost full capacity throughout the year to full fill the need of our country. Tana Beles hydropower plant is the largest hydropower plant which starts to work in May, 2010 with an investment cost of $500 million and capacity of 460 MW. The project is planted in Amhara region using the water source of Lake Tana. To make this large and very necessary renewable energy resource sustainable using energy

2 storage system will be vital. This study will figure out a pumped storage system for the hydropower plant for additional power production and for the sustainability of the water resource.

Pumped storage system is the only viable, large-scale resource that is being broadly utilized today for storing energy, and it offers the best option available for harnessing off-peak generation from renewable sources. The contributions of pumped storage hydro to our nation‟s transmission grid by providing stability services, storage capacity needs, and expanding the green job market are considerable today.

The high energy demand of the pump will be considered to be covered using the excess electrical power production during night or weekends and if the resource is available using wind solar PV hybrid systems.

The author will try to assess the technology not only for other mini hydro power plants but also for irrigation and other purposes merely in Amhara region, Ethiopia. The feasibility of the system will be considered technically and economically for the hydropower plant.

Keywords: Pumped storage system, Tana Beles hydropower plant, Amhara region, Ethiopia, Benefit of storage system

ACKNOWLEDGEMENT

After GOD, I greatly admire and transfer my sincere gratitude to Swedish government and Royal Institute of Technology, KTH, for giving me this fabulous chance. The knowledge I discovered from here awakens me to contribute my share for the world. I really thank you and please continue in your great job!

I cannot find words to express my gratefulness to my local facilitator Dr. Solomon T.MARIAM for your strengthen words and great effort for DSEE program.

My supervisors; Mr.Babak Rezapoor (KTH), Professor. Samanthapudi Parabrahma Chary (supervisor at Bahir Dar University), Mr. Assefa Ayalew (co-supervisor at Bahir Dar university), I sincerely thank you for your help.

This thesis would have remained a dream had it not been for my friends Abeyou Wale, Siraje, Bruk, and Amlaku. When I was in dark because of lack of data, they lightened my way; THANK YOU!

At last but not least I was not going to finish this study if my mother, Abundeje Belay, my father, Alemu Tilahun, My brothers and sisters; Hibret, Fantahun, Getenet, Tigist, Temesgen, HiwoteMARIAM, Lenger and my dear friends; Assefa Asmare, Nega Belete were not there.

TABLE OF CONTENTS

ABSTRACT ...... 2 ACKNOWLEDGEMENT ...... 4 TABLE OF CONTENTS ...... 5 LIST OF FIGURES...... 8 LIST OF TABLES ...... 9 NOMENCLATURE ...... 10 1.0 INTRODUCTION ...... 11 1.1 Problem statement ...... 12 1.2.1 The main objective ...... 12 1.2.2 The specific objectives ...... 12 1.2.3 Method of Attack ...... 12 1.2.4 Scope ...... 13 2.0 LITERATURE REVIEW ...... 13 2.1 Hydro power plant ...... 13 2.1.1 Hydropower Coverage from the World Electricity Sources, 2003 ...... 13 2.1.2 Hydropower Coverage from the World Energy Source: 2008 ...... 14 2.1.3 Hydropower coverage from the world Energy source, 2010 [REN21, 2010] 14 2.2 Energy and Hydropower in Ethiopia ...... 16 2.2.1 Renewable resources in Ethiopia...... 18 2.3 Limitations/ Impacts of hydropower ...... 19 2.4 Need of energy storage to secure systems sustainability ...... 19 2.5 Types and comparisons of energy storage mechanisms...... 20 2.6 Energy storage methods in Ethiopia ...... 22 3.0 PUMPED STORAGE SYSTEMS ...... 22 3.1 Introduction ...... 22 3.2 Elements of pumped storage systems ...... 23 3.3 Types of pumped storage systems ...... 24 3.3.1 Pure pumped storage ...... 24 3.3.2 Pumped-back pumped storage ...... 24 3.3.3 Seasonal pumped storage ...... 24 3.3.4 According to mode of operation ...... 24 3.3.5 According to design ...... 24 3.4 Pumped storage systems; past, present, future ...... 24 3.5 Review of literatures on pumped storage system ...... 25

3.6 Production of energy in pumped storage energy ...... 27 3.6.1 Generation mode ...... 27 3.6.2 Pumping mode: ...... 27 3.6.3 Benefits of pumped storage plant ...... 28 3.6.4 Pumped Storage System overall efficiency ...... 28 3.6.5 Basic components of pumped storage plant are: ...... 28 3.7 Wind- Solar- PV hybrid systems for pumped storage plant ...... 29 4.0 TANA-BELES HYDROPOWER PLANT ...... 29 4.1 Lake Tana...... 31 4.2 Technical specification of the power plant ...... 33 5.0 ASSESSED PROBLEMS ON THE HYDRO POWER PLANT ...... 36 5.1 Available water ...... 36 5.2 Lower reservoir ...... 37 5.3 Pumped storage system for Tana Beles hydropower plant ...... 38 5.4 Why need for pumped storage system? ...... 38 5.5 Pump power ...... 39 5.5.1 First scenario, five months where the power plant work in full load; Q=160m3/s ...... 39 5.5.2 Second scenario, seven months, where plant flow rate becomes 77m3/s40 5.6 Available power for the pump ...... 41 5.6.1 Solar and wind potential ...... 41 5.6.2 Power from the grid ...... 44 5.7 Load arrangement for pumping power ...... 47 6.0 LAY OUT OF THE PROPOSED PUMPED STORAGE SYSTEM ...... 48 6.1 Analysis for the proposed pumped storage system ...... 49 6.1.1 Benefits of pump scheme ...... 49 6.1.2 Efficiency of the system ...... 49 6.1.3 Cost of storage unit ...... 50 6.1.4 Net benefits of the pumped storage system ...... 50 6.1.5 End user cost avoid ...... 51 6.1.6 Reduced demand charges ...... 51 6.1.7 Electric service reliability ...... 51 6.1.8 Power quality ...... 52 6.1.9 Avoided peak generation cost ...... 52 6.1.10 Emission ...... 53 7.0 RESULTS ...... 53 8.0 CONCLUSION ...... 54 9.0 SUGGESTED FUTURE WORK ...... 55 10.0 CONTRIBUTION OF THE PRESENT WORK ...... 55 6

11.0 REFERENCES ...... 56 12.0 APPENDIXES ...... 58 1) Ethiopia Electric Power Corporation consumption cost tariff [EEPCO, 2011] ...... 58 A) Translated in English ...... 58 B) Raw data from EEPCO ...... 59 2) Total active load in the grid for 30 days and 24 hours, January ...... 60 A) January ...... 60 B) February ...... 61 3) Average total active load ...... 66 4) Volume at the maximum flow rate (5 months) ...... 67 5) Volume distribution at the minimum flow rate (7 months in a year) ...... 68 6) Flow Rate Distribution in a Year ...... 69 7) Volume of lower reservior for the two scenarios ...... 70 8) Load Distribution for Tana Beles Hydropower Plant for 23 Days and 24 Hours of June ...... 71 10) Grid Load Variation for 23 days ...... 73 11) Load variation between pure hydro and pumped storage system ...... 74 12) Tana Beles Load variation for 24 hours ...... 75

LIST OF FIGURES

Figure1.1 : Electricity coverage by percent in year 2012 [Author, data from EEPCO, 2011] ...... 11 Figure 2.1: The World‟s Electricity Sources [IHA White paper, 2003] ...... 14 Figure 2.2: Share of Global Electricity from Renewable Energy, end of 2008 (GW) [REN21, 2010] ...... 14 Figure 2.3: Renewable Energy share of Global final Energy Consumption, 2009 .... 15 Figure 2.4: Renewable Energy Share of Global Electricity Production, 2010 [REN21, 2010] ...... 15 Figure 2.5: Ethiopia Energy Production Share by Type [EEPCO, 2011] ...... 16 Figure 2.6: Hydropower Production in Ethiopia [GENI, IEA, 2011] ...... 17 Figure 2.7: Total primary energy consumption in Ethiopia [EIA, 2010] ...... 17 Figure 2.8: Hydropower: basins, rivers, pour points [SWERA, 2011] ...... 18 Figure 3.1: Pumped Storage Scheme Configuration [Wikipedia, 2010] ...... 23 Figure 3.2: Load Demand (pumping) and Generation ...... 27 Figure 4.1: Share of installed capacity (%) of power plants [EEPCO, 2010] ...... 30 Figure 4.2: Longitudinal Profile of Tana Beles Hydropower Plant [project report] .... 30 Figure 4.3:Topography of Tana Beles Hydro Power Plant Station [The authour] ..... 31 Figure 4.4: Lake Tana Photo ...... 32 Figure 4.5: Tana Beles hydropower plant layout [Author, from project report] ...... 33 Figure 5.1: Generated power for a year [Author from data available at table 6] ...... 37 Figure 5.2: Variation on the Volume of Lower Reservoir within a day ...... 38 Figure 5.3: Solar and Wind Resource at the Power Station ...... 41 Figure 5.4: Solar Potential Availability ...... 42 Figure 5.5: Wind Potential (speed) Availability ...... 42 Figure 5.6: HOMER input relation ...... 43 Figure 5.7: Total Load Variation on the Grid for 23 Days ...... 45 Figure 5.8: Minimum, Peak Load and Capacity of Hydropower Plants in the Grid .. 45 Figure 5.9: Tana Beles Hydropower Plant Power Variation each days ...... 46 Figure 5.10: Power Generation Variation for Tana Beles Hydropower Plant ...... 47 Figure 5.11: Average Load on the Grid Starting from Mid Night ...... 48 Figure 6.1 : Layout of Tana Beles after pumped storage system ...... 49 Figure 7.1: Power distribution after the installation of pumped storage system ...... 54

LIST OF TABLES

Table 1.1: Growth Estimation in the First Half of the 21st Century [Hecht and Miller, 2010] ...... 11 Table 2.1 Wind and Solar resources in Ethiopia [PkfAS, 2011] ...... 19 Table 2.2: Comparison of Storage Systems [ESA] ...... 21 Table 4.1: Overall status of Tana Beles hydropower plant [The author from project report data] ...... 35 Table 5.1: Annual flow rate distribution for each month [Beles Hydropower plant report] ...... 36 Table 5.2: Summary of the two scenarios ...... 40 Table 5.3: Cost for selected renewable resources [EIA, 2011] ...... 43 Table 5.4: Hydropower plants connected to the grid [EEPCO] ...... 44 Table 6.1: Diesel power systems on the grid [EEPCO, 2011] ...... 52 Table 7.1: Summary of the benefits of pumped storage system ...... 53

NOMENCLATURE

Abbreviations

HRW: Hydro Review Worldwide CAES: Compressed Air Energy Storage PSB: Buffer Storage tank VRB: Vanadium Redox Battery ZnBr: Zinc- bromide battery NaS: Network-Attached Storage Ni-Cd: Ni-Cd storage batteries SMES: Superconducting Magnetic Energy Storage DSMES: Distributed Superconducting Magnetic Energy Storage E.C.: Electrochemical Capacitors SO2: Sulphur dioxide NOX: Nitrogen Oxides PHES: Pumped Hydroelectric Energy Storage KWh: Kilo Watt Hour MW: Mega Watt SWERA: Solar and Wind Energy Resource Assessment HOMER: The optimization model for distributed power EIA: U.S Energy Information Administration GENI: Global Energy Network Institute EEPCO: Ethiopian Electric Power Corporation UK: United Kingdom ESA: Electricity Storage Association

1.0 INTRODUCTION

Human‟s evolution from early stage which is “Gatherers” to moderate society energy have been used in different The world is facing a large and frequent growth on population size which definitely followed by increment in other sectors, demands. As some reports indicate at the first half of the 21st century there will be rapid increase of growth in different extremes.

Table 1.1: Growth Estimation in the First Half of the 21st Century [Hecht and Miller, 2010]

Population growth 50% Economy growth 500% Energy consumption and manufacturing activity 300% Energy use 44%

This increment has to be faced with the global journey to green energy systems. Non renewable sources may help to answer the demand question but these will give the world irreversible headache. The ecological problems preceded from unwise human role will not be taken care of by the world since it got limited reserve and capacity. Despite the limits, still majority of the energy production must be from renewable sources. The major drawbacks of renewable energy systems are intermittency nature and the incapability to fit peak load demand which can be addressed by energy storage systems. For a sustainable energy policy having energy storage system is a precondition. Energy storage systems are both technically and cost wisely effective.

Ethiopia: land locked, second-most heavily populated and tenth largest by area country [Wikipedia, 2011] in the Horn of Africa. Ethiopia has total population of 83 million and electricity production of 3.2 billion per KWh [GENI, 2011] which is not nearly comparable. The existing 85% [GENI, 2011] of energy production comes from hydroelectricity. So far only 13 percent of Ethiopia‟s population has access to electricity but that is expected to rise to 20 percent by 2012 [MBendi, 2011].

Figure 1.1 : Electricity coverage by percent in year 2012 [Author, data from EEPCO, 2011]

Amhara region: is one from the nine regions of Ethiopia. Bahir Dar is its capital city and the official language is Amharic. Lake Tana, the source of Blue Nile river and largest in Ethiopia, is located there.

1.1 Problem statement

The river Blue Nile and the Lake Tana which is the source of Blue Nile are both in the Amhara region. The feasibility study of the pumped storage system in Amhara region naturally has to incorporate this reality at least in abstract form. Tana Beles hydropower plant is the largest hydropower plant which starts in May, 2010 with an investment cost of $500 million and capacity of 460 MW [Ethiopian News, 2010]. The project is planted in Amhara region using the water source of Lake Tana. Even though hydrological assessments have been taken care of, there has to be also consideration of the dramatic climate change of the globe; which put the sustainability of the hydropower plant in question. To make this large and very necessary renewable energy resource sustainable using energy storage system will be vital. This study will figure out a pumped storage system for the hydropower plant for additional power production and for the sustainability of the water resource.

1.2 Objectives and method of attack

1.2.1 The main objective

Assessing the application of pump storage systems so as it helps to maximize the power production of the country by manipulating the water source after the hydro power plant turbine efficiently. And also by considering the general feature of Tana Beles hydropower plant in the eye of sustainability and help to make the energy production and the power storage sustainable.

1.2.2 The specific objectives

 Assessing the load distribution of the country.  Evaluate the general condition of Tana Beles hydro power plant  Configuring the demand for pumped storage system.  Analysis and design of pumped storage systems on the selected place.  Checking the potential of wind and solar- PV power source of pump.  Assessing the energy demand of the pump from excess electrical power production during night or weekends and wind solar PV hybrid systems.  Maximizing storage efficiency, storage capacity and power output of the selected site.  Perform the Cost analysis and Economic viability of the pumped storage system

1.2.3 Method of Attack

1. Go to the selected site and survey the power plant. 2. Consider the practical conditions of the power plant and decide what to analyze. 3. Literature review for the study. 4. Collect data on the load center. 5. Analyze the data using Microsoft Excel program. 6. Configure the results. 7. Make recommendation based on the result.

8. Analyze the benefits of the result. 9. Make recommendation.

1.2.4 Scope

Since there is vital resource problem towards software and books in the study area, the study is limited in detail analysis. The study will show the limitations of the Tana Beles hydropower plant and recommend a system for higher efficiency towards different extremes. Further detail pumped storage system analysis need software applications.

2.0 LITERATURE REVIEW

2.1 Hydro power plant

A simple mechanics, water falling from high height hits a turbine at low height turns the turbine which turns a generator to produce electricity this is what we call it hydro power. The head, volume of water, speed of water are the most important parameters to know the potential (energy) of one hydropower plant. Hydro power plant is highly reliability, highly efficient and highly flexible energy resource.

P (W) = g H Q t (1)

Where  is density of water (m3/s); g is gravitational constant (m/s); H is head 3 (vertical distance the water drops) (m); Q is water flow (m /s); t is turbine efficiency.

Hydropower can be planted with an included reservoir or without reservoir (“run of- river). It can be classified as small and large according to the countries scale. Smaller scale can also called small (1MW-10MW), mini (100KW-1MW), micro (< 100KW), Pico-hydro (<5KW). And it can also be divided by considering its purpose as single or multi-purpose.

Hydro power is contributing its share in large scale for the renewable world. Since it is the major renewable electricity producing system it provides major global environmental benefits.

2.1.1 Hydropower Coverage from the World Electricity Sources, 2003

The world electricity generation sources are more of contained on the non-renewable sources. This net production has been thought as a reason for the degradation of the climate. Producing clean energy must be the agenda of the world. Renewable energy is valuable in different extremes; it can be the basic way to the dream of sustainable systems as the same time it will help the economy of the country without creating little or no effect on the climate. A lot of job opportunities will be created, and non extinct resources will be manipulated as much as possible. There are lot of renewable resources on the globe but the major coverage is by fossil fuels and 19% [IHA White paper, 2003] of the world„s electricity source is from hydro.

Figure 2.1: The World‟s Electricity Sources [IHA White paper, 2003]

2.1.2 Hydropower Coverage from the World Energy Source: 2008

The world energy distribution is becoming more and more related with the renewable resources. Wind and Solar systems have been planted with high capacity. Specially developed countries are starting to focus on the generation of green energies. Hydropower generation is contributing its share in the process of clean energy production. Developing countries are using it as a base for their power production. Even though it is not competent with other resources like solar and wind; hydropower takes 15% [REN21, 2010] of world electricity production in 2008. And since large hydropower plants are planted all over the globe a great deal of growth in production is achieved. The production reached its estimated capacity in 2009 which is 980GW; it indeed was 950MW in 2008 and 920MW in 2007 [REN21, 2010]. This value is for all, small and large, kind of hydropower types (all sizes). Hydropower supplied 15 percent of global electricity production in 2008.

Figure 2.2: Share of Global Electricity from Renewable Energy, end of 2008 (GW) [REN21, 2010]

2.1.3 Hydropower coverage from the world Energy source, 2010 [REN21, 2010]

Recent data indicates the coverage of hydropower from global electricity production reached 16% which shows an addition of 30GW from the previous, amounts to 1.01 TW. Countries are contributing in vast from which China and Brazil take the lead. The report also gives the share of final energy consumption in year 2009 using chart.

Figure 2.3: Renewable Energy share of Global final Energy Consumption, 2009 [REN21, 2010]

As shown above (figure 3), renewable energy share from the total final consumption is 16% which is the summation of traditional biomass 10%, hydropower 3.4%, biomass/solar/geothermal hot water/ heating 1.5%, biofuels 0.6%, wind/solar/biomass/geothermal power generation 0.7%. Hydropower is the next from traditional biomass which is direct use of wood for cooking and heating. Hydropower coverage is moderate but from large scale it is modest.

And also the renewable energy share for year 2010 from global electricity production is indicated as in the figure which covers 16.1% share from the total. The hydropower share is showing large increment in percent.

Figure 2.4: Renewable Energy Share of Global Electricity Production, 2010 [REN21, 2010]

Since the system is very attractive in different extremes like cost; low investment cost, and long life span, the growth of hydropower plant is increasing year to year.

Further developments and studies are necessary to enlarge the capacity of the plant so as it can help the journey to sustainable energy development.

2.2 Energy and Hydropower in Ethiopia

Ethiopia‟s electric energy generation (KWh) according to the data of EEPCO is 51.16 per capita. And also the installed capacity performance (MW) in year 2010 is 2060. Hydro covers 88%, Diesel 11% and Geothermal 1%; the diesel power plants are isolated systems and 60 MW is rented for facial time. From hydro power plants Tana Beles covers 22%. The total number of customers who are connected to get electric energy from the system amounts to1, 896,265 which is from 75.8 million population size of Ethiopia. The total energy generation and sales is 3.981 and 3.264 TWh respectively.

There is considerable resource of hydropower in most part of the country. The 88%- 90% [EEPCO, 2011] of Ethiopia‟s Electric generation is based on hydroelectric sources.

Ethiopia as a developing country is joining the journey to green electric production with large motivation.

Figure 2.5: Ethiopia Energy Production Share by Type [EEPCO, 2011]

Global energy network institute indicate the generation and consumption of electricity in Ethiopia using graphs. Almost total production is from hydropower plant and considerably less from oil and very less from geothermal.

Figure 2.6: Hydropower Production in Ethiopia [GENI, IEA, 2011]

The annual rate of energy consumption growth reaches up to 10%. Currently less than half of the Ethiopia towns have access to electricity. The graph shows electricity net consumption versus billion kilowatt hours; the consumption is showing high percentage increment since 2000.

Figure 2.7: Total primary energy consumption in Ethiopia [EIA, 2010] 17

In summer season a great deal of shortage in the electric power supply has been in the grid. Three days a week there have been a black out of electricity in the main towns. Still the rural areas don‟t have electric power access at all. Still the goal to offer electric power for all Ethiopians is far away. All the infrastructures for electric power generation are governmental. The Ethiopian Electric Power Corporation (EEPCO) had been planting 8hydro, 13 diesel generators (some for stand-by use only) and one geothermal power plant, which is frequently out of order.

2.2.1 Renewable resources in Ethiopia

The basic renewable resource for the country is hydropower. SWERA explores hydropower sources; basins, rivers, pour points as shown in figure.

Figure 2.8: Hydropower: basins, rivers, pour points [SWERA, 2011]

There is substantial amount of water resources. There are twelve major river basins forming four drainage systems:

 The Nile basin; Blue Nile, Baro-Akobo, Setit-Tenkeze  The Noth-East Coast; Ogaden and Gulf of Aden basins  The Rift Valley; Awash, Denakil, Omo-Gibe and Central Lakes  The Shebelli-Juba basin; Wabi-Shebelle, Genale-Dawa

And the country is also rich in solar and wind resources which are being exploited in very micro level.

Table 2.1 Wind and Solar resources in Ethiopia [PkfAS, 2011]

Source Unit Potential Annual Exploited exploitation percent Wind GWh 100,000 0.10-0.20 ~0.0% Solar KWh/m2 .day 5.5-6.5 10GWh ~0.0%

Since Ethiopia‟s energy source is based on hydropower the availability is susceptible to the water dearth.

2.3 Limitations/ Impacts of hydropower

IHA report entitled “role of hydropower in sustainable development” lists down the advantages and disadvantages of hydropower and from it 75% goes for the advantage and the other is for its impacts [IHA White paper, 2003]. The emission of GHG or acid rain or atmospheric pollution is not a headache in case of hydropower. The system is costly, needs bulky constructions and huge water. Besides huge cost the basic impacts are:

 Larger ecological and social consequences than design benefits. This is due to almost permanent dam construction and resettlement. Life of biodiversities inside the water will largely be affected and it needs attention.  Water as life-sustaining resource is not as much used/ manipulated as it is displaced. After hitting the turbine the water is lead to irrigation and other rivers and there is also considerable amount of evaporation from the dam. This will make the flow of water from upper reservoir irreversible.  Sedimentation from the water flow.  Inefficient for peak hour demands

Water as a fuel and as a basic resource must be used efficiently. The system must be furnished with some infrastructures for tracking the diversities and sedimentations. Through environmental assessments must be done to secure the positive values of the system. The other basic issue is the inefficiency of the plant in peak hour demands. And there is considerable difference between the erection cost, long time taking constructions and the reasonable system output. Different advancements should be done to make the system efficient enough so as it works for its maximum.

2.4 Need of energy storage to secure systems sustainability

Renewable resources have to be manipulated in large scale to get the path of sustainable energy systems. Energy must be utilized effectively. The produced energy must be in function and also the capacity of plants must increase. Due to the nature of loads and sources the utilization and storing of energy produced is complicated. Large plants operate with almost constant output for long periods which indicates their incapability to react to variable loads. These (Hydropower, Nuclear, Geothermal) oblige them to provide power with base load. This minimizes the

19 capacity of the production and the inefficiency for the plants to fit peak hour demand. The variability in the grid can be shown in mathematical correlation as follows [Hebner, Aanstoos, 2010] :

L (T) = ∑ li(t) (2)

= C + F (T) (3)

Where ∑li(t) is over all loads on the network; t is instantaneous time; T is scale of minutes to hours; C is base load on the grid; F (T) is slowly varying function of time or daily and annual periodicity

Electricity must be stored using other strategies to use it for another time; especially hydropower must be directly used as soon as it is generated. Two strategies directed in a literature to cope with load variations [R. Hebner and T. Aanstoos, 2000] are;

 On short term changes ( variation in the individual loads); variations are compensated by small frequency change in the system  On long term changes (F(T)); handled by changes in power level of sources.

When the system is stable: Stable systems;

S (T) = L (T) = ∑ si = the summation of nearly constant source

When the load varies there will not be stable system which implies L (T) < S(T).This problem sometimes covered by disconnecting selected loads. If else to make the system almost stable; S (T) ≈ L(T) there will be rolling blackouts. This greatly indicates the need of power storage system for the dream of sustainable systems.

2.5 Types and comparisons of energy storage mechanisms

The short review of storage mechanisms is shown in the table below;

Storage Main Disadvantages Power Energy Technologies Advantages (Relative) application Application (relative) Pumped High Capacity, Special site Not feasible Fully Storage Low Cost requirement or capable and economical reasonable CAES High capacity, Special site Not feasible >> low cost requirement, need or gas fuel economical Flow Batteries: High capacity, Low energy Reasonable >> PSB independent density for this VRB power and application ZnBr energy ratings Metal-Air Very high Electric charging Not feasible >>

energy density is difficult or economical NaS High power and Production cost, Fully >> energy safety concerns capable and densities, high (addressed in reasonable efficiency design) Li-ion High power and High production >> Feasible but energy cost, requires not quite densities, high special charging practical or efficiency circuit economical Ni-Cd High power and >> Reasonable energy for this densities, application efficiency Other High power and High production >> Feasible but Advanced energy Cost not quite Batteries densities, high practical or efficiency economical Lead-Acid Low capital cost Limited cycle life >> >> when deeply discharged Flywheels High power Low energy >> >> density SMES,DSMES High power Low energy >> Not feasible density, high or production cost economical E.C. Long cycle life, Low energy >> Reasonable Capacitors high efficiency density for this application

Table 2.2: Comparison of Storage Systems [ESA]

When comparing storage systems using capital cost per unit power ($/kW), Capital cost per unit energy ($/ kWh-output), system ratings and discharge time at rated power as a parameters. From the comparison we can conclude that pumped storage system is viable method to store energy for a developing country like Ethiopia. When capital cost per unit power and capital cost per unit energy are considered pumped storage system is on the middle of better for energy management application and better for ups and power quality application. And when discharge time at rated power and system power ratings put to consideration pumped storage system is at the highest corner for both cases.

The application of storage system is an additional cost for systems, but since it has a great additional feature for power systems it must be applied for smooth power distribution in the electrical power grids.

Appropriate and wise selection of storage system is the very first step for appropriate storage system integration with a power plant.

2.6 Energy storage methods in Ethiopia

As mentioned in detail in literature review Ethiopia‟s power production is mainly dependent on hydropower plant and there is no storage system being used for the hydro plants. There is no other renewable resource being used but mini solar power systems in application of lighting for rural areas and these use battery for storage.

3.0 PUMPED STORAGE SYSTEMS

3.1 Introduction

In the production of electric power we will consider two cases; base load and peak load. The first tries to satisfy the enormous amount of need so it has to be produced in large amount. The later is for the time of high power demand so it has to produce a flexible power in a sufficient amount to cope with the big load fluctuation. For base load the world is using technologies capable of producing mass power; like large hydro power, nuclear power, fossil fuel plants are being used. But from the emission and contamination point of view respects hydropower is the clean choice the world has. For the peak load gas thermal, hydropower, pumped storage systems and other various generations are being used. Again from the emission point of view hydropower and pumped storage systems are the most clean and green peak load generators. When renewable sources are linked to a grid back- up capacity and for a stand –alone system energy storage is a vital issue. At this time the only system available for this issue is pumped storage system. Large scale pumped storage systems are helping for peak lead power demand and energy storage Pumped storage plant involves pumping water from a lower reservoir to an upper reservoir and later returning water from the upper reservoir to the lower reservoir or to a different location or reservoir to generate electricity or for other irrigation purposes. The pumped storage applications balance demand, which tends to vary during the day, with supply, which tends to be constant. When water is pumped up to the top reservoir we are storing gravitational potential energy in it. In the place where there is no absolute synchronization between generation and consumption, where there is water shortage, and for the locations where there are storage lakes pumped storage system is a striking opportunity. In every electricity networks there is a surplus or lack of electricity, pumped storage system will control and guarantee a safe operation in the electricity grid. Pumped storage system is the only renewable which can enable to face intermittent loads and to meet the global sizzling target to reduce greenhouse gas emissions and build clean renewable energy capacity. Pumped storage has a great deal of role to play in enhancing the reliability and flexibility of electricity and mitigating the adverse effects of generating systems. Pumped storage plants at the normal peaking cycle operation include good ramping and load-following capability, quick- start capability with spinning reserve and frequency regulation. The entire cycle of modern, large pumped storage plant has efficiency between 70-85% [Boyle, 1996; Miller and Winters, 2009; Sorensen, 1979].

The cycle can able to change from pumping to full generation in 2 to 10 min and from generation to pumping in 5 to 20min [Barnes and Levine, 2011].

Figure 3.1: Pumped Storage Scheme Configuration [Wikipedia, 2010]

Pumped storage system reduces GHG emissions from the system. A research held in United Kingdom demonstrates the great reduction in emission: For example: Dinorwig Pumped Storage Power Station saves SO2 between 7,136 to 16,177 tons (0.45 to 1 percent of all UK power station production) [IHA, 2003] mission annually. And NOX annual emission reduction is between 123 and 1,264 tons (0.02 to 0.25 percent). [IHA, 2003] This is remarkable in terms of reduction of toxic emissions and journey to the world goal towards the production green energy.

3.2 Elements of pumped storage systems

There are reservoirs which are upper reservoir and lower reservoir. The first one located at a place where the water which is going to hit the turbine going to be stored (at high elevation). It can be a constructed dam or lake. And the later one is placed at water exiting after the power house.

The next element of the system; water conductor systems are connecting lines which joins the reservoirs to the power plant. It includes penstocks and tunnels. For the case of pumped storage systems deceleration, acceleration and content of water matters the design.

The third element; power plant holds pumping/generating turbines can be one or more in number, and supporting auxiliary equipments which are going to be used for control, protection and operation. Due to researches and developments made with time pumped storage plants of these days use reversible pump-turbine with vertical shafts to connect to the generator-motors. 23

3.3 Types of pumped storage systems

3.3.1 Pure pumped storage

Consists of two off stream reservoirs where electric power generation is primarily dependent on the pumping operation rather than on natural in flow into the upper reservoir.

3.3.2 Pumped-back pumped storage

Generally comprises two reservoirs on the same river so that electric generation relies on both natural inflow and the water that is pumped back.

3.3.3 Seasonal pumped storage

It is an operation that balances the variability of natural fluctuation of river flow, which is generally seasonal, with demand, which may be more uniform and may possibly vary in a direction opposite to supply.

3.3.4 According to mode of operation

 Seasonal, pumping water into the upper reservoir at high river flow  To store electricity produced at night by nuclear power plants for use during peak times.  To increase power production of large hydroelectric dams by allowing extra water to be released during times of peak demand.

3.3.5 According to design

 The construction is done inside the mountain, the upper reservoir in the hills beyond the mountain and the lower on the valley floor; e.g. Dinorwig Power Plant; with a capacity of 1.32GW  Located on the lake and pumps water directly from the lake; e.g. Ludington Pumped Storage Plant; with a capacity of 1.872GW  The upper reservoir on the mountain whereas the lower reservoir on shore line where rain water is collected and directed with tunnels to the upper reservoir. e.g. Cruachan Plant in Scotland; with a capacity of 440MW  Using ocean as lower reservoir; e.g. Japan Pumped Storage Project,1999

3.4 Pumped storage systems; past, present, future

Symbiotics energy in the site available at http://www.symbioticsenergy.com summarizes the development of pumped storage system. Switzerland was the first country to introduce the system to the world; the first recorded date in history is 1909 in northern part of Switzerland, Schaffhausen with a capacity of 1500KW. Since then developments on the system have been done to increase the efficiency of the system and countries all over the world start to practice the system. Which are 1929

Reversible pump, 1937 Reversible pump- turbine; Brazil, 1954 Pump turbine; America, 1964 Reversible motor-generator; German, 1966 Reversible pump turbine; Belgium, 1970 Pump turbine Raccoon Mountain; America, 1970 Motor generator; Luxemburg, 1971 Motor generator; German, 1974 Reversible pump turbine; Argentina, 1976 Pump turbine, America, 1977 Motor generator, America, 1981 Reversible pump turbine, Korea, 1983 Pump- turbine, Africa.

United States first pumped storage system was built in 1929 with better efficiency from the Switzerland‟s system because of newly introduced reversible- pump turbine.

This technology currently is representing about 3% of generation capacity with a total of more than 127,000MW installed capacity in 100 power stations [Baker et al,2008]and [ESA, 2009]

Since the system is the way to develop flexible, clean and green energy, its market is expanding. As industry reports put forward the market will increase 60% the coming four years; in 2014 the capacity of pumped storage systems capacity will reach to 203GW [Ingram et al, 2009] For the future, there are remarkable large capacity pumped storage plants all over the world. HRW summarizes seven pumped storage projects held on three continents, Europe, Asia, Africa, will provide an additional power of 4.6GW of environmentally friendly electrical energy.

Many plants are on construction and believed to be in operation at 2015. The technology is on the truck of development; vast constructions with huge capacities will be proceed in this 20s century.

Research has been made in areas of this technology and different writers are saying and writing about the system.

3.5 Review of literatures on pumped storage system

Energy storage system papers clearly state the necessity and efficiency of storage systems. Energy storage council [ESC, 2011] summarizes energy storage systems on the paper titled Energy Storage, and shows the crucial need of storage systems. Electricity value chain, six dimension when large scale energy storage is added, layout is proposed. The paper concludes by indicating the necessity of storage system and also comparison of these systems had been done.

[Jonah G. Levine, 2003] A thesis titled pumped hydroelectric energy storage and spatial diversity of wind resources as methods of improving utilization of renewable energy sources uses a model with power and capacity, revenue, cost and payback parameters to figure out the distinctiveness of the selected site technically and economically from each other. Avoided peak generation cost natural Gas Generation Cost is considered and the avoided peak generation cost is figured out. And the emission (CO2 and SO2) is also considered when natural gas plant is replaced for peak hour. The overnight capital cost of the pumped storage system selected and the values for constituting components (land and land rights, Power Station structures and improvements, Reservoirs and Water Ways, Pumps Turbines Valves Governors, Generator Motors and Static Starting Equipment, Accessory Electrical 25

Power plant Substation Equipment, Roads, Contingencies Engineering and Overhead, Allowance for funds during construction) also considered in percent of the capital cost. Revenue and payback time calculated for each sites. Wind power systems also clarified and analyzed in the paper vastly.

Authors [James et al] on hand book titled Energy Storage Benefits and Market Analysis Handbook made detail analysis on storage system. Electric energy storage application areas had overviewed in grid system, end-user/utility customer and renewable subparts. The application and benefit (reduction in cost) of storage system analyzed. In the next chapter market potential assessment is dealt on the selected place, California. The market estimate is done considering combined applications and the considered benefits. Chapter four of the handbook deals on benefits of the storage system in the streams of financial viability and economical value. Financial benefit and viability thoroughly considered. In the last chapter general benefit assessment had done by combining all benefits from the system. The combined effect is showed using graph which considers price ($/kWh), load (kW), and hours of a day.

The hand book uses two methods to compare the storage systems in-terms of the way it is used (application) and benefit (the money it offers). The application may be specific but the benefits available from the system may provide any kind of benefits. The application stream categorized in to three sub-systems (Grid system, End- user/utility customer, and renewable) and thirteen divisions. Under grid system bulk electricity price arbitrage, central generation capacity, ancillary services, transmission support, reduce transmission capacity requirements, reduce transmission congestion, and transmission and distribution upgrade deferral. End- user/utility customer there are time-of-use energy cost management, demand charge management, electric service reliability (reliability) and electric service power quality (PQ). Renewables sub-system got renewable capacity firming (renewable capacity) and renewable contractual time-of-production payments. According to the function of the storage system selected, the benefits will be analyzed. A storage system must be cost effective, cost competitive and beneficiary.

For this work, the pumped storage application will be configured and the benefit will be analyzed using selected properties. [J.P. Deane et al, 2009] on their paper titled Techno-economical review of existing and new pumped hydro energy storage plant summarize pumped storage systems technically around USA, Europe and Japan which are new and proposed ones which amounts 7000MW and economically by comparing with conventional thermal, nuclear, wind, geothermal, PHES, conventional hydro and the % of PHES from the total mix.

This paper will focus on analyzing the application of pumped storage system on the already installed hydropower plant called Tana Beles in Ethiopia. The author will check the potential of wind and solar power systems for integration with pumped storage system. The economical one, hybrid system or pure pumped storage system, will be then analyzed technically and economically in detail so as it can help to indicate potential power generation constantly throughout the year.

3.6 Production of energy in pumped storage energy

Pumped storage plant is a system which produces energy by storing the potential energy using the water as a medium. The volume of the upper or lower reservoir limits the energy capacity. Potential energy generation [KWh] is the product of power output and runtime; which is a function of reservoir volume and flow rate.

Potential Energy= (J) (3)

Where mw is mass of water (kg); H is height difference (elevation) (m); g is gravitational acceleration (m/s2)

3.6.1 Generation mode

Considering a pumped storage system in generation mode for an hour, the power generated will be:

g Eg=gHV g (W) (4)

3 Where Eg is power generated (W);  is density of water (Kg/m ); g is gravitational 2 g acceleration (m/s ); g is conversion coefficient for the mode; V is volumetric flow rate at the mode (m3/s); H is head (m) (generation mode)

Figure 3.2: Load Demand (pumping) and Generation

3.6.2 Pumping mode:

The power consumed when the water is lifted from the lower reservoir to the upper reservoir (pumping):

 Ep = (W) (5) 

p 3 Where Ep is pumping energy (W); V is Volumetric flow rate for pumping (m /s); p is conversion coefficient for pumping.

3.6.3 Benefits of pumped storage plant

 Optimization of hydropower plant, electric networks  High global cycle efficiency  Enables increased use of renewable energy sources.  Constructive environmental impact when carefully assessed and implemented  Enhance the profit of unstable electricity market.

3.6.4 Pumped Storage System overall efficiency

There are different kinds of losses in which the system will face.

 Motor –generator efficiency [Khartchenko, 1998]  Turbine efficiency  Pumping and generating flow rates  Efficiency lost in traversing the tubes between each reservoir and the turbine [Dixon, 1998]  Change in climate; hotter seasons will have high evaporation  Leakage in water conductor system  Losing considerable amount of water for other purposes than generating electricity.

Due to all the above and other reasons the efficiency of pumped storage system will not be larger than 85%.

ESA indicates the efficiency of the system in terms of the water lifted to the upper reservoir as; the electrical energy required to pump water from the lower reservoir to the high head of the system, higher reservoir can be recovered with an efficiency of 70-85% [ESA, 20010] upon generation. According to the type of the plant the efficiency will vary.

3.6.5 Basic components of pumped storage plant are:

1. Upper and lower reservoir 2. Penstock 3. Motor generator 4. Pump turbine 5. Tail race

The basic components of the system; pump, Turbine, Motor, Generator can be arranged in different ways for adjusting system efficiency, compactness of the system and so on. From different configurations this three are the basic ones

 Each components act like a unit; pump coupled to a motor; and a turbine coupled to a generator.( Four units) - Very huge in size  A single reversible motor/ generator system coupled with pump and turbine. (Three units)

- The efficiency can be increased via using multistage pumps.  Multi stage reversible pump turbines; reversible motor generator will be coupled with a reversible pump turbine. ( Two units) - Relatively decreased efficiency - Compact - Low installation cost.

3.7 Wind- Solar- PV hybrid systems for pumped storage plant

If the climatic conditions are favorable, sun irradiation and wind potential, integrating this intermittent power sources with pumped storage will lead to smooth and sustainable power production. This green power from surplus wind and solar resources will be used to pump water back to the upper reservoir. This will not only increase the capacity of the power plant but also offers to the intermittent nature of solar and wind power generation. Conventional pumped storage system uses the excess energy produced from the hydropower plant to pump the water to the upper reservoir, but for the places with high potential of solar and wind resources using hybrid systems to for the pump will increase the plant efficiency and will be the great goal to the global dream; green, sustainable energy.

[G. Z. Chen et al] on their paper Determination of Installed Capacity of Pumped Storage Station in WSP Hybrid, power Supply System detail analysis on the hybrid system done considering case study. The paper concludes by indicating the benefit of using pumped storage system hybrid with wind and solar power in supplying electric quantity and power quality for a grid.

Outcomes:  Stable and continuous power output,  The electricity quality can greatly be increased and  Period of power supply will be extended

4.0 TANA-BELES HYDROPOWER PLANT

Tana Beles is one of the largest hydropower plant which contributes 22% from the total power production of the country. The hydropower plant is new as the same time it is the largest from available hydropower plants.

Figure 4.1: Share of installed capacity (%) of power plants [EEPCO, 2010] Though it is the largest it got many draw backs as indicated before and due to this it is selected for further study by the author.

The particular layout of the plant:

Figure 4.2: Longitudinal Profile of Tana Beles Hydropower Plant [project report]

Water for this station will be released from Lake Tana through a tunnel. The tunnel will feed a vertical penstock shaft at the floor of which an underground powerhouse will be located. The powerhouse will contain 4 Francis turbines of 115 MW each for a total installed capacity of 460 MW. From the powerhouse the flow is conveyed via a 7.1 km tailrace tunnel to the Beles River. The net head will be about 311 m and the rated discharge is 160m3/s. According to Salini and Pietrangeli (2006) the power plant will operate at a plant factor of 0.48, so that the average outflow from Lake Tana will be as high as 77m3/s. This will inquire 70% of the average natural outflow of Lake Tana. From the four turbines; the three are used at normal condition for the production of power and the fourth one is used as standby turbine for the time of

30 maintenance or for power production at the time of high lake level. When there is a substantial risk of the water level dropping below the minimum operation level; the operation of only one turbine or complete shutdown of the plant may arise. The minimum operation level of hydropower plant is 1784 masl and the maximum is 1987masl. The fluctuation on the lake level will result in a significant amount of reduction in energy. For example, the minimum level of 1784 masl and a minimum level of 1784.75 masl; when this two compared there is a reduction in energy of less than 2.5% however.

Figure 4.3:Topography of Tana Beles Hydro Power Plant Station [The authour]

The blue area shown is lake Tana and the red spots are hydropower stations around. Tana Beles hydropower plant station is the one at the left hand side of the lake. The water is drained from lake Tana.

The cities at the border of lake Tana are Bahir Dar and Kunzila. The hydropower plant is available at Kunzila. The lake hold islands and it is rich with vast bio diversities.

4.1 Lake Tana

The lake has 3000 km2 surface area and the depth of the lake is around 9.5 m which is about 14m below the average water level. For the hydropower plant operation a minimum of 1784 masl operation level is designed. The lake has multi functions like fisheries, navigation, tourism, and for environmental conditions. 31

 Fisherie; it is a very important activity for the people around the lake. 25 different species and 15 endemic species are available on the lake.It has a catchment capacity of 15,000 tonnes which is around 43Kg/ha/year.[ BCEOM,1996a]. The plantation of this hydropower plant may harm the habitats (breeding areas) of the fish; which may show the decline of fish population.

Figure 4.4: Lake Tana Photo

 Navigation: there are lot of islands and isolated areas where the only transportation method is based on the lake. Transportation of people, goods; for markets, schools, health facilities for almost basic needs of the rural areas. The minimal level of the lake should have to be 1785 masl. According to the Transport and Navigation Enterprise in Bahir Dar below this level navigation is restricted. This will not concede with the minimum working level of the Tana Beles hydropower plant which is 1784 masl. There was historical problem ones in June 2003; when the level of lake was 1784.26. At the level 1784.45 masl ships were not able to have a way on the lake because of the concentration of rocks. This did lead to a big problem on markets, schools and health services for those island people. Since the minimum level of the hydropower plant is much lower than the minimum level in which the ships can move; it has high risk on the transport and navigation works done on the lake. If the minimum operation level increases to 1784.75 there will be a reduction of about 25% in the storage capacity and energy production.

 Tourism: There are 37 islands and from those 19 have ancient monasteries and churches on them. These historical places are most visited places for tourists. And Tis Issat fall (smoking water) is also most visited area. This is a place where large income is generated from tourists. Around 30,000 Ethiopia, 10,000 foreigners [Ethiopian tourism beuro, 2009] per year visit the place. Because of the hydropower plant the beauty of the fall and the transport to the Lake Tana monasteries will fall to high risk.

 Environment: the temperature of the cities around the lake is comparably very high. At summer time, the sun shines burningly. The wind from the lake is very

important to minimize the hotness of the cities. And also from construction point of view many habitats will be distracted.

The target of the government is to:  Maximize the power production  Make sufficient water available for the cropping patterns.  assure the minimum level of the lake not to limit the only available way of transport  Comforting and increasing the attraction of the historic places for tourist  Working on the well-being of species of the lake shores; limit the lake variation  Avoiding high water level in the lake; to eliminate risk of flood.

The above listed agendas were tried to be minimized on the plantation of the hydropower plant but still the water level will be the great problem because of the climate change our globe dealing with.

4.2 Technical specification of the power plant

The country‟s electric power consumption is almost totally covered by hydropower plant; the hydropower plants must work in full load to fulfill the needs from the customer. Currently Tana Beles works till 00:00AM (6:00 mid night; local time) at full load. After this time, it starts to work with the efficiency of 50% or less.

Parts of the hydro plant are:

Figure 4.5: Tana Beles hydropower plant layout [Author, from project report]

1. UPPER RESERVIOR  Is Lake Tana  Full Storage Level: 1,787.0 masl 33

 Minimum operating level: 1,784.0 masl

2. PENSTOCKS  no branches: 4  Total length of the four branches: 155.0 m  Diameters: 5.6/2.8/2.2 m ( max … min )

3. TURBINES  (4 x 115 MW);  Vertical axis Francis Type,  Rotating speed: 375.0 rpm,  Number of units: 4 No.,  Runner Discharge diameter: 1.9 m,  Specific speed [m*kW]: 96,  Rated head 40.0 m3/s design flow: 315.0 m,  Output at Rated Head: 115.0 MW

4. TAILRACE TUNNEL  Invert level: 1,460.7 masl at ch 12+928,  Length: 7.108 km.  OUTLET PORTAL with 1,450.0 m invert level of the portal  1,452.1 masl tail water level at design flow (Q= 160 m3/s)

Table 4.1: Overall status of Tana Beles hydropower plant [The author from project report data]

5.0 ASSESSED PROBLEMS ON THE HYDRO POWER PLANT

5.1 Available water

The mean flow rate of the power plant throughout the months of a year is

Months Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Flow rate (m3 /s) 160 77 77 77 77 77 77 160 160 160 160 77

Table 5.1: Annual flow rate distribution for each month [Beles Hydropower plant report]

There are two extremes, maximum flow or designed flow rate which is 160m3 /s and the minimum flow, 77 m 3 /s. The maximum generated power available is only for five months. The other seven months generate under half of the designed capacity. The maximum generation periods are on the rainy season of Ethiopia. For the months; February, March, April, May, June, July and December as shown in Table 5.1, there is a great decrement in generating capacity of the power plant. Since these months are in summer season, it is facial time for the country where every sectors work fulltime. Which means the energy demand will reach its maximum. Since the power generation is not getting reach to the demand, there are days of blackouts again and again. The available power is not sufficient enough to fulfill the current demand of the grid. And also the continuous shut down and half load working condition will definitely harm the parts of the plant.

450

400

350

300

250

200 Power, MWPower, 150

100

0 0 1 2 3 4 5 6 7 8 9 10 11 12 Months of a year

Figure 5.1: Generated power for a year [Author from data available at table 6]

As shown in the figure 14, there is great variation between the two conditions. For the hydropower plant, four Francis turbines are instead with a capacity of 115 MW which will be ideal for most of the time in a year. This minimized capacity must be enhanced by applying different mechanisms.

The hydro power plant upper reservoir is Lake Tana and there is no installed lower reservoir; the water is left to join Beles River after generation; as indicated in the earlier chapter this power plant is dependent on the capacity of Lake Tana and the lake water level is a vital issue for the country since it is way of transport for islands and tourism sectors. The installation of pumped storage system will make the power generation unconditional, it is possible to get the demanded, available power constantly throughout the year; even in the drier seasons too. Since the cost of installation is tremendous, its function must have to be also satisfactory. For the pumped storage system the first step is the preparation of lower reservoir.

5.2 Lower reservoir

There is no installed lower reservoir after the tailrace; since the water after tailrace is joining the Beles River. So the preparation of reservoir is the first step. There are two vital periods where the power as well as the reservoir volume tremendously changes.

The reservoir volume with respect to the time is considered. Assuming the power plant works with full capacity at peak hours of a day; which is from morning 7AM to12PM and starting from 1AM to 6AM the plant works with half capacity. The expected volume of water at the lower reservoir in each hours of a day is shown in the graph where the maximum volume in the lower reservoir after 18hrs of full load generation is 10.368 * 10 6 m3 for the five months where the flow rate is 160 and

for the rest 7 months where the maximum available flow rate becomes 77 ; the reservoir volume after 18 hours of full load work will be 4.9896 *106 m3.

7761.6 7207.2 6652.8 6098.4 5544 4989.6 4435.2 3880.8 3326.4 2772

V ( 10^3 ( 10^3 m^3) V 2217.6 1663.2 1108.8 554.4

5:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 1:00 2:00 3:00 4:00 6:00 7:00 8:00 9:00

------

10:00 10:00

11:00 12:00 11:00 12:00

- -

- - - -

4:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 1:00 2:00 3:00 5:00 6:00 7:00 8:00

12:00 9:00 12:00 9:00

10:00 11:00 10:00 11:00 Hours 5 months of a year 7 months of a year 37

Figure 5.2: Variation on the Volume of Lower Reservoir within a day

This is a great loss for the plant, because this will increase the load on the machine components which will be preceded by vibration increment and other losses than working 100%. So what is going to be assessed in this paper is the implementation of pumped storage system to store energy which helps us to manipulate it in the time of numerous power consumptions. Especially as indicated in the earlier chapter this hydropower plant is erected using Lake Tana as a reservoir which by itself is a habitat of different fish species, a main way of transportation for basic tourist islands inside the lake; if the level of water decreases beyond what is mentioned in chapter two large ships can‟t be in operation.

5.3 Pumped storage system for Tana Beles hydropower plant

Most of the problems in the site can be minimized or removed by the application of pumped storage systems. The efficiency and the capacity of the plant will increase and as the same time the sustainability of the project will be assured. Two options can be applied for the application of the system;

1. In the first case, the water can be returned to the upper reservoir (lake) then to the lower reservoir to generate power. Since all the turbines are Francis turbines they can work as a pump at the same time. Lower reservoir will be prepared for the purpose of storing water as a lower reservoir. The power needed to pump the water will be covered from the peak power production of the plant and/or from intermittent renewable resources like wind and solar- PV hybrid systems. All design parameters will be dealt on.

2. The second option will be to build other mini hydropower plants using the water after the Tana Beles hydropower house; re-using the water again and again instead of leading to the Beles River will enhance the capacity of the water. Water is a resource of the globe which obliges us to be respected and utilized efficiently. This large amount of water leaving the turbine must be in generation of power. The water will be collected after the first power house then pumped to the higher reservoir and the same operation will continue. The power need for the pump will be covered by the peak load generation of the hydropower plant and/ or renewable intermittent energy resources.

The country is way behind from fulfilling the need of net consumption of electric power. Every possible measure has to be taken care to enhance the power production.

5.4 Why need for pumped storage system?

1. The power production of the country is not even fulfilling the demand by half, so it needs to be enhanced. 2. Since 88% of the production is dependent on hydropower; the potential will definitely be seasonal and can‟t cover the peak demand. This must have a solution.

3. The demand show increment in dry season because schools and industries work fulltime. 4. The country‟s economical growth and capability to cover the fuel for diesel generators for time of peak hours is not efficient so other mechanisms have to be done in already installed hydropower plants. And pumped storage system will be the answer.

Since pumped storage is power consuming system the basic demand for application is the pump power.

5.5 Pump power

The proposed pumped storage system is planned to work for 7 hours, the other 17 hours of the day the conventional hydropower plant work in its normal mode.

The maximum volume outflow within 17hours in the rainy and dray season is 9,792,000 m3 and 4,712,400 m3. The installed power plant got two purposes which are power generation and irrigation this implies that all the volume of water in the lower reservoir may not be returned back to the upper reservoir.

5.5.1 First scenario, five months where the power plant work in full load; Q=160m3/s

For this study 24 hours flow was analyzed by considering full capacity of the plant where, flow rate is 160m3/s, and total power capacity of 460MW. The analysis was made using excel; from each hourly collected volume of water 40% will be released to the surrounding for irrigation purpose. Since there are vast agricultural plants proposed around the sites which expect large amount of water from the hydropower plant. The maximum volume of water available in the lower reservoir after working for 17 hours is 5875200m3.

5.5.1.1 Flow rate

The expected flow rate of water in the pumping mode; to pump the water back to the upper reservoir for 7hrs;

Q= (6)

The plant turbine flow rate; 40 must be taken as flow rate for the pump too, so as the pumping mode synchronizes with the generation. Six reversible Francis pump- turbine systems are necessary to pump back the water to the upper reservoir. The water in hours of pumping-generating mode will be diverted to outside for irrigation purpose. Each pump/turbine will have a flow rate of 38.857m3/s.

5.5.1.2 Pump power

Power input= (7)

Where (m3/s) stands for the density of the fluid to be pumped; water in this case, is for acceleration due to gravity (m/s2) and H, Q stands for both gross head(m) and volumetric flow rate(m3/s) respectively. Where the efficiency of pump considers all components water conductors, pump, motor, transformer which totals 78.0-90.02 %Frank et al, 2011].

Putting all values into the above formula, the pump power needed amounts to 141.844 MW.

Total power consumed to pump the water to the upper reservoir taking the gross head of the hydropower plant amounts to 141.844MW for each flow rate, each pump, and total for the six pump/turbine amounts to 851.064MW.

5.5.2 Second scenario, seven months, where plant flow rate becomes 77m3/s

In these dry months the expected flow rate for the hydropower plant is 77m3/s which will lead to a lower water level in the lower reservoir, as the same time a great demand for electricity in peak hours. The government use diesel power plants to full fill peak hour demand. By considering the demand, in this scenario 24 hours gathered water will be pumped to the upper reservoir. So the recorded volume of the lower reservoir after 24hr is 5682600m3.

5.5.2.1 Flow rate

The same relation is used as the first scenario and the respective flow rate for the total volume of water considered will be 225.5m3/s. The same number of pump/turbines will be used and flow rate for each will be 37.58m3/s.

5.5.2.2 Pumping power

Taking the gross head of the hydropower plant and efficiency of the pump as before, the pump power for each will be 137.182MW. And total power which will be consumed for the six installed systems will be 823.094 MW.

Scenarios can be compared and concluded as below:

Cases Scenario 1 Scenario 2 No. of months 5 7 Available seasonal Flow rate (m3/s) 160 77 No. of working hours to collect the water to lower 17 24 reservoir (h) Available water in lower reservoir (m3) 5875200 5682600 Number of pump/turbines needed 6 6 Flow rate of pump/turbine (m3/s) 38.857 37.58 Pump power for each (MW) 141.844 137.182 Total pump power needed (MW) 851.064 823.094

Table 5.2: Summary of the two scenarios

5.6 Available power for the pump

The power demand for the six pumps amounts 851.064MW each need 141.844MW to pump the water to the upper reservoir. Pumped storage system is power demanding system; it needs power to produce. To cover this power input we have different methods;

1. Power from the installed hydropower plant in the time of off peak hours 2. Wind and PV cells 3. Power from the grid

5.6.1 Solar and wind potential

5.6.1.1 Solar resource distribution around the site

The hydropower plant is located 11°49′10″N 36°55′08″E11.81944°N 36.91889°ECoordinates and daily solar radiation and wind speed data available is taken from online sources at SWERA monthly renewable energy data; and wind speed_nasa_low [ SWERA, 2011]. The data was inserted to homer and checked for the available potential.

Figure 5.3: Solar and Wind Resource at the Power Station

Figure 5.4: Solar Potential Availability

As shown from the figure the most frequent available solar potential is the very list value in KW/m2, the other larger potentials frequency is almost null.

Figure 5.5: Wind Potential (speed) Availability

Wind maximum speed is almost 3.7m/s and it is the most frequent potential available. The scaled annual average solar radiation is 5.84kWh/m2/d and annual average wind speed is 3.7m/s which is measured 50 meters above ground. Wind turbine used to be designed to reach its rated power within 10- 12m/s wind speed which will not be possible in case of Tana Beles.

These values of wind and solar will made this option not feasible but to check how much it is worse HOMER is used.

5.6.1.2 Is the solar wind data feasible for power production?

To Check the feasibility of using solar and wind system for the pump HOMER software was used. Grid, PV, wind and primary load inputs have been made. The data inserted in Primary load window is hourly pump demand and in PV, wnd windows resources, cost and sizes to be considered are inserted.

Figure 5.6: HOMER input relation

Latest cost estimation for electric power generating systems is available from U.S. Energy Information Administration Office of Energy Analysis to be used for homer.

Nominal Overnight Fixed operation Power capacity capital cost and plant (kW) ($/kW) Maintenance cost ($/kW) Onshore 100,000 $2,438 $28.07 wind Offshore 400,000 $5,975 $53.33 wind Small PV 7,000 $6,050 $26.04 Large PV 150,000 $4,755 $16.7 Pumped 250,000 $5,595 $13.03 storage

Table 5.3: Cost for selected renewable resources [EIA, 2011]

From the table we can conclude that pure pumped storage system is by far incomparable from the hybrid system. Especially for the target place applying pumped storage system, since the hydropower plant is already in place, has only little cost input. This available data was inserted to HOMER and checked to see the feasible way.

From the iteration made by Homer a hybrid system having 0.7MW PV, 3MW wind and 100MW grid electricity will cost $335,288,960-$335,387,968 initial capital cost and 196,672,512$/yr-196,672,512$/yr.

The hybrid system will not be feasible due to 1. There is excess electrical power in the grid during off-peak hours which can be used for the pump. 2. The excess electrical power in the grid is relatively cheap than the overall cost of wind and solar power systems in a place with lower resource potential. 3. For a country with very low economical growth manipulating the hydroelectric resource wisely and effectively is the only choice. 43

5.6.2 Power from the grid

Ethiopia is currently using few of the installed power plants in full load due to different impracticalities. From these few power plants most of the country‟s energy demand is served from hydropower plants erected in different parts of the country.

Hydropower plants currently connected to the grid Generating capacity, MW Tana Beles 460 Gilgel G. II 420 Tekeze 300 Gilgel G. I 184 Melka W 153 Finchaa 134 Koka 43.2 Awash II 32 Awash III 32 Total capacity = 1758.2MW

Table 5.4: Hydropower plants connected to the grid [EEPCO]

From ICS generation plants elevens are hydro power plants with total capacity of 1842.6MW and fifteen diesel plants with total capacity of 172.3MW and 1 geothermal with a capacity of 7.3 MW which accounts a total of 2.0222GW [EEPCO,2011].

From the collected data, grid power distribution in Ethiopia for six months; January, February, March, April, May, June is as shown in figure 20. The data is taken starting from mid night, 00:00 for 24 hours and 30 days. For peak demand hour data was taken in variation of 15 minutes and the others in an hour. Taking the average total active load from the grid in each active minutes, the variation of total active load in each months is available. Hourly load recording format using graph is shown below in figure 20.

The grid holds the main active power sources of the country Tana Beles, Gilgel G. II, Tekeze, Gilgel G. I, Melka W. Finchaa, Koka, Awash II, Awash III, Aluto, Awash 7 Kilo. From these sources most are hydro. The active load from each power plant is considered as shown in appendixes 2. 30 days of a month and 24 hours of each day with the respective active load is considered.

The variation for the months; minimum load in case of off-peak hours and the maximum is in time of peak hours. As Figure 20, the graph starts at midnight from minimum load and starts to fall down till early morning till 07:00. Then start to rise to 44 peak hour load and continues its cycle. The load varies between 384.75 MW and 903MW in each day with almost the same pattern. The very minimum power demand is after midnight till morning.

January February March April May June 900.00 850.00 800.00 750.00 700.00 650.00 600.00

550.00 500.00 450.00 400.00

Power, MW Power, 350.00 300.00 250.00 200.00 150.00 100.00 50.00

0.00

10:45 15:00 21:30 00:00 01:00 02:00 03:00 04:00 05:00 06:00 07:00 08:00 09:00 09:15 09:30 09:45 10:00 10:15 10:30 11:00 11:15 11:30 11:45 12:00 13:00 14:00 16:00 17:00 18:00 18:15 18:30 18:45 19:00 19:15 19:30 19:45 20:00 20:15 20:30 20:45 21:00 21:15 21:45 22:00 23:00

Figure 5.7: Total Load Variation on the Grid for 23 Days

From the above figure the greater active load is during June. Between the first minimum and last maximum points there is a load variation of 518.25 MW. The available power from sources also doubles the maximum active load of the grid. The detail load variation is shown in the attached excel appendixes 9. The relation between peak load of a day, minimum load of a day and the capacity of the hydropower plants connected to the grid is shown below.

1800 1600 1400

1200 1000 800

Power(MW) 600 400 200 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Days of June

Capacity of the selected power plants Peak load demand minimum load

Figure 5.8: Minimum, Peak Load and Capacity of Hydropower Plants in the Grid

Enormous amount of off-peak load is available in the grid; this load will be used for peak hours by applying pumped storage system. For peak hours the government used to use diesel power cycles but it is not efficient enough to fulfill the demand. Since June got the maximum distribution than other months, it will be used for further calculation.

5.6.2.1 Specific share of Tana Beles hydropower plant in the grid

Figure 5.9 using data available at Appendixes 8, shows active load share of Tana Beles from the grid in June. Comparing the daily load, it is not uniform and same time there is a large gap between the highest and the lowest power. The design power capacity for the plant is 460MW but it is not working in its full load because of water shortage. Its current working condition is indicated in figure 5.9. The graph analyzes load variation of the hydropower plant starting from 0:00 (midnight) till 24 hour.

360.00 345.00 330.00 315.00 300.00 285.00 270.00 255.00 240.00 225.00 210.00 195.00 180.00 165.00

Power, MWPower, 150.00 135.00 120.00 105.00 90.00 75.00 60.00 45.00 30.00 15.00

0.00

09:15 18:45 00:00 01:00 02:00 03:00 04:00 05:00 06:00 07:00 08:00 09:00 09:30 09:45 10:00 10:15 10:30 10:45 11:00 11:15 11:30 11:45 12:00 13:00 14:00 15:00 16:00 17:00 18:00 18:15 18:30 19:00 19:15 19:30 19:45 20:00 20:15 20:30 20:45 21:00 21:15 21:30 21:45 22:00 23:00 Hours

Figure 5.9: Tana Beles Hydropower Plant Power Variation each days

The power plant capacity is 460MW as indicated in earlier parts of the work, but as indicated in the power graph it is not working in its full capacity. Especially starting from 23:00 (11PM) the power drops to its minimum which is 100.80, 109.30, 107.20, 110.30, 109.30, 108.00, 158.10 starting from 00:00, 01:00, 02:00, 03:00, 04:00, 05:00, 06:00 respectively. The overall minimum and maximum power distribution and the capacity of the power plant is as shown in the below graph.

Tana Beles Full load of Tana Beles 460 440 420 400 380 360 340 320

300 280 260 240 220 200

Power, MWPower, 180 160 140 120 100 80 60 40 20

19:00 01:00 03:00 05:00 07:00 09:00 09:30 10:00 10:30 11:00 11:30 12:00 14:00 16:00 18:00 18:30 19:30 20:00 20:30 21:00 21:30 22:00 00:00 hours of a day

Figure 5.10: Power Generation Variation for Tana Beles Hydropower Plant

The data taken was distributed to 24 detail hours and sometimes a variation of 15 minutes also taken in time of peak hours to make it specific. This data was analyzed for a total of 23 days of June, 2011, to see clearly the peak load and the minimum load which came repeatedly. Average value for these days were taken in each detailed minutes, hours and checked how the load varies. The load in the grid varies in broad manner between the pumping hours and peak load hours.

5.7 Load arrangement for pumping power

The pumping hours start from 0:00- 6:00 and the load on the grid amounts from 495.42MW, 458.62MW, 447.25MW, 445.21MW, 447.24MW, 472.00MW, and 521.21MW respectively. From the current peak load 913.93 MW there is a variation of 418.51MW, 455.31MW, 466.68MW, 468.72MW, 466.69MW, 441.93MW, and 392.72MW respectively. This can be directly used as a resource power for the pump with the addition of the power from the hydropower plant. The ICS system of EEPCO has 1758.2 MW of capacity from the hydropower plants. This power can be utilized efficiently in time of off-peak using this system in a profitable manner. Taking the constant middle line in between the pump working hours and others, the variation of load looks like as below.

Figure 5.11: Average Load on the Grid Starting from Mid Night

As shown in the above load graph, there is a major power difference within 24 hours framework. For the seven points starting from 00:00 at midnight the load on the grid is very little as compared to the maximum power distribution on the grid in time of peak hours. After the installation of the pumped storage system the grid will work in its peak to cover the power demand of the pump for seven hours. The maximum power from the Tana Beles hydropower plant in the grid in time of pumping is 158.10 MW, therefore there will be an excess of 302 MW, and the rest (549. 064MW) will be covered from the grid.

6.0 LAY OUT OF THE PROPOSED PUMPED STORAGE SYSTEM

For the pumped storage system installation most of the necessary parameters are already installed. Upper reservoir, penstock, turbine, generator and tailrace are already in place. Two reversible pump/turbines will be added, four motor for the already placed Francis turbine will be installed. Lower reservoir will also be prepared with maximum volume design volume.

Figure 6.1 : Layout of Tana Beles after pumped storage system

6.1 Analysis for the proposed pumped storage system

6.1.1 Benefits of pump scheme

1. Maximize the power distribution for peak hour demand 2. Increasing water availability and performance of Tana Beles hydropower plant in dry seasons 3. To replace the diesel power systems with renewable energy in time of facial season 4. Increasing the quality and reliability of the electric service

The application area can be more of categorized to End-user/utility customer category [James et al., 2004].

6.1.2 Efficiency of the system

The summary of the two scenarios as indicated in Table 7, to generate 115MW power the system must use 141.844MW of power to give potential energy for the water. So overall cycle efficiency will be;

Generated power= pumping power *;

=0.8107=81.07%81.1%

The system is planned to charge for 7 hours; with 81% efficiency. To discharge for x hours the system must charge for 7 hours. =7 hours. The system will discharge for

5.67 hours. [James et al, 2004]

6.1.3 Cost of storage unit

This cost is directly dependent on the stored energy and inversely proportional to the efficiency of the system.

Storage cost ($) = Storage unit cost ($/kWh) *

As the information given by EEPCO the peak hours are starting from 9AM-12AM and 7PM-10PM. There is no timely varied cost tariff for electricity in Ethiopia except for industry purposes there is peak load and off-peak load tariff. For domestic purposes the tariff is uniform. As shown in Appendix 1, the cost variation between peak hour and off- peak hour in small industry is very large; there is a difference of 0.1991$/kWh. This indicates the expensive value of peak loads. Since the power needed to charge the system is very large, we will consider the tariff setup for large industry tariff; which is 0.4736$/kWh for peak hour and 0.3664$/kWh for off-peak hour. The Power for the pump will be used from off-peak hours starting from midnight.

After inserting the values in the formula; unit cost of storage in $/kWh and Energy of the system in kWh, the cost of storage amounts 290645.2$.

The benefit from the storage system must exceed the cost of storage otherwise using a storage system will not be feasible.

6.1.4 Net benefits of the pumped storage system

Input data: cost General cost tariff 0.3805$/kWh Peak hour tariff 0.4736$/kWh Off-peak hour tariff 0.3664$/kWh

Financial life (plant life for life cycle financial evaluation: 10 years Price Escalation (electric energy and capacity costs rise up rate during the storage plant‟s financial life) (cost/price): 2.5%

Discount rate for PV calculation (Discount Rate) 9used to make present value calculation to estimate life cycle benefits): 10%

Present Value (PV) Factor (used to convert a single/first year value into a present value): 7.17

6.1.5 End user cost avoid

Peak hour energy discharge cost= Discharging hours * peak hour cost There are 5.67 hours of discharge and it works for the whole year.

= 5.7 hours/day * 365day/year * 0.4736$/kWh = 980.138$/kW-year

Charging cost (off-peak hour energy) = Charging hours * off- peak hour cost There are seven hours of charging.

=7 h/day * 365 d/ year * 0.3664 $/kW = 936.152 $/kW

The cost reduction available is 43.986 $/kW-year The life cycle benefit can be found using present value factor;

= 43.986 $/kW-year * 7.17 = 315.379 $/kW

6.1.6 Reduced demand charges

Demand cost reduction: Peak hour cost- off peak hour cost

= 0.4736 $/kWh- month - 0.3664 $/kWh = 0.1072 $/kWh

Total Annual benefit:

=0.1072 $/kWh * 24h/day * 365 day/year =939.072 $/kW-year

For ten year life the present value (Life cycle benefit); PV factor=7.17 = 939.072 $/kW-year * 7.17 = 6733.1462 $/kW

The total lifecycle cost considering benefits with demand charge reduction and energy cost reduction:

= 6733.1462 $/kW + 315.379 $/ kW =7048.5252 $/ kW The benefit is by much greater than the storage cost.

6.1.7 Electric service reliability

Energy storage systems provide reliability for electric power services. The reliability includes:

1. It will be a solution for extended durations 2. Repeated shutdown of processes can be completed 3. A big deal transfer to on-site electric production resources

N. B The objective of the storage system will fix the discharge duration. If an orderly shutdown is the target, the discharge duration is an hour or more. And if the target is an orderly transfer to a generation device, the discharge duration can be few minutes.

6.1.8 Power quality

Electric power interruptions, harmonics, low power factor, power delivery frequency variation, voltage magnitude variation are some of the examples for poor quality of power. These problems can be helped with usage of storage system. Loads downstream against short duration load effects can be protected with the application of the system.

N.B Discharge duration for this application ranges from a few seconds to about a minute.

6.1.9 Avoided peak generation cost

Since the installed hydropower plants fail to cover the peak hour demand fully. Ethiopian Electric Power Company, EEPCO use diesel power generators for drain seasons and peak hour demands. The diesel power systems available on the ICS grid is

Station Capacity, MW Station Capacity, MW Kaliti 14.00 Axum 3.20 Dire Dawa 38.00 Adwa 3.00 Awash Sabatt killo 35.00 Mekelle 5.70 Nazareth Diesel* 30.00 Shire 0.80 Debre Zeit Diesel* 30.00 Jimma 1.10 Koka 2.30 Nekempt 1.10 Dire Dawa (MU) 4.50 Ghimbi 1.10 Adigrat 2.50 ICS Sub Total 172.3

Table 6.1: Diesel power systems on the grid [EEPCO, 2011]

These power plants have fuel cost which is the main, basic issue. So this peak load generation cost will be substituted by pumped storage system. There are 8 peak hours (day time starting from 3-6 and night time starting from 1-4).

If there is diesel power plant generation cost, and pumped storage system generation cost then their difference will be avoided cost per MWh then multiplied by the amounts of peak hours will give avoided cost per MWh per year.

From EEPCO tariff data Diesel power generation cost: 83.363 $/kW-month

Assuming all the diesel plants work and produce 172.3MW power and it works for 5.7 hours for a day. The total cost for a month is

(83.363 $/kW) * (172.3 MW * 5.7 h/day * 30 day)-month= 2.456 million $

Pumped storage generation cost: 68.369 $/kW-month

Avoided peak generation cost: = 83.363 $/kW-month – 68.369 $/kW= 14.994$/kW- month

6.1.10 Emission

The pumped storage system is pure with zero GHG emission, but when diesel power plant application for peak load hours exists there will be enormous amount of emission. So when diesel is used for peak hour. Diesel power generation is the main supplier to air pollution. The main ones are particulate matter, human carcinogen particles [EPA]; emit cancer causing agents, inflammation, high level of NOx, releases concentrated airborne fine particles. It is the source of poor and sick air quality.

For example the CO2 emissions from a gallon of diesel amounts 22.2 pounds/gallon [EPA]. Unfortunately there is no cost value for the reduced emission in Ethiopia. When it is compared with zero emission level of pumped storage system and terrible emission of diesel power plants the avoided emission value is by far considerable.

7.0 RESULTS

The application of pumped storage system for Tana Beles hydropower plant has a great significance towards many extremes and it is summarized on the table below.

CRITERIA ADVANTAGE Water availability Since the water is going to be recycled, there will be power production in continuous manner End user cost avoid 315.379 $/kW

Efficiency The system is planned to charge for 7 hours; with 81% Reduced demand 7048.5252 $/ kW charges Electric service Gives reliability for electric power services reliability Power quality Increases Avoided peak 14.994$/kW-month generation cost Emission Totally avoided

Table 7.1: Summary of the benefits of pumped storage system

After the installation of the pumped storage system, the average power on the grid increases in time of both off-peak and peak hour. The pump power will be covered from the grid and the stored energy will add six peak hours power consumption. Using available data, appendixes 11, and the variation between the pure hydropower system and with pumped storage system is indicated as below.

1200

1000

800

600

400 Power, MWPower,

200

19:15 19:45 20:15 00:00 02:00 04:00 06:00 08:00 09:15 09:45 10:15 10:45 11:15 11:45 13:00 15:00 17:00 18:15 18:45 20:45 21:15 21:45 23:00 Hours

Average load for 24 hours, pure hydro grid average power after pumped storage system

Figure 7.1: Power distribution after the installation of pumped storage system

- Six reversible pump turbines; four are in place and two are going to be added. - Power for the pump is going to be taken from the grid and full load of Tana Beles plant. - Charging will be applied beginning from 00:00 to 7:00 and discharging at any favorable time for 6 peak hours. - The pumped storage system will help the country by totally removing diesel power plants. This will add environmental and economical benefits. - The power quality and quantity is going to be improved.

8.0 CONCLUSION

Tana Beles hydro power plant is one of the plants with high rated output, but the sustainability of the plant is dependent on the water level of Lake Tana. Because of climatic changes and natural flow the level of the lake is not constant. Especially in time of dry seasons it almost decreases by half. This variability makes the power plant less efficient than the designed and dreamed goal. This study checks the proposed problem and did suggest a pumped storage system for the power plant. The proposed pumped storage system will have six reversible pump/turbines. Water will be collected for 17 hours in time of rainy season, 5 months and for 24 hour in dry season which is 7 months. The power available from the pump will be bought from

54 the grid and Tana Beles hydropower. The pumped storage system will be beneficial in cost wise and in the coverage of peak hour power demand.

9.0 SUGGESTED FUTURE WORK

At the point of summarizing this study, it is strongly recommended to enhance the capacity of renewable energy resources so as maximum efficiency is manupilated. The energy coverage of the country is at ground level. The only viable energy source for the country is hydropower. And considering the limits of hydropower plant to full fill the peak hour demand further studies must be done on the already installed hydropower plants and other potential areas of the country.

Full technical design of pumped storage systems must be done using softwares. Discovering and analyzing potential areas for the pumped storage system and feasibility study must be done to applly solar-wind hybrid pumped storage systems. These will contribute its share to the journey of green energy.

The final recommendation is to study the feasibility of applying pumped storage system between two hydropower plants. One is the new one, millennium hydropower; (5200 MW), and the other is Tana Beles hydropower plant (460MW). The millennium hydropower plant is going to start construction this year and believed to be finished at 2015. Since the two are on the same Nile basin and appropriate distance, the plants can work integrated using pumped storage system in between.

Detail and further studies should be done to maximize the capacity of the main power source, hydropower in the country.

10.0 CONTRIBUTION OF THE PRESENT WORK

The inefficiencies of the hydro power plant are configured. Since it is a hydropower plant its infrastructures are almost permanent. And it should kick its designed goal. So the contribution from the study is to indicate, show and proves the feasibility of the water re-using method which is application of pumped storage system for the hydropower plant so as it function in its full capacity inspite of shutt downs, and degredation of the main water source, Lake Tana. The application of the system will cover the peak hour demand. This will decrease fuel costs and emissions from diesel power plants. The technical parameters for the implementation of the system is indicated. As proved from the study, hybrid system is not feasible but pure pumped storage system.

11.0 REFERENCES

Frank S. Barnes, Jonah G. Levine., 2011. Large Energy Storage Systems Handbook (Mechanical and Aerospace Engineering Series). 1 Edition. CRC Press.

Thomas, Kao, Robert., 1998. Standard Handbook of Powerplant Engineering. 2nd ed. New York: McGraw-Hill.

Pumped storage power plant: On Edersee is Eon on hydropower | Economics Newspaper. 2010. Pumped storage power plant: On Edersee is Eon on hydropower | Economics Newspaper. [ONLINE] Available at: http://economicsnewspaper.com/policy/german/pumped-storage-power-plant-on- edersee-is-eon-on-hydropower-8350.html. [Accessed 02 April 2010].

EIA - Updated Capital Cost Estimates for Electricity Generation Plants. 2011. EIA - Updated Capital Cost Estimates for Electricity Generation Plants. [ONLINE] Available at: http://www.eia.gov/oiaf/beck_plantcosts/. [Accessed 05 April 2011].

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International Hydropower Association., 2010. Benefits of pumped storage. [ONLINE] Available at: http://www.hydropower.org/psd/articles/introduction.html. [Accessed 22 December 10].

World Resources Institute. 2009., Energy and Resources COUNTRY PROFILE - Ethiopia. [ONLINE] Available at: http://earthtrends.wri.org/text/energy- resources/country-profile-60.html%20+%202010. [Accessed 06 May 2010].

Ethiopia - Wikipedia, the free encyclopedia. 2009. Ethiopia - Wikipedia, the free encyclopedia. [ONLINE] Available at: http://en.wikipedia.org/wiki/Ethiopia. [Accessed 06 December 2009].

HOMER National Renewable Energy Laboratory (NREL); 2006 1617 Cole Boulevard Golden, CO, 80401. http://www.nrel.gov/homer

GENI., 2006. Ethiopia Energy Issues. [ONLINE] Available at: http://www.geni.org/globalenergy/library/energy-issues/ethiopia/index.shtml. [Accessed 06 December 11]. EEPCO. 2011. EEPCO. [ONLINE] Available at: http://www.eepco.gov.et/. [Accessed 05 December 2011].

Dr. Tariq Iqbal. 2011., Feasibility Study of Pumped Hydro Energy Storage for Ramea. [ONLINE] Available at: http://www.mun.ca/harriscentre/reports/arf/2009/ARF_Iqbal_RameaHybrid.pdf. [Accessed 05 November 2010].

SMEC International Pty Ltd (2007)

SMEC International Pty Ltd (2008)

EEPCO Beles Multipurpose Project (2006)

James M. Eyer, Joseph J. Iannucci, Garth P. Corey., 2004. Energy Storage Benefits and Market Analysis Handbook. [ONLINE] Available at: http://prod.sandia.gov/techlib/access-control.cgi/2004/046177.pdf. [Accessed 05 September 2010].

Roger Peters, P.Eng. with Lynda O‟Malley., 2008. STORING Renewable power. [ONLINE] Available at: http://www.google.com.et/url?sa=t&rct=j&q=storing%20renewable%20power%20rog er%20peters%2C%20p.eng.%20with%20lynda%20o%E2%80%99malley%2C%20yo rk%20university&source=web&cd=1&ved=0CBUQFjAA&url=http%3A%2F%2Fpubs.p embina.org%2Freports%2FStoringRenewablePower- jun17.pdf&ei=I1PdTtfHJ5HTsgaN- oizBA&usg=AFQjCNGjpaTgC53aSzmfGcJT6IiVCnS0mg&cad=rja. [Accessed 05 September 2010].

REN21., 2010. Renewables 2010 Global Status Report (Paris: REN21 Secretariat). [ONLINE] Available at: http://www.ren21.net/Portals/97/documents/GSR/REN21_GSR_2010_full_revised%2 0Sept2010.pdf. [Accessed 15 October 2010].

IHA White Paper., 2003. The Role of Hydropower in Sustainable Development. [ONLINE] Available at: http://www.ewra.net/ew/pdf/EW_2006_13-14_08.pdf. [Accessed 11 June 2009]

Björn Bolund, Urban Lundin, Mats Leijon., 2005. EUSUSTEL WP3 Report. [ONLINE] Available at: http://www.eusustel.be/public/documents_publ/WP/WP3/EUSUSTEL%20WP3%20St orage.pdf. [Accessed 06 December 2010].

(RREX) Renewable Resource Energy Explorer., 2011. (RREX) Renewable Resource Energy Explorer. [ONLINE] Available at: http://na.unep.net/swera_ims/map2/hydro.php?country=ethiopia#. [Accessed 21 May 2011].

12.0 APPENDIXES

1) Ethiopia Electric Power Corporation consumption cost tariff [EEPCO, 2011]

A) Translated in English

Cost for domestic Small voltage industry time tariff; $/kWh Large voltage uses industry/time/tariff/15KV; $/kWh $/kWh

General 0.4735 General cost 0.5778 General cost tariff 0.3805 cost tariff tariff

0-50 0.273 Peak hour 0.7426 Peak hour tariff 0.4736 tariff

51-100 0.3564 Off-Peak hour 0.5435 Off-peak hour tariff 0.3664 tariff

101-200 0.4993 General cost tariff for domestic Road light tariff General cost tariff 0.4843 201-300 0.55 General cost 0.6723 tariff

301-400 0.5666 0-50 0.6088

401-500 0.588 >50 0.6943

>500 0.6943

B) Raw data from EEPCO

2) Total active load in the grid for 30 days and 24 hours, January A) January January Days 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Ave TimeTotal activeTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeload Loadload 01:00 397 375 428 422 432 409 448 443 415 458 433 358 410 431 453 377 371 433 434 443 435 441 366 417 412 421 404 385 413 372 414 02:00 368 365 408 419 405 403 436 425 390 418 391 349 394 396 424 366 357 440 423 437 419 416 353 388 398 410 401 362 400 359 397 03:00 367 369 413 412 410 400 435 392 378 427 400 351 421 406 403 362 380 427 415 420 425 423 356 409 385 408 395 366 396 363 397 04:00 371 366 425 395 418 402 433 404 386 433 421 360 411 414 409 376 406 413 414 421 420 416 338 405 375 404 400 382 393 351 399 05:00 374 392 474 446 431 428 442 424 408 466 444 374 398 442 425 389 420 430 429 441 453 432 375 445 381 429 433 407 408 376 421 06:00 424 476 474 512 506 497 499 488 510 535 497 444 474 496 472 415 486 504 501 524 519 461 437 487 497 491 481 468 445 443 482 07:00 493 584 611 645 604 647 598 532 617 666 552 507 595 592 516 579 623 611 617 627 603 450 542 541 596 608 573 582 511 544 579 08:00 510 600 627 636 592 615 619 544 625 682 573 564 608 637 551 595 630 627 609 639 639 534 583 616 643 639 605 611 538 586 603 09:00 535 642 669 681 628 674 646 550 674 711 598 594 644 671 555 617 678 645 643 695 650 544 630 676 682 681 632 648 541 641 636 09:15 533 647 672 690 642 663 661 567 687 726 582 594 654 685 556 624 688 650 650 707 645 556 624 681 692 666 650 649 548 679 642 09:30 540 657 696 693 648 674 662 566 691 742 582 597 640 678 553 629 699 651 655 720 646 561 637 675 696 683 644 648 540 692 647 09:45 531 667 701 691 640 693 681 561 702 745 580 596 651 676 555 643 707 652 667 729 642 553 637 675 696 695 655 674 541 690 651 10:00 529 679 702 696 653 702 681 568 695 749 582 596 660 677 546 664 701 666 659 723 643 545 651 678 696 717 663 639 527 681 652 10:15 535 695 703 688 651 700 685 565 698 733 587 610 651 679 555 644 712 660 663 728 649 545 650 705 691 719 663 645 526 673 654 10:30 495 686 703 697 658 696 685 567 717 742 583 615 655 707 549 655 696 691 666 731 652 541 651 697 699 707 673 664 442 696 654 10:45 531 690 724 672 662 710 692 568 712 762 582 609 666 703 549 557 705 690 676 733 653 544 663 692 706 711 673 675 460 718 656 11:00 557 698 721 680 667 723 696 569 734 782 577 609 726 709 553 625 704 712 673 744 666 548 673 698 713 735 678 673 469 707 667 11:15 553 702 722 722 692 713 705 573 745 771 580 604 691 709 558 676 692 692 679 749 683 548 690 711 709 736 673 674 467 719 671 11:30 561 715 753 714 686 735 706 571 739 768 566 609 706 695 565 108 694 699 682 755 664 547 686 718 719 733 676 679 477 732 655 11:45 557 717 732 727 700 731 712 579 743 767 565 606 693 721 569 115 705 699 665 749 672 550 683 722 729 732 679 684 473 703 656 12:00 555 718 730 723 699 731 706 573 754 765 564 598 687 711 569 175 706 694 665 754 659 547 685 713 727 733 671 684 473 711 656 13:00 535 687 691 711 654 676 677 561 723 754 541 576 654 689 554 453 662 675 621 728 622 504 675 689 698 715 621 666 477 694 639 14:00 505 655 656 671 626 678 632 538 691 729 496 564 644 666 531 643 656 639 596 715 586 475 635 650 685 684 593 666 446 678 621 15:00 482 657 646 670 623 675 640 503 685 705 480 557 640 648 503 660 674 653 559 702 567 471 642 635 658 668 584 638 428 664 611 16:00 463 667 656 688 637 686 639 501 705 674 486 550 637 645 501 663 666 628 506 702 577 469 623 629 686 692 571 621 463 655 610 17:00 468 673 656 684 650 700 632 505 718 645 492 555 627 647 440 657 680 637 574 699 572 465 616 618 755 681 585 622 340 643 608 18:00 481 650 636 658 624 664 629 550 690 602 499 546 610 624 480 623 649 607 586 672 582 506 596 612 580 628 569 603 492 626 596 18:15 532 647 636 669 621 665 614 558 688 623 521 566 632 626 498 610 631 604 587 660 571 499 595 620 597 635 578 586 513 599 599 18:30 575 709 715 707 657 702 694 594 739 642 550 412 665 653 555 659 662 639 622 678 592 533 619 654 619 675 606 593 556 670 632 18:45 676 630 737 732 762 765 754 687 790 736 629 529 725 735 629 740 728 706 713 760 678 607 669 683 625 720 667 669 620 689 693 19:00 728 714 801 801 772 804 788 734 811 796 720 647 791 774 669 760 784 750 800 811 738 658 710 770 625 763 739 745 670 748 747 19:15 753 758 830 820 802 816 792 762 835 821 721 726 788 803 719 825 794 765 790 852 757 708 752 759 668 778 773 786 732 756 775 19:30 757 804 822 830 806 826 797 773 849 829 728 741 792 813 744 819 817 788 821 855 790 723 748 773 670 776 783 807 748 759 786 19:45 763 820 825 826 803 826 785 790 838 834 732 742 792 801 757 819 813 801 808 852 786 728 741 764 717 697 787 800 744 756 785 20:00 761 805 821 821 804 822 789 773 838 832 730 750 791 803 760 812 800 805 810 843 786 723 739 760 717 732 785 801 754 752 784 20:15 756 793 822 818 798 816 787 775 833 829 724 752 780 798 761 807 791 805 807 837 781 711 736 753 717 754 780 790 762 753 781 20:30 752 797 796 796 801 820 788 772 819 819 722 754 770 797 756 794 799 796 817 828 777 711 729 746 715 759 760 773 758 746 776 20:45 740 790 802 795 791 808 764 759 812 819 721 741 771 779 746 796 794 785 781 800 767 708 717 734 708 759 760 769 746 737 767 21:00 720 796 793 781 778 803 759 746 795 797 702 732 758 779 729 772 786 771 775 795 753 688 716 725 709 769 739 763 737 741 757 21:15 697 744 777 751 757 769 690 756 786 775 684 718 737 761 733 746 758 744 739 777 734 664 680 710 673 750 734 753 722 734 735 21:30 664 719 749 754 743 708 707 737 765 756 661 701 706 734 694 722 734 719 717 730 701 644 666 700 653 734 717 724 688 717 712 21:45 651 727 690 732 689 709 689 723 723 734 644 664 682 712 660 693 708 692 694 707 693 619 643 686 625 710 688 691 659 695 688 22:00 606 680 672 647 676 656 681 669 721 724 596 663 662 691 621 657 662 669 688 701 682 587 619 607 629 690 641 661 630 679 659 23:00 498 563 559 551 564 560 581 559 597 588 508 530 532 562 507 538 555 546 569 562 562 481 563 526 518 600 530 553 477 546 546 00:00 410 475 463 465 484 482 497 451 494 484 400 457 466 474 422 459 466 456 459 463 485 403 444 451 447 458 415 453 384 459 454 Peak Load763 820 830 830 806 826 797 790 849 834 732 754 792 813 761 825 817 805 821 855 790 728 752 773 755 778 787 807 762 759 Min. Load367 365 408 395 405 400 433 392 378 418 391 349 394 396 403 108 357 413 414 420 419 403 338 388 375 404 395 362 340 351 900 900 800 800 700 700 600 600 500 500 400 400 300 300 200 200 100 100

0 0

01:00 10:30 21:30 03:00 05:00 07:00 09:00 09:30 10:00 11:00 11:30 12:00 14:00 16:00 18:00 18:30 19:00 19:30 20:00 20:30 21:00 22:00 00:00

16:00 19:30 01:00 03:00 05:00 07:00 09:00 09:30 10:00 10:30 11:00 11:30 12:00 14:00 18:00 18:30 19:00 20:00 20:30 21:00 21:30 22:00 00:00

B) February

February Days 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Ave TimeTotal activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load active loadLoad 01:00 428 407 397 420 461 419 375 419 402 449 419 424 44 382 435 451 426 424 436 428 373 416 438 394 445 434 432 403 417 440 408 02:00 418 396 412 404 431 424 350 393 387 440 398 405 46 366 419 422 381 412 429 380 385 406 407 364 438 428 418 392 354 406 390 03:00 402 400 366 398 411 428 354 409 392 425 390 413 46 362 426 431 397 407 427 360 382 398 429 374 431 414 432 387 361 411 389 04:00 403 393 388 404 447 424 352 397 394 423 400 413 24 380 417 442 410 410 419 454 369 409 405 379 433 416 432 374 371 411 393 05:00 408 415 424 420 458 451 383 423 411 458 441 462 34 397 442 451 428 425 444 361 398 420 457 401 452 450 473 399 405 438 414 06:00 533 488 489 501 504 483 429 472 489 510 512 505 44 467 522 553 491 504 525 445 465 482 465 481 504 523 489 483 483 493 478 07:00 638 615 558 609 596 538 527 544 621 655 620 599 54 593 647 661 653 626 621 538 617 609 532 606 647 571 517 564 631 623 581 08:00 618 614 605 622 617 575 527 589 630 635 616 479 64 595 642 581 628 571 645 547 536 625 582 611 646 634 532 612 520 655 578 09:00 677 682 690 712 679 570 565 668 663 668 662 429 64 640 684 627 669 634 639 565 574 701 625 680 718 681 566 670 564 700 622 09:15 706 697 681 700 658 569 568 676 660 674 679 458 64 646 694 644 673 684 637 570 600 698 623 696 714 686 566 685 566 692 629 09:30 698 727 697 694 661 546 601 689 663 686 669 351 64 642 694 651 707 671 655 574 606 698 636 694 725 670 565 697 580 722 631 09:45 720 720 705 696 665 548 598 699 678 685 682 338 64 651 688 646 694 680 656 574 605 721 649 700 742 698 553 699 618 735 637 10:00 729 711 713 717 663 568 593 699 684 704 683 341 64 665 692 658 712 698 676 583 605 723 650 699 717 692 556 712 628 736 642 10:15 735 718 713 711 662 579 597 692 684 703 683 341 86 678 688 664 700 686 682 584 617 737 659 689 718 689 565 710 624 721 644 10:30 722 725 716 711 673 565 607 667 699 729 695 340 82 673 700 658 704 688 671 584 646 740 667 688 739 696 562 735 625 732 648 10:45 728 724 721 734 684 564 623 689 707 720 702 339 82 688 716 668 717 750 702 606 651 746 666 686 737 712 585 724 658 728 659 11:00 745 738 732 731 687 568 644 699 711 713 712 335 82 681 723 676 718 747 714 587 656 744 669 711 742 708 573 754 647 746 663 11:15 750 739 735 745 694 567 639 690 713 729 722 336 82 682 728 675 720 745 715 589 672 745 674 702 738 704 573 756 684 787 668 11:30 747 737 727 733 696 574 642 707 723 728 725 336 84 689 730 693 723 741 717 584 687 739 684 708 734 703 574 745 663 639 664 11:45 752 734 730 738 702 576 648 724 731 714 725 338 84 708 729 696 711 741 726 579 686 740 685 710 728 701 585 764 654 719 669 12:00 746 733 729 730 698 571 655 717 724 711 727 340 86 698 729 656 726 732 714 580 680 742 688 704 729 702 588 748 662 733 666 13:00 708 693 694 698 681 553 661 705 688 670 660 337 84 625 686 656 688 684 684 561 643 701 633 680 680 659 571 721 630 694 634 14:00 671 656 659 664 647 532 627 642 672 665 637 286 74 633 667 594 631 642 659 529 597 656 560 645 644 628 531 701 614 666 601 15:00 646 654 645 658 625 506 642 595 663 650 620 283 64 624 663 590 616 649 629 521 587 662 531 655 629 622 508 662 598 656 588 16:00 655 666 635 662 627 513 593 619 699 658 644 304 54 643 651 577 622 662 622 519 586 684 553 640 652 590 488 688 597 680 593 17:00 664 685 639 693 622 532 635 611 698 662 635 318 52 618 652 617 625 660 617 503 588 659 573 650 661 604 494 681 630 671 598 18:00 513 658 620 645 611 524 634 621 663 612 623 318 48 628 642 571 611 632 604 492 555 644 573 632 637 610 498 679 634 639 579 18:15 511 607 601 634 612 525 634 618 674 636 614 317 68 634 630 602 610 633 590 494 555 629 561 616 627 618 511 708 636 624 578 18:30 595 661 645 662 636 554 658 626 711 676 623 369 68 647 680 630 628 655 583 490 583 639 602 674 656 638 539 699 624 668 604 18:45 640 775 682 705 698 602 702 684 748 688 677 364 90 683 719 688 683 703 675 565 621 685 650 694 707 664 637 713 706 719 652 19:00 736 811 769 783 736 653 759 712 793 755 742 386 100 755 782 762 757 783 733 626 729 784 731 763 761 741 681 734 795 794 715 19:15 759 816 807 810 794 702 793 791 825 794 799 400 132 811 848 787 786 820 792 730 795 844 801 805 802 791 724 764 830 834 760 19:30 758 803 821 815 795 694 820 806 829 804 788 414 138 825 839 812 789 834 815 754 814 836 803 818 824 791 756 763 832 837 768 19:45 769 802 807 825 795 730 824 795 833 808 813 423 138 826 840 788 790 842 796 763 828 834 800 820 819 786 751 760 833 827 769 20:00 763 801 809 814 802 729 824 816 829 804 811 420 138 818 837 777 800 843 793 751 804 831 798 821 819 784 741 755 828 829 766 20:15 765 813 802 807 793 727 818 811 827 787 789 418 138 817 831 785 797 831 799 769 822 829 801 809 815 778 752 749 824 816 764 20:30 760 807 798 791 789 727 807 790 801 781 787 411 128 817 814 763 793 829 803 763 825 809 790 810 806 768 708 748 814 830 755 20:45 755 789 790 789 774 714 799 769 796 775 772 394 108 811 814 763 785 817 793 763 819 803 789 807 803 753 707 748 815 835 748 21:00 752 784 783 793 766 674 791 773 783 765 763 394 104 805 800 757 771 801 756 750 815 798 786 793 791 743 721 709 812 828 739 21:15 732 775 764 769 748 689 771 749 779 749 766 393 104 781 805 740 774 773 770 729 796 785 779 771 778 745 715 729 795 809 729 21:30 730 752 726 743 734 658 722 730 765 737 727 383 100 754 783 733 742 763 740 643 765 753 738 758 743 728 703 699 789 805 705 21:45 704 723 715 722 692 656 712 712 731 714 718 365 78 734 751 692 730 729 717 633 732 718 660 729 705 721 669 629 762 753 677 22:00 692 681 699 690 675 613 646 673 703 680 566 350 695 729 692 689 701 681 617 714 704 678 724 651 674 622 650 720 724 667 23:00 537 508 535 567 551 470 545 522 578 526 558 318 546 600 543 547 547 564 462 520 552 532 581 567 550 494 545 596 562 535 00:00 429 433 469 477 474 406 471 442 506 459 449 278 466 521 492 466 477 510 384 474 466 437 485 477 470 413 458 521 457 458 Peak Load769 816 821 825 802 730 824 816 833 808 813 599 138 826 848 812 800 843 815 769 828 844 803 821 824 791 756 764 833 837 Min. Load402 393 366 398 411 406 350 393 387 423 390 278 24 362 417 422 381 407 419 360 369 398 405 364 431 414 413 374 354 406 900 900 800 800 700 700 600 600 500 500 400 400 300 300 200 200 100 100

0 0

10:00 12:00 18:30 20:30 00:00 01:00 03:00 05:00 07:00 09:00 09:30 10:30 11:00 11:30 14:00 16:00 18:00 19:00 19:30 20:00 21:00 21:30 22:00

09:30 19:30 03:00 05:00 07:00 09:00 10:00 10:30 11:00 11:30 12:00 14:00 16:00 18:00 18:30 19:00 20:00 20:30 21:00 21:30 22:00 00:00 01:00

C) March

March Days 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Ave TimeTotal activeTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactive loadLoad

01:00 430 425 424 436 401 109 428 456 427 444 447 378 420 434 438 415 444 460 392 456 457 463 449 446 449 413 346 443 432 463 421

02:00 404 420 423 405 390 153 388 410 429 435 426 357 406 403 426 434 421 421 385 430 435 451 432 440 431 392 371 421 329 440 404

03:00 397 408 429 416 381 226 390 429 412 426 416 376 403 409 407 424 448 418 383 424 430 451 414 431 421 382 388 413 310 443 404

04:00 419 406 429 428 387 272 415 431 436 427 418 366 420 417 414 429 435 440 385 435 437 443 431 454 424 392 398 415 311 441 412

05:00 426 431 416 434 410 302 446 459 451 443 461 389 430 420 442 477 465 454 400 580 466 473 456 459 410 420 436 450 349 465 437

06:00 513 496 504 480 507 343 488 516 498 506 460 467 521 528 520 524 520 499 498 570 537 592 570 513 509 511 549 555 342 507 505

07:00 651 615 585 556 608 473 598 626 651 623 550 596 661 670 662 644 640 440 613 685 652 729 651 630 548 656 664 677 433 687 616

08:00 673 635 628 604 593 535 608 645 665 656 576 576 676 655 647 658 654 574 605 684 611 693 638 643 555 657 621 671 579 677 630

09:00 718 713 677 576 636 571 660 687 712 698 597 644 700 699 728 728 729 585 691 733 650 754 693 676 590 662 676 712 670 735 677

09:15 710 708 683 584 654 597 655 710 731 700 592 667 734 713 724 698 723 596 679 758 668 760 702 700 585 709 689 750 685 749 687

09:30 726 703 686 575 660 591 658 698 732 708 593 667 738 713 737 720 721 594 689 748 670 774 694 719 593 724 691 755 696 753 691

09:45 728 721 686 582 658 588 662 720 757 727 517 672 745 733 754 731 753 622 683 757 677 788 721 725 593 746 702 728 681 790 698

10:00 736 717 693 585 650 568 678 725 755 725 555 673 758 731 760 728 714 626 698 747 691 781 706 736 601 762 686 663 723 758 698

10:15 736 718 692 589 652 603 709 726 756 732 502 670 757 730 765 753 733 652 706 760 704 770 730 735 607 766 713 708 711 746 704

10:30 738 714 712 608 670 608 702 725 759 731 467 682 763 728 773 745 728 642 718 773 704 777 745 742 605 780 716 716 713 769 708

10:45 744 717 724 595 663 642 706 732 742 748 476 680 767 738 792 745 733 639 733 792 706 792 761 744 617 786 727 728 716 781 716

11:00 745 731 758 606 676 671 706 745 752 746 491 681 775 759 790 750 744 641 731 806 715 793 758 750 621 785 726 759 750 804 726

11:15 751 736 731 605 676 714 717 752 752 740 498 693 770 752 811 740 759 635 736 804 716 810 763 766 621 812 738 746 731 744 727

11:30 754 747 738 600 675 721 719 759 751 723 504 695 771 765 801 741 762 619 733 806 717 785 758 768 624 797 741 744 762 751 728

11:45 762 728 738 614 683 753 719 764 756 723 489 692 761 758 804 734 757 614 732 806 717 796 751 745 627 799 717 736 735 767 726

12:00 752 723 739 603 675 742 709 747 752 713 485 681 764 755 782 738 742 614 738 802 711 790 747 755 611 800 704 704 719 677 716

13:00 693 692 708 567 643 727 689 713 713 716 590 678 718 724 715 676 723 576 683 757 653 752 667 726 586 776 647 698 656 695 685

14:00 670 664 673 555 639 724 665 705 686 659 571 662 703 662 698 654 691 547 637 729 584 713 659 670 545 718 619 683 660 677 658

15:00 648 658 651 527 629 714 333 698 675 702 538 624 681 683 706 661 669 504 629 711 608 701 640 649 508 750 623 674 624 694 637

16:00 660 678 650 529 620 746 397 680 708 681 534 621 699 701 703 659 656 502 629 762 624 712 648 657 541 735 630 696 635 690 646

17:00 667 665 650 522 623 710 544 686 684 656 519 626 704 710 704 659 669 493 645 740 610 712 650 653 524 729 555 716 654 697 646

18:00 636 653 643 546 608 697 655 669 615 671 537 614 687 687 700 619 641 510 642 714 605 683 621 672 527 716 600 719 555 692 638

18:15 634 650 638 567 605 710 688 659 666 655 546 620 678 675 677 625 652 522 640 722 597 688 650 662 552 711 615 701 536 687 641

18:30 661 645 639 630 648 718 707 673 708 674 589 682 700 686 726 660 658 544 665 721 659 703 650 689 589 743 650 722 628 740 670

18:45 716 702 733 654 732 759 778 762 758 721 663 721 743 771 749 706 732 642 725 803 730 762 730 732 626 800 714 810 668 767 730

19:00 780 774 762 729 771 781 838 830 813 794 762 782 825 854 822 780 799 720 787 833 821 869 789 818 751 863 761 865 723 839 798

19:15 836 811 809 796 807 832 854 843 829 810 772 822 857 854 871 802 826 787 857 904 850 896 777 824 808 870 838 877 794 839 832

19:30 839 818 829 810 826 844 845 847 842 835 797 842 877 861 877 823 845 796 860 893 857 899 836 855 829 850 838 867 824 846 844

19:45 842 821 819 812 832 843 840 842 836 836 793 841 871 864 881 832 836 814 870 891 859 891 844 848 826 854 853 879 850 842 845

20:00 836 818 817 811 831 836 829 850 830 819 801 843 877 870 872 831 835 799 866 883 867 890 840 852 831 861 844 869 855 831 843

20:15 837 817 804 809 815 824 821 826 824 825 785 841 854 862 860 832 810 819 867 864 866 870 834 838 827 865 842 849 838 832 835

20:30 830 799 783 802 816 825 824 807 817 825 784 833 861 853 851 815 811 792 865 864 864 880 820 839 821 860 835 851 834 822 829

20:45 823 809 784 781 794 791 826 801 812 807 782 823 842 834 842 807 804 775 862 837 853 868 814 830 793 858 836 845 827 802 819

21:00 803 805 777 771 772 793 813 796 804 810 768 816 830 829 832 805 796 767 847 835 850 855 810 815 789 836 828 841 803 805 810

21:15 783 784 742 733 776 755 799 789 776 782 745 806 818 817 811 788 791 753 834 823 838 835 785 792 788 811 812 820 799 779 792

21:30 746 757 739 714 748 724 778 756 767 759 714 783 766 806 791 779 768 721 810 806 812 812 770 772 752 717 789 786 769 758 766

21:45 738 737 712 684 717 726 741 715 733 737 677 768 762 750 758 750 753 713 783 771 781 774 747 774 719 0 764 754 755 706 717

22:00 690 707 701 642 642 680 707 714 687 710 589 716 752 722 732 699 729 674 753 745 751 732 700 729 687 0 747 721 720 716 683

23:00 554 561 582 515 554 511 582 554 563 575 506 576 565 573 589 559 585 535 600 599 603 566 574 602 539 12 591 590 581 582 549

00:00 474 477 472 426 473 465 488 469 480 469 400 469 475 475 495 485 503 427 497 507 503 497 486 511 437 133 491 466 506 491 465 Peak Load 842 821 829 812 832 844 854 850 842 836 801 843 877 870 881 832 845 819 870 904 867 899 844 855 831 870 853 879 855 846

Min. Load 397 406 416 405 381 109 333 410 412 426 400 357 403 403 407 415 421 418 383 424 430 443 414 431 410 0 346 413 310 440

1000 900 900 800 800 700 700 600 600 500 500 400 400 300 300 200 200 100 100

0 0

20:00 03:00 05:00 07:00 09:00 09:30 10:00 10:30 11:00 11:30 12:00 14:00 16:00 18:00 18:30 19:00 19:30 20:30 21:00 21:30 22:00 00:00 01:00 62

D) April April Days 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Ave TimeTotal activeTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeloadTotal activeload Loadload 01:00 455 426 428 496 448 431 453 455 464 396 451 464 465 443 404 487 285 368 388 422 418 450 454 395 425 446 447 408 468 451 433 02:00 439 416 418 470 437 407 445 424 422 380 459 415 447 410 409 436 266 365 366 407 411 438 432 388 409 431 410 363 446 438 413 03:00 437 407 417 467 351 413 448 443 431 393 473 429 436 422 361 416 288 355 373 400 402 418 431 378 420 430 417 384 442 416 410 04:00 451 435 414 461 399 420 441 447 454 403 448 439 434 414 396 423 278 355 371 402 418 437 458 379 422 440 434 409 446 431 419 05:00 482 444 447 494 447 452 460 456 469 415 490 464 473 452 482 431 300 366 422 422 434 471 464 400 442 470 435 428 470 450 444 06:00 529 500 545 586 550 549 560 538 502 515 583 525 562 455 584 459 329 477 511 528 523 544 524 491 539 587 526 557 530 512 524 07:00 629 545 695 708 669 664 661 650 574 646 700 656 660 508 666 463 434 567 591 638 622 629 581 593 658 685 580 642 635 590 618 08:00 645 571 681 697 656 667 648 690 571 646 684 618 664 523 703 482 480 574 590 607 620 673 595 597 655 657 618 685 656 607 625 09:00 705 580 741 754 734 674 680 727 620 743 717 654 732 552 728 470 544 230 630 663 661 694 615 644 688 694 656 732 710 619 653 09:15 712 569 763 769 747 720 713 739 590 722 755 663 731 571 716 465 542 259 648 661 665 718 615 647 697 690 684 756 729 625 663

09:30 710 573 768 775 738 715 724 755 570 745 763 677 735 560 722 467 548 289 649 673 677 719 602 666 714 697 684 748 709 623 667

09:45 730 596 791 780 739 760 720 747 570 751 785 704 765 573 735 462 547 344 658 672 693 711 601 669 718 722 686 759 711 621 677 10:00 734 601 788 772 742 744 738 759 577 750 805 692 748 574 728 465 550 383 658 689 691 709 607 687 729 706 681 780 717 610 680 10:15 733 600 798 787 750 750 745 767 579 746 790 697 758 575 744 456 548 519 672 700 692 708 588 687 750 714 695 764 721 602 688 10:30 749 608 792 795 745 769 750 775 594 756 791 710 782 572 744 474 561 518 671 717 690 716 608 689 749 730 706 777 742 625 697 10:45 736 618 822 786 753 764 749 769 599 808 811 715 648 572 742 463 571 523 670 714 698 739 606 692 742 742 714 802 739 592 697 11:00 733 625 815 798 755 769 752 767 607 786 810 729 537 573 752 464 571 581 678 732 700 749 604 709 749 741 725 812 747 615 700 11:15 743 618 817 783 759 776 743 785 595 797 810 730 590 576 750 445 567 629 693 746 701 756 609 705 763 758 737 821 759 606 706 11:30 751 625 811 794 754 787 742 797 602 799 825 723 657 416 758 460 567 656 699 728 701 749 608 719 764 762 728 818 765 609 706 11:45 747 620 816 797 752 788 729 774 607 683 804 722 672 486 757 458 559 672 694 712 703 759 617 726 758 751 743 815 767 635 704 12:00 736 621 802 796 743 786 722 769 607 631 808 716 697 483 767 455 565 685 686 712 687 755 613 723 762 746 720 802 764 636 700 13:00 691 569 757 738 692 745 681 714 578 740 757 675 706 488 720 458 565 667 629 685 652 732 592 698 726 731 682 741 714 604 671 14:00 659 467 738 723 660 673 668 709 556 702 686 616 668 482 688 429 546 640 636 663 623 712 556 671 695 697 603 740 703 499 637 15:00 650 492 716 710 681 676 637 683 530 704 673 633 713 487 664 403 528 615 621 656 615 676 537 670 695 693 529 725 674 501 626 16:00 600 498 713 712 682 713 644 673 536 732 679 642 647 476 638 398 520 624 618 658 615 671 517 673 679 703 579 710 666 536 625 17:00 629 589 732 712 680 720 657 671 504 733 682 650 647 480 645 331 510 607 608 646 633 654 490 687 614 696 605 689 649 514 622 18:00 627 527 702 683 665 686 632 671 532 697 662 602 630 516 654 381 513 586 605 619 610 650 535 654 660 672 613 667 667 538 615 18:15 628 537 690 695 673 702 639 691 540 734 689 628 643 522 675 399 518 575 595 615 615 654 572 670 656 683 601 674 663 553 624 18:30 649 573 735 717 707 725 661 697 576 719 732 653 670 545 704 425 546 597 626 645 640 695 590 668 666 678 637 712 679 583 648 18:45 702 646 782 795 759 777 719 778 583 781 764 757 729 609 723 458 621 661 671 717 703 743 651 730 729 747 706 743 736 650 706 19:00 779 753 836 851 835 830 807 823 730 861 819 802 804 678 769 520 692 721 691 761 782 747 718 804 799 833 762 817 781 727 771 19:15 817 810 868 877 873 874 834 864 775 883 845 857 826 722 803 537 732 772 700 814 815 825 767 849 873 874 815 858 824 775 812 19:30 844 828 896 880 866 873 840 873 806 883 850 865 814 746 829 586 56 757 697 814 833 847 787 852 873 869 831 853 837 786 799 19:45 845 830 880 874 865 863 839 872 817 885 860 866 825 735 816 566 56 767 697 815 834 853 778 865 881 874 847 858 846 787 800 20:00 834 835 892 871 867 848 849 873 808 871 862 872 826 764 817 585 59 762 693 820 838 854 783 871 830 867 838 855 841 778 799 20:15 835 834 888 870 866 857 843 868 804 875 850 867 819 767 789 591 66 756 689 814 832 843 782 867 843 864 835 849 834 779 796 20:30 823 832 875 853 846 855 842 845 808 868 843 867 790 764 743 586 72 755 796 814 826 835 774 861 841 862 834 848 827 778 792 20:45 821 818 874 843 835 838 834 830 801 868 827 851 788 751 734 582 55 748 796 809 818 822 756 816 843 847 810 839 820 767 781 21:00 804 814 855 820 830 826 817 821 789 857 814 843 777 727 729 565 95 757 746 777 802 821 741 828 820 843 794 828 810 754 770 21:15 788 792 843 815 816 814 808 800 764 822 791 826 774 741 732 554 107 751 776 755 779 792 702 820 809 826 770 810 790 720 756 21:30 771 743 826 777 797 787 786 790 727 788 777 805 755 724 733 534 153 732 723 751 748 773 670 823 778 767 751 790 769 709 735 21:45 738 725 830 760 771 758 746 750 707 775 751 776 740 707 722 502 220 693 747 719 730 756 628 810 751 750 720 764 746 680 716 22:00 712 696 784 732 752 727 724 715 677 729 707 753 716 679 711 489 394 677 709 708 701 730 625 800 717 744 679 737 715 647 696 23:00 567 608 619 592 618 550 621 599 537 584 572 607 572 521 638 381 450 546 579 528 573 592 502 558 599 604 541 594 508 508 562 00:00 477 497 532 496 485 591 521 484 444 501 475 538 479 425 571 266 465 440 466 467 473 487 410 478 505 454 437 514 475 419 476 Peak Load845 835 896 880 873 874 849 873 817 885 862 872 826 767 829 591 732 772 796 820 838 854 787 871 881 874 847 858 846 787 Min. Load 437 407 414 461 351 407 441 424 422 380 448 415 434 410 361 266 55 230 366 400 402 418 410 378 409 430 410 363 442 416

1000 900 800 800 700 600 600 500 400 400 300 200 200 100

0 0

07:00 12:00 03:00 05:00 09:00 09:30 10:00 10:30 11:00 11:30 14:00 16:00 18:00 18:30 19:00 19:30 20:00 20:30 21:00 21:30 22:00 00:00 01:00

E) May May Days 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Ave TimeTotal activeTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactiveTotal loadactive loadLoad 01:00 390 427 457 454 464 475 470 394 451 436 453 428 446 456 409 455 461 435 425 462 410 399 433 470 479 509 504 481 417 469 447 02:00 390 423 447 443 457 449 302 382 422 423 439 405 430 437 408 440 464 436 426 440 394 389 442 459 461 494 467 459 420 439 430 03:00 378 405 440 436 446 460 428 378 422 416 434 408 457 433 404 452 453 420 418 439 381 417 437 460 445 473 428 464 384 432 428 04:00 365 401 443 442 449 467 434 383 425 424 439 424 436 440 399 447 461 427 428 447 384 391 441 480 451 464 448 482 383 439 432 05:00 410 423 491 440 487 510 470 411 458 469 471 450 461 461 438 480 484 462 441 467 412 413 468 455 507 500 500 475 444 474 461 06:00 531 555 545 577 595 568 68 509 583 540 594 541 541 519 544 552 589 552 544 503 501 516 545 590 582 587 571 515 549 589 537 07:00 610 648 670 670 685 656 238 612 701 643 684 625 623 569 655 677 689 688 655 599 545 579 646 697 657 694 660 548 611 710 631 08:00 584 652 647 694 669 698 274 619 692 649 680 591 661 604 663 675 672 664 651 651 591 597 626 680 659 726 706 567 615 678 638 09:00 644 729 703 744 712 734 424 671 744 709 655 623 708 620 725 715 738 717 686 702 610 660 702 740 733 778 746 614 674 745 690 09:15 675 727 727 733 702 740 449 700 751 729 676 622 705 628 737 726 737 734 692 691 604 691 709 732 743 785 757 618 681 755 699 09:30 654 744 732 754 706 749 485 705 760 729 719 632 712 630 742 727 748 757 688 691 609 712 712 739 717 804 741 643 689 771 707 09:45 648 746 751 755 717 769 518 722 767 750 728 641 41 632 759 748 757 752 712 699 615 707 731 752 734 808 743 653 692 770 694 10:00 673 748 761 770 721 766 553 717 749 745 736 636 49 647 776 752 765 758 698 713 613 679 720 771 733 824 776 652 705 808 700 10:15 676 767 771 763 727 778 496 730 774 747 741 662 64 639 785 762 775 771 700 712 622 675 741 786 737 820 786 657 713 788 705 10:30 669 753 777 775 731 771 385 752 802 747 746 677 67 630 804 757 717 787 705 741 618 655 750 788 764 844 775 643 718 786 704 10:45 683 761 789 773 745 781 355 743 761 747 751 681 67 629 794 762 677 800 690 740 593 664 763 816 778 849 791 654 731 787 705 11:00 694 773 786 776 755 846 408 746 782 754 766 683 176 636 792 770 749 795 699 749 590 676 771 802 808 858 802 657 737 811 722 11:15 703 775 792 780 745 796 441 768 794 759 763 680 65 639 797 791 581 795 703 766 602 682 769 803 779 857 812 658 739 819 715 11:30 704 773 800 781 740 789 500 764 785 761 782 682 96 634 802 772 637 805 700 763 597 705 793 801 783 858 817 659 747 842 722 11:45 705 770 788 770 733 785 481 784 795 737 650 675 99 640 811 780 702 808 706 757 600 708 797 806 775 862 807 652 735 837 718 12:00 709 758 788 766 728 795 536 758 774 756 646 659 167 633 810 779 757 802 702 749 617 708 760 769 762 833 806 656 737 830 718 13:00 681 718 760 729 684 708 556 714 743 732 702 624 401 604 765 752 766 764 673 679 556 725 736 735 736 788 750 628 710 805 697 14:00 645 694 713 705 670 702 24 695 760 695 687 622 296 588 737 723 729 727 661 658 522 707 721 694 732 739 719 577 687 750 653 15:00 523 709 673 697 658 637 149 679 692 666 704 614 549 162 735 715 721 700 671 648 498 720 703 695 724 770 733 528 655 750 636 16:00 629 702 702 685 664 681 296 695 712 682 737 629 601 183 751 714 569 717 698 625 488 711 715 711 746 770 709 547 693 710 649 17:00 642 699 703 664 676 692 459 680 710 709 697 619 643 420 727 681 737 711 691 649 531 725 703 712 725 766 692 561 689 746 669 18:00 591 693 687 685 645 667 567 678 697 664 641 561 656 569 748 659 669 680 654 621 522 683 670 659 730 727 659 445 655 722 650 18:15 632 720 682 691 627 651 572 684 703 676 656 561 658 601 758 666 680 690 650 620 546 689 656 673 697 703 658 475 652 719 655 18:30 713 727 701 707 663 687 638 704 722 722 698 631 703 648 766 690 694 705 679 638 569 703 671 698 725 722 687 519 685 737 685 18:45 739 777 753 757 720 730 690 766 763 758 722 705 739 702 791 755 730 761 718 689 593 753 731 763 777 757 727 581 704 781 731 19:00 774 813 829 774 755 785 767 797 833 821 784 762 795 718 843 798 790 824 832 743 735 834 756 802 812 816 799 624 804 790 787 19:15 799 850 862 772 789 824 784 616 867 861 797 817 814 736 852 849 835 860 842 786 766 868 843 846 836 838 836 668 842 774 811 19:30 805 848 897 752 780 754 773 108 889 878 808 856 824 757 851 862 873 872 853 783 797 884 881 864 889 892 845 716 862 807 809 19:45 805 850 884 754 782 775 785 49 886 871 797 850 821 754 848 868 869 869 872 785 794 887 885 877 891 897 854 740 875 812 809 20:00 808 845 877 760 763 826 792 65 883 877 799 857 784 749 844 864 867 871 861 811 801 876 892 874 889 900 857 761 865 820 811 20:15 802 838 888 741 777 814 792 104 874 879 794 843 774 743 838 859 863 857 845 802 796 873 878 875 878 884 854 769 851 832 807 20:30 799 824 853 754 768 835 785 188 859 866 781 837 802 748 828 841 847 852 844 794 790 870 873 869 875 887 862 765 858 830 806 20:45 791 815 852 760 767 826 743 216 860 844 781 825 795 740 818 831 823 836 831 776 774 852 863 871 864 871 843 761 848 830 797 21:00 794 798 841 765 763 824 753 273 775 834 781 814 777 728 817 823 811 815 823 757 760 831 847 843 859 859 830 753 838 804 786 21:15 782 769 834 773 760 806 754 325 801 830 755 796 767 729 800 809 810 807 840 734 743 809 826 821 831 781 807 714 811 811 774 21:30 756 762 722 744 745 783 719 388 783 787 733 767 750 704 763 776 784 772 796 726 698 762 784 803 821 803 796 685 785 754 748 21:45 714 728 759 735 735 773 698 412 758 746 707 719 738 667 746 746 736 763 730 690 691 723 753 721 770 800 842 659 793 726 726 22:00 655 699 729 730 704 734 658 506 724 644 655 710 705 641 743 716 714 721 723 656 647 693 711 727 726 712 722 639 708 699 692 23:00 565 566 602 588 599 603 536 525 571 542 532 570 590 511 566 579 556 551 608 564 494 584 587 570 610 625 608 544 585 574 570 00:00 469 498 523 509 464 521 428 472 477 492 473 419 500 451 487 487 481 483 485 499 434 470 519 520 531 563 556 477 480 499 489

Peak Load 808 850 897 781 789 846 792 797 889 879 808 857 824 757 852 868 873 872 872 811 801 887 892 877 891 900 862 769 875 842

Min. Load 365 401 440 436 446 449 24 49 422 416 434 405 41 162 399 440 453 420 418 439 381 389 433 455 445 464 428 445 383 432 1000 900 900 800 800 700 700 600 600 500 500 400 400 300 300 200 200 100 100

0 0

18:30 22:00 01:00 03:00 05:00 07:00 09:00 09:30 10:00 10:30 11:00 11:30 12:00 14:00 16:00 18:00 19:00 19:30 20:00 20:30 21:00 21:30 00:00

F) June June Days 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Ave TimeTotal activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load activeTotal load active loadLoad

01:00 461 429 485 450 449 424 467 460 500 485 481 488 414 446 447 453 481 484 466 407 468 451 453 459

02:00 443 403 464 440 434 406 452 452 466 470 456 473 444 458 427 474 469 475 450 390 456 438 448 447 03:00 433 402 467 419 433 399 454 445 477 468 459 465 434 461 437 461 466 484 444 394 465 433 439 445 04:00 443 413 465 444 435 402 472 445 470 471 469 449 435 465 451 454 464 479 432 385 477 434 435 447 05:00 504 423 492 463 457 436 509 463 496 490 477 509 448 513 439 492 487 484 465 416 469 454 467 472 06:00 0 610 596 531 516 511 568 568 576 576 567 533 553 551 552 558 569 545 533 502 542 422 506 521 07:00 18 701 702 676 596 618 669 676 659 662 659 613 652 661 660 663 662 665 549 608 639 602 645 620 08:00 24 690 701 705 612 677 684 697 723 700 690 629 687 708 691 700 716 694 628 658 661 653 663 652 09:00 174 754 761 755 622 727 739 756 768 742 753 643 743 749 778 755 738 743 636 695 696 721 759 705 09:15 218 769 763 769 618 722 737 778 777 756 756 639 757 762 754 776 746 737 626 738 728 757 744 714 09:30 320 765 767 790 643 725 727 789 783 777 786 626 761 789 761 769 748 725 636 731 715 705 751 721 09:45 413 771 792 790 636 738 749 790 791 805 780 634 774 777 778 786 770 759 646 731 732 774 761 738 10:00 509 771 779 795 638 741 756 799 791 799 798 637 784 787 781 789 779 739 643 733 734 772 752 744 10:15 549 790 803 802 632 749 776 812 793 800 796 625 782 790 782 800 773 766 644 748 734 791 760 752 10:30 619 812 798 762 661 753 784 821 802 807 801 633 793 788 825 809 785 760 653 755 745 783 771 762 10:45 732 791 797 799 664 768 794 831 814 816 805 640 796 800 825 727 783 781 652 776 758 792 773 770 11:00 765 796 818 791 662 784 804 821 820 800 825 643 783 821 837 841 771 787 652 787 749 794 781 780 11:15 805 832 823 811 659 792 819 840 833 795 816 645 812 829 835 845 791 780 648 791 762 801 788 789 11:30 830 842 818 811 662 791 833 848 836 804 820 641 810 839 843 821 795 768 643 826 764 803 798 793 11:45 836 841 819 803 663 805 832 848 811 808 821 644 814 841 841 838 800 771 648 825 763 807 784 794 12:00 806 830 800 797 659 797 805 840 816 781 815 636 800 846 840 830 789 780 649 812 770 805 779 786 13:00 813 775 751 778 636 782 745 801 775 736 791 616 773 770 774 785 739 771 633 769 720 774 753 750 14:00 762 759 740 750 598 790 751 764 756 723 759 588 750 750 741 762 676 741 609 752 696 736 650 722 15:00 769 751 713 706 586 775 749 711 754 750 744 577 728 741 753 719 681 719 573 391 636 727 693 16:00 796 764 713 723 575 768 748 734 756 755 726 558 725 736 763 721 695 633 563 508 661 715 697 17:00 758 745 733 725 528 764 709 745 754 731 724 540 735 712 736 704 704 608 571 685 505 742 689 18:00 734 703 678 684 551 724 675 705 707 683 690 554 683 680 706 630 617 632 575 713 592 696 664 18:15 734 793 704 683 563 742 676 708 737 682 693 559 686 656 691 643 646 631 581 724 611 703 675 18:30 740 740 724 702 584 762 689 726 751 700 701 604 700 654 693 660 660 651 602 721 603 707 685 18:45 762 768 742 735 651 789 724 777 800 741 731 649 728 692 749 668 687 693 629 770 623 748 721 19:00 831 817 805 781 715 839 795 836 791 797 776 739 779 750 810 733 768 759 685 808 663 830 778 19:15 886 882 848 826 735 888 846 877 835 887 814 764 855 802 833 801 784 776 755 792 728 801 819 19:30 900 902 852 831 794 897 868 891 857 881 859 793 860 829 867 825 794 811 781 825 745 826 840 19:45 903 905 843 836 808 907 883 886 867 894 834 819 848 843 871 847 827 838 798 857 749 856 851 20:00 914 902 858 833 803 894 883 884 873 888 869 842 835 846 872 854 832 836 800 871 745 846 854 20:15 905 889 853 840 804 891 879 887 869 876 864 832 851 840 860 852 827 842 804 864 744 833 850 20:30 887 882 844 828 797 876 870 873 864 866 850 840 856 826 862 834 826 835 792 825 729 820 840 20:45 889 862 833 807 782 857 856 879 858 835 841 820 863 816 848 826 820 823 757 810 720 810 828 21:00 883 854 817 802 771 826 843 858 842 823 833 814 837 792 830 804 799 805 763 802 713 805 814 21:15 853 834 784 786 756 802 824 828 862 805 820 774 814 764 812 798 780 766 736 793 777 768 797 21:30 830 797 747 722 729 770 809 758 776 793 792 760 624 740 786 798 734 752 721 763 744 741 759 21:45 798 765 721 741 687 699 748 755 755 788 758 719 741 713 750 765 715 730 738 718 723 702 738 22:00 728 769 678 719 648 666 719 749 697 735 715 696 700 671 710 711 694 707 678 688 701 698 704 23:00 649 633 587 582 531 575 589 614 617 631 657 575 596 558 600 606 597 594 532 585 566 579 593 00:00 467 547 492 502 459 497 494 529 499 522 566 428 459 489 515 502 510 500 437 503 487 498 495 Peak Load914 905 858 840 808 907 883 891 873 894 869 842 863 846 872 854 832 842 804 871 777 856 798 Min. Load 0 402 464 419 433 399 452 445 466 468 456 428 414 446 427 453 464 475 432 385 456 422 435 1000 900 900 800 800 700 700 600 600 500 500 400 400 300 300 200 200 100 100

0 0

09:00 01:00 03:00 05:00 07:00 09:30 10:00 10:30 11:00 11:30 12:00 14:00 16:00 18:00 18:30 19:00 19:30 20:00 20:30 21:00 21:30 22:00 00:00

03:00 21:30 01:00 05:00 07:00 09:00 09:30 10:00 10:30 11:00 11:30 12:00 14:00 16:00 18:00 18:30 19:00 19:30 20:00 20:30 21:00 22:00 00:00

3) Average total active load

Monthly average power, MW Hours January February March April May June 00:00 454.25 457.54 464.85 475.73 488.92 495.42 01:00 414.47 407.92 420.81 433.04 447.23 458.62 02:00 397.43 390.35 403.60 413.46 429.51 447.25 03:00 397.13 388.79 403.52 409.91 428.26 445.21 04:00 398.75 393.10 411.86 418.55 431.52 447.24 05:00 420.60 414.20 437.41 444.35 461.05 472.00 06:00 482.11 477.88 504.70 523.90 536.56 521.21 07:00 578.91 580.92 615.80 617.89 631.42 619.74 08:00 602.53 578.49 629.63 625.40 637.83 651.77 09:00 635.82 622.26 676.66 653.07 690.24 704.60 09:15 642.32 628.80 687.11 662.76 698.61 714.24 09:30 646.50 631.04 690.91 666.55 706.81 721.17 09:45 650.90 636.86 698.22 677.25 693.91 738.14 10:00 652.34 642.28 697.70 680.45 700.32 743.68 10:15 653.56 643.75 704.24 687.83 705.42 752.11 10:30 653.88 647.96 708.36 696.93 704.47 761.66 10:45 656.33 658.51 715.54 696.59 705.11 770.19 11:00 667.30 663.09 725.51 699.55 721.58 779.62 11:15 671.26 667.65 727.26 705.56 714.96 789.20 11:30 655.25 663.76 727.71 705.87 722.45 793.32 11:45 655.88 668.62 725.85 704.10 718.46 794.06 12:00 656.00 665.88 715.79 699.85 718.35 786.28 13:00 639.36 634.25 685.23 670.94 697.45 750.40 14:00 620.96 600.95 657.50 636.92 652.66 721.85 15:00 610.60 588.48 637.03 626.26 635.90 693.29 16:00 609.55 592.69 646.09 625.03 649.04 697.08 17:00 607.88 598.34 645.78 622.11 668.61 688.96 18:00 595.79 579.02 637.74 615.26 650.10 664.10 18:15 599.44 577.75 640.86 624.34 654.93 674.87 18:30 631.53 603.93 670.20 648.35 684.97 685.20 18:45 692.96 652.29 730.16 705.63 731.10 720.73 19:00 747.32 714.83 797.90 771.08 786.92 777.51 19:15 774.77 759.58 831.69 811.83 810.94 818.78 19:30 786.37 767.57 843.54 799.01 808.69 840.37 19:45 784.90 768.80 845.41 799.91 809.49 850.89 20:00 783.85 766.36 843.09 798.81 811.22 853.72 20:15 780.89 763.91 835.19 795.92 807.26 850.26 20:30 775.63 755.49 829.49 792.17 806.10 840.19 20:45 766.71 748.34 818.78 781.39 796.89 827.89 21:00 756.86 738.67 810.01 770.12 786.31 814.38 21:15 735.14 728.68 792.14 756.13 774.49 797.06 21:30 712.10 704.94 765.68 735.25 748.35 758.54 21:45 687.65 676.93 716.58 715.83 725.91 737.62 22:00 658.93 666.61 683.13 696.20 691.76 703.52 23:00 546.19 535.24 549.22 562.24 570.23 593.40

4) Volume at the maximum flow rate (5 months)

Secon Flow V*10^ V*10^3- Hours ds rate Volume 3 40%V*10^3 V*10^3 1:00-2:00 3600 160 576000 576 345.6 345600 2:00-3:00 7200 160 1152000 1152 691.2 691200 3:00-4:00 10800 160 1728000 1728 1036.8 1036800 4:00-5:00 14400 160 2304000 2304 1382.4 1382400 5:00-6:00 18000 160 2880000 2880 1728 1728000 6:00-7:00 21600 160 3456000 3456 2073.6 2073600 7:00-8:00 25200 160 4032000 4032 2419.2 2419200 8:00-9:00 28800 160 4608000 4608 2764.8 2764800 9:00-10:00 32400 160 5184000 5184 3110.4 3110400 10:00-11:00 36000 160 5760000 5760 3456 3456000 11:00-12:00 39600 160 6336000 6336 3801.6 3801600 12:00-1:00 43200 160 6912000 6912 4147.2 4147200 1:00-2:00 46800 160 7488000 7488 4492.8 4492800 2:00-3:00 50400 160 8064000 8064 4838.4 4838400 3:00-4:00 54000 160 8640000 8640 5184 5184000 4:00-5:00 57600 160 9216000 9216 5529.6 5529600 5:00-6:00 61200 160 9792000 9792 5875.2 5875200 6:00-7:00 3600 80 10080000 10080 6048 6048000 7:00-8:00 7200 80 10368000 10368 6220.8 6220800 8:00-9:00 10800 80 10656000 10656 6393.6 6393600 9:00-10:00 14400 80 10944000 10944 6566.4 6566400 10:00-11:00 18000 80 11232000 11232 6739.2 6739200 11:00-12:00 21600 80 11520000 11520 6912 6912000 12:00-1:00 25200 80 11808000 11808 7084.8 7084800

5) Volume distribution at the minimum flow rate (7 months in a year)

Hours Seconds Flow rate Volume V*10^3 1:00-2:00 3600 77 277200 277.2 2:00-3:00 7200 77 554400 554.4 3:00-4:00 10800 77 831600 831.6 4:00-5:00 14400 77 1108800 1108.8 5:00-6:00 18000 77 1386000 1386 6:00-7:00 21600 77 1663200 1663.2 7:00-8:00 25200 77 1940400 1940.4 8:00-9:00 28800 77 2217600 2217.6 9:00-10:00 32400 77 2494800 2494.8 10:00-11:00 36000 77 2772000 2772 11:00-12:00 39600 77 3049200 3049.2 12:00-1:00 43200 77 3326400 3326.4 1:00-2:00 46800 77 3603600 3603.6 2:00-3:00 50400 77 3880800 3880.8 3:00-4:00 54000 77 4158000 4158 4:00-5:00 57600 77 4435200 4435.2 5:00-6:00 61200 77 4712400 4712.4 6:00-7:00 3600 77 4851000 4851 7:00-8:00 7200 77 4989600 4989.6 8:00-9:00 10800 77 5128200 5128.2 9:00-10:00 14400 77 5266800 5266.8 10:00-11:00 18000 77 5405400 5405.4 11:00-12:00 21600 77 5544000 5544 12:00-1:00 25200 77 5682600 5682.6

6) Flow Rate Distribution in a Year

Months Flow rate Power JANUARY 160 425.2 FEBRUARY 77 204.6 MARCH 77 204.6 APRIL 77 204.6 MAY 77 204.6 JUNE 77 204.6 JULY 77 204.6 AUGUST 160 425.2 SEPTEMBER 160 425.2 OCTOBER 160 425.2 NOVEMBER 160 425.2 DECEMBER 77 425.2

7) Volume of lower reservior for the two scenarios

First scenario; Flow rate=160 m^3/s Second scenario; Flow rate=77 m^3/s Flow V*10^3- Flow Hours Seconds rate Volume V*10^3 40%V*10^3 V*10^3 Hours Seconds rate Volume V*10^3 1:00-2:00 3600 160 576000 576 345.6 345600 1:00-2:00 3600 77 277200 277.2 2:00-3:00 7200 160 1152000 1152 691.2 691200 2:00-3:00 7200 77 554400 554.4 3:00-4:00 10800 160 1728000 1728 1036.8 1036800 3:00-4:00 10800 77 831600 831.6 4:00-5:00 14400 160 2304000 2304 1382.4 1382400 4:00-5:00 14400 77 1108800 1108.8 5:00-6:00 18000 160 2880000 2880 1728 1728000 5:00-6:00 18000 77 1386000 1386 6:00-7:00 21600 160 3456000 3456 2073.6 2073600 6:00-7:00 21600 77 1663200 1663.2 7:00-8:00 25200 160 4032000 4032 2419.2 2419200 7:00-8:00 25200 77 1940400 1940.4 8:00-9:00 28800 160 4608000 4608 2764.8 2764800 8:00-9:00 28800 77 2217600 2217.6 9:00- 10:00 32400 160 5184000 5184 3110.4 3110400 9:00-10:00 32400 77 2494800 2494.8 10:00- 11:00 36000 160 5760000 5760 3456 3456000 10:00-11:00 36000 77 2772000 2772 11:00- 12:00 39600 160 6336000 6336 3801.6 3801600 11:00-12:00 39600 77 3049200 3049.2 12:00- 1:00 43200 160 6912000 6912 4147.2 4147200 12:00-1:00 43200 77 3326400 3326.4 1:00-2:00 46800 160 7488000 7488 4492.8 4492800 1:00-2:00 46800 77 3603600 3603.6 2:00-3:00 50400 160 8064000 8064 4838.4 4838400 2:00-3:00 50400 77 3880800 3880.8 3:00-4:00 54000 160 8640000 8640 5184 5184000 3:00-4:00 54000 77 4158000 4158 4:00-5:00 57600 160 9216000 9216 5529.6 5529600 4:00-5:00 57600 77 4435200 4435.2 5:00-6:00 61200 160 9792000 9792 5875.2 5875200 5:00-6:00 61200 77 4712400 4712.4 6:00-7:00 3600 80 10080000 10080 6048 6048000 6:00-7:00 3600 77 4851000 4851 7:00-8:00 7200 80 10368000 10368 6220.8 6220800 7:00-8:00 7200 77 4989600 4989.6 8:00-9:00 10800 80 10656000 10656 6393.6 6393600 8:00-9:00 10800 77 5128200 5128.2 9:00- 10:00 14400 80 10944000 10944 6566.4 6566400 9:00-10:00 14400 77 5266800 5266.8 10:00- 11:00 18000 80 11232000 11232 6739.2 6739200 10:00-11:00 18000 77 5405400 5405.4 11:00- 12:00 21600 80 11520000 11520 6912 6912000 11:00-12:00 21600 77 5544000 5544 12:00- 1:00 25200 80 11808000 11808 7084.8 7084800 12:00-1:00 25200 77 5682600 5682.6

8) Load Distribution for Tana Beles Hydropower Plant for 23 Days and 24 Hours of June

Hours 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

00:00 75.80 64.70 78.80 66.70 90.90 92.50 100.80 100.40 75.10 85.70 100.00 63.40 100.20 60.40 96.40 85.50 80.30 64.30 79.30 93.00 64.60 62.70 80.98

01:00 109.30 86.30 63.90 68.50 70.20 90.70 81.10 100.70 100.70 76.00 78.60 69.50 56.60 106.90 60.40 94.40 86.70 67.10 69.60 75.70 95.30 68.40 61.80

02:00 107.20 89.80 60.90 68.50 69.10 90.00 79.20 100.10 100.10 72.80 71.20 70.10 64.70 103.80 63.70 91.90 87.00 69.60 69.10 75.40 99.90 67.30 66.50

03:00 110.30 87.40 63.50 68.80 68.00 90.60 81.80 101.00 101.00 70.40 70.70 60.60 65.90 102.00 64.90 94.10 85.50 70.10 70.40 71.60 99.20 67.70 65.20

04:00 109.30 89.50 62.50 70.20 68.60 91.20 80.30 100.40 100.40 80.30 71.30 61.50 65.30 104.40 63.60 94.60 85.70 70.50 69.10 75.00 105.30 70.70 65.90

05:00 108.00 94.00 69.30 71.30 71.10 93.00 77.40 104.50 104.50 75.10 74.30 61.80 63.90 106.20 71.00 95.60 67.80 69.80 64.90 79.20 100.50 70.10 69.50

06:00 Fault 158.10 114.40 69.80 88.70 91.90 78.90 112.30 112.30 99.90 92.20 83.60 68.60 106.20 64.60 95.30 90.40 69.60 66.70 74.70 100.20 59.50 67.90

07:00 Fault 220.60 264.00 197.70 100.40 126.60 80.30 210.20 210.20 204.00 223.20 106.30 177.70 107.20 75.00 182.40 161.90 160.60 63.30 94.90 98.60 82.40 112.00

08:00 Fault 234.40 267.00 230.80 100.10 180.70 98.50 261.50 261.50 221.50 230.60 104.20 198.40 177.00 129.20 217.90 226.00 160.80 69.90 160.50 100.20 88.40 111.60

09:00 28.50 241.20 300.70 253.70 97.60 229.80 243.20 287.10 260.50 233.20 230.60 101.70 215.30 235.70 225.10 250.20 258.80 175.80 62.80 179.00 100.20 152.40 169.90

09:15 71.30 241.20 296.60 254.80 99.80 220.00 251.70 283.60 280.60 244.00 223.90 101.00 215.10 235.00 229.90 253.80 265.40 172.20 64.70 199.00 80.60 179.20 190.40

09:30 98.70 238.70 300.00 255.40 103.80 224.40 244.30 288.90 277.60 267.20 227.40 99.90 219.80 286.50 226.50 261.50 266.50 174.00 65.00 194.50 85.60 130.20 195.40

09:45 116.40 250.00 299.20 256.50 103.10 240.70 244.30 293.60 277.40 268.40 222.40 101.90 212.40 301.20 234.30 268.40 286.90 205.50 68.00 198.80 101.70 190.60 198.50

10:00 175.00 249.70 296.20 255.80 102.30 243.30 267.20 294.60 277.40 262.00 228.00 104.10 216.60 312.10 235.60 268.00 290.30 192.00 62.40 199.00 94.80 193.70 190.70

10:15 190.10 250.40 300.10 268.40 110.00 241.00 274.00 294.10 279.70 263.70 226.70 101.30 212.00 314.40 240.20 276.90 285.80 186.10 66.40 197.00 96.40 202.10 199.30

10:30 211.70 266.60 297.40 274.70 112.30 244.60 271.00 288.10 278.50 267.60 221.40 99.90 200.10 311.90 253.40 285.60 288.20 190.20 66.70 199.40 103.80 220.30 201.80

10:45 302.50 270.30 300.30 273.20 113.50 248.90 277.90 291.10 279.60 274.30 222.90 99.30 207.70 318.60 253.70 190.20 283.90 193.10 66.40 199.70 103.90 227.20 200.30

11:00 306.90 270.60 300.20 274.10 113.60 262.60 281.80 295.30 278.50 265.30 225.90 100.10 219.30 319.50 270.30 289.60 281.40 196.90 66.40 201.90 108.60 226.70 200.60

11:15 305.00 270.90 304.00 290.50 113.60 261.70 304.90 285.50 300.20 263.40 223.50 99.80 220.00 321.70 275.30 289.50 291.00 197.10 64.30 203.30 104.70 229.30 215.10

11:30 305.70 271.00 300.70 292.30 113.00 264.80 307.30 283.60 300.40 268.10 225.80 98.50 219.80 310.80 279.20 292.30 293.90 191.40 67.30 210.30 102.00 234.60 230.70

11:45 319.70 288.90 300.70 288.40 114.00 281.20 309.90 283.70 292.60 270.30 228.00 99.90 220.00 305.10 279.60 301.70 296.20 191.30 66.70 210.30 102.70 231.80 229.90

12:00 304.70 289.80 290.30 287.80 114.30 289.80 298.00 287.00 300.20 260.40 223.10 99.30 221.00 298.00 276.50 298.60 282.70 189.60 67.90 203.70 106.60 228.40 226.50

13:00 318.60 281.20 285.70 282.70 111.70 290.30 305.40 280.20 299.10 260.80 219.90 99.80 220.00 277.50 263.40 278.80 279.10 191.20 64.30 190.70 98.00 221.80 217.30

14:00 299.90 283.70 283.90 279.30 112.40 305.00 300.80 280.60 299.80 260.00 224.10 101.60 230.00 286.10 217.60 280.90 263.50 190.80 67.40 198.20 116.10 212.00 228.90

15:00 303.50 278.40 268.00 282.60 105.90 304.80 308.00 280.00 301.70 268.10 221.80 99.50 221.00 288.00 227.20 277.60 227.50 187.20 61.30 191.50 127.4 218.00 229.50

16:00 318.30 286.20 292.70 301.80 101.00 304.30 310.10 280.60 301.02 271.70 227.50 96.20 229.90 282.60 228.80 276.00 236.80 200.60 Fault 204.90 127.4 205.30 242.08

17:00 299.90 273.00 297.70 301.70 100.40 315.50 296.60 301.20 300.80 260.10 218.40 100.40 220.00 277.70 218.90 271.70 246.30 182.70 58.70 206.90 127.4 205.00 230.95

18:00 303.20 259.30 273.40 284.80 103.40 305.30 299.70 299.50 297.50 250.70 210.10 101.00 200.40 247.20 211.20 241.80 309.00 187.00 59.70 187.70 127.4 198.20 225.34

18:15 303.10 289.70 284.00 290.30 102.60 310.90 300.30 300.80 301.10 260.70 210.00 102.20 201.10 232.70 204.00 250.90 256.80 188.80 60.30 190.50 127.4 200.10 225.83

18:30 302.20 290.30 292.30 303.90 101.30 310.60 300.40 300.60 302.90 261.00 212.40 100.70 200.90 235.50 205.90 254.50 265.00 190.20 76.30 185.50 127.4 200.80 228.21

18:45 313.60 291.60 282.30 305.50 100.20 310.40 314.70 306.60 304.30 261.00 219.00 99.80 200.50 242.80 231.80 251.80 262.10 198.00 99.30 184.00 127.4 213.60 232.74

19:00 321.50 302.20 288.60 303.70 106.60 310.00 310.00 306.70 313.60 271.90 216.70 101.50 214.20 248.00 247.90 252.70 296.30 200.70 109.90 186.90 127.4 231.10 239.46

19:15 321.30 286.60 290.90 300.70 106.90 314.90 316.20 333.40 330.50 298.40 219.60 102.80 248.90 252.50 252.40 277.60 284.50 200.50 108.90 171.50 127.4 232.30 244.49

19:30 321.20 300.90 294.10 301.60 107.70 311.80 316.60 333.70 330.40 307.00 230.80 105.40 255.60 258.30 261.00 291.00 287.90 205.30 110.00 189.60 127.4 251.60 249.95

19:45 316.60 297.90 293.30 300.40 105.60 317.10 311.70 337.10 334.80 310.50 215.30 99.50 253.90 264.10 260.60 297.80 303.90 210.90 109.20 193.90 127.4 257.60 250.87

20:00 328.00 298.10 295.00 300.70 106.30 311.40 313.40 332.50 335.60 309.80 220.70 99.50 251.00 263.80 260.80 296.60 288.70 213.30 103.20 186.40 127.4 253.50 249.80

20:15 319.60 296.00 294.40 299.30 105.60 320.90 308.60 336.90 329.80 303.10 224.20 100.00 258.20 259.30 258.10 296.40 285.60 210.30 109.90 183.20 127.4 247.30 248.82

20:30 312.60 292.00 288.60 297.40 104.70 312.80 303.40 333.10 331.80 300.00 217.60 96.40 259.40 251.10 254.70 287.20 287.00 210.10 106.90 177.00 127.4 245.60 245.31

20:45 319.40 284.30 286.00 296.50 102.50 311.30 303.20 332.60 332.50 296.00 217.30 99.80 262.50 255.20 259.10 286.30 286.60 208.60 104.20 183.70 127.4 240.80 245.26

21:00 316.60 283.20 278.60 297.70 101.90 291.70 300.50 327.60 329.00 309.10 222.70 96.50 260.00 249.10 252.80 280.60 278.50 205.20 106.50 178.10 127.4 244.40 242.62

21:15 300.30 292.30 287.40 290.80 99.80 259.70 291.20 301.50 328.80 268.90 202.14 97.00 259.70 239.90 249.70 273.00 254.80 160.30 95.90 175.90 206.10 225.20 234.56

21:30 291.00 270.00 211.50 245.40 101.10 249.60 260.70 258.60 220.50 246.30 176.10 92.70 215.70 198.80 239.00 250.30 173.00 100.5 96.5 137.80 164.10 150.50 197.71

21:45 258.80 241.90 145.00 191.60 98.60 201.10 213.40 240.10 162.60 199.80 165.00 95.60 173.80 167.00 239.60 226.00 110.50 96.40 95.00 110.50 137.00 85.40 166.12

22:00 186.70 242.00 96.50 130.20 99.60 176.70 161.30 202.80 100.70 134.40 100.00 92.57 147.40 140.90 187.30 181.30 86.60 98.90 94.30 100.20 101.40 85.20 133.95

23:00 100.10 93.10 95.80 97.60 87.50 100.70 100.50 100.20 71.30 85.50 101.10 67.40 100.20 92.20 94.10 89.50 83.20 94.70 72.00 92.50 74.80 64.60 89.03

Peak load328.00 302.20 304.00 305.50 114.30 320.90 316.60 337.10 335.60 310.50 230.80 106.30 262.50 321.70 279.60 301.70 309.00 213.30 110.00 210.30 206.10 257.60 250.87 Minimum 28.50 86.30 60.90 68.50 68.00 90.00 77.40 100.10 71.30 70.40 70.70 60.60 56.60 92.20 60.40 89.50 67.80 67.10 58.70 71.60 74.80 59.50 61.80

9) Capacity of hydropower plants, peak and minimum load of the grid

842.6

1842.6 1842.6 1842.6 1842.6 1842.6 1842.6 1842.6 1842.6 1842.6 1842.6 1842.6 1842.6 1842.6 1842.6 1842.6 1842.6 1 1842.6 1842.6 1842.6 1842.6 1842.6 1842.6

Capactity

842.1 871.2 776.6 855.7

913.93 905.22 858.02 840.32 807.79 907.14 883.17 890.56 873.08 894.06 868.65 863.42 846.34 871.93 854.27 831.91 841.93 803.92 797.83

Peakload

422 435

444.9 455.5 427.9 427.2 453.4 432.2 455.7

401.63 463.85 419.33 432.78 399.23 451.63 466.29 468.23 414.19 445.63 463.61 474.68 384.75

Min loadMin

1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20 21 22 23 days

10) Grid Load Variation for 23 days Hours Average load, MW 0:00 495.42 1:00 458.62 2:00 447.25 3:00 445.21 4:00 447.24 5:00 472.00 6:00 521.21 7:00 619.74 8:00 651.77 9:00 704.60 9:15 714.24 9:30 721.17 9:45 738.14 10:00 743.68 10:15 752.11 10:30 761.66 10:45 770.19 11:00 779.62 11:15 789.20 11:30 793.32 11:45 794.06 12:00 786.28 13:00 750.40 14:00 721.85 15:00 693.29 16:00 697.08 17:00 688.96 18:00 664.10 18:15 674.87 18:30 685.20 18:45 720.73 19:00 777.51 19:15 818.78 19:30 840.37 19:45 850.89 20:00 853.72 20:15 850.26 20:30 840.19 20:45 827.89 21:00 814.38 21:15 797.06 21:30 758.54 21:45 737.62 22:00 703.52 23:00 593.40

11) Load variation between pure hydro and pumped storage system

Hours Pure Hydro PSS 00:00 495.42 1044.49 01:00 458.62 1007.68 02:00 447.25 996.32 03:00 445.21 994.27 04:00 447.24 996.31 05:00 472.00 1021.07 06:00 521.21 1070.27 07:00 619.74 619.74 08:00 651.77 651.77 09:00 704.60 796.38 09:15 714.24 806.02 09:30 721.17 812.95 09:45 738.14 829.92 10:00 743.68 835.46 10:15 752.11 843.89 10:30 761.66 853.44 10:45 770.19 861.97 11:00 779.62 871.40 11:15 789.20 880.98 11:30 793.32 885.10 11:45 794.06 885.84 12:00 786.28 786.28 13:00 750.40 750.40 14:00 721.85 721.85 15:00 693.29 693.29 16:00 697.08 697.08 17:00 688.96 688.96 18:00 664.10 664.10 18:15 674.87 674.87 18:30 685.20 685.20 18:45 720.73 720.73 19:00 777.51 869.29 19:15 818.78 910.56 19:30 840.37 932.15 19:45 850.89 942.67 20:00 853.72 945.50 20:15 850.26 942.04 20:30 840.19 931.97 20:45 827.89 919.67 21:00 814.38 906.16 21:15 797.06 888.84 21:30 758.54 850.32 21:45 737.62 829.40 22:00 703.52 703.52 23:00 593.40 593.40

12) Tana Beles Load variation for 24 hours