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Power Systems Engineering Thesis

2020-05-05

DESIGN AND PERFORMANCE

ANALYSIS OF MICRO HYDRO

ELECTRIC POWER SYSTEM AT

DIVERSION WEIR IRRIGATION PROJECT

Baye, Tilahun

http://hdl.handle.net/123456789/10806

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i

BAHIR DAR UNIVERSITY

BAHIR DAR INSTITUTE OF TECHNOLOGY

SCHOOL OF RESEARCH AND POSTGRADUATE

STUDIES

FACULTY OF ELECTRICAL AND COMPUTING ENGINEERING

DESIGN AND PERFORMANCE ANALYSIS OF MICRO HYDRO

ELECTRIC POWER SYSTEM AT DIVERSION WEIR IRRIGATION

PROJECT

[Case study - River Fetam at Zalima Village Bure Woreda]

By

Tilahun Baye

Bahir Dar, Ethiopia

October 20, 2017

ii

DESIGN AND PERFORMANCE ANALYSIS OF MICRO HYDRO ELECTRIC POWER

SYSTEM AT DIVERSION WEIR IRRIGATION PROJECT

[Case study - River Fetam at Zalima Village Bure Woreda]

By

Tilahun Baye

A thesis submitted to the school of Research and Graduate Studies of Bahir Dar

Institute of Technology, BDU in partial fulfillment of the requirements for the degree

of

Master of Science in the electrical power system in the faculty of engineering

.

Advisor Name: Dr. Tassew Tadiwose

Bahir Dar, Ethiopia

October 20, 2017

i

DECLARATION

I, the undersigned declare that this thesis is my original work, and has not been

presented for a degree in this or any other university, and all sources of materials used

for the thesis have been fully acknowledged.

Name of the student Tilahun Baye Signature _________

Date of submission: 10/10/2017

Place: Bahir Dar

This thesis has been submitted for examination with my approval as a university

advisor.

Advisor Name: Dr. Tassew Tadiwose

Advisor‟s Signature: ______________

ii

© 2017

By: Tilahun Baye (as it appears on the title page)

ALL RIGHTS RESERVED

iii

Bahir Dar University

Bahir Dar Institute of Technology-

School of Research and Graduate Studies

Faculty of Electrical and Computing Engineering

THESIS APPROVAL SHEET

Student:

……………………… ….………………… …………………..

Name Signature Date

The following graduate faculty members certify that this student has successfully

presented the necessary written final thesis and oral presentation for partial fulfillment of

the thesis requirements for the Degree of Master of Science in Electrical Power System

Engineering

Approved By:

Advisor:

……………………… ….………………… ………………….. Name Signature Date

External Examiner:

Getachew Biru (Dr.-Ing) 09/10/2017

………………………… …………………… ………………...

Name Signature Date

Chair Holder:

…………………………. …………………… …………………

Name Signature Date

Faculty Dean:

……………………….... …………………… ………………….

Name Signature Date

iv

ACKNOWLEDGEMENTS

First and foremost, a lot of thanks and glory to almighty God who made me a person I am

today and for His blessing for me to complete my MSC Project and this thesis is the

symbolic of the support and guidance that I get from all my family specially my mother

Father Baye and my beloved wife Slenat Brehan

Next, I would like to express my heart-felt appreciation and special gratitude to all persons

who, in one way or another contributed to the accomplishment of the study. Special

appreciation and deepest thanks go to the project research advisor Dr. Tassew Tadiwose

(Bahir Dar Institute of Technology) for his continued guidance, inspiration,

encouragement and support throughout the study period, which made the successful

completion of this study smoothly.

My appreciation also goes to my family who has been so tolerant and supports me all

these years. Special thanks for their encouragement, love and emotional supports that they

had given to me. Besides, I would like take this opportunity to thank all my friends Abiye

Wogayew, Habtamu Mamu & BoB for their close support and help.

v

ABSTRACT

Ethiopia is a developing country with a total access to electricity not exceeding 58% (in

2017) and the number of household connected to this access is 25%. About 85% of the

population lives in places where access to electricity is less than 5%. The village for this

study, Zalima rural Village (11.610 N, 28.400 E) has a total population of 2035 and 275

households. The village is about 1.2km from Fetam Irrigation canal power house

substation; which makes the extension of the grid not yet practical and off grid

electrification is the best option for the village. The community in the Zalima Village uses

Kerosene for lighting, water for milling and biomass for cooking and dry cells for radios.

Nothing has been done so far in developing the renewable energy resources, such as

micro hydro energy in the village.

In this study, finical and economic feasibility of micro hydro power electric supply system

to the village is analyzed using HOMER software as complete sensitivity analysis tool.

Hydro potential of the village is analyzed by measuring the gross head of the irrigation

canal with the help of serving data and stream flow irrigation canal data obtained from

Bureau of Water, Irrigation and Energy of Development of Amhara. Electric load for the

basic needs of the community, such as, for lighting, radio, water pumps, and flour mills is

estimated. One primary school and one health posts are also considered for the

community. Additionally one Orthodox churches also considered. As a result, many

feasible standalone the system was then optimized and determined the best configuration

result using the Homer software. For primary load of 203 kwh/d and 18.9 KW hydro

turbines backup Generator 7KW. Micro-hydro system combinations are generated, and

accordingly, total net present cost (NPC) of the micro hydro configuration and cost of

energy (COE) for micro hydro system is $67,044 and $0.07/kWh, respectively. Further

HOMER calculates the emissions of the following six pollutants CO2, CO, UHC, PM, SO2,

& NO2 as a result the system is environmentally friendly and free from greenhouse gases.

These facts indicate that electrifying rural villages using micro hydro systems is beneficial

and suitable for long-term investments.

Index terms: Micro - hydro, off - grid system, Backup Generator, HOMER

vi

TABLE OF CONTENTS

DECLARATION .............................................................................................. i

ACKNOWLEDGEMENTS .......................................................................... iv

ABSTRACT ..................................................................................................... v

TABLE OF CONTENTS .............................................................................. vi

LIST OF ABBREVATIONS .......................................................................... x

LIST OF SYMBOLYS .................................................................................. xi

1. INTRODUCTION ....................................................................................... 1

1.1 Background ................................................................................................................................................ 1

1.2 Problem Statement ..................................................................................................................................... 2

1.3 Objective of the study ................................................................................................................................ 3

1.4 Scope of the study ...................................................................................................................................... 3

1.5 Significance of the study ............................................................................................................................ 4

1.6 Thesis Outline ............................................................................................................................................ 4

2. LITERATURE REVIEW .......................................................................... 5

2.1 Micro-Hydropower Generation System ..................................................................................................... 7

2.2 Classification of hydro power based on the demand for electrical power................................................ 10

2.3 Civil Work Components of Micro Hydro power unit .............................................................................. 11

2.4 Powerhouse Components ......................................................................................................................... 13

2.5 Types of Hydraulic Turbines ................................................................................................................... 15

2.4.1 Impulse Turbines .................................................................................................................................... 15

2.4.2 Reaction Turbine .................................................................................................................................... 17

3. METHODOLOGY.................................................................................... 20

4. ENERGY DEMAND ASSESSMENT OF THE STUDY VILLAGE ... 22

4.1 Profile of the Village under study ............................................................................................................ 22

4.2 Primary and Secondary Data Collection .................................................................................................. 22

4.2.1 Primary data ........................................................................................................................................... 22

4.2.2 Secondary data ....................................................................................................................................... 23

4.3 Energy Demand Assessment and Load Scheduling of the Village .......................................................... 24

4.3.1Load projection for the village ................................................................................................................ 26

5. SYSTEM DESIGN AND PERFORMANCE ANALYSIS OF MICRO

HYDRO ELECTRIC POWER.................................................................... 29

5.1 Study design and Selection of System Components MHP....................................................................... 29

5.1.1 Intake water way .................................................................................................................................... 30

5.1.2 Inlet and Outlet Zone ............................................................................................................................. 34

5.1.3 Head race Canal ..................................................................................................................................... 35

vii

5.1.4 Forebay..... ............................................................................................................................................. 36

5.1.5 Factors to be considered in Penstock Selection and Design ................................................................... 38

5.2 Electromechanical Equipment ................................................................................................................. 40

5.2.1 Turbine Selection ................................................................................................................................... 40

5.2.2 Selection of Generator............................................................................................................................ 42

6. RESULTS AND DISCUSSION ............................................................... 45

6.1 Overview of HOMER Software ............................................................................................................... 45

6.2 Simulation Result of HOMER Software (compere analytical method) ................................................... 46

6.3 Sensitivity simulation result ..................................................................................................................... 49

7. COUNCLUSIONS AND RECOMMMENATIONS .............................. 53

7.1 Conclusions .............................................................................................................................................. 53

7.2 Recommendations .................................................................................................................................... 54

REFERENCES.. ............................................................................................................................................ 56

APPENDIX....... ............................................................................................................................................. 58

Appendix 1: Secondary data Year Stream flow Irrigation canal ..................................................................... 58

Appendix 2: Study area location (source document BoWIERD Amhara) ...................................................... 59

Appendix 3: Fetam Tajet irrigation system (source BoWIERDA) ................................................................. 60

viii

LIST OF FIGURES Figure 2-1 Cross –flow turbine ................................................................................................................................... 17

Figure 2-2 Turbine application chart Source [source: st. onge environmental engineering]....................................... 19

Figure 3-1 Flow Chart of the Research Methodology ................................................................................................. 20

Figure 5-1Flood discharge position of diversion canal ............................................................................................... 29

Figure 5-2Inlet and Outlet Zone .................................................................................................................................. 35

Figure 5-3Design of forebay tank ............................................................................................................................... 38

Figure 5-4 Design of penstock pipe ............................................................................................................................ 39

Figure 5-5 net design head .......................................................................................................................................... 40

Figure 5-6 Design of net head ..................................................................................................................................... 40

Figure 6-1 Diagram of the project with HOMER ....................................................................................................... 46

Figure 6-2 Hydro resource of Fetam River left side irrigation canal [AWIEB] .......................................................... 47

Figure 6-3 Hourly & Monthly/Seasonal primary load demand data of Zalima Shenbekuma Village upper

steram ................................................................................................................................................................. 48

Figure 6-4 Cost summary of renewable system components ...................................................................................... 49

Figure 6-5 Cash flow Summary by cost category for project life time ....................................................................... 50

Figure 6-6 Annual electric energy production by Hydro system ................................................................................ 51

Figure 6-7 State of backup of generation system ........................................................................................................ 52

Figure 6-8 Emission of system generation .................................................................................................................. 52

ix

LIST OF TABLES

Table 2-1 Hydro power category (source Lecture Notes) ........................................................................................... 10

Table 2-2 Efficiency of different turbines ................................................................................................................... 18

Table 5-1Design of Headrace and Left side Irrigation Transferring Canal ................................................................. 36

Table 5-2Selection of T-14 cross flow turbine plan .................................................................................................... 42

Table 5-3Design of Micro Hydropower by Irrigation Canal Fetam River output data ............................................... 43

Table 6-1Economic input of HOMER ........................................................................................................................ 45

Table 6-2 Categorized simulation result for the proposed renewable system ............................................................. 48

x

LIST OF ABBREVATIONS

MHP Micro hydro power

EREDPC Ethiopian Rural Energy Development and Promotion Center

ESCOs Energy Service Companies

IAEA International Atomic Energy Agency

IHA International Hydropower Association

COE Cost of energy

MoWIE Ministry of Water, Irrigation and Energy

EEU Ethiopian Electric Utility

AC Alternating current

REF Rural Electrification Fund

UEAP Universal Electricity Access Program

UF Utilization Factor

m.a.s.l Meter above Sea Level

HPP Hydro Power Plant

ANRS Amhara National Regional State

BoWIERD Bureau of Water Irrigation and Energy Resource Development

HRC Headrace canal,

ITC Irrigation Transfer Canal

HDP High density politely

COE Level zed cost of energy/useful electrical energy produced by the system.

NPC Net Present Cost

xi

LIST OF SYMBOLYS

KV Kilo Volt

MWh Mega Watt Hour

rpm revolution per minute

v Velocity

W Width

OD Outside diameter

PN Nominal pressure

g gravity

1

CHAPTER ONE

1. INTRODUCTION

Now, life without energy is unimaginable. The access to electricity has proven to be a key

factor necessary for socioeconomic development, both for the peoples and infrastructure

of a country. It is a basis for urbanization and industrialization in the current modern

times. With electricity, lines being confined to large cities and towns, developing

countries lag far behind in many sectors when compared to industrialized countries.

Ethiopia, despite being the one of Eastern African country, has a very poor electricity

penetration rate. Electricity is available for 58% of the population and only 25% of the

households are connected to the central grid; even the above coverage is confined to

major towns and cities [26].

Since the Ethiopian Government advocates Green Economy Renewable energy sources

(solar, wind, hydropower etc.) are attracting and got more attention as an alternative

energy sources than conventional biomass based energy system it accounts 90 % of the

total primary energy consumption in the country [26].

1.1 Background

According to EEU, current data with only 25% of households connected and 58% of the

he population is estimated to have access to electricity and the per capital energy

consumption is100kWh, which is the lowest in the sub-Sahara average, that is 510kWh.

Most of the non-electrified regions are found in rural part of the countries. These regions

can be electrified either by extending the grids of the existing power systems or by

constructing isolated (standalone) power systems. In general, it is preferred to go for the

extension of the existing grids but they are not always affordable the fact that most of the

non-electrified parts are located in remote and difficult areas, like hilly regions, forests,

and they are scattered, which demand enormous investment for grid. [26]

Hence off-grid electrification for remote place is nowadays become attractive and

alternative option for remote villages, which are detached from the central grid. There is a

2

huge potential for utilizing renewable energy sources, for example solar energy, wind

energy, or micro-hydropower to provide a quality power supply to remote areas. The

abundant energy available in nature can be harnessed and converted to electricity in a

sustainable way to supply the necessary power demand and thus to elevate the living

standards of the people isolated from the central grid. The Ethiopia Government is now

aware the national utility alone through Continuous grid extension cannot accelerate rural

access to electricity. To improve rural access to electricity, the government has recently

updated its strategies and improved any obstacle and constraints to accelerated off-grid

rural electrification.

Therefore; Bure woreda, is a small town having many rural villages far from the central

grid, of which Zalima Village is one of the village that does not have access to electricity,

in spite of having year round flowing river crossing and near left side irrigation canal, the

name of the river is Fetam River.

1.2 Problem Statement

In Amhara region off grid electrification for remote place is nowadays become attractive

and alternative option for Zalima Shenbekuma village and dwell around the site which are

detached from the central grid. There is a huge potential for utilizing renewable energy

sources, for example solar energy, wind energy, or micro-hydropower to provide a quality

power supply to remote areas. One of the reasons to have low electricity access in

Ethiopia is the costs of extending the electric grid and the scarcity of energy becomes

greater due to the high rate of population growth and weak energy supply system. The

pace of energy supply has been out stripped by that of energy demand.

The generally backward infrastructural development in Ethiopia radically limits the pace

of economic growth. Particularly the rural communities are adversely affected. This has a

negative impact on the overall economy of the nation, as the rural communities are the

basis for agricultural development, which is the backbone of the economy of the nation.

Out of many infrastructural facilities that the small communities lack, the absence of

appropriate form of energy is the most obvious one. Lack of energy has a detrimental

3

effect on the growth of the nation since energy is the driving engine of economic

development.

1.3 Objective of the study

General Objective:-The main objective of this research is to study of micro-hydropower

system and energy storage for electrification at Fetam Rive irrigation canal of remote

villages for Zalima Village to sustainably and efficiently satisfy the energy demand of

remote village, where central grid electricity has not reached yet due to many

geographical and economic constraints.

Specific Objective

To assess and analyze daily/monthly/annually primary data of load demand

(such as Energy, power and light sources) for the technical and financial

feasibility of the site.

To perform analysis the average stream flow of daily/monthly/annually

secondary data (such as irrigation canal flow) for the technical feasibility of

micro hydropower energy potentials of the site.

To simulate complete sensitivity analysis of total net present cost/NPC/,

Levied CEO $/kWh and operation and maintenance cost $/yr. considering the

system life time using NREL Homer energy software/ Microsoft excel/.

1.4 Scope of the study

The scope of this study shall collect and analyze relevant data and information to examine

and select the most suitable systems configuration, recommend necessary action,

necessary measures that configure a system to accommodate the current and near future

electrical energy demand for the village. The study only focuses a micro-hydro resource

assessment of among different renewable energy resource in the village, like solar, wind

biogas and biomass. In doing so, we shall recommend for further production of a model by

other researchers and the limitations of this research shall then clearly be told as to give a

way to next coming researchers and those who are interested in the area.

4

1.5 Significance of the study

Ethiopian government has uncompromised policy in generating power from renewable

energy sources in GTP-2, similarly this thesis work focuses on renewable energy which is

assessment of a remote area Micro hydropower energy system to supply the rural

community detached village electrification energy system.

Policy makers and concerned bodies can use this study as a real problem solving approach

for similar and related studies.

Furthermore, this study gives answer to the site viability for the proposed system if there

is a concerned body /governmental or non-governmental organizations/ who can work on

the practical implementation.

1.6 Thesis Outline

This thesis contains seven chapters organized as follows. Chapter one provides a general

overview of about, steam flow and energy consumption. It also describes the background

information of the country under investigation, sets the objectives, formulation of

the problem statement, gives limitations, the scope of the study and purpose and

describes. In chapter two different literatures using of micro hydro energy in the rural

electrification purpose are presented and reviewed.

Chapter three: This section of the thesis is methodology section. In chapter four it

introduces about the case study area and energy consumption.

Chapter five: the designing steps in analysis method of micro hydro energy at diversion

weir of irrigation canal systems are presented and also include HOMER software and

simulation of hydro turbine system. Chapter six includes the result and discussion of the

designed system HOMER software.

The conclusion of the thesis has been taken by summing up all the findings and

summarizes them in chapter seven.

5

CHAPTER TWO

2. LITERATURE REVIEW

Several researches have been conducted in hybrid/micro hydro off-grid power generation

all over the world and in Ethiopia. Different scholars used different Technology option

and approaches to evaluate the various configurations of renewable energy resources, such

as solar energy, wind energy, micro hydropower and their hybrid configurations. A

number of studies results have been published some of the thesis paper are reviewed and

evaluated in the following paragraph.

Yohannes .T presented a case study of rural area in Ethiopia entitled “Application of

Micro-hydro pv/battery off- grid hybrid energy system for Ethiopian rural area‟

Simulating of a Micro Hydro-Wind hybrid power generation system for rural area of

Ethiopia” of Guder River His objective was to develop a hybrid system cost competitive

to supply energy for remote villages for a model community of 874 households with three

Protestant churches and two Orthodox churches also considered. He discussed many

feasible hybrid system combinations are generated, and accordingly, total net present cost

(NPC) of the hybrid configuration and cost of energy (COE) for PV/ micro hydro/ battery

hybrid system is $394,819 and $0.044/kWh, respectively, which is much lower than

previously studied Micro hydro/wind hybrid system and PV/hydro/wind hybrid systems,

and this value is less than the current grid price of Ethiopian ($0.06) [EEU]. [29]

Berihun G. presented a case study of rural area in Ethiopia entitled “Modeling and

Simulating of a Micro Hydro-Wind hybrid power generation system for rural area of

Ethiopia” by using HOMER & Matlab software. His objective was to develop a hybrid

system cost competitive to supply energy for remote villages for a model community of

660 households with, one primary school two churches one mosque and one health center.

He discussed two option, Wind/Micro hydro hybrid and Standalone Micro hydro system

by comparing the cost of energy to identify cost competitive for the remote village

compared to extending the existing grid to the area since the break even grid extension is

23.6km which is less an the extension of the grid, so grid extension can be an option.

According to him, the COE most favorable Wind/Micro hydro hybrid system is

6

$0.112/kWh. Moreover, COE of standalone Micro-hydro system is $0.035/kWh. He

concluded micro hydro system is the most economical and can only satisfy the energy

demand of the village and technically feasible option. [28]

As per GIZ report, Ethiopia is one of the lowest electrification levels in the sub-Saharan

Africa. The rural electrification level is less than 1.5 percent which is the lowest in the

world. After more than a century of history, the benefits of electricity are still limited to a

small section of the population in urban areas. In the Southern Nations, Nationalities and

Peoples‟ Regional State (SNNPR) Of Ethiopia, there exist three smaller hydropower

schemes in Yadot (350 kW), Dembi (750 kW) and Sor (5 MW). Currently GIZ is

supporting 4 off-grid sites (7, 30, 35, and 50 kW) and one grid-connected site (200 kW).

For example, the Gobecho I micro hydropower plant is built on a small river in Bona

Zuriaworeda of the Sidama zone in SNNP state with over 50,000 Euro; this project can

generate about 7 kilowatts of energy and provides electric power to more than 160

residents of the woreda. Form this report I understand in Amhara region there is no

implemented project there for I will make the design then interested company will work

on it. [30]

All most all of the above scholar‟s paper shows the hybrid system either only PV/wind

excluding hydro or PV/Wind/Hydro include wind turbine. But in this study only Micro-

Hydro. This system is best of all due to the reason Ethiopia have plenty of Huge amount of

Hydro potential in almost many parts of the country

In addition from the above literature reviews, it is observed that no researcher use RET Screen

or other simulation software for the design of hybrid micro power and almost all of them

dedicated to feasibility studies. Hence, HOMER is widely used for most of the RES based

systems. Thus, based on the above literature reviews, HOMER software is taken for the

purposes of this study to carry the feasibility assessment..

7

2.1 Micro-Hydropower Generation System

Water is the most common source of energy in Ethiopia. It accounts 97.65 percent of the

total energy mix [14]. Hydropower engineering refers to the technology involved in

converting the pressure and kinetic energy of water in to more easily used electrical

energy. The prime mover in the cost of hydropower is a water wheel or hydraulic turbines,

which transform the energy of the water in to mechanical energy [27].

Micro-Hydropower basics:- A micro-hydropower system is a small system in the range

of 5-100 KW. The simplest micro-hydropower plant is based on a run-of-river design,

which means it does not have water storage capability. It will produce power only when

water is running or it might have relatively small water storage capability. Micro-

hydropower is an interesting prospect for providing electricity for rural communities. [9]

General Principal of MHP: - Power generation from water depends upon a combination

of head and flow. Both must be available to produce electricity. Water is diverted from a

stream into a pipeline, where it is directed downhill and through the turbine (flow). The

vertical drop (head) creates pressure at the bottom end of the pipeline. The pressurized

water emerging from the end of the pipe creates the force that drives the turbine. The

turbine in turn drives the generator where electrical power is produced. More flow or more

head produces more electricity. Electrical power output will always be slightly less than

waterpower input due to turbine and system inefficiencies.

Water pressure or Head created by the difference in elevation between the water intake

and the turbine. Head can be expressed as vertical distance (feet or meters), or as pressure,

such as pounds per square inch (psi). Net head is the pressure available at the turbine when

water is flowing, which will always be less than the pressure when the water flow is

turned off (static head), due to the friction between the water and the pipe. Pipeline

diameter also has an effect on net head.

Flow is quantity of water available, and is expressed as „volume per unit of time‟, such as

gallons per minute (gpm), cubic meters per second (m3/s), or liters per second (l/s). Design

flow is the maximum flow for which the hydro system is designed. It will likely be less

8

than the maximum flow of the stream (especially during the rainy season), more than the

minimum flow, and a compromise between potential electrical output and system cost.

Sites where the gross head is less than 15m would normally be classed as “low head”.

From 10-50m would typically be called “medium head”. Above 50m would be classed as

“high head”.

Figure2 1Using a head drop structure of existing irrigation canal (Source Micro Hydro

Power Resource Assessment Handbook)

To determine the power potential of water in a stream it is necessary to know the flow

quantity of water available from the stream and the available head. The quantity of water

available for power generation is the amount of water (in m3 or liters) which can be

diverted through an intake into the pipeline (penstock) in a certain amount of time. This is

normally expressed in cubic meters per second (m3/s) or in liters per second (l/s)

Head is the vertical difference in level (in meters) through which the water falls down.

The theoretical power (p) available from a given head of water is in exact proportion to

the head and the quantity of water available [9].

9

* * *P Q H g (2.1)

Where, P= power at the generator terminal, in kilowatts (kW)

H= the gross head from the pipeline intake to the tail water in meters (m)

Q= flow in pipeline, in cubic meters per second (m3/s)

= The efficiency of the plant, considering head loss in the pipeline and the

efficiency of the turbine and generator 9.81 is a constant and is the product of

the density of water and the acceleration due to gravity (g)

This available power will be converted by the hydro turbine in mechanical power.

In studying the subject of hydropower engineering, it is important to understand the

different types of Hydro power plant development. The flowing classification system is

used in this text:

Run-of-river developments. A dam with a short penstock (supply pipe) directs

the water to the turbines, using the natural flow of the river with very little

alteration to the terrain stream channel at the site and little impoundment of the

water.

Diversion and canal developments. The water is diverted from the natural

channel into s canal or a leg penstock, thus changing the flow of the water in the

stream for a considerable distance.

Storage regulation developments. An extensive impoundment at the power plant

or at reservoirs upstream of the power plant permits changing the flow of the river

by storing water during high –flow periods to augment the water available during

the low-flow periods, the supplying the demand for energy in a more efficient

manner. The word storage is used for long-time impounding of water to meet the

seasonal fluctuation in water, availability and the fluctuations in energy demand.

While the word pondage refers to short-time (daily) impounding of water to meet

the short-time changes of energy demand [8].

10

Pumped Storage Developments. Water is pumped from a lower reservoir to a

higher reservoir using inexpensive dump power during periods of low energy

demand. The water is then run down through the turbines to produce power to

meet peak demand [9].

2.2 Classification of hydro power based on the demand for electrical

power.

Based-load developments: - When the energy from a hydropower plant is used to

meet all or part of the sustained and essentially constant portion of the electrical

load or firm power requirements, it is called a base-load plant. Energy available

essentially at all times is referred to firm power.

Peak-load developments: - Peak demands for electric power occur daily, weekly,

and seasonally, plants in which the electrical production capacity is relatively high

and the volume of water discharged through the units can be changed readily are

used to meet peak demands. Storage or pondage of the water supply necessary [9].

Classification of hydro power by installed capacity

Classification of hydropower according to installed capacity is different from different

scholars. However, here with the most common classification source hydropower

engineering lecture notes in BDUIT). Table 2.1 Hydropower classification by installed

capacity (source Lecture Notes)

Table 2-1 Hydro power category (source Lecture Notes)

S.no. Types of plant Installed capacity in

(KW)

1 Pico < 5

2 Micro < 100 3 Mini < 1000 4 Small to medium < 6000

5 Large > 6000

11

Classification of hydro power by head: - Hydraulic head is a key site-specific factor

affecting the turbines type selection, equipment, and construction costs of an SHP. Hence,

a set of representative reference models should developed for different head ranges and

corresponding turbine types:

Low head (2-25m): axial flow (AF) Kaplan/propeller, cross-flow

Medium head (25-70m): conventional Kaplan/propeller, Francis

High head (>70 m): Francis, Turgo, Pelton

2.3 Civil Work Components of Micro Hydro power unit

The civil components described in this section are those major components such as the

intake, headrace canal, de-Sanding basin, spillway, forebay tank, penstock pipes and

tailrace (BPC Hydro consult, 2006).

Operating reserve/Head Storage/:

Operating reserve provides a safety margin that helps ensure reliable electricity

supply despite variability in the electric load and the renewable power supply.

Virtually every real power system must always provide some amount of operating

reserve, because otherwise, the electric load would sometimes fluctuate above the

operating capacity of the system, and an outage would result.

Intake

Intake is the primary means of passage of water from the source of water. Intake

could be of side intake type or the bottom intake type. Usually, trash racks have to

be placed at the intake, which acts as the filter to prevent large water born objects

to enter the waterway of Micro Hydro Project. [15]

Headrace Canal

Headrace canal conveys the water to the fore bay. Sometimes, pipes can also be

used in place of the canals. [20]

Settling Basin

In order to reduce the sediment density, which has negative impact to other

components of the MHS (Micro Hydropower System) de-sanding basins are used

to capture sediments by letting the particles settle by reducing the speed of the

12

water and clearing them out before they enter the canal. Therefore, they are usually

built at the head of the canal. They are equipped with gate valves for flushing the

settled undesirable sediments. De sanding basin is capable of settling particles

above 0.2-0.3 mm of size [9].

Spillway

Spillways need to be designed to remove the excess water due to floods, in order to

minimize the adverse effects to the other components of the MHS (Micro

Hydropower System) spillways are often constructed in de-sanding basin and the

fore bay, from which the excess water is safely diverted to the water source.

Fore bay tank

The fore bay tank serves the purpose of providing steady and continuous flow into

the turbine through the penstocks. For bay also acts as the last settling basin and

allows the last particles to settle down before the water enters the penstock.

Forebay can also be a reservoir to store water-depending on it size (large dams or

reservoirs in large hydropower schemes are technically forebay). A sluice will

make it possible to close the entrance to the penstock. In front of the penstock a

trash rack need to be installed to prevent large particles to enter the penstock. A

spillway competes the forebay tank [8].

Penstock

The penstock is the pipe, which conveys water under pressure from the forebay tan

to the turbine. Penstock is a significant component of the MHP scheme and needs

to be designed and selected carefully as it represents a major expense in the total

budget (for some high head installations this alone could cost as much as 30% of

the total costs). Here the main aspects to consider are head loss and capital cost.

Head loss due to friction in the pipe decreases dramatically with increasing pipe

diameter. Conversely, pipe costs increase steeply with diameter. Therefore a

compromise between cost and performance is considered for design and selection

of pipe diameter and material.

Tailrace

Tailrace is very similar to headrace canal described previously in this section. The

only difference with that of the headrace canal is that it is situated at the end of the

13

civil components and is used to convey the water back to the source after use in the

micro hydro plant.

2.4 Powerhouse Components

The powerhouse components of Micro-Hydropower are used to the conversion of

mechanical energy of water into electrical energy takes place. Powerhouse consists of

electro-mechanical equipment such as turbines, generator and drive systems.

Turbine

In a Micro Hydropower System, hydraulic turbine is the primary component,

which converts the energy of the flowing water into mechanical energy through the

rotation of the runner. The choice of particular turbine depends upon technical

parameters such as design head and discharge at which the turbine is to operate as

well as other practical considerations such as the availability and cost of

maintenance personnel. The optimum speed of the turbine is the particular speed of

its rotor at which the turbine performs its best. The turbine needs to operate at this

optimum speed in order to get maximum possible output at all loading conditions.

Generators

Although this study is not overly concerned with the selection, and uses of

generators in the micro hydropower system it is, however, relevant to describe the

basic types of generators and how they are integrated in the micro hydropower

system. There are two types of generators in use for hydroelectricity generation;

either synchronous or induction generators. Synchronous generators are the

primary types of generators, which are used extensively in large-scale power

generation. When the power output levels are generally low (less than 10 MW),

induction generators are extensively used. Induction generators are also the

preferred type of generators in MHP (Micro Hydro Project) because they can

operate at variable speeds with constant frequency, are available cheaply and

requires less maintenance than the synchronous generators. Both of these

generators have the possibility to be used connected to the grid or just standalone

operation (Upadhayay, 2009).Advantage of synchronous generators are of high

efficiency even in partial loading, independent control of real and reactive powered

14

frequency, reliable power source with stable frequency and voltage for

independent network.

Drive Systems

The main purpose of the drive systems is to transmit the power from turbine to the

generators at a stable voltage and frequency at a required direction and required

speed. Like any normal drive systems, in a MHS also, drive systems comprise of

generator shaft, turbine shaft, bearings, couplings, gearboxes, belts, and pulleys.

The different types of drive systems common in MHS (Micro Hydropower

System) are direct drive, “V” or wedge belts and pulleys, timing belt and sprocket

pulley and gearbox drive systems. A direct drive system is one in which the turbine

shaft is connected directly to the generator shaft. In contrast, “V” or wedge belts

and pulleys are the most commonly used type of drive systems in MHS (Micro

Hydropower System). However, in very small systems (less than 3 kW) where

efficiency is critical, timing belt and sprocket pulley are commonly used.

Gearboxes are suitable in large machine where drive belts are not efficient. Due to

high maintenance and alignment costs of gearboxes, they are less frequently used

in MHS (Micro Hydropower System) (Upadhayay, 2009).

Electrical Load Controllers

All MHS (Micro Hydropower System) will have to have switchgear in order to

separate the power flow when necessary and to control the electrical power flow.

There are several different kinds of switches used in an MHS (Micro Hydropower

System) such as isolators, which are manually operated, switch fuses which

additionally can provide fuse for current limiting, MCCB (Molded Case Circuit

Breakers) which are used for protection from over current or short circuits and also

on. The choice of electronic load controller is largely dependent upon the type of

generator installed in MHS. For instance,when the induction generator is used in

the MHS. It is necessary to install induction generator controllers (IGC) [9].

Hydraulic Turbines: - The device, which converts hydraulic energy into mechanical

energy or vice versa, is known as Hydraulic Machines. The hydraulic machines, which

convert hydraulic energy into mechanical energy, are known as hydraulic turbines.

15

2.5 Types of Hydraulic Turbines

Turbines can be categorized mainly in two types: Impulse turbine and Reaction turbine.

Turbine is the heart of hydro system, as they transform the hydraulic energy in the

mechanical one, which is a more easily usable form of energy.

2.4.1 Impulse Turbines

The impulse turbine generally uses the velocity of the water to move the runner and

discharges to atmospheric pressure. The water stream hits each bucket on the runner.

There is no suction on the down side of the turbine, and the water flows out the bottom of

the turbine housing after hitting the runner. An impulse turbine is generally suitable for

high head, low flow applications.

There are three basic types of impulse turbines, which distinguished and which have

different physical principles and characteristics. These are the Pelton turbines, the Turgo-

turbine and the Cross flow-turbine (also known as Banki-Mitchell or Ossberger-turbine).

Pelton Turbinen

Pelton turbines are impulse turbines where one or more jets impinge on a wheel

carrying on its periphery a large number of buckets. Each jet issues water through

a nozzle with a needle valve to control the flow they are only used for high heads

from 60m to more than 1000m. The axes of the nozzles are in the plan of the

runner. In case of an emergency stop of the turbine (e.g. in case of load rejection),

the jet may be diverted by a deflector so that it does not impinge on the buckets

and the runner cannot reach runaway speed. In this way the needle valve can be

closed very slowly, so that overpressure surge in the pipeline is kept to an

acceptable level (max1.15 static pressure) [17].

Turgo turbines

The Turgo turbine can operate under a head in the range of 30-300m. Its buckets

areshaped differently from the Pelton turbine and the jet of water strikes the plane

of its runner at an angle of about 200. Water enters the runner through one side of

the runner disk and emerges from the other whereas the volume of water

16

decreases. Pelton turbine can admit is limited because the water leaving each

bucket interferes with the adjacent ones, the Turgo runner does not present this

problem. The resulting higher runner speed of the Turgo makes direct coupling of

turbine and generator more likely, improving overall efficiency and decreasing

maintenance cot. Despite the advantages, Turgo turbines are seldom build today

and are only applied in very small MHPs.

Cross-Flow Turbine

A cross flow turbine gets its name from the way the water flows through, or more

correctly „across‟ the rotor as shown in Figure 2.4 below (hence across flow or

cross flow). The water flows over and under the inlet guide-vane which directs

flow to ensure that the water hits the rotor at the correct angle for maximum

efficiency. The water then flows over the upper rotor blades, producing a torque on

the rotor, then through the center of the rotor and back across the low rotor blades

producing more torque on the rotor. Most of the power is extracted by the upper

blades (roughly 75%) and the remaining 25% by the lower blades. Obviously the

rotor is rotating, so what are the upper blades one moment will be the lower blades

the next [20]. The cross flow turbine is also named as Banki turbine. Its structure is

simple, but the Efficiency is low, used for small power stations with o Water head

of 4m-150m Output power could be up to 300 KW The advantage of cross-flow

turbines is they can be easily manufactured, cheap compare to other turbine type,

easy to repair. It can generate power even during low flow rate period

17

Figure 2-1 Cross –flow turbine

2.4.2 Reaction Turbine

A reaction turbine develops power from the combined action of pressure and moving

water. The runner is placed directly in the water stream flowing over the blades rather

than striking each individually. Reaction turbines tare generally used for sites with lower

head and higher flows than compared with the impulse turbines [17].

Kaplan and Propeller turbines

Kaplan and propeller turbines are axial-flow reaction turbines; generally used

for low heads from 2m to 40m. The Kaplan turbine has adjustable runner

blades and may or may not have adjustable guide-vanes. If both blades and

guide-vanes are adjustable, it is described as “double-regulated”. If the guide –

vanes are fixed it is “single-regulated”. Fixed runner blade Kaplan turbines are

called propeller turbines. They are used when both flow and head remain

practically constant, which is a characteristic that makes them unusual in small

hydropower schemes [17].

Francis turbines

The Francis turbine is a reaction turbine where water changes pressure as it

moves through the turbine, transferring its energy. A watertight casement is

needed to contain the water flow. Generally, such turbines are suitable for

18

sites such as dams where they are located between the high-pressure water

source and the low-pressure water exit. Francis turbines can be designed for a

wide range of heads and flows and along with their high efficiency makes

them one of the most widely used turbines in the world. Large Francis turbines

are usually designed specifically for each site so as to gain highest levels of

efficiencies (these are typically in the range of over 90%). Francis turbines

cover a wide range of head- from 20 meters to 700 meters, and can be

designed for outputs power ranging from just a few kilowatts to one Gig watt.

Hydro Turbine Efficiency

It is important to remember that the efficiency characterizes not only the ability of a

turbine to exploit a site in an optimal manner but also its hydrodynamic behavior.

Average efficiency means that the hydraulic design is not optimum and that some

important problems may occur (as for instance cavitations, vibration, etc). That can

strongly reduce the yearly production and damage the turbine.

Each power plant operator should ask the manufacturer for an efficiency guarantee (not

output guarantees) based on laboratory developments. It is the only way to get insurance

that the turbine will work properly. The origin of the guarantees should be known, even

for very small hydro turbines.

Table 2-2 Efficiency of different turbines [31]

Turbine type Best efficiency

Kaplan single regulated 0.91

Kaplan double regulated 0.93

Francis 0.94

Pelton multi-jet 0.90

Pelton single jet 0.89

Turgo 0.85

Cross-flow 0.80

19

Figure 2-2 Turbine application chart Source [source: st. onge environmental engineering]

20

CHAPTER THREE

3. METHODOLOGY

The methodology to accomplish this thesis work block diagram is as shown below:

Figure 3-1 Flow Chart of the Research Methodology

21

Literature Review: - Published Journals, different energy books, different literatures

related to problem statement and micro hydro power energy efficient rural electrification

system and load estimation, potential assessment techniques of micro hydropower

resources and optimization system components software guides like Homer Energy has

been reviewed.

Data Collected: - Primary and secondary data has been collected from the site and

concerned bodies.

Primary data collection such as needs for electricity system daily, monthly &

annually power load (kW)/Energy (kWh). Demand and consumption ($/kWh) from

the field and by interview of responsible bodies.

Secondary data collection such as max & minimum flow rate data and assessment

of micro hydro energy potentials of the site from river and irrigation canal has

been made.

Materials required for the study:-

Google Earth & Google Map

Software: HOMER for micro hydropower optimization and sensitivity analysis

tool, and MS Excel for load data estimation processing

Digital Camera: important photos related to the study will be taken and

documented.

Standard tables and charts: to determine flow of stream in the study area.

GPS

22

CHAPTER FOUR

4. ENERGY DEMAND ASSESSMENT OF THE STUDY VILLAGE

4.1 Profile of the Village under study

The selected off-grid remote rural village for this thesis is Fetam River Tajet diversion

weir irrigation project of left side main canal. The project area is located in Bure zuria

woreda, Zalima Shenbekuma village in specific location called Tajet. It can be accessed

by 180km asphalted road that runs from Bahir dar to Addis Ababa and 20km, gravel road

along the route, which joins Bure and Wolega.

4.2 Primary and Secondary Data Collection

4.2.1 Primary data

Primary dates are those data that are collected by the researcher his/herself by conducting

field survey. During the field survey, the primary data necessary for this study are the

selection of site river diversion weir irrigation canal available head of the diversion of

irrigation canal, the number of religious institutes and type of community services, such

as, school and health post. The gross head is measured by sit survey, of irrigation canal to

diversion weir canal elevation with approximately of 5.4m; whereas the number of

Churches, Community services is collected from Zalima Shenbekuma village

Administration, Zalima Shenbekuma village health office, Zalima Shenbekuma village

Education office and the local people live near to the selected River diversion weir left

side irrigation canal. Accordingly the primary data collected are listed below in Table 3.1

23

Table3. 1 Primary data

Data Collected Value Data Source

Left Side Irrigation Canal

Gross Head of storge

1 Field survey direct Measurement with

GPS and Irrigation project designe

docment.

Distance from power house to

village

1.2Km Filed surivey direct Measurement with

GPS

Number of Primary school 1 Zalima Shenbekuma village Education

Offices

Number of Health Post 1 Zalima Shenbekuma village Health

Offices

Number of Churches

- Orthodox Churches

2

Zalima Shenbekuma village

Administration Office

Number of Population

I. 2007 Census

II. Current Population

6124

8104

2007 Census and Burea Woreda

Administration. (25% total number of

Population living Zalima rural village and

the other Shenbekuma rural village )

4.2.2 Secondary data

Is a data that is not collected by the researcher for his purpose; others collect it for other

purpose. Secondary data more appropriate for this study are, stream flow of the river,

irrigation canal , population size & number of households, energy equipment cost related

to the proposed Steam flow is collected from Bureau of Water, Irrigation and Energy

Development of Amhara; whereas the population size & number of households and token

from Central Statics Agency and Zalima Shenbekuma village administration

respectively. [CSA, 2007] The following table show secondary data collected for the

village under study:

24

Table3. 2Secondary data

Secondary Data Collected

Value Data Source

Fetam river Stream flow(From

1980-2009)

20 year ANRS Bureau of water

Irrigation and energy

left side Irrigation Canal Stream

flow

436l/s ANRS Bureau of water

Irrigation and energy

(Irrigation Design document)

4.3 Energy Demand Assessment and Load Scheduling of the Village

To improve the life of the society energy is very important and crucial. Due to the low

income of the society, scattered placement, the house hold energy demand of the village is

lower than that of in the urban area.

The electrical energy produced from the proposed Micro hydropower system is supplied

to home appliances, community service, and religious institute. Home appliances include

lighting. Radio receiver, community services energy requirement includes lighting, power

for office equipment‟s and water pumping .The primary load is residential with some load

for health post, religious institute and schools. The load of the village is composed of the

household devices such as lights radios and batter charges and that of refrigerators; water

heater devices are included in the calculation for health post. Table 5. The table shows

estimation of each appliance‟s rated power, its quantity and the hours of use by each house

health post, churches and school in a single day.

According to Burea Woreda Administration., the population living area in the selected

village is divided in to two classes based on their geographical area upper /downstream.

Based on geographical area the Wereda Administration selected 275 households‟ Zalima

kebel and 545 households Shenbekuma Keble the study selected upper stream (Zalima

Keble) for load planning, the current population size described in the above paragraph is

considered

25

Table3. 3Summary of energy demand of the village

No End Use Device Unit end use

Power[W]

Qty. Operating hours Daily Energy

Demand[kWh/d] Period hr/d

Small House Loads(275)

1 Lighting 11 3 18:00-23:00 5 45.375

2 Radio at Weekday 30 1 18:00-20:00 2 16.5

3 Battery charge 30 1 09:00-12:00 3 24.75

Sub total 86.625

Health Post

1 Vaccine

Refrigerator

60 1 00;00-23:00 24 1.44

2 Small Refrigerator 200 1 00:00-23:00 24 4.8

3 Microscope 15 1 09:00-12:00

18:00-23:00

6 0.09

4 Lighting 11 5 09:00-17:00 8 0.44

5 Water Heater 1000 1 08:00-11:00 3 3

6 Miscellaneous 20 1 00:00-23:00 24 0.48

Sub total 10.25

Schools

1 Lighting 15 32 18:00-20:00 2 0.96

2 Computer 100 4 08:00-12:00 4 1.6

3 Different office

lighting

15 6 18:00-20:00 2 0.18

4 Miscellaneous 20 1 00:00-23:00 24 0.48

Sub total 3.22

Church

1 Lighting 11 25 18:00-20:00 2 0.55

2 Megaphone 15 10 06:00-08:00 2 0.3

3 Miscellaneous 20 1 00:00-23:00 24 0.48

Sub total 1.33

Others

1 Pump 6000 1 01:00-04:00 3 18

2 Flour Mill 7000 2 04:00-07:00

11:00-14:00

6 84

Sub total 102

System daily total

energy Demand

203.425

26

4.3.1Load projection for the village

Predictions of future events and conditions are called forecasts, and the act of making such

predictions is called forecasting. Forecasting is a key element of decision-making. . Its

purpose is to reduce the risk in decision making and reduce unexpected cost [9].

Energy Consumption in the Future across the residential, commercial and industrial

sectors in the Village will be strongly influenced by economic growth. Increasing personal

income, capital investment and housing starts are major contributors in continued growth

in electricity demand.

For this study, Load, projection for the village is considered from the country average. The

electricity demand forecast considers both the peak demand for electricity and average

demand throughout the year. Peak demand refers to the highest level of electricity

consumption that the utility can supply at any one time. According to EEU the Target

Scenario electricity, demand will be expected to grow by 30% for the period 2017-2020

EEU. From this Forecasting Estimation we assume the village Energy Demand also will

increases by 25% because village Energy Demand is lower than urban Demand.

Therefore, for the village under study the current energy Demand is 203.4kWh/d, peak

energy demand is 24kW and 74,241kWh/year. However, From Simulation Result 53% of

the Energy is Excess energy, for the time being this excess energy will be damped by

damping resistor, when the demand increases the excess energy can be utilized. Hence, the

Village future Energy Demand Growth will be satisfied by this excess energy Generated

by the designed hybrid system.

27

Table3. 4 Load demand

Figure4 1 Load demand

The total estimated peak load is not the actual peak load that will be seen by the system,

because not all the loads allocated for a certain period might be operated on at the same

time. Therefore, a demand factor is applied to the load data. Based on experience on

electrical engineering and engineering judgment, the demand factor is assumed 0.8.

Additionally a 10% spinning reserve is assumed in the system as well. To import the load

data into HOMER hourly load profile for the whole year is required. A load profile of

8,760 hours was thus created for a year based on hourly estimated load for different

months.

End

Time

Load

demand

[kwh/day]

1 0.32

2 6.32

3 6.32

4 6.32

5 14.32

6 14.32

7 14.47

8 0.47

9 9.97

10 10.04

11 10.04

12 14.79

13 14.375

14 14.375

15 0.375

16 0.375

17 0.375

18 0.32

19 18.49

20 18.49

21 9.395

22 9.395

23 9.395

24 0.32

Total 203.38

28

The average daily energy demand of the village after assuming demand factor of 0.8 and

becomes 163kWh, hence the yearly energy demand is estimated as:

Annual Average Energy=163KWh*365day=59,393KWh/year

29

CHAPTER FIVE

5. SYSTEM DESIGN AND PERFORMANCE ANALYSIS OF MICRO HYDRO ELECTRIC POWER

The off-grid power generation system studied in this thesis is standalone micro hydro

power generation and diesel generator backup purposes of station.

Advantages of the system are the stability and immobility of the system and a lower

maintenance requirement, thus reducing downtime during repairs or routine maintenance.

Besides this, as well as being indigenous and free, renewable energy resources also

contribute to the reduction of emissions and pollution.

The Micro hydro power generation system makes use of hydro turbine to produce

electricity as the primary source to supply the load. The micro hydropower system is with

including a diesel generator as a standby system.

5.1 Study design and Selection of System Components MHP

The study of conveyance facilities are provided to guide the diverted Irrigation water

from the power intake to a penstock and removing surplus water back to the irrigation

channel and includes the headrace, the head pond or forebay, the side spillway and

flushing channel.

Figure 5-1Flood discharge position of diversion canal

30

Design Flood discharge of Diversion canal and level

i. Diversion Irrigation canal bed elevation at site of weir =1976.50masl

ii. F.S.L of the headrace canal at the head =1979.80masl

iii. Minimum driving head for full supply discharge = 0.5masl

iv. Pond level require to be maintained assuming 0.1m

Head loss in the weir intake and settling basin = 1980.4masl

Thus the total minimum height of weir required is 1980.4-1976.50 = 3.9 m

The crest level/ floor level of the scouring canal free bored has been fixed 0.3m higher

than the lowest average irrigation canal bed level at 1976.80masl. So that any deposited

silt in front of intake structure shall be disposed of easily .The downstream profile of the

scouring sluice has been kept at a slope of 2.5H to 1V and that of the weir proper at a

slope of 2H to 1V.

Similarly the crest level of the weir of diversion canal has been fixed at 1980.7masl

considering the head required to transfer the flow to headrace canal and a downstream

profile kept at a slope of 2.5H to 1V . The deepest diversion canal bed level at the weir site

is around 1979.0masl.

5.1.1 Intake water way

The water way of the intake to discharge or draw 0.436cum can be determined by using

the discharge formula.

2dQ C A gh (5.1)

Where, Q: Design discharge = 0.436m3/sec

Cd: discharge coefficient =0.6

A: Area of the water way

h: net head or water depth = design intake water level – inlet apron elevation

g: Gravity of

Pond level 1980.40masl

31

Inlet apron level 1978.90masl

The head available above the inlet apron 1.5m but assuming that the available head above

the center of the intake to be 0.5m the area of the water way to pass the required discharge

is computed as:

For the design purpose the velocity of water to pass through the orifice is taken as, V = 1.3

m/s. This value was so taken because for MHS (Micro Hydropower System) the

recommended velocity through the orifice during normal flow is 1.0 - 1.5 m/s). Based on

this premise, it is possible now to calculate the, Area of orifice, (A)

2.436

0.331.3

QA m

V (5.2)

However it is also necessary to consider, whether this design will work during the

monsoon season when the water floods by taking into consideration the value of discharge

through the orifice during flood flow (Q flood).

. 2 r hQ AV AC g h h (5.3)

Letting C=0.6 (for roughly finished masonry)

3

0.33*0.6 2*9.8 1.4 0.5 0.83floodmQ

s

This value will be important at the later stage when designing the spillway since the

orifice is only designed to take 0.436 m3/s.

Design of spillway

It was already pointed out in the section discussing design parameters that the design of

the spillway can be made with calculations of its different dimensions.

The dimension of the spillway are given by,

32

For the design of the spillway it is first necessary to consider what would be the length

required if the design flow was 0m3/s.

Because the material for spillway was chosen as crested weir with round edges C w = 1.6

Q flood = 0.832 m3/s

Q design = 0.436 m3/s

H overtop (h flood – h sp) = 100 mm by convention,

In this case the length of the spillway would be,

1.5

flood design

spillway

w flood

Q QL

C h hsp

(5.4)

1.5

flood design

spillway

w flood

Q QL

C h hsp

= 7.1 m

Settling basin

The water drawn from Fetam River Tajet diversion weir left side irrigation canal for

power generation may carry suspended sediment particles. This silt load may be composed

of hard abrasive materials such as quartz and will cause damage or wear to the hydro-

mechanical elements like turbine runners, valves, gates and penstocks. To remove this

material a structure called settling basin should be constructed, where the velocity of the

flow will be reduced resulting in settling out of the material, which has to be periodically

or continuously flushed out. In order to satisfy the requirement for a good hydraulic

performance the basin is divided into three main zones: inlet zone, settling zone, and

outlet zone.

33

Determination of the design grain size limit

The hydraulic design of a settling basin is normally begins with analyzing the quantity and

quality of sediment carried by the river and determining the necessary degree of removal

on the basis of theory and practical experience but in the absence of the enough sediment

data the limiting size of the suspended matter allowed to deposit is determined from the

low head plants: d limit = 0.2 to 0.5mm

Thus considering the available head, the turbine type (Cross flow) and the size of the

project a limiting size of 0.2mm is adopted for the design of the basin.

/lV a d m s =0.197m/s (5.5)

Where, dl: diameter of the smallest sediment particle to be settled in 0.2mm

„a‟ constant given as a = 0.44 for d = 0.2mm.

V: Settling velocity (m/s)

Settling velocity

The fall velocity of a spherical particle of diameter 0.2mm and relative density of 2.65 is

found to be around 3.1cm/s at around 250 temperatures.

Now assuming the width of the basin to be 1.6 m the depth of flow D can be computed

from the continuity equation as:

0.436

1.6*.2

QD

WV =1.36 says 1.4m (5.6)

Where W: Width of the basin (assuming 1.6m)

D: depth of flow (m)

V: Settling velocity (m/s)

34

During a turbulent flow settling is slower in a flowing water due to the retarding effect of

turbulent flow on subsiding particles, thus the settling velocity is need to be adjust as:

0

mvs

0.1320.111

D

0.031 (0.111*0.2) 0.0086ms

Where; : adjusts settling velocity

: settling velocity of subsiding particles

: Coefficient of subsiding particles

t: adjusts settling time

Using adjusts settling velocity the settling time is computed using the formula:

1.4

162.750.0086

Dt s

(5.7)

The length of the basin is thus,

162.5*0.2 32.55 33L Vt m m (5.8)

Therefore a study design of stilling basin which has a depth of 1.4m, width of 1.6m and

length of 33.0m is provided.

5.1.2 Inlet and Outlet Zone

The main function of the inlet is to decrease gradually the turbulence and avoid all

secondary currents in the basin. This is achieved by decreasing the flow velocity through

gradually increasing the flow cross-section, i.e., by providing gradual expansion of the

width and depth.

In order to achieve a uniform approach of water over the whole chamber width, the

transition is designed using the formula:

35

2 tan 3

B b LI

11m (5.9)

Where I: transition length

B: stilling basin width = 1.6m

b: width of intake = 0.8m

Ѳ: expansion angle = 14.5o

1.6 .8

2 112 tan14.5

I

, hence the design is save.

Outlet Zone

This is a kind of transition provided following the settling zone to facilitate getting back

the flow into the conveyance system with the design velocity by gradually narrowing the

width and depth. The outlet transition wall is designed to Converge 2.5:1

Figure 5-2Inlet and Outlet Zone

5.1.3 Head race Canal

The head race is a conveyance for the diverted left side irrigation canal water from the

weir intake to the forebay and can be provided in the form of a canal, The general

topography of the project area is characterized by a moderate gentle slopes and a very

steep slope terrain that extends downward to left side irrigation canal. Thus, the headrace

36

canal is aligned to run parallel to the left side irrigation canal and closely follow the line of

the terrain that corresponds to the full supply level of the canal. The total length of the

headrace canal is around 50m.the cross section is designed as a concrete lined rectangle

canal up to the full supply depth and a free board of 0.3m vertical masonry wall is

provided. To prevent the interference of animals and humans the power canal is provided

with a top cover concrete slab. The details of the study design are shown in table.

Table 5-1Design of Headrace and Left side Irrigation Transferring Canal

Canal

ID

Required

discharge

Manning's

roughness

Bed

slope

Side

slope

Bed

width

Water

depth

b/d

rati

o

Free

boar

d

Velocity Design

discharge

(Qr) m3/s 'n' (s)

b (m) d (m) m V (m/s) (Qd)

HRC* 0.436 0.015 0.0016 0.75 0.8 0.55 1.7 0.3 1.01 0.447

ITC** 0.436 0.015 0.0016 0 0.8 0.55 1.7 0.3 1.01 0.447

5.1.4 Forebay

A sufficient covering water depth should be provided for preventing the occurrence of a

vortex at the mouth the penstock and air movement to the penstock. The minimum

submergence depth is

1.707*s

vY

gd (5.10)

Where Y s: the minimum submergence depth

v: velocity at the inlet to the conduit( m/s)

d: depth of the conduit(m)

g: 9.81 is a constant and is the product of the density of water and the acceleration

due to gravity (m/s2

)

2.8

1.707* 2.19.81*0.5

sY m

To avoid the inflow of sediment to the penstock, the bottom of the inlet basin of the

penstock is raised by 0.5m from the lowest portion of the forbay resulting to a total water

37

depth of 3.1m i.e. 0.5m depth of inlet conduit plus 2.1m submergence depth plus 0.5m

dead storage depth.

Therefore the study design of forebay will have a final size of 17m length, 1.6m width and

3.1m depth.

A gradual transition section should be provided between the power canal and the forebay

basin and the total length of the transition is determined using the formula:

2 5.62 tan 3

B b LI m

Where I: transition length

B: forebay width = 1.6m

b: bottom width of head race canal = 0.8m

Ѳ: expansion angle = 14.5o

The study design capacity of the forebay tank

* *FV W D L (5.11)

31.6*3.1*17 84.3FV m

Where VF: Volume of forebay (m3)

W: Width of forebay (m)

D: Depth of forebay (m)

L: Length of forebay (m)

38

Figure 5-3Design of forebay tank

5.1.5 Factors to be considered in Penstock Selection and Design

After selecting the material for the penstock pipe, it is necessary to determine its diameter.

The most important design parameter in this selection is that the velocity of the water

should be in between 2.5 m/s to 3.5 m/s. If the velocity is lower or higher it can cause loss

in the power output and thus be uneconomical in the longer run. In study selected

HDP pipe OD 500 PN16 because low cost and high flexible pipe.

4*

*p

Qd

V

(5.12)

Where, d pipe = inside diameter of the pipe (m)

Q = design flow (m3/s)

V = average velocity in the pipe (m/s)

39

Figure 5-4 Design of penstock pipe

40

5.2 Electromechanical Equipment

5.2.1 Turbine Selection

Hydrological Data

i. Design discharge (Qd) = 0.447m3/s which was taken 90% minimum reliable

discharge (after deducting the total loss). So as to sustain the minimum

guaranteed power available with minimum initial investment.

ii. Net design head (H) = 4.42 which is calculated from the following parameters

(at design value)

Figure 5-5 net design head

Figure 5-6 Design of net head

2 3netH H H (5.13)

1977.5 1973.09 4.4netH masl masl m

Where

H net – Effective head

41

Hg - Gross Head of Elevation (1980.4masl)

HL1 - Elevation of intake to forebay (1979.6masl)

HL2 - Elevation of penstock (1977.5masl)

HL3 - Elevation of installation head (1973.09masl)

Turbine performance Analysis T-14 Model values in design are as follows;

Formula (1): Inlet width

11max

1.

.o

net

Qb

q D H (5.14)

Where ob In let width

11maxq Unit discharge (flow) =0.80 (for T-14 Turbine model no)

D Rotor diameter =0.3 m

4.9o

net

Qb

H =887m

Formula (2): Shaft power output

max max9.8* * *e tP H Q =15.47 KW (5.15)

Where t Turbine efficiency 0.80 (for T-14 Turbine model no)

Formula (3) Turbine speed (rpm)

11t net

nn H

D =266rpm (5.16)

Where tn Turbine speeds

11n Unit Speed 38 (for T-14 Turbine model no)

42

Table 5-2Selection of T-14 cross flow turbine plan

5.2.2 Selection of Generator

Considering the facts that the synchronous generators are of high efficiency even in partial

loading, independent control of real and reactive powered frequency, reliable power

source with stable frequency and voltage for independent network and since it can be

designed and manufactured for any actual site condition.

The unit generator input power is same as the turbine output power 14.3kw from

mechanical design. Taking the efficiency of a generator as 95%, the output power of the

generator is calculated as 14.3x0.95=13.58kw.

365 24

1000

KWh days houersAnnulyAvergeEnergy power

year year

(5.17)

Item Unit Parameter

Net head/Design head/ m 4.41

Design discharge m3/s 0.447

Diameter of runner m 0.3

Unit speed (opt) rpm 38

Unit flow (opt) m3/s 0.8

Efficiency of turbine % 74

Unit flow (max) m3/s 0.94

Efficiency of turbine(max) % 73

Width of runner mm 887

Shaft power output kw 14.3

Shaft power output(max) kw 15.47

Turbine speed rpm 266

If turbine width is determined

Width of runner mm 900

Discharge m3/s 0.45

Turbine speed rpm 266

Run away speed rpm 478

43

13.58*365*24 118,961AnnulyAvergeEnergy KWh year

Based on the above mathematical analysis the total energy produced by the micro

hydropower is 118,961kWh/year. From this discussion, the Micro-hydropower system

totally meets the energy demand of the village

Table 5-3Design of Micro Hydropower by Irrigation Canal Fetam River output data

Description Unit

Diversion Weir type for Irrigation Canal Trench and Sharp crested weir

Number of diversion weir 1

Design Flood (Q f) 0.83m3/s

Weir Crest Level 1980.4masl

Bed Level 1976.5masl

Height of Weir (P) 3.9m

Length of Weir (L) 7.1m (including under sluice)

Intake with Trash rack/Gate Rectangular channel

Design Discharge 0.447 m3/s

Intake sill level 1979masl

Water level 1980.4masl

Scouring sluice invert level 1976.8masl

Power conduit type Closed conduit Rectangular canal

Canal height, H 0.85m

Canal width (W b) 0.8 m

Canal Length (L) 50m

Forebay type Rectangular

Area of forebay (17.5 x 1.6) 28m2

Water Level 1979.6masl

Flushing conduit invert level 1976.5masl

Penstock Inlet Invert level 1977.0masl

Penstock type Mild Steel pipe

Penstock diameter 0.9 m

Total length of penstock (L) 66 m

Powerhouse Surface type

Powerhouse area (W x L) (4 x 5) m2 Including control room

Floor Level 1972.755masl

Power production

Gross Head (Hg) 5.4 m

Net Head (H n) 4.41m

Plant discharge 0.447m3/s

Output power 13.5Kw

Turbine type horizontal shaft cross flow turbine

44

Description Unit

Turbine output power 14.3 kW

Rated speed 266 rpm

Turbine max efficiency 0.80

Turbine Coupling type Belt

Energy production 118 M W h/year

Electrical system Standalone type

Voltage level 400/230v

45

CHAPTER SIX

6. RESULTS AND DISCUSSION

6.1 Overview of HOMER Software

Renewable Optimization Model for Electric Renewable (HOMER) is a free computer

model developed originally by the National Renewable Energy Laboratory (NREL) in the

United States. This software application is used to design and evaluate technically and

financially the options for off-grid and on-grid power systems for remote, stand-alone and

distributed generation applications. It allows considering a large number of technology

options to account for energy resource availability and other variables. Since then

HOMER has remained a free software application which has evolved in to a very robust

tool for modeling both conventional and renewable energy technologies.

Table 6-1Economic input of HOMER

No. Hydro turbine Diesel Generator Size of energy equipment 1 KW 1 KW Capital Cost ($) 2000 256 Replacement cost ($) 1750 243 O& M Cost ($/Yr.) 57 0.05$/hr Life time 25yr 10yr(3.2hr./day)

46

6.2 Simulation Result of HOMER Software (compere analytical method)

Figure 6-1 Diagram of the project with HOMER

The inputted data fed for the HOMER simulation software described the primary load, and

micro hydro system components and its costs (Hydro turbine and Generator 1) and

different sizes as mentioned in the previous sections. The system‟s simulations are

performed by HOMER for each of the 8,760 hours in a year. The simulation output

consists of several combinations of each source, with initial capital and net present cost of

each of them.

47

Then monthly average data left side irrigation canal were fed to HOMER software. The

software calculated stream flow values for months of the year.

Figure 6-2 Hydro resource of Fetam River left side irrigation canal [AWIEB]

48

Figure 6-3 Hourly & Monthly/Seasonal primary load demand data of Zalima Shenbekuma Village upper

steram

Table 6-2 Categorized simulation result for the proposed renewable system

49

6.3 Sensitivity simulation result

This model shows how micro-hydro systems integrate with backup Generator system a

stand-alone application.

Sensitivity analysis was carried out and Figure 4.3 shows the variation of stream flow

against at fixed diesel price, the most cost effective set up for a particular set of hydro

generation system is also included.

Figure 6-4 Cost summary of renewable system components

As shown in figure 6.4.the largest capital cost is hydro $28600 and the lowest is for

Generator $2000

50

Figure 6-5 Cash flow Summary by cost category for project life time

As depicted in figure 6.5 the larger cost is expended in the first year and which is capital

cost of the project. Salvage value is calculated at the end of 25th year.

51

Figure 6-6 Annual electric energy production by Hydro system

Figure 6.6 depicts the constant of stream flow available throughout the hours of the day,

month and year b/c constant input load447m3/s.

52

Figure 6-7 State of backup of generation system

Figure 6.7 depicts participate of backup generation of the system almost none black color.

Figure 6-8 Emission of system generation

Figure 6.8 depicts the large Emission is use backup generation and no emission defect

hydro

53

CHAPTER SEVEN

7. COUNCLUSIONS AND RECOMMMENATIONS

7.1 Conclusions

This thesis aimed to investigate and design a micro hydro power generation system and

power conditioning to answer the research questions raised in the begging of the thesis, is

the micro hydro system technically feasible? The micro hydro system Designed to supply

electricity to the village, which equipped with residential loads, a health post and primary

school, and some commercial use, to improve the life of people as well the infrastructure

in the village where they are detached from the central grid. The study of the renewable

potentials of the site is based on the recently recorded data of 20 years average stream

flow and irrigation canal flow data obtained from ANRS Bureau of water Irrigation and

energy. HOMER does the analysis of the renewable energy resources. From the results,

the micro hydro potential of the site is found to be considerably high, and sufficient for

supplying the village in the current and near future energy demand of the village. In

General, this study relates the technical and environmental impact of the off-grid system.

The Overall Conclusion of the research work reported in this thesis is summarized as

follows:

1 From Technical point of view, Micro Hydro system is proposed in the Thesis.

From the simulation result the majority of the energy is obtained from

hydropower, which accounts 98% and backup generators 2% of the total load

consumption. Hence the backup generators should be avoided it only incurs

and increase the project cost.

2 From Environmental Stand point, the renewable energy fraction of the project

is 98%, which implies the total energy almost obtained from Renewable

Energy Resources. Due to this study promoting clean energy and its

contribution to the reduction of Pollutant emission released to the environment.

3 Finally the Author proposed that Off-grid Micro-Hydro system is technically

and economically feasible and Environmentally Friendly Configuration. Thus

the government, non-governmental organizations and private sectors should

54

make combined efforts to improve the quality of life of the communities living

in rural areas.

7.2 Recommendations

The following recommendations are made out of this research; some of them are directed

to other researchers while the others are directed to decision makers. Ethiopia has a huge

potential of renewable energy resources, which can be used for rural electrification

through the off-grid system. There are, however, many challenges like low purchasing

capacity of the rural community, unfavorable conditions towards the utilization of

renewable energies, absence of awareness how to use these resources, etc.

Thus the government, non-governmental organizations and private sectors should make

combined efforts to improve the low rate of rural electrification in Ethiopia.

The implementation for this micro hydro system in the village can serve as a pilot

system for the whole country. This will build for more research, study and

analysis.

As far as the environmental aspects are concerned, this kind of micro hydro energy

systems have to be wide spread in order to cover the energy demands of rural

communities, and in that support Ethiopian Government Green Economic Police as

well way to help reduce the greenhouse gases emission and the deforestation of the

environment in general.

The study done is on one randomly selected village of Bure Woreda administration

in Amahra region and it does not cover all around Amahra region. Future

researchers should extend such a research work in other potential sites and make

the rural people beneficial with renewable energy resource.

In spite of the huge hydroelectric potential of Ethiopia, sever power cuts in recent

years have a heavy impact on the country‟s economy. Micro hydro system

recommended to be built in for the future application to crate sustainable energy

supply of the country.

55

Finally the software used in this study used are free trial version, Used licensed

software for more reliable analysis.

56

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58

APPENDIX

Appendix 1: Secondary data Year Stream flow Irrigation canal

Month Stream flow (l/s)

January 447

February 447

March 447

April 447

May 447

June 447

July 447

August 447

September 447

October 447

November 447

December 447

Average 447

59

Appendix 2: Study area location (source document BoWIERD Amhara)

60

Appendix 3: Fetam Tajet irrigation system (source BoWIERDA)