Energy conversion is the process of changing one form of energy into another, a fundamental capability that enables modern civilization to function. It can occur in various ways, from converting the kinetic energy of wind into mechanical power through windmills to transforming solar energy into electrical energy in solar panels. This transformation is essential not just for daily usage but also for harnessing and utilizing natural resources more efficiently. In the context of rural electrification, this process plays a critical role. By converting available local energy resources into electricity, rural communities can access a stable and reliable power supply. This not only improves the quality of life but also supports economic development by powering homes, schools, businesses, and healthcare facilities. Consequently, energy conversion facilitates the broader goal of rural electrification, demonstrating the interconnection between technological innovation and societal advancement.

1. Chapter - 10
Rural Electrification in Ethiopia
Tesfaye B.

2. Introduction
• Above 90% of energy sources in Ethiopia are from hydro
and the remaining's are from wind, geothermal and solar
resources.
• The hydro energy resource potential of Ethiopia is
estimated to be 30 to 45GW (159TWh/year) based on
Water and Power Consultancy Services (WAPCOS ).
• The following tables show that the operational projects of
hydro and wind projects.
2

3. Cont…
Fig. existing hydro power plants in Ethiopia 3

4. Cont…
Fig. existing wind power plants in Ethiopia
4

5. Rural Electrification
• Almost more than 80% of the people are living in rural
areas of Ethiopia.
• So the Ethiopian government has formulated a national
rural electrification strategy where both the public
electricity service company (EEPCO) and the private or
non-government sector will be involved in extending
services to the rural population.
• Implementation of the public sector rural electrification
program is already in progress and hundreds of rural towns
will be the beneficiaries of this program in the coming few
years.
5

6. Cont…
• The second private-led rural electrification strategy
focuses on electrification of rural areas not to be covered
by EEPCO's system expansion plan for the next few
years.
• This strategy will be implemented through a newly
established Rural Electrification Fund (REF), the
resources of which will be made available to viable
projects and eligible private and non-government project
promoters on a loan basis.
6

7. Rural Electrification Fund
• Rural Electrification Fund was established by
Proclamation No.317/2003.
• It was established to provide loan and technical service
for Rural Electrification Projects.
• It was also established to encourage utilization of
electricity for productive uses and on improving energy
availability and quality of rural service sectors.
• The Rural Electrification Fund is administered under the
ministry of water and energy by Alternative Energy
Technology Dissemination Director (AETD), which
serves as the Rural Electrification Fund Administrator.
7

8. Cont..
• A Rural Electrification Board (REB) directs the activities
of the Directorate.
• The Development Bank of Ethiopia (Trust Agent) is the
financial intermediary between the Rural Electrification
Fund and Project Promoters.
• The Development Bank of Ethiopia disburses funds
during project implementation and later recovers loans in
line with the loan agreement agreed upon by the
Directorate and the Project Promoters.
8

9. Cont…
• The technologies that are expected to be covered under
the program include:
1. Solar home system
2. Bio-Gas Plants
3. Small Scale Wind Energy System
9

10. 1. PV/Solar option for rural electrification
10

11. Cont.…
11
• PV Modules or Solar Panel - converts sunlight
instantly into DC electric power.
• Inverter - converts DC power into standard AC power
for use in the home, synchronizing with utility power
whenever the electrical grid is distributing electricity.
• Battery - stores energy when there is an excess
(coming in and distribute it back out when there is a
demand). Solar PV panels continue to re-charge
batteries each day to maintain battery charge.
• Charge Controller - prevents battery overcharging and
prolongs the battery life of your PV system.

12. Cont..
12
Types of PV Systems
• Photovoltaic-based systems are generally classified
according to their functional and operational
requirements, their component configuration, and how
the equipment is connected to the other power sources
and electrical loads (appliances).
• The two principle classifications are Grid-Connected
and Stand Alone Systems.

13. Cont.…
Grid Connected System
• Grid-connected or utility-intertie PV systems are designed
to operate in parallel with and interconnected with the
electric utility grid.
• The primary component is the inverter, or power
conditioning unit (PCU).
• The inverter converts the DC power produced by the PV
array into AC power consistent with the voltage and
power quality required by the utility grid.
• The inverter automatically stops supplying power to the
grid when the utility grid is not energized.
13

14. Cont.…
• A bi-directional interface is made between the PV system
AC output circuits and the electric utility network,
typically at an on-site distribution panel or service
entrance.
• This allows the power produced by the PV system to
either supply on-site electrical loads, or to back feed the
grid when the PV system output is greater than the on-site
load demand.
14

15. Cont.…
• During periods when the electrical demand is greater
than the PV system output (night-time), the balance of
power required is received from the electric utility.
Fig: Grid connected PV system
15

16. Cont.…
Stand Alone System
• Stand-alone PV systems are designed to operate
independent of the electric utility grid, and are generally
designed and sized to supply certain DC and/or AC
electrical loads.
• Stand-alone systems may be powered by a PV array only,
or may use wind, an engine-generator or utility power as
a backup power source in what is called a PV-hybrid
system.
• In many stand-alone PV systems, batteries are used for
energy storage.
16

17. Cont..
• Below is a diagram of a typical stand-alone PV system
with battery storage powering DC and AC loads.
Fig: standalone PV system
17

18. Cont..
• Hybrid means a combination of different energy sources
Fig: PV-wind-generator hybrid system for single house
18

19. 2. Bio-Gas Plants
Bio-Mass Conversion:
• There are four types of conversion technologies currently
available, each appropriate for specific biomass types and
resulting in specific energy products:
• Thermal conversion is the use of heat, with or without the
presence of oxygen, to convert biomass materials or feed
stocks into other forms of energy. Thermal conversion
technolgies include direct combustion, pyrolysis, and
torrefaction.
• Thermochemical conversion is the application of heat and
chemical processes in the production of energy products
from biomass. A key thermo-chemical conversion process
if gasification. 19

20. Cont..
• Biochemical conversion involves use of enzymes,
bacteria or other microorganisms to break down biomass
into liquid fuels, and includes anaerobic digestion, and
fermentation.
• Chemical conversion involves use of chemical agents to
convert biomass into liquid fuels. Trans esterification is
the most common form of chemical-based conversion.
20

21. 3. Small Scale Wind Energy System
Types of Turbines:
• A wind turbine is a device that converts kinetic
energy from the wind into electrical power.
• Wind turbines can be separated into two basic types,
namely horizontal axis wind turbine and vertical axis
wind turbine.
Horizontal Axis Wind Turbines (HAWT):
• A HAWT has a similar design to a windmill; it has blades
that look like a propeller that spin on the horizontal axis.
21

22. Cont..
• Horizontal axis wind turbines have the main rotor shaft
and electrical generator at the top of a tower, and they
must be pointed into the wind.
22

23. Cont..
• Small turbines are pointed by a simple wind vane placed
square with the rotor (blades), while large turbines
generally use a wind sensor coupled with a servo motor to
turn the turbine into the wind.
• Most large wind turbines have a gearbox, which turns the
slow rotation of the rotor into a faster rotation that is more
suitable to drive an electrical generator.
23

24. Cont..
HAWT advantages
• The tall tower base allows access to stronger wind in
sites with wind shear. In some wind shear sites, every
ten meters up the wind speed can increase by 20% and
the power output by 34%.
• High efficiency, since the blades always move
perpendicularly to the wind, receiving power through
the whole rotation.
HAWT disadvantages
• Massive tower construction is required to support the
heavy blades, gearbox, and generator.
24

25. Cont..
• Components of a horizontal axis wind turbine (gearbox,
rotor shaft and brake assembly) being lifted into position.
• HAWTs require an additional yaw control mechanism to
turn the blades toward the wind.
• HAWTs generally require a braking or yawing device in
high winds to stop the turbine from spinning and
destroying or damaging itself.
25

26. Cont..
Vertical Axis Wind Turbine (VAWT):
• Vertical Axis Wind Turbines, as shortened to VAWTs,
have the main rotor shaft arranged vertically.
• The main advantage of this arrangement is that the wind
turbine does not need to be pointed into the wind. This is
an advantage on sites where the wind direction is highly
variable.
• With a vertical axis, the generator and other primary
components can be placed near the ground, so the tower
does not need to support it, also makes maintenance
easier.
• The main drawback of a VAWT generally creates drag
when rotating into the wind. 26

27. Cont..
• It is difficult to mount vertical-axis turbines on towers,
meaning they are often installed nearer to the base on
which they rest, such as the ground or a building rooftop.
• The wind speed is slower at a lower altitude, so less wind
energy is available for a given size turbine.
27

28. Cont..
• Air flow near the ground and other objects can create
turbulent flow, which can introduce issues of vibration,
including noise and bearing wear which may increase the
maintenance or shorten its service life.
28

29. Cont..
VAWT advantages
• No yaw mechanisms are needed.
• A VAWT can be located nearer the ground, making it
easier to maintain the moving parts.
• VAWTs have lower wind startup speeds than the typical
the HAWTs.
VAWT disadvantages
• Most VAWTs have an average decreased efficiency from a
common HAWT.
• Having rotors located close to the grounds where wind
speeds are lower and do not take advantage of higher
wind speeds above.
29

30. Problems based on Solar Power:
1. Calculate the solar energy (KWh) by considering the below data.
A = Total solar panel Area (m²) = 20 m²
r = Solar panel yield (%) = 15%
H = Annual average solar radiation on tilted panels (shadings
not included) = 1250 KWh/m².
PR = Performance ratio, coefficient for losses = 0.75.
Solution:
• The global formula to estimate the electricity generated in
output of a photovoltaic system is:
E = A * r * H * PR
= 20 * (15/100) * 1250 * 0.75 = 2812.5, KWh.
30

31. Cont.…
2. How much area of solar panel is required for generating
1500 KWh of solar energy? The data are
r = solar panel yield (%) = 15%
H = Annual average solar radiation on tilted panels
(shadings not included) = 1250 KWh/m².
PR = Performance ratio, coefficient for losses = 0.75.
Solution:
• The global formula to estimate the electricity generated in
output of a photovoltaic system is:
E = A * r * H * PR
31

32. Cont..
1500 = A * (15/100) * 1250 * 0.75
A = 1500 / [(15/100) * 1250 * 0.75]
A = 1500 / 140.625 = 10.67 = 11m2.
• Hence for generating 1500 KWh of solar energy, we
required approximately 11 m2 of solar panel area.
3. Calculate the usable capacity of the battery of 12V / 110
Ah.
Solution:
• Usable capacity of a battery = 0.7 * full capacity of a
battery (since usable capacity of battery is only 70% of
full capacity)
= 0.7 * (12*110) = 0.7 * 1320 = 924 Wh.

33. Thank you !