![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.](https://image.slidesharecdn.com/chapter10-240228082832-9dbd7897/85/Rural-electrification-in-Ethiopia-chapter-10-32-320.jpg)
Rural electrification in Ethiopia (chapter 10)
- 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 !