• Hydropower is mainly located at hilly area.
• Hydroelectric power plant is economical, renewable and conventional.
• The amount of electrical energy that can be generated by a hydroelectric power plant depends upon quantity of water.
• Hydropower cannot produce continuous power supply.
• Potential of Nepal:

Gross Potential: 83 GW

Technical Potential: 44 GW

Economical Potential: 42 GW

• Highest hydropower potential of Nepal is Karnali and Mahakali river basin i.e (32000 MW + 4000 MW = 36000 MW)
• Hydropower currently supplies around 17% of the worlds total electric power supply.
• Potential of world:

Gross Potential: 38,607 TWhr/yr

Technical Potential: 14,605 TWhr/yr

Economical Potential: 8,772 TWhr/yr

• Installed capacity in world:

World: 1416 GW

China: 421 GW

Brazil: 110 GW

USA: 102 GW

Canada: 83 GW

Nepal: 3 GW

• Nepal first hydropower plant was Pharping hydropower plant in 1911 AD capacity (500 KW).
• First hydropower of Nepal from private sector is Khimti in 2000 AD by HPL capacity (60 MW).
• License for hydropower projects are:

Survey: 5 yrs (Period)

Generation: 30 yrs (Export)

                       35 yrs (Domestic) …..+ 5 yrs (incase of Hydrological condition)

Transmission: 15 yrs (add 10 yrs)

• Types of hydropower in Nepal:

PROR:

a.Upper Tamakoshi (456 MW)

b. Kaligandaki (144 MW)

c.Marshadi (69 MW)

d.Middle Marshandi (70 MW)

Storage:

a. Kulekhani (60 MW)

• World hydropower plants:

1.Three George Dam Hydropower (22.5 GW)

2.Baihetan Dam (16 GW)

3. Itaipu Dam Hydropower (14 GW)

References:

• Dandekar, M. M., & Sharma, K. N. (2010). Water Power Engineering. Vikas Publishing House.
• Punmia, B. C., Pande, B. B. L., Jain, A. K., & Jain, A. K. (2016). Irrigation and Water Power Engineering. Laxmi Publications.
• Singh, Bharat (2018). Fundamentals of Hydrology and Hydropower Engineering. Nem Chand & Bros.
• Central Water Commission, Government of India (2019). Handbook on Hydroelectric Engineering.
• International Energy Agency (IEA) (2021). Hydropower Status Report. Retrieved from www.iea.org
• Nepal Electricity Authority (NEA) (2022). Annual Report on Hydropower Projects in Nepal. Retrieved from www.nea.org.np
• United States Bure

The post Hydropower Project Planning: Capsule Summary appeared first on OnlineEngineeringNotes.

Micro hydropower plant:

• It is a small-scale hydropower that typically produce upto 100 KW of electricity using natural flow of water.

Scope:

• Generates from 5 KW to 100 KW of power.
• Can be used in remote and rural parts.
• Suitable for area which have reliable source of water.
• Can be used in place with limited grid access.
• Cost effective energy solution.

Application:

• Generating electricity for domestic, commercial and industrial use.
• Use for irrigation and water supply system.
• Tourism.
• Water purification.

1.2 Introduction to policy of Micro Hydropower Plant development in Nepal

• Alternative Energy Promotion Centre (AEPC) is a government institution established on November 3, 1996 under Ministry of Science and Technology with objective of developing and promoting renewable/ alternative energy technologies in Nepal.

Various policies of government regarding Micro Hydro Development in Nepal:

• Hydropower Development Policy 2001
• Renewable Energy Subsidy Policy 2000/2006
• Subsidy Delivery Mechanism 2000/2006
• Rural Energy Policy 2006

Highlights of different hydropower development policies:

• To generate electricity at low cost.
• To extend reliable and qualitative electric service.
• To tie up electrification with economic activities.
• Participation of local bodies.
• To render support to the development of rural economy.
• Make electric service available to as many people as possible.

1.3 Advantage and relevance of Micro Hydropower in Nepal

• Provide a reliable and cost-effective source of renewable energy in Nepal helping to reduce the country’s dependence on fossil fuel.
• Provide energy for household, business and industries helping to increase the economic development of Nepal.
• Helps to reduce deforestation and emission of carbon dioxide providing environmental benefit.
• Relatively easy to install and maintain, making an ideal solution for rural area that lack access to electricity.
• Helps to develop local infrastructure, such as road and transmission line.
• Can create jobs for local in operation, maintenance and construction work.
• Takes short period to construct.

References:

• Dandekar, M. M., & Sharma, K. N. (2010). Water Power Engineering. Vikas Publishing House.
• Punmia, B. C., Pande, B. B. L., Jain, A. K., & Jain, A. K. (2016). Irrigation and Water Power Engineering. Laxmi Publications.
• Singh, Bharat (2018). Fundamentals of Hydrology and Hydropower Engineering. Nem Chand & Bros.
• Central Water Commission, Government of India (2019). Handbook on Hydroelectric Engineering.
• International Energy Agency (IEA) (2021). Hydropower Status Report. Retrieved from www.iea.org
• Nepal Electricity Authority (NEA) (2022). Annual Report on Hydropower Projects in Nepal. Retrieved from www.nea.org.np
• United States Bureau of Reclamation (2020). Design of Small Dams. U.S. Government Printing Office.

The post Micro Hydropower Plant appeared first on OnlineEngineeringNotes.

1.Diversion weir:

• Structure built in a river to divert water from the main channel into a canal or penstock.

2.Intake:

• Opening to draw design flow from the river.

3.Gravel trap:

• Used to reduce the velocity  of water and prevent erosion.

4.Settling basin:

• Used to capture sediment and other debris.

5.Headrace canal:

• Used to transport water from source to power plant.

6.Penstock:

• Pipe or conduit used to convey water from reservoir to turbine.

7.Power house:

• Building with equipment used to generate electricity from hydropower.

8.Tailrace:

• Outlet channel where used water is released.

1.2 Different type of intake

Intake

Function:

• Control flow of water.
• Prevent entry of debris, trash and ice etc.
• Minimize sediment entry.

Location of intake:

• Should be located at upstream side of power house.
• Located in an area with large and consistent river flow.
• Should be located such it has minimum environmental impact.
• Should be located in area free from debris and sediment.

Types of intake:

1. Runoff river intake:

a.Side intake:

• Common type of intake in ROR plant.
• Suitable for mild slope river.
• Longitudinal axis of the intake is aligned perpendicular to the axis of the river.

b.Frontal intake:

• Suitable for clean and wide river.
• Longitudinal axis of the intake is aligned parallel to the axis of river.
• Trash and debris are attracted towards intake.

c.Drop intake or Bottom rock intake:

• Trash rack is provide over the intake.
• Suitable for very steep river carrying boulder.
• Simple and inexpensive.

2.Reservoir intake:

a.Dam intake:

• It is provided in the body of the dam and used in high head hydroelectric plant.

b.Tower intake:

• Used in large projects.
• Tower intake are categorized as dry tower intake and wet tower intake.

c.Submerged intake:

• Used in small power plants.
• Used in reservoir or river which do not have higher sediment concentration.
• Economical.

d. Shaft intake:

• Vertical shaft driven into the river bed which carries water through underground conveyance system to the power house for power generation.

Importance of intake:

• Helps to ensure a steady flow of water to the turbine. Hence, increasing their efficiency.
• Help to reduce entry of debris in turbine and preventing from damage.
• Used to divert water from one area to another in order to meet demand or balance out river flow.
• Necessary for proper functioning hydropower system.
• Controls water level.

Consideration for location of intake:

• Adequate inflow.
• Least debris intake.
• Least environmental impact.

Design concept in intake:

• Design suitable type of intake based on site and hydraulic condition.
• Satisfy the velocity condition.
  • Approach velocity= 1m/s
  • Trash rack= 0.6-0.75 m/s
  • Intake gate= 1-2 m/s
• Decide number of opening of intake.
• Account for contraction effect due to abutment or piers.
• Calculate hydraulic losses i.e transition loss, exit loss etc.
• Ensure no entry of air.

i.e The system can trap air due to the formation of vertex due to hydraulic jump condition.

• Ensure the release of trapped air to avoid formation of vacuum.

Head loss in trash rack:

a.Kirschmer’s formula

b. General formula

1.3 Performance standards of headwork’s

Control of bed load and floating debris intake

1.Trash rack:

• Placed at the entrance to the intake to prevent entry of floating debris and large stone.
• Trash rack are fabricated with stainless steel or plastic bars.

2.Undersluice:

• Provided to flush out the sediments deposited in front of the intake and control the bed level in its approach area.
• Located close to intake.

3.Gravel trap:

• Constructed close to intake in order to prevent gravel from getting into the canal.
• Main function is to collect the bed load.
• Location is based on the site condition, availability of flushing head and gravel carrying capacity of the canal.

Hydraulic design of gravel trap:

Hydraulic design of gravel trap is similar to settling basin design.

Himalayan intake:

• Himalayan intake is a special type of intake that has proper system for management of both floating debris and bed load.
• It is a geometric design of an intake structure to be used in run-off-river hydropower intake in steep Himalayan river.
• The purpose is to maintain a reservoir volume for daily peaking by providing means of flushing of sediments from reservoir.
• The intake is designed to function in a river which carry both floating debris and large amount of coarse sediments.

1.4 Sediment handling measures

Himalayan river are more prone to erosion due to :

• Young geology
• Fragile geology
• Intense rainfall
• Steep catchment

Sediment handling measure:

1.Catchment management:

• Vegetation screen may be developed by promoting the growth of vegetation in the catchment as well as the entrance to the headwork.
• It would trap a large amount of sediment if flood water pass through them before entering the head works hence helping in reducing the sediment and prevent from entering.

2.Control sediment deposition

• Water having higher sediment content is discharged to the downstream through the undersluice.

3.Construction of sediment excluder or sediment ejector:

• Sediment excluder are constructed in the river pocket.
• Sediment ejector are constructed in the canal.

4.Construction of sloping intake

5.Construction of gravel trap

6.Construction of sedimentation tank

Settling basin:

• It is the structure to remove suspended sediments from the conveyance water for power plant.
• The main principle of the design of settling basin is to reduce the main velocity of the flow.

Purpose of settling basin:

• To remove the fine grained suspended matter from water drawn from intake.
• To remove the suspended particle and minimize the wear and tear of nozzle and runner of turbine.
• To remove sediment as it causes abrasion and erosion of civil structure’s.
• To operate and maintain power plant.

Design criteria of settling basin:

1. Optimum removal of sediment:

• Settling basin shall be designed to remove as much of sediment load in water in econological way.
• As removal of all suspended sediment is not physically possible so the design shall attempt to remove as much of possible so that hydraulic transport capacity of water conveyance sytem is maintained.

2.Settling capacity:

• The size of basin must be large enough to allow a percentage of fine sediment to fall out of suspension and deposited on the bottom.

3.Storage capacity:

• The basin should be able to store the settled particle for sometime unless it is flushed out.

4.Flushing capacity:

• The basin should be able to flush all settled particle along with the incoming flow in the basin by opening flushing gate or valves.

Components of settling basin:

Design of settling basin:

Estimation of sediment volume:

1.5 Flushing of settling basin

1.Continuous flushing type:

• These type of basin are designed with hoppers. The settled particle pass through the bottom of the hoppers to the collecting channel and are flushed continuously.
• Uses surplus water for flushing i.e about 10% of plant discharge.
• Does not interfere in power production during flushing process.
• Complex compared to discontinuous type.
• Main problem is clogging of sediment extracting system.
• Example: Hopper type and Hydro cyclone.

2.Discontinuous flushing type (Periodic or Intermittent):

• Sediment are not flushed continuously.
• Simple in design and are much less susceptible to clogging.
• In first phase, the suspended sediment are allowed to settle in the settling zone.
• In second phase the deposited sediment are removed by different systems.
• Flushing is only required when settling basin is overloaded.

References:

• Dandekar, M. M., & Sharma, K. N. (2010). Water Power Engineering. Vikas Publishing House.
• Punmia, B. C., Pande, B. B. L., Jain, A. K., & Jain, A. K. (2016). Irrigation and Water Power Engineering. Laxmi Publications.
• Singh, Bharat (2018). Fundamentals of Hydrology and Hydropower Engineering. Nem Chand & Bros.
• Central Water Commission, Government of India (2019). Handbook on Hydroelectric Engineering.
• International Energy Agency (IEA) (2021). Hydropower Status Report. Retrieved from www.iea.org
• Nepal Electricity Authority (NEA) (2022). Annual Report on Hydropower Projects in Nepal. Retrieved from www.nea.org.np
• United States Bureau of Reclamation (2020). Design of Small Dams. U.S. Government Printing Office.

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Hydropower project planning stages is divided into three main categories:-

1. Reconnaissance

• It is first stage of project planning.
• It is mainly based on secondary data from maps, aerial photographs and visual inspection.
• This is done mainly for license acquisition purpose.

Objective:

• To identify the suitable project for the stated purpose.
• To provide preliminary cost figure of the project.

Major steps are:-

• Data collection
• Desk studies
• Field work and design
• Estimation
• Environmental and social studies
• Economic assessment
• Report

2. Prefeasibility

• In prefeasibility study the review of the study made in reconnaissance studies is further studied in detail from precise instrument, data series of long time and field survey data.

Objective:

• Establish the need and justification for the project.
• Formulate the plan for developing the project.
• Determine the technical, economic and environmental practicability of the project.
• Make recommendation for further action.

Major steps are:-

• Data collection
• Desk studies
• Field work and design
• Estimation
• Environmental and social studies
• Economic assessment
• Report

3. Feasibility

• In this level pf study the detailed study of the project is carried out in order to determine the technical, economic and environmental feasibility of the project.

Objective:

• To carry out detail design of the project.
• To direct project towards construction.

Major steps are:

• Data collection
• Desk studies
• Field work and design
• Estimation
• Environmental and social studies
• Economic assessment
• Report

1.2 Hydrological data processing

a. Mass curve:

• It is a graph of cumulative values of a water quantity (runoff) against time.
• Also known as Ripple curve.
• It is and integral curve of a hydrograph.

Characteristics:

• It is continuously rising curve.
• The slope at any point on the curve represent the inflow rate.
• If the curve rises sharply, it indicates the high rate of inflow within that period.
• If the curve is horizontal, the flow is zero.
• If the curve is convex, it indicates flood.

Uses:

• It helps in designing the size of the storage required for hydro-electric power plant.
• Check the consistency of many kinds of hydrologic data.

b. Flow Duration Curve (FDC):

• It is the plot of discharge versus percentage of time exceedance of discharge.

Characteristics:

• The slope of flow duration curve depends upon the interval of the data.
• FDC is a decreasing curve.
• Chronological sequence is disturbed in flow duration curve.
• With the increase in storage, the flow duration curve becomes flatter.
• Area under flow duration curve gives flow volume.

Use:

• It is useful in planning and designing of water resource projects.
• It helps in the design of drainage system and in the flood control studies.

1.3 Reservoir planning and regulation

Reservoir:

• When a barrier is constructed across the river, the pool of water formed on the upstream side of the barrier is called reservoir.

Classification of reservoir:

1. Flood control reservoir

• Main purpose of the reservoir is to temporarily store the flood water and release slowly at a safe rate.
• Gates and spillways are used for flood control.

2. Storage or conservation reservoir

• Used to maintain minimum supplies of water for irrigation, hydropower and industries.
• Used to store excess water.

3. Distribution reservoir

• Small capacity reservoir used to fulfill the water supply requirement of a particular city.
• Made of masonry or cement concrete.

4. Multipurpose reservoir

• Reservoir planned and designed for more than one purpose.
• Used to protect from flood, irrigation, water supply and hydroelectric purpose.

Site selection for reservoir:

• Should be located in area with maximum inflow and minimum percolation.
• Site should be accessible by road.
• Site should be located at narrow opening of the basin.
• Construction materials for the dam should be available locally.
• Site should have sufficient water depth.
• Site should be free from objectional minerals.

Regulation of reservoir:

• It is defined as the rational distribution of river flow in time and space among different fields of water resource system.

Need of reservoir regulation:

• The hydroelectric plant will not operate with efficiency if it is operated be low certain head.
• To prevent the excessive siting in the reservoir.

Useful life of reservoir:

• It is impossible to completely stop the flow of sediments of water into reservoir. A dead storage is made available to accommodate the volume of sediments.
• The useful life of reservoir is said to exist till the storage is reduced to 20% of designed capacity.

1.4 Environmental study policy based on type and size

• In order to check whether the proposed project has significant effect on the environment and whether such effect could be avoided or mitigated by any means or not, various studies are carried out at different stages of project planning which is known as Environmental Assessment (EA).
• There are two types of environmental study policy:
  • IEE (Initial Environmental Examination)
  • EIA (Environmental Impact Assessment)

Process of EIA/IEE:

1. Environmental screening:
   • Process determine whether EIA or IEE is required or not.
2. Scoping:
   • Purpose of scoping is to gather and identify the matters which should be covered in environmental information submitted to concerned authority.
   • Involvement of relevant authorities, affected groups.
   • Identification of relevant or significant issues to examined.
3. TOR (Terms of Reference):
   • Provides basic guideline to conduct project specific EIA or IEE.
4. EIA/IEE Report:
   • For IEE it is review by MOEn(Ministry of energy) and approved.
   • EIA is review by MOEn and approved by MOEST (Ministry of Environment, Science and Technology).

1.5 Climate change and ecology:

River Engineering:

• In Himalayan area discharge of river is low and velocity is also low but in plain area discharge is high and velocity is low. So, this leads to sedimentation of structure and to prevent this various river training structure like guide bank is required.

Social cost:

• Hydropower projects becomes barrier to aquatic life.
• Due to large hydraulic structure it changes the flow regime of river.
• Hydropower project may affect particular social group of the community.

Population displacement:

• Destroys forest, wildlife habitat, agricultural land area by flooding.

Change in lifestyle:

• Pollution
• Health issue

Global worry:

• Global warming due to deforestation
• Destroy vegetation and agriculture

Clean energy alternatives:

• Solar energy
• Wind energy
• Geothermal energy

References:

• Hydropower Development: Engineering & Policy Perspectives – John S. Gulliver & Roger E. A. Arndt
• Renewable Energy Systems: Hydropower and Beyond – Godfrey Boyle

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