Small Scale Hydropower Project Design General Aspects

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Renewable Energy and Energy Efficiency
Partnership (REEEP) Training workshop for GTIEA
Cogen Africa ProjectsNovember 10 11,
2007Nairobi, Kenya
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Presentation Outline

• Hydropower in General
• Fundamentals of Small Hydro Technologies
• Barriers to the Development Implementation of
  SHP
• New Financing Model for SHP

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Hydropower in General Aspects How Hydropower
Works

• Water constantly moves through a vast global
  cycle, evaporating from lakes and oceans, forming
  clouds, precipitating as rain or snow, then
  flowing back down to the ocean.
• Hydropower is using water to power machinery or
  make electricity.
• Hydropower uses water as fuel that is not reduced
  or used up in the process. Because the water
  cycle is an endless, constantly recharging
  system, hydropower is considered a renewable
  energy.

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• Water into watts
• To determine the power potential of the water
  flowing in a river or stream it is necessary to
• determine both the flow rate of the water and the
  head through which the water can be made to fall.
• The flow rate is the quantity of water flowing
  past a point in a given time. Typical flow rate
  units are l/s or m3/s. The head is the vertical
  height, in m, from the turbine up to the point
  where the water enters the intake pipe or
  penstock.
• The potential power can be calculated as follows
  Theoretical power (P) Flow rate (Q) x Head (H)
  x Gravity (g) 9.81 m/s2 ) Where Q is in m3/s, H
  in m and g 9.81 m/s2 ) then, P 9.81 x Q x H
  (kW)

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Types of Hydropower Facilities
L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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Advantages and Disadvantages of Hydropower

• Advantages
• Hydropower is fuelled by water, so it's a clean
  fuel source.
• Hydropower doesn't pollute the air like power
  plants that burn fossil fuels, such as coal or
  diesel.
• Hydropower relies on the water cycle, which is
  driven by the sun, thus it's a renewable power
  source.
• Hydropower is generally available as needed
  engineers can control the flow of water through
  the turbines to produce electricity on demand.
• Hydropower plants provide benefits in addition to
  clean electricity. Impoundment hydropower creates
  reservoirs that offer a variety of recreational
  opportunities, notably fishing, swimming, and
  boating. Most hydropower installations are
  required to provide some public access to the
  reservoir to allow the public to take advantage
  of these opportunities.
• Other benefits may include water supply and flood
  control if you have storage scheme.

L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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Advantages and Disadvantages of Hydropower - cont

• Disadvantages
• Fish populations can be impacted if fish cannot
  migrate upstream past impoundment dams to
  spawning grounds or if they cannot migrate
  downstream to the ocean. Remedies are fish
  ladders or elevators, or by trapping and hauling
  the fish upstream by truck. Other remedies can be
  by maintaining a minimum spill flow past the
  turbine.
• Hydropower can impact water quality and flow.
  Hydropower plants can cause low dissolved oxygen
  levels in the water, which can be remedied by
  various aeration techniques, which oxygenate the
  water.
• Hydropower plants can be impacted by drought.
  When water is not available, the hydropower
  plants can't produce electricity. What is the
  remedy for this ? Subject for discussion for
  all!!!

L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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B. Fundamentals of SHP Technologies Design and
General Aspects
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L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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Introduction to Small Scale Hydropower

• 1st Question Why bother develop it after all?'
  Why not leave waterfalls and the beautiful
  landscape intact? Exercise for the
  participants!!
• The following elements will be covered
• The Process of Evaluating a Site
• The water resources and its potential
• Civil Engineering Works
• Electromechanical Equipment
• Economical Considerations Evaluation

L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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The Process of Evaluating a Site

• Identification of the Site
• Evaluation of the water resources available for
  the plant and consequentially its annual energy
  production
• Preliminary Definition and Cost Evaluation of the
  Plant
• Preliminary Evaluation of Economics of the Scheme
  after researching on financial alternatives,
  benefits available from governments, tax
  incentives, etc.
• Review of Regulatory requirements and its
  administrative procedures.

L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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The Water Resources and its Potential

• Hydrology
• Velocity-Area method
• Dilution Methods
• Flow measuring structures e.g rectangular weir,
  V-noth weirs, flumes.
• Slope-Area method
• Sizing a power plant
• FDC provides means of determining quickly how
  much of the available water resources can be used
  by turbines of different sizes.
• Power available from flow varies with time since
  Q is varying is given by P QH?? where Q is
  discharge, H is net head, ? is specific weight of
  water (9.81 kN/m3), ? is overall efficiency (may
  initially est. to be 0.8).
• Annual energy production
• Can be estimated to a 1st approximation by
  measuring the usable area under the FDC,
  converting to an actual qty of water in m3 in a
  specific time, multiplying that by 9.8 and the
  net head (averaged) and mean efficiency
  (estimated). The result is annual energy in kJ
  which is converted to kWh by dividing by 3600.

L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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Typical Basic Layout Schematic Diagram
Civil Engineering Works
L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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Civil Engineering Works

• Dams/Weirs has 2 functions
• To increase the available head
• To create a reservoir to store water
• Intakes have the following functions
• To conduct water into the penstock or power
  canal/tunnel
• To minimise the amount of debris and sediment
  carried by the incoming water.
• Waterways
• Tunnels/Canals these convey water either
  directly or via penstock to the turbines
• Forebay designed to provide only enough storage
  to provide extra volume needed during the turbine
  start-up
• Penstocks these are pressure pipes conveying
  water to the turbines
• Tailraces these return water back to rivers
  after passing thru the turbines
• Powerhouse location for turbines, generators,
  etc
• lt100 m head, the size of P/Hse concrete volume
  are a function of turbine size
• gt100 m head, the size is governed by diameter of
  the generator casing.

L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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Electromechanical Equipment

• Hydraulic Turbines They convert potential energy
  to mechanical energy. 3 categories of
  conventional turbines
• Kaplan Propeller turbines these are axial flow
  reaction turbines used for low head
• Francis turbines these are radial flow reaction
  turbines with fixed runner blades and adjustable
  guide vanes used for medium heads.
• Peltons these are impulse turbines with single
  or multiple jets, each jet issuing thru a nozzle
  with a needle to control the flow. They are used
  for both medium and high heads.

L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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Electromechanical Equipment-cont.Classification
of Turbine types
L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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Electromechanical Equipment-cont.
Turbine types based on Head and Discharges
L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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Electromechanical Equipment - cont

• Turbines Type, geometry and dimensions depends
  primarily on
• Net head
• Rated (design) discharge
• Specific speed, Ns determines the type basic
  shape of the runner other parts of the unit.
  NNsH(5/4)/vP where N is synchronous speed in
  rpm (N(60f)/of poles), H is head and P is power
• Runaway speed theoretical speed that can be
  attained when hydraulic power is at its max and
  electrical load is disconnected.
• Ratio power to net head
• Cost, of course!!

L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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Electromechanical Equipment-cont.

• Generators these transform mechanical energy to
  electrical energy. There are two choices
  Synchronous alternators equiped witha DC
  excitation system and Asynchronous Generator
  which draws excitation from the grid.
• Control equipment
• Governors that can be mechanical or electrical
• Switchgear panel and protection
• Automatic control
• Powerstation auxiliary electrical equipment
• Station service transformer
• DC control power supply
• Outdoor substation

L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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Economical Considerations

• Preamble Profitability of a scheme is a function
  its capital and of the revenues from the sale of
  electricity.
• Main parameters influencing costs and revenues
• Type of turbine
• Number of Units turbines with murtiple runners
  or multiple nozzles
• Speed of rotation
• Turbine setting
• Control equipment
• Size of powerhouse
• Sale of electricity

L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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Economical Considerations-cont

• Type of turbine
• For the same head, certain turbines are more
  difficulty to manufacture than others
  consequently they are more expensive. E.g for low
  heads, a Propeller is cheaper than a Kaplan
  designed for the same rated discharge. In medium
  heads, a cross-flow turbine is cheaper than a
  Francis whose runner is more complex.
• Number of Units
• Turbines with multiple runners or multiple
  nozzles
• Speed of Rotation
• Higher specific speed mean smaller turbine
  dimensions and higher speed generators. Since the
  turbine cost decreases with an increase in speed,
  there is a major incentive to use ever higher
  specific speed. Furthermore, in small units, if
  the speed is high enough, a standard generator
  may be directly coupled to the turbine, thus
  saving the cost of the gear box

L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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Economical Considerations-cont

• Turbine Setting
• The negative aspect of high specific speeds,
  requiring a deeper setting to avoid cavitation,
  must also be included in the assessment
• Additional foundation excavation
• Extra dewatering costs
• Higher costs of draft tube gate because of higher
  tailwater head etc
• Control Equipment
• Turbines like Kaplan with double regulation (if
  both runner blades guide vanes are adjustable)
  require a more complex control system that
  increases the costs. But others like the Pelton
  wheel accept rather rudimentary control system
  like a deflector infront of the nozzle.

L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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Economical Considerations-cont

• Size of the Powerhouse
• The powerhouse concrete volume can be determined
  based on a number of units and their throat
  diameter. Often the cost of the civil work is
  higher than the cost of the equipment. Reducing
  the cost of the unit size decreases the cost of
  the powerhouse.
• Sales of electricity
• The revenue from the sale of electricity produced
  by one unit is given by the following equation
• R9.81QHnnTa where
• Q is discharge in m3/s
• Hn is net head in m
• n is overall efficiency of the system running
  time
• Ta is electricity tarriff

L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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Economical Evaluation

• Static Methods
• Payback (recovery or break even period) Method
  determines of years required for invested
  capital to be offset by resulting benefits.
• Return on Investment Method calculates average
  annual, net of yearly costs, such as
  depreciation, as a percentage of the original
  book value of the investment.
• Dynamic Methods these take into account total
  costs benefits over the life of the investiment
  and the timing of the cash flow
• Net Present Value (NPV)
• Benefit-Cost ratio (B/C)
• Internal Rate of Return (IRR)

L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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C. Barriers Challenging the Development
Implementation of SHPs

• Investor confidence is lacking
• Financing Financial institutions are generally
  not familiar with small hydropower sector.
• Technical capability The engineering and
  consulting firms in Africa have limited
  experience with carrying out F/S, design
  Construction of SHP. Without high quality
  assessment F/S then investment will not come in
  this sector
• Lack of infrastructure for manufacturing,
  installation and operation. Most of the countries
  in Africa do not have any facility to manufacture
  even the most rudimentary turbines or parts that
  might be critical in maintenance of the schemes.

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Barriers Challenging the Development
Implementation of SHPs - cont

• Policy Regulatory uncertainty Gvt policies in
  most EATTA countries generally support
  development of SHP but there are no clear
  targeted regulations incentives for
  specifically promoting independent generation for
  captive use or for feeding into the grid and
  public private partnership for rural
  electrification.
• Market Uncertainty lack of clear rules to allow
  the sale of power produced by SHP, say beyond tea
  factory limits the size of projects reduces
  of financially attractive SHP.
• Lack of entrepreneurial Culture amongst our
  selves i.e. cant take calc. risks,
  determination, perseverance, creativity

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D. New Financing Model for SHP

• This is an entrepreneurial centered approach
  featuring a combination of services and
  financing.
• Under this model, a financier works to bring
  small, privately owned companies together with a
  commercial investor to back SHPs.
• The financier provides a range of services to
  privately owned coys who want to supply clean
  electricity to their factories and communities
  around to help them improve their lives and
  income
• The financier provides the following services
• Accepting project risks
• Offering convertible debt (i.e. Debt that may be
  converted to equity) at reasonably attractive
  terms.
• Providing debt and equity financing options
  appropriate for the size of the entreprise and
  market conditions
• Providing support services to the developer b4
  and after an investment
• Forstering partnership and relationship with
  social investors and partial risk sharing lenders

Sunday, November 15, 2009
L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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D. New Financing Model for SHP - cont

• The entrepreneurial model should work as follows
• The financier provides first the seed money to
  pay for legal, engineering or environmental
  preparation
• The funding can range from USD 100,000 to USD 3
  Million depending on the size of the project and
  it is a case by case. For our case, if we are
  superimpose GTIEA Project - FSP phase on this
  model, the seed money comes to about USD 2.8
  Million.
• The financier acts like as an advisor helping and
  entrepreneur with the business plan development ,
  working with banks to get the construction
  funding, negotiating PPAs and training developers
  on approaches to business management and
  expansion.
• Once an enterprise begin to meet its objectives,
  it may be appropriate to provide a growth loan

Sunday, November 15, 2009
L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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D. New Financing Model for SHP - cont

• The entrepreneurial model would look like

Sunday, November 15, 2009
L.B. Kassana/Training Workshop for GTIEA Cogen
Africa Projects -Nairobi Kenya, Nov 9-10, 2007
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CONCLUSION

• Small hydro has proven itself as a major
  contributor to electrification in developing
  countries, e.g China India as examples where
  small hydro has been developed in large parts of
  the countries.
• The interest in small hydro on the African
  continent as emerged over the last couple of
  years, has resulted in a number of projects that
  will pave the way for large scale introduction of
  small hydro. The current interest by African
  Governments, international donors, development
  banks and the private sector in increasing energy
  access in Africa will facilitate the uptake of
  this robust, environmentally friendly form of
  energy. GTIEA Project is a result of this
  interest!
• The challenge upon us now is to maintain the
  momentum created and ensure that the current
  interest will be translated into more small hydro
  plants installed.