Renewable Energy and Energy Efficiency Partnership (REEEP) Training workshop for GTIEA &

L.B. Kassana/Training Workshop for L.B. Kassana/Training Workshop for GTIEA & Cogen Africa Projects -Nairobi GTIEA & Cogen Africa Projects -Nairobi

Kenya, Nov 9-10, 2007Kenya, Nov 9-10, 2007 11Thursday, April 20, 2023Thursday, April 20, 2023 11

Renewable Energy and Energy Efficiency Partnership (REEEP) Training workshop

for

GTIEA

&

Cogen Africa ProjectsCogen Africa Projects

November 10 – 11, 2007November 10 – 11, 2007Nairobi, KenyaNairobi, Kenya


Kenya, Nov 9-10, 2007Kenya, Nov 9-10, 2007 22

Presentation Outline:A. Hydropower in General

B. Fundamentals of Small Hydro Technologies

C. Barriers to the Development & Implementation of SHP

D.D. New Financing Model for SHPNew Financing Model for SHP

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A.A. Hydropower in General Aspects – Hydropower in General Aspects – How Hydropower Works 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:1. determine both the flow rate of the water and the head through

which the water can be made to fall.

2. 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.

3. 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 FacilitiesTypes of Hydropower Facilities





Advantages and Disadvantages of HydropowerAdvantages and Disadvantages of Hydropower

Advantages:

1. Hydropower is fuelled by water, so it's a clean fuel source.2. Hydropower doesn't pollute the air like power plants that burn fossil fuels,

such as coal or diesel.3. Hydropower relies on the water cycle, which is driven by the sun, thus it's

a renewable power source.4. Hydropower is generally available as needed; engineers can control the

flow of water through the turbines to produce electricity on demand.5. 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.

6. Other benefits may include water supply and flood control if you have storage scheme.





Disadvantages:

1. 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.

2. 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.

3. 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!!!

Advantages and Disadvantages of Hydropower - contAdvantages and Disadvantages of Hydropower - cont

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B. Fundamentals of SHP Technologies:B. Fundamentals of SHP Technologies:

Design and General AspectsDesign and General Aspects





Introduction to Small Scale HydropowerIntroduction 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





The Process of Evaluating a SiteThe 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.





The Water Resources and its PotentialThe 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 = QHγη where Q is discharge, H is net head, γ is specific weight of water (9.81 kN/m3), η 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.





Typical Basic Layout & Schematic DiagramTypical Basic Layout & Schematic Diagram

Civil Engineering WorksCivil Engineering Works





Civil Engineering WorksCivil 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– <100 m head, the size of P/Hse & concrete volume

are a function of turbine size– >100 m head, the size is governed by diameter of the

generator casing.





Electromechanical EquipmentElectromechanical 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.





ElectromechanicalElectromechanical Equipment-contEquipment-cont..Classification of Turbine typesClassification of Turbine types





Electromechanical Equipment-cont.Electromechanical Equipment-cont.Turbine types based on Head and Discharges





Electromechanical Equipment - contElectromechanical 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. N=Ns*H(5/4)/√P 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!!





Electromechanical Equipment-cont.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





Economical ConsiderationsEconomical 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





Economical Considerations-contEconomical 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





Economical Considerations-Economical Considerations-contcont• 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.





Economical Considerations-Economical Considerations-contcont• 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:• R=9.81*Q*Hn*nTa 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





Economical EvaluationEconomical 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)



C. Barriers Challenging the Development & Implementation of SHPs

1. Investor confidence is lacking2. Financing: Financial institutions are generally not

familiar with small hydropower sector. 3. 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

4. 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.



Barriers Challenging the Development & Implementation of SHPs - cont

5. 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.

6. 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.

7. Lack of entrepreneurial Culture amongst our selves i.e. can’t take calc. risks, determination, perseverance, creativity





D. New Financing Model for SHPD. 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





D. New Financing Model for SHP D. New Financing Model for SHP - contcont

• 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





D. New Financing Model for SHP D. New Financing Model for SHP - contcont• The entrepreneurial model would look like:

Financier e.g.GEF/Gvt/IDA

Private Enterprise e.g. Tea companies

thru EATTA

Commercial Investore.g. development

& commercial banks

Partnership



1. 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.

2. 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!

3. 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.

CONCLUSION

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