Rural Electrification System

1. TUTORIAL GROUP 17B Rural Electrification System Alex Louden Ben Jacobs David Jackson Henry Robson Rebecca Cooper

2. Introduction Design Project: Design a reliable, cost effective rural electrification system for villagers in Kandal province. Mini or macro hydropower systems may be a viable alternative.

3. Background • World Bank, Asia Development Bank & Global Environmental Facility = funds • Main usage: Domestic lighting, radios, televisions, heating/cooling = small amounts of electricity, 24 hours a day

4. Current Power System • 24 Power stations around Cambodia • 35% Hydroelectric • Distribution: Charge car batteries @ depot

5. Decision Tree - 1

6. 1 Method of Generation • Hydro – simple storage, suits Cambodia • Wind – low topography, not suitable • Solar – expensive, maint. issues • Tidal – unsuitable areas, high enviro impact • Biogas – not efficient, bad for environment

7. Decision Tree - 2

8. 2 Type of Hydro Generation • Dam • Hydrokinetic turbine (TVA:Hydropower, 2004) • (Treehugger, 2008)

9. 2-1 Types of Dam

10. 2-1 Dam Sketches Embankment Dams (Polaha & Ingraffen, 1999)

11. 2-2 Types of Hydrokinetic Turbine

12. 2-2 Hydrokinetic Sketches Axial Flow Cross Flow (HydroVolts, 2008)

13. Decision Tree - 3

14. 3 Turbine Choice (ESRU, 2002)

15. Decision Tree – 1-3

16. Decision Tree - 4

17. 4 Location • Reserved = can’t do major changes • Huge volume of water = expensive & difficult • Reversible = difficult = expensive  General solution, no specific location (Salidjanova, 2007)

18. Selection Factors • The project function (s) • The physical factors • The economic factors • The environmental considerations • The social considerations

19. Materials (NTNU, 2007) Intake gate For the intake grate we have chosen to use a stainless steel grate with 1cm² holes. This will prevent fish from being sucked in by the turbine and will also filter out most of the rubbish and rocks that are collected by the river along the way. We have chosen this as it is a relatively easy material to obtain, it is cheap and it is erosion resistant. Other parts Scroll casing The scroll casing for the lower heads is typically made out of concrete and a wooden mould is used to get the required accuracy this is then fused with the concrete from the stay ring. For the larger heads where higher hydraulic pressure is needed, steel plating is used which are wielded to the stay ring. However, as the head we are damming will not be large, this does not apply. The guide vane cascade The guide vane cascade of Kaplan turbines are constructed in the same way as for Francis turbines. In the sense of operation a regulating ring rotates the guide vanes through the same angles simultaneously when adjustments follow changes of the turbine load. The vanes of the turbine are made of high carbon steel or dual phase steel and the trunnions are TIG wielded onto the plates. The vanes are designed purposely to maintain optimal hydraulic flow and are given a smooth oxide coating to reduce hydraulic friction. Runner This part of the turbine is the part that contains the blades. This is one of the hardest parts to design as it varies depending on how much water pressure it is to hold. Assuming our location, we would need a 4 or a 5 blade runner made of high carbon steel or manganese steel with approximately 14% manganese. Both of these metals are incredibly resistant against wearing and are both very strong. For the hub, we will use a low carbon steel as strength is not as much of an issue. Runner blade servomotor This part generally consists of a fixed piston in a moving cylinder all integrated inside the hub which is located on the runner. This will be made out of low carbon steel, dipped in zinc to prevent corrosion and lubricated with crude oil maintained at high pressure to avoid water seeping in. Problems with this task included finding a metal that was corrosion resistant as well as supplying the appropriate support needed for this part. Turbine shaft This part is made out of a material called Eglin steel and has integral flanges at both ends of the shaft. This material was chosen as it is relatively low cost steel that works well in tension and provides the support needed. Draft tube This part can be separated into two different parts, the draft tube cone and the lining inside the escarpment. The process of this part is to convert the high amounts of kinetic energy as the water leaves the turbine into pressurised energy. We have decided to make this part out of unlined concrete and the lining at the base of the cone to be made out of HSMA (high strength macro alloy) as this part is one of the more expensive parts to produce. Also, as the kinetic energy plays a major role in the turbines efficiency, the draft tube must be specifically designed for every dam.

20. (Hydropower.com.cn, 2006) Solution • Kaplan turbine • 2-70 m head • 1.0-200 m3s-1 flow rate • 68.2-750 rpm • 100kW-100MW output • 0.8-8.0 m runner diameter (Hydropower.com.cn, 2006)

21. Target Output • Take highest standard 112MW amongst 1.2 million people • Aiming for 1 plant per village =~100kW

22. Final Design Specifications • Small concrete-faced embankment dam 2-5m wide, 1-2m high • General solution for suitable location on river • Grate-filtered water passage – removing debris • Another water passage to regulate drainage during flood season • Kaplan turbine – chosen for suitable at high velocities and low hydraulic head

23. Future Additions • Additional outlets from dam • Incorporate filters – filter fine debris • Distillation process – removal of poisons • Include irrigation channels or pipelines – for irrigation, bathing, flushing toilets, washing clothes, etc

24. Economic Evaluation In any project of this complexity and size, the economic factors need to be closely analysed to provide justification that the project will in fact be suitable and economically beneficial for the region. The sponsors and the clients need to know that the money and resources that are injected into the project will be put to good use and will eventually provide some gain. Currently in Cambodia 84 percent of the country live in rural or isolated areas and of that 84 percent only 13 percent have access to electricity. The average energy consumption in this 13 percent is approximately 48kWh per person per year. This power is usually delivered by a 12V car battery that is recharged by diesel generators. To recharge each battery, on average, costs $0.50. To make the proposed hydroelectric plant viable it needs to be able to provide electricity that is cheaper to purchase than this current margin. An important piece of information to also note is that the country, as a whole, runs on 220V Ac power as provided by EWB. Evidence has shown that Cambodian residents would be willing to part with a few extra dollars to purchase incandescent globes rather than candles to provide light. While incandescent globes may cost more initially than candles, the life-span is much more significant and would provide three times the light output of candles. However, before they can even consider purchasing light globes they need to be reassured that the power source is dependable and constant. Using hydroelectric power, this is possible. There have been other suggestions about alternative energy sources but through extensive research and analysis it has been shown that the best solution for the power development in Kandal Province specifically is Hydropower. One form of economic evaluation is that of Benefit-Cost Analysis. This is where a comparison is made between the expected benefits from a certain project and the expected costs of implementing and maintaining that project. The benefits refer to the income that the project will accumulate once it has been built or possibly the number of possible functions that it can be used for, depending on each project. The cost simply refers to the initial outlay of resources and funds which are required to construct the project, i.e. dam. It can be argued that for a project to be feasible and thus get approval, the benefits must be calculated to, at some point in the structures life-span, outgrow the initial cost, thus generating revenue. The best benefit versus cost ratio is a unity ratio or 1/1. This means that any cost that goes into the project will be generated back at a later date. In this way, the project (a hydroelectric dam), will be able to cover its own costs of maintenance and initial construction. This ratio will need to be looked at more closely in the future, if the design is to go ahead. Another economic factor of dam construction and hydropower implementation is that of repayment rates. It is important to look at repayment rates as they can signify whether the actual construction of the project will be justified in the long term. If the repayments rates will need to be high to cover the costs of the project, i.e. the consumer will have to pay large sums of money for the product, then it is unlikely to be justifiable to construct. Dam construction, however, is usually designed to last for many years, even decades; as a result repayment rates can be set rather low. This means that it takes longer for the dam to cover its initial cost outlay; however it does encourage more frequent users and thus a more consistent repayment. As a result the cost to construct the dam in the first place can be justified as the cost will be recuperated over time. An important factor to consider when designing dams is that they very rarely have only one purpose. They often serve as catchment areas for irrigation or just a better water source for surrounding habitations. In this way, the proposed dam structure could draw revenue from other locations to justify the initial outlay of resources. This is not taken into account in this report; however, it is important to remember that the cost of constructing a dam and hydropower facility can be recuperated from other sources than just the consumer of power. Initial cost will be justified over time

25. Cost Evaluation The proposed design for our dam will be constructed out of small rocks held together with a clay paste. These materials can be found from the surrounding environment and hence will not need to be purchased, thus reducing the cost of the anticipated design. Steel grating A steel grating will be used, for environmental reasons. The grating will stop fish from being sucked into the turbines. Steel grating bought in bulk, so there will be spares. The total cost will be approximately $300. Scroll casing The scroll casing for the lower heads is made out of concrete: The prices for concrete a typically very inexpensive, around $80-$90 per cubic yard. The scroll casings together will cost approximately $3000. Concrete Costs on average for concrete are $87.42 per cubic yard. (Julie Kaine, 2008) Steel The upper heads of the scroll casing need stronger material, higher hydraulic pressure is needed, steel plating is used which are wielded to the stay ring. The prices of steel have been steadily increasing, the most updated data that was found proceeds: • The guide vane cascade • The ‘vanes’ of the turbines are made out of high carbon steel or dual phase steel. The cost of carbon steel varies greatly over time, going from $900 per tonne to $250 a year later. The total cost of the guide vanes will cost approximately $1000. The average updated was $US237 and $US293 per tonne above the lows recorded in December 2007. – Meps • Runner and Runner blade servomotor • The 4 or 5 blade runner will also be made of high carbon steel, as will the servomotor. This blade will be have designed and ordered, costing $10,000. • Turbine shaft • The turbine shaft will be made from Eglin Steel. This steel is relatively low cost at around $130-180 per metric tonne. The shaft will cost approximately $1500. • Draft tube • The draft tube is to be made of unlined concrete and the lining at the base of the cone to be made out of HSMA (high strength macro alloy. The Draft tube concrete approximately $500 and the HSMA alloy will be another $300 maximum. • The concrete pricing remains the same. The HSMA is on the other hand in the higher price bracket at around $200-280 per metric tonne. • Labour Costs • To build the Hydro Plant there will need to be some main Employees that will need to be acquired such as Engineers etc. These are • The Load Forecast Analyst: Analysts usually receive a base salary per month. But the average salary annum for a load forecast analyst is $67,000. Of Course the salary will vary due to location, age and experience of the Analyst. • A Senior Fisheries Biologist will be needed. There wage is normally based hourly, an average of around $34.20 is paid. • A DER Manager will also be required. Their base salary averages around $80,000 • A Vegetation Maintenance Manager: Their average salary is $76,000 • An Equipment specialist has an average wage of $80,000 • A Specialist Engineer for project will require at least $80,000 per annum • Then a Senior and Junior engineer would be required to work together on the project. • Junior engineer requires $60,000 per annum; senior engineer $80,000 and upwards per annum. d design for our dam will be constructed out of small rocks held together with a clay paste. These materials can be found from the surrounding environment and hence will not need to be purchased, thus reducing the cost of the anticipated design. Steel grating A steel grating will be used, for environmental reasons. The grating will stop fish from being sucked into the turbines. Steel grating bought in bulk, so there will be spares. The total cost will be approximately $300. Scroll casing The scroll casing for the lower heads is made out of concrete: The prices for concrete a typically very inexpensive, around $80-$90 per cubic yard. The scroll casings together will cost approximately $3000. Concrete Costs on average for concrete are $87.42 per cubic yard. (Julie Kaine, 2008) Steel The upper heads of the scroll casing need stronger material, higher hydraulic pressure is needed, steel plating is used which are wielded to the stay ring. The prices of steel have been steadily increasing, the most updated data that was found proceeds:

26. Cost Evaluation Summary • Labour: $20,000 (3-4 months to build) • Capital: $60,000 • Additional $? • Estimated cost: < $100,000

27. Environmental Investigation • Have designed to reduce environmental impact • Wildlife habitat – research & location choice • Abandoned construction facilities – recycle materials after use • Loss of fish – slipway & grate • Historical sites – check with historian • Flood control • Slipway/Quick-release/Blow holes – chosen

28. Conclusion Future power system: • Local environmentally friendly hydropower dam • Generating & distributing electricity to village • Potential to filter/distil water for drinking • Potential to have irrigation channels/pipelines for other water uses = better standard of living for Cambodians

29. 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30. Question Time

31. Plan 2 • Make Dam • ... • Profit!?!