RENEWABLE ENERGY TECHNOLOGY: MICRO HYDRO POWER GENERATION FOR ELECTRIFICATION

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1 RENEWABLE ENERGY TECHNOLOGY: MICRO HYDRO POWER GENERATION FOR ELECTRIFICATION Dr. S. K. Dave 1, Ashokkumar A. Parmar 2, Nikhil M. Vyas 3, P. S.Chadhari 4 Lecturer & I/C Head Civil Eng, Applied Mechanics., B.B.I.T., V. V. Nagar, Gujarat, India 1 Lecturer, Electrical Dept., B.B.I.T. / GTU, V. V. Nagar, Gujarat, India 2 Lecturer & I/C Head Elect. Engg., Electrical Dept., B.B.I.T., V. V. Nagar, Gujarat, India 3 Lecturer, Electrical Dept., B.B.I.T. / GTU, V. V. Nagar, Gujarat, India 4 Abstract: People choose micro hydro-electric systems for a variety of reasons. Environmental motivations are very common. In situations where the resource exists reasonably close to the end use, and pipeline and transmission distances can be moderate, hydro-electricity may be more economical than tapping other renewable resources. Micro hydro-electric systems can eke a large amount of energy out of a small water flow with minimal impact. Because they run 24 hours a day, these systems can be low-wattage while generating enough energy to make a big dent in a typical home s energy use, and, in offgrid systems, even minimize or eliminate the need for having batteries. While care needs to be taken not to impact wildlife, micro hydro-electric systems can be unobtrusive, use only a portion of stream flow, and quietly produce clean electricity with almost no ongoing impact. While all energy generation and use has some impact, it s instructive to compare the impact of grid sources such as coal, oil, and nuclear with renewables. If we had a truly level playing field, where all players had to take their cost, embodied energy, and environmental impact into account, small hydro systems would likely be shown to have the least impact. A combination of a solid resource, a well-designed system, good maintenance, available incentives, and utility costs may even make a compelling economic argument to tap that stream on your property. Micro hydro systems can, at a minimum, save you dollars, while providing clean, reliable electricity. These systems can make you entirely independent of the grid, or they can be connected to the grid, allowing you to sell back surplus electricity for a credit and providing backup when the utility fails, giving you the best of both worlds. Additional benefits include that maintenance is done at ground level (unlike wind) and the system s production is around the clock (unlike wind and solar). If you want a reliable electricity supply, it s hard to beat a micro hydro system. This paper is focusing on Micro hydro, a run-of-river application which does not require dam or reservoir for water storage. It is cost effective, environmentally friendly and the turbine can be manufactured locally. Several applications in developing countries are highlighted. Small-scale hydro turbines are reviewed and their applications at power production environment. In this paper an attempt is made to discuss a methodology on development & operation of Micro hydropower projects for running the generator and use to light up the house are common to rural folks. Use of other alternative renewable energy modules, All rights reserved by ISSN :

2 which is available for a number of hours per day, It is required to find suitable option to provide cheap and reliable option. Keywords: Alternative Energy, Energy storage, Permanent Magnet DC Generator, Micro-Hydro Generation System, Small-scale hydropower, turbine, run-of-river, Renewable Energy I. INTRODUCTION The hydroelectric power is the principal source of electric power in some 30 countries, and provides about one fifth of the world's annual electrical supply. Its power stations include some of the largest artificial structures in the world. The water flow inside the pipelines has potential of kinetic energy to spin small scale generator turbine for electricity generation. The electricity can be generated at the same time those usual activities are done without extra charge on the water bill consumption. The classification of hydro power plant on the basis of different aspect is done. a.) Classification according to the availability of head: 1) Low head power plants (<10m) 2) Medium head power plants (10-50m) 3) High head power plants (>50m) b.) Classification according to the nature of load: 1) Base load power plants 2) Peak load power plants c.) Classification according to the quantity of water available: 1) Run-off river plant without pondage. 2) Run-off river plant with pond age. 3) Storage type plants. 4) Pump storage plants. 5) Mini and micro-hydel plants. Figure 1: General & actual layout with some Micro hydro installation (sources: d.) Classification based on the power development by the plant: 1) Large hydro plant. (>100MW) 2) Medium hydro plant. (15-100MW) 3) Small hydro plant. (1-15MW) 4) Mini hydro plant. (>100KW) 5) Micro hydro plant. (5-100KW) 6) Pico hydro plant. (>5KW) e.) Classification based on the purpose: 1) Single Purpose 2) Multi Purpose II. DEFINITION OF MICRO HYDRO POWER TECHNOLOGY Micro hydro is a type of hydroelectric power that typically produce up to 100 kw(100 to 1,000 kw) of electricity using the natural flow of water. These installations can provide power to an isolated home or small community, or are sometimes connected to electric power All rights reserved by ISSN :

3 networks. There are many of these installations around the world, particularly in developing nations as they can provide an economical source of energy without the purchase of fuel. III. COMPONENTS & WORKING OF MICRO HYDRO The basic idea with micro hydropower is to convert the energy of falling water from some height to electricity. The micro hydropower plants visited in Lao PDR were of the run of the river type, which is illustrated in figure 3.1. A weir is blocking the river and some of the water is led through an intake to the canal. The canal brings the water to the fore bay from where the penstock starts, which the water falls through to the powerhouse. A turbine in the powerhouse converts the potential energy of the water to mechanical energy that drives the generator, which in turn produce electricity. Afterwards the water is returned to the river. Construction details of a micro hydro plant are site-specific. Sometimes an existing mill-pond or other artificial reservoir is available and can be adapted for power production. In general, micro hydro systems are made up of a number of components. The most important include the intake where water is diverted from the natural stream, river, or perhaps a waterfall. An intake structure such as a catch box is required to screen out floating debris and fish, using a screen or array of bars to keep out large objects. In temperate climates this structure must resist ice as well. The intake may have a gate to allow the system to be dewatered for inspection and maintenance. The intake then tunnels water through a pipeline (penstock) to the powerhouse building containing a turbine. In mountainous areas, access to the route of the penstock may provide considerable challenges. If the water source and turbine are far apart, the construction of the penstock may be the largest part of the costs of construction. At the turbine, a controlling valve is installed to regulate the flow and the speed of the turbine. The turbine converts the flow and pressure of the water to mechanical energy; the water emerging from the turbine returns to the natural watercourse along a tailrace channel. The turbine turns a generator, which is then connected to electrical loads; this might be directly connected to the power system of a single building in very small installations, or may be connected to a community distribution system for several homes or buildings. Figure 2: Float flow measurement installation for micro hydel plant (Sources: Usually micro hydro installations do not have a dam and reservoir, like large hydroelectric plants have, relying on a minimal flow of water to be available year-round. Measuring Water Flow Rate : All rights reserved by ISSN :

4 The first step in determining the hydro power potential of a water source is to measure the flow rate. It has been defined as the quantity of water flowing past a point at a given time. There are several methods available to measure water flow rate such as salt dilution method, bucket method, weir method and so on. However, in mountainous region such as that of Nepal salt-dilution method of determining the head is the most common one. The salt dilution method is especially appropriate in this case because most of the water source used for the MHS (Micro Hydropower System) is small flow stream. Salt 24 dilution method is thought to be accurate and quick in cases of shallow mountain streams such as in our case. Measuring Potential Power and Energy : According to the Bernoulli energy equation, energy in water is stored in terms of pressure energy, velocity energy and elevation energy. The actual power that can be generated from the given source of water is thus, P=ρ.g.H.Q.η (1.1) Where, P = electrical or mechanical power produced, W ρ = density of water, kg/m3 g = acceleration due to gravity, m/s2 H = elevation head of water, m Q = flow rate of water, m3/s η = overall efficiency of MHs(Micro Hydropower system ) It can be seen clearly from the equation that the power generated by the water available depends upon the flow rate of the water, elevation head (elevation difference between intake and exit of water), and gravitation force, density of water and efficiency of the hydropower system. The goal of the hydro power is to convert the available water energy into mechanical or electrical energy. Figure 3: Construction element for Micro Hyde plant (Sources: Construction of Intake Weir: The water that enters through the intake is optimum both during the high river flow (monsoon) or the low river flow (summer) seasons. The weir may be of natural or of artificial construction. One important design parameter for the construction of intake weir is that its height should 26 be kept at minimum but enough to channel the required flow of water. Headrace Canal Design : The canal dimensions and cross section while designing the headrace canal are governed by various factor such as capacity, velocity of the water, slope of the side, head loss and seepage and the type of sediment disposition in the canal. Spillway Design: Spillways along the power channel are designed to permit overflow at certain points along the channel. The spillway acts as a flow regulator for the channel. During floods the water flow All rights reserved by ISSN :

5 through the intake can be twice the normal channel flow, so the spillway must be large enough to divert this excess flow. The spillway can also be designed with control gates to empty the channel. The spillway should be designed in such a manner that the excess flow is fed back to the without damaging the foundations of the channel. Construction of Settling Basin: The water diverted from the stream and carried by the channel usually carries a suspension of small particles such as sand that are hard and abrasive and can cause expensive damage and rapid wear to turbine runners. To get rid of such particles and sediments, the water flow is allowed to slow down in settling basins so that the sand and silt particles settle on the basin floor. The deposits are then periodically flushed. The design of settling basin depends upon the flow quantity, speed of flow and the tolerance level of the turbine (smallest particle that can be allowed). The maximum speed of the water in the settling basin can thus be calculated as slower the flow, lower is the carrying capacity of the water. The flow speed in the settling basin can be lowered by increasing the cross section area. Forebay Tank: Having discussed the construction of the settling basin it should be noted here that the construction of the forebay tank is very much similar to the design of the settling basin. The only difference between the construction of the forebay tank and the settling basin is that the forebay tank is connected to the penstock pipes. Penstock Selection and Design The factors that need to be considered in designing and selecting the penstock material are briefly described in this section. The most important factor to be considered while designing the penstock pipe is the material to be used as a penstock. Usually mild steel and HDPE pipes are used in MHP (Micro Hydro Project). There are several factors to be considered when selecting material to be used in the penstock pipe. Generators: Synchronous generators are used in most MHP (Micro Hydro Project) because it has the ability to establish its own operating voltage and maintain frequency while it is operating in a remote location. Figure 4: Generator types with specifications & Protection (Sources: %20Hydro%20ekids%20Technical)%20Information.pdf Selection of Turbines and its Components : All rights reserved by ISSN :

6 The parameters that help in the choice of turbine are tabulated below in table 4. It is primarily the head measurement that determines the selection of a suitable turbine for a particular MHS (Micro Hydropower System). (Hydraulic Energy Program et al., 2004). For example, in cases where the head measurement is more than 50 meters, pelton or turgo types of turbines are chosen over others. Similarly, when the head measurement is in between 10 meters and 50 meters, cross-flow, turgo or multijet pelton types of turbine are preferred. In cases where the head measurement is lower than 10 meters, cross-flow turbine is preferred. The selection for reaction type of turbines is also made in a similar way, and these criteria are summarized in figure 3.6 Figure 5: Types of turbine for Micro hydro (Sources: %20Hydro%20ekids%20Technical%20Information.pdf) IV. SPECIFICATION & STANDARD The power to be generated for the MHP (Micro Hydro Project) is determined largely based on the demand of the local community (e.g. Pangrang Village Development Committee, 2010). Survey was carried out by Pangrang Village Development Commit-ted in 2010 to collect information regarding the demand for power in the locality and the villager s willingness to pay for the electricity supplied. In the demand survey the headcount of the villagers according to households and rural commercial demand such as for offices; schools and so on were also calculated. All rights reserved by ISSN :

7 Figure. 6: Micro hydro plant specification Sources: V. MICRO HYDRO POWER IN INDIA In the State of Uttarakhand, Uttarakhand Renewable Energy Development Agency (UREDA) is constructing MHPs for remote village electrification as well as for grid feeding. All rights reserved by ISSN :

8 Figure 7: Details of Micro hydro plant under construction in India (Sources: So far 44 MHPs of composit capacity 4.29 MW have been commissioned and more than 300 Villages & Hamlets have been electrified through these projects. Earlier the projects were constructing on turn-key basis but from year 2005, Govt. of Uttarakhand has decided to construct MHPs for village electrification on community participation. For construction of MHPs, tripartite Agreements have been signed between UREDA, Alternate Hydro Energy All rights reserved by ISSN :

9 Center (AHEC), IIT, Roorkee and Concern User Energy Committee (UEC). As per tripartite Agreement AHEC, IIT, Roorkee is providing technical specialized services for construction of MHPs, preparation of DPR etc. and UREDA is providing its services for monitoring, funding and guidance to UECs. The Ghatta is a traditional waterwheel with a vertical axis used extensively in the Himalayan region. The water generally hits the waterwheel from above while the axis of the waterwheel is vertical. The turbine (waterwheel) is made out of wood to enable simple building and repair techniques to be used. As a consequence of this design the traditional waterwheel have very low efficiency and power output (maximum 12 kw). VI. CONCLUSION AND SUMMARY PERFOMANCE The use of hydropower can make a contribution to savings on exhaustible energy sources (fossil fuels). MHP contributes to sustainable development by being economically feasible, respecting the environment (avoiding greenhouse gas emissions) and allowing decentralized production for the development of dispersed populations. MHP plants create local jobs for the monitoring of the operation of the plant. There are some common misconceptions about micro-hydro power that need to be addressed. With the right research and skills, micro hydro can be and excellent method of harnessing renewable energy from small streams. Figure. 8: Factors enhancing performance of Micro hydro plant in India (Sources: Figure 9 :strategy utilized for diffusion of MHP(Sources: Various approaches have been used to diffuse micro hydro the world over that varies according to All rights reserved by ISSN :

10 Local circumstances. Generally, the approach or strategy utilized for diffusion of MHP involved a Combination of the above stated aspects. REFERENCES [01] N. Smith and G. Ranjitkhar, Nepal Case Study Part One: Installation and performance of the Pico Power Pack, Pico Hydro Newsletter, April [02] P. Maher. Kenya Case Study 1 at Kathamba and Case Study 2 at Thima. Available: [03] P. Maher and N. Smith, Pico hydro for village power: A practical manual for schemes up to 5 kw in hilly areas, 2nd ed., Intermediate Technology Publications, May [04] J. Mariyappan, S. Taylor, J. Church and J. Green, A guide to CDM and family hydro power, Final technical report for project entitled Clean Development Mechanism (CDM) project to stimulate the market for family-hydro for low income families, IT Power, April [05] A. Williams, Pico hydro for cost-effective lighting, Boiling Point Magazine, pp , May [06] A. Harvey, A. Brown, P. Hettiarachi and A. Inversin, Micro hydro design manual: A guide to small-scale water power schemes, Intermediate Technology Publications, [07] H. K. Verma and Arun Kumar, Performance testing and evaluation of small hydropower plants, International Conference on Small Hydropower Kandy, Sri Lanka, October 2007 [08] Ministry of power, Government of India 2010 ( [09] Central Electricity Authority, New Delhi ( ) [10] Micro-Hydro Design Manual, A.Harvey et al., IT Publications Ltd, London 1993.A comprehensive technical guide to small-scale hydropower projects, focusing mainly on projects <500kW. It covers the whole topic from initial site survey, through to equipment selection and installation. [11] An international hydropower industry guide as compiled by The International Journal of Hydropower and Dams mainly oriented towards larger companies and projects. [12] The James & James database of Renewable Energy Suppliers and Services, holding the details of nearly12,000 renewable energy companies and organisations from around the world. [13] J. Mariyappan, S. Taylor, J. Church and J. Green, A guide to CDM and family hydro power, Final technical report for project entitled Clean Development Mechanism (CDM) project to stimulate the market for family-hydro for low income families, IT Power, April [14] Hydropower A handbook for Agency Staff. Environment Agency, May 2003A. [15] A. Harvey, A. Brown, P. Hettiarachi and A. Inversin, Micro hydro design manual: A guide to small-scale water power schemes, Intermediate Technology Publications, All rights reserved by ISSN :