MICRO HYDRO PROJECT PLANNING AND MANAGEMENT PRJ 002
MULTIPURPOSE MINI / MICRO HYDRO PROJECT PLANNING AND MANAGEMENT PRJ 002
NYAKINDA WALTER F17/10476/2003 SUPERVISOR: MR. WALKADE EXAMINER: DR. MANG’OLI...
They require considerably less funding and a shorter time to implement They permit the local population participation in all activities Since the site is usually next to the load centre, transmission distances are short Decentralised nature of these schemes coincide with the dispersed nature of rural population The interference with the environment is minimal They do not require elaborate civil works and the power generating equipment is relatively simple and can be locally manufactured
Project Feasibility A list of studies that should be undertaken:• Topography and geomorphology of the site. • Evaluation of the water resource and its generating potential • Site selection and basic layout • Hydraulic turbines and generators & their control • Environmental impact assessment and mitigation measures • Economic evaluation of the project and financing potential • Institutional framework and administrative procedures to attain the necessary consents
Components of a mini / micro hydro power scheme
Lateral Intake
Sediment Trap
Losses
Power produced can be calculated as follows:
P= ρ Q g H η Where: n ρ = specific water density [kg/m3] n Q = Discharge [m3/s] n H = "net head" [m] n g = acceleration due to gravity [m/s2] n H g = specific hydraulic energy of machine [J/kg] n η = turbine efficiency
Turbine Selection based on Head and Discharge
Cross-flow turbine
Synchronous generators The synchronous speed is given by: Nsync = 120 f P Where: f = frequency p = number of poles n
Asynchronous generators n
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These are simple squirrel-cage induction motors running at a speed directly related to system frequency. The generator is accelerated to a speed above synchronous speed. For stand-alone plants the generator must be supplied with reactive power. This is achieved by adding a bank of capacitors across the machine terminals.
Slip is given by:
S = Nsync – Nm Nsync Where: Nsync = synchronous speed Nm = motor speed
Nm = 120 f (1 - s) P The generating speed (Ng) is given by:
Ng = 120 f (1 + s) P
Typical efficiencies of small generators Rated power [kW] 10 50 100 250 500 1000
Best efficiency 0.910 0.940 0.950 0.955 0.960 0.970
Community ownership Programmes promoting the use of micro-hydro power in developing countries have concentrated on the social, as well as the technical and economic aspects of this energy source. Ø Technology transfer and capacity building programmes have enabled local design and manufacture to be adopted. Ø Local management, ownership and community participation has meant that many schemes are under the control of local people who own, run and maintain them. Ø
CASE STUDY - TUNGU-KABIRI MHP PROJECT n
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The site selected for the project case study was on River Tungu about 200Km north of Nairobi, and 12Km from Chuka town, close to Mbuiru village. About 200 members of this community came together and formed a commercial enterprise to own, operate and maintain the micro hydropower plant. Each individual bought a share in the company, with a maximum share value of about US$50. The members also contributed labour, dedicating every Tuesday for over a year to the construction work
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The day-to-day operations of the plant are managed by a 10-member community power committee The electricity is currently used mainly for microenterprises such as a welding unit, a batterycharging station, a beauty salon, a barber shop, photographic studio, video hall and some retail outlets. The scheme now distributes electricity over an area of 3 square kilometres.
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The canal length is 250m The penstock length is 20m Head height is 13.5m The facility is rated at 18 kW; it produces 18kW mechanical power or 14 kWe. Flow rate in canal is 200 l/s with an effective 180 l/s running a T12 cross-flow turbine. The cross flow turbine is connected to a 40 kW synchronous generator that produces 3-phase AC power.
MHP in Kenya
CONCLUSION n
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So far only a few mini hydro schemes have been realised, either as part of the national grid supply or as stand-alone systems for agro-industrial establishments or missionary facilities. Only few examples of community-based installations are known.
FURTHER WORK n
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It is expected that the recent liberalisation of the Kenyan power market will facilitate the engagement of private project developers and independent power producers in areas presently not sufficiently served by the national grid. The Ministry and the Kenya Bureau of Standards is preparing standards and code of practice to govern the installation and operation of SHP, this steps are expected to encourage the development of community based mini/micro hydro power initiatives
