MICRO AND SMALL HYDRO ENERGY SYSTEMS

SUBMITTED BYPARAMJIT SINGH

Economic of Small Micro/Hydro Power Plants

• Introduction

• Economic evolution

• Financial aspects of Micro Hydro Plants

Cost benefit ratio and Annual Return

• 1) Operation and maintenance charges as 1% of total cost.

• 2) Annual depreciation calculated as per Indian

Electricity Act, 1948. • 3) Interest rate @ 8% of total cost and• 4) 0.5% generation reserves fund on total cost.

The Annual total cost fixed charge worked out to Rupees 30.802 Lacs.The net energy generatio after deduction of 1%Transmission losses and friction losses work out to3.3116 MKWH. Hence cost per unit generation work out to 93.0 paisa per unit

Measures to reduce the costs

1. The number of units should be limited to 2-3 to save the cost of Civil Engineering, cost of building, cost of Hydro-Mechanical equipments, duplication of control system, cabling etc.

2. Instead of going for full Kaplan one can use semi Kaplan where guide vanes are fixed and variation in water is obtained from runner blade operation. So simpler version of water level controllers can be used.

C. Reduction in time and civil work consideration

• a) Installation of prepackaged Turbine, pre assembled at the workshop to reduce time and cost of assembly at site.

• b) Use of siphons penstocks.

Conclusion

• Though it is observed that the Cost/ KW is high as compared to Large Hydro Projects and Micro/Pico Hydro Plant supplies power to very limited locality, a village can have its own micro Hydro Power Plant (HPP). The Panchayat can build, operate and maintain the HPP and village houses can consume the electricity

Pumps as Turbines

A pump-as-turbine (PAT) microhydro plant is just what it sounds like—the turbine is actually the impeller of a centrifugal pump “running backward” and the generator is simply the pump’s induction motor. PAT installations have been running reliably and efficiently for years. Utilities around the world also use the concept in massive pumped-storage installations. For village and household scales, the technology was pioneered by Arthur Williams in his book Pumps as Turbines

Pumps as turbines

Advantages

Low price, high availability.

Disadvantages

Limited efficiency

Steep efficiency characterictics

Poor or none regulation capabilities

Conclusion

Application of pumps in turbine operation instead of single or double regulated hydraulic turbines may be economically justified in case of stable hydrological conditions, low capacities and discharges.

Main research directions

identifying home manufactured impeller pumps suitable for energy generation purposes determining performance characteristics for specified series of types and establishing general relationships between bep parameters in both modes of operation low-cost modifications of the flow part geometry aimed at enhancing performance characteristics in turbine mode of operation

Pumps as turbines- typical application fields

oil and chemical industry

- decompression processes for gas/liquid separation

and washing/clearing chemical media

- hydrocarbon synthesis

micro hydropower plants

CONCLUSION1. The experience cumulated so far shows that pumps in turbine operationmay be sometimes a reasonable option for the purposes of hydraulicenergy recovery in industrial installations and electrical energy generationin some micro hydropower plants.2. While the simplified formulae used to assess bep parameters in turbiningregime basing on the pump mode performance data may be considered agreat help when planning a new installation, their limited validity shouldbe always kept in mind.3. Therefore it is highly desirable to encourage pump manufacturers to testat least some of the offered machines also in turbine mode of operation.Providing access to pump versions modified for the purpose of possible usein turbine mode of operation may further widen their markets andcontribute to better utilization of available SHP potential.4. The success of the energy recovery unit described in the previous sectionshows open possibilities for more rational energy economics even in caseof some critical industrial installations.