FAQ.

Frequently Asked Questions (FAQs) on Hydropower        Ø      How much is the world’s electricity supplied by Hydroelectric Power Plants? Ø      What are the different types of Hydroelectric Power Plants? Ø      What are the major components of a Hydroelectric Power Plant? Ø      What is the classification of Hydro Projects based on Installed Capacity? Ø      How energy is generated in Hydroelectric Power Plant? Ø      Which is the largest Hydropower station in the world? Ø    How does cost of generation from Hydropower Plant compare with other sources of electricity? Ø      Why hydropower is called renewable source of energy? Ø      Which is the oldest Hydropower Plant in India? Ø      What is the estimated total Hydropower potential of India? Ø      How much of the total Hydro power potential has been exploited so far in India? Ø      What are the different types of dams? Ø    Why the unit sizes of hydro generating machines are not standardized as in case of thermal power plants? Ø      What is the record completion period of a Hydro Power Station in India of more than 100 MW? Ø      Which Hydro Station has been completed recently which has the lowest tariff rate? Ø      What are the different types of Hydro Schemes? Ø      Which is the largest Operating Hydro Power Station in the World? Ø      What are the major reasons for balancing Hydro-thermal mix? Ø      Why Hydropower stations are preferred solution for meeting peak loads in grids? Ø      What are approaches to tackle sedimentation problem of reservoir? Ø      What are the effects of sedimentation in Hydropower stations? Ø      What are the major thrust areas in the field of Environmental Conservation & Management for developing hydropower? Ø      Do Hydropower projects involve large submergence of land? Ø      Does development of Hydropower project leads to large scale displacement? Ø      Do Hydropower projects cause huge destruction of forests? Ø      What is the project Cost and how it is funded?. Ø      What is the standard debt equity ratio for financing a hydropower project? Ø      Why, in the financing of project cost, Equity component is kept lower than Debt? Ø      What are the main sources of Debt and Equity? Ø      What are the objectives of Tariff Policy of Govt. dated 6.01.2006? Ø      What is Availability Based Tariff (ABT)? Ø      What are the components of Bulk Electricity tariff of Hydro Plants? Ø      How much Return on Equity is allowed to Hydro Generating Stations? Ø      What are the ‘pass through’ components in the tariff of Hydro Generating Stations? Ø      What is Net Present Value (NPV)? Ø      What is Internal Rate of Return (IRR)? Ø      What are the benefits of hydropower projects?  Frequently Asked Questions (FAQs) on Hydropower  How much is the world’s electricity supplied by Hydroelectric Power Plants? ± 2700 TWH is generated every year.  Hydropower supplies at least 50% of electricity production in 66 countries and at least 90% in 24 countries. What are the different types of Hydroelectric Power Plants?  There are basically four types of power plants: -  1.      Pelton turbines - It is impulse turbine which is normally used for more than 250 m of water head. 2.      Francis - This is a reaction turbine which is used for head varying between 2.5m to 450m 3.      Kaplan – It is propeller type of plant with adjustable blades which are used for heads varying between 1.5 m to 70 m 4.      Propeller – It is used for head between 1.5 to 30 m 5.      Tubular – This is used for low and medium height projects. Normally for head less than 15 m.   What are the major components of a Hydroelectric Power Plant?  The major components of a Hydroelectric Power Plant are:- Dam/Barrage Head works i.e. power intake, head regulator and desilting chambers etc. Head race tunnels/channels Surge shaft/surge chambers Pressure shaft/Penstock Underground and surface power house Tailrace channel or tailrace tunnel.   What is the classification of Hydro Projects based on Installed Capacity?  Micro:  upto 100 KW  Mini:     101KW  to 2 MW Small:   2 MW to 25 MW Mega:    Hydro projects with installed capacity >= 500 MW              Thermal Projects with installed capacity >=1500 MW   How energy is generated in Hydroelectric Power Plant?  A hydroelectric power plant consists of a high dam that is built across a large river to create a reservoir, and a station where the process of energy conversion to electricity takes place. The first step in the generation of energy in a hydropower plant is the collection of run-off of seasonal rain and snow in lakes, streams and rivers, during the hydrological cycle. The run-off flows to dams downstream. The water falls through a dam, into the hydropower plant and turns a large wheel called a turbine. The turbine converts the energy of falling water into mechanical energy to drive the generator After this process has taken place electricity is transferred to the communities through transmission lines and the water is released back into the lakes, streams or rivers. This is entirely not harmful, because no pollutants are added to the water while it flows through the hydropower plant.  Which is the largest Hydropower station in the world?  Three gauges project in China on Yang-Yang river is the largest power station in the world having installed capacity of around 18,200 MW.  How does cost of generation from Hydropower Plant compare with other sources of electricity?  The hydro power generation is highly capital-intensive mode of electricity generation but being renewable source of energy with no consumables involved; there is very little recurring cost and hence no high long term expenditure.  It is cheaper as compared to electricity generated from coal and gas fired plants. It also reduces the financial losses due to frequency fluctuations and it is more reliable as it is inflation free due to not usage of fossil fuel.  Why hydropower is called renewable source of energy? Hydropower is called renewable source of energy because it uses and not consumes the water for generation of electricity, and the hydropower leaves this vital resource available for other uses.   Which is the oldest Hydropower Plant in India?  The oldest Hydropower power plant is in Darjeeling District in West Bengal.  It’s installed capacity is 130KW and was commissioned in the year 1897.   What is the estimated total Hydropower potential of India?  The hydro power potential of India is around 1,48,701 MW and at 60% load factor, it can meet the demand of around 84,000 MW.  How much of the total Hydro power potential has been exploited so far in India?  Around 19.9% of Hydropower potential has been exploited in India.  What are the different types of dams?  Different types of dams are conventional concrete dam, Roller compacted concrete dam, rock fill dam, Concrete Faced Rock fill Dam(CFRD), Earth fill dam, arch dam, barrages etc.  Why the unit sizes of hydro generating machines are not standardized as in case of thermal power plants?  Since the size of hydro generating machines are based on availability of water in river and the water head available at a particular project site, the size of the machines keeps varying from location to location and river to river. The sizes are also based on logistics and variation of water in river during the year.  What is the record completion period of a Hydro Power Station in India of more than 100MW ?  Chamera – II HE Project (300 MW) in Distt. Chamba, HP. has been completed in a record period is Four & Half years .  Which Hydro Station has been completed recently which has the lowest tariff rate?  Dhauliganga HE Project (280 MW)in the Distt. of Pithoragarh of Uttranchal  was completed in Nov. 2005.  It is selling electricity @ Rs.1.83 / Kwh to beneficiary States of Northern Region .   What are the different types of Hydro Schemes?  Different types of Hydro Schemes are : i.        Purely Run - of -  River Power Station. ii.       Storage type Power Station. iii.       Run – of – River Stations with Pondage.            Which is the largest Operating Hydro Power Station in the World?   The world’s Largest Hydro Electric Power Station is ITAIPU with installed capacity of 12600 MW and a reliable output of 75,000 MU in a year.  It is located at the Border of Brazil and Paraguay.   What are the major reasons for balancing Hydro-thermal mix?  Seasonal load curves of our regional grids match with the pattern of hydro power generation. During summer/monsoon season when the generation at hydro power plants is high, the load factor of the system is high due to heavy agricultural load. During winter, the thermal stations operating at base load and hydro stations working as peak load stations will take care of weather beating loads. Thus the operational needs of hydro & thermal stations are complimentary and the balanced mix helps in optimal utilization of the capacity. Why Hydropower stations are preferred solution for meeting peak loads in grids?  Due to its unique capabilities of quick starting and closing, hydropower stations are found to be economical choice to meet peak load in the grid.  What are approaches to tackle sedimentation problem of reservoir?  The following are some approaches to tackle sedimentation problem of reservoir:-  Catchment Area Treatment (CAT) for reduction of silt load includes forestations of the catchment area and constructions of check dams on the tributaries and upstream of the river. Effective desilting arrangements for prevention of silt. Silt resistant equipments of withstanding the silt. Effective operation of the reservoir to minimize silt deposition.   What are the effects of sedimentation in Hydropower stations?  The major effects of reservoir sedimentation are :  It reduces the active storage capacity, which may reduce the capability of the reservoir to deliver the benefits in course of time. It makes the flood management in the reservoir more difficult. Damages to turbines and other under water parts due to abrasive action of silt.   What are the major thrust areas in the field of Environmental Conservation & Management for developing hydropower?  Following safeguards/management plans are implemented at various NHPC projects to ensure development of hydropower in an environmentally sustainable manner:           Compensatory Afforestation in lieu of forest land diverted for the project.          Catchment Area Treatment (CAT) to minimise erosion in the catchment of the reservoir, thereby reducing siltation in the reservoir.       Resettlement & Rehabilitation of Project Affected Population.     Restoration of Dumping Sites and Quarry Sites using engineering and biological measures.      Reservoir Rim Treatment plan to stabilise reservoir periphery.      Conservation measures for flora and fauna, to conserve flora and fauna native to the ecosystem of the area.      Subsidized Fuel Distribution to worker population and project affected population to minimise fuel demands on the adjacent forests.      Health Management Plan for the worker population and affected population to prevent epidemics and maintain optimum health standards.     Fishery Management by construction of fish ladders wherever possible, to enable migration of fishes and by promoting reservoir fisheries.Green Belt Plan to make the surroundings of project construction areas green.       Dam Break Analysis and Disaster Management Plan for downstream areas vulnerable to flooding in case of Dam breach.  Do Hydropower projects involve large submergence of land?  Submergence of land, thereby loss of flora and fauna and large scale displacement, due to the hydropower projects is sometimes exaggerated. The following table shows that project catering only to hydro power needs, cause little submergence.  A sample of following 12 projects contributing 6231 MW of power required submergence of only 4850 ha of land i.e. the  area of  submergence per MW is only 0.78 ha.   Sl. No Name of the project State Capacity (in MW) Submergence area    ( in ha) 1 Chamera-I H.P. 540 975 2 Chamera-II H.P. 300 25 3 Chamera-III H.P 231 29.90 4 Parbati-II H.P. 800 27 5 Parbati-III H.P 520 21.61 6 Tanakpur Uttarakhand 120 140 7 Dhauliganga-I Uttarakhand 280 29 8 Rangit Sikkim 60 13 9 Teesta-V Sikkim 510 68 10 Uri J&K 480 Nil 11 Dul Hasti J&K 390 85 12 Subansiri Lower Arunachal Pradesh 2000 3436 Total 6231 4849.51 ~  4850   Does development of Hydropower project leads to large scale displacement?  This is not always true. The details of the affected families in some of the NHPC’s commissioned Power Stations and under- construction / proposed projects are given below:    Sr. No. Name of the project Installed capacity (MW) No. of families displaced No. of  families partially affected Total number of affected families 1 Uri Power Station, J&K 480 121 350 471 2 Uri-II HE project, J&K 240 46 85 131 3 Nimoo- Bazgo H.E. Project, Leh, J&K 45 Nil 19 19 4 Chutak H. E. Project, Kargil, J&K 44 Nil 105 105 5 Tanakpur Power Station, UK 120 60 100 160 6 Chamera Power Station Stage I, H.P 540 1174 380