96 MW SIPPI H.E. PROJECT Ringong ARUNACHAL PRADESH Preliminary Feasibility Report February 2015 TABLE OF CONTENTS CHAPTER DETAILS PAGE NO. CHAPTER I Executive Summary 3 CHAPTER II Background Information 11 CHAPTER III Project Area 16 CHAPTER IV Topographic & Geo-technical Aspects 18 CHAPTER V Hydrology 23 CHAPTER VI Conceptual Layout and Planning 30 CHAPTER VII Power Potential Studies 38 CHAPTER VIII Power Evacuation 41 CHAPTER IX Environmental Aspects 43 CHAPTER X Infrastructure 57 CHAPTER XI Construction Planning & Schedule 65 CHAPTER XII Economic Evaluation 70 CHAPTER – I EXECUTIVE SUMMARY CHAPTER I EXECUTIVE SUMMARY 1.1 INTRODUCTION Sippi Hydroelectric Project located in Upper Siang District of Arunachal Pradesh envisages a run of the river scheme with utilization of water of river Ringong for power generation and harnessing a head of about 150.0 M. The project with a proposed installation of 96MW (3X32 MW) would afford an annual energy generation of 414.09 GWH in a 90% dependable year. The tariff from the project would be Rs. 3.84 per unit (levelised). The diversion weir site is located at latitude 29°0’50.23’’ N & longitude 94°48’23.84’’E. The barrage site is approachable from Along-Migging-Tuting road at a distance of about 291 Km from Along and 289 Km from Yingkiong, Distt, Head quarter of Upper Siang District. The nearest rail head is located at Nagoan (Assam) and nearest airport is at Leelabari North Lakhimpur (Assam). 1.2 SCOPE OF WORKS SIPPI HE Project envisages construction of: • One no. 6.5 m diameter, 600 m long Diversion Tunnels with u/s coffer dam • 20m height Un-Gated Weir • Intake Structure with one gate • 3 nos. 100 m long De-silting basins of 8 m width and 12 m height. • One no. 6.5 m diameter D shaped concrete lined 1.5 km long Head Race tunnel. • One no. 15m diameter & approx. 30 m high Surge Shaft. • Three no. steel lined circular Pressure Shafts of 3.0 m diameter 200 m long each. • Surface Power House of size 70m x22 m x 3 5 m consisting of 3 Vertical Francis units of 32MW each. • Tailrace channel of about 500 m length 1.3 HYDROLOGY The river Ringong drains a catchment area of about 732 Sq Km at the proposed barrage site based on using the Google earth images. At present there is no Gauge Discharge data on Ringong Asi and in the absence of the Gauge discharge data in the catchment, water availability of pre feasibility study, for the proposed project has been computed by considering flow series of Yamne-I HEP on catchment area proportion basis. Accordingly the Design discharge is considered as 73.5 Cumecs and the installed capacity for this project has been worked out to 96 MW. The Annual energy generation in 90% dependable year has been worked out to 414.09 GWH considering 100% machine availability. The design flood for the 1:100 year frequency has been assumed as 5cumecs per square kilometer of the catchment which works out to 3660 Cumecs. 1.5 POWER EVACUATION ASPECTS The power generated from all the projects coming in the region like Sippi HEP, Pango HEP, Jidu HEP and Palsi HEP would be first pooled at Mosing Switchyard and then evacuated through 400 KV double circuit line either at Passighat or at Along for further evacuation to Northern Grid through HVDC link of PGCIL. 1.6 ENVIRONMENTAL ASPECTS The project is located in Ringong river catchment in Upper Siang district, Arunachal Pradesh. The total land requirement for the construction of the project would be about 40 Ha. Based on assessment of environmental impacts, management plans have to be formulated for catchment area treatment, compensatory afforestation and other environmental issues. These issues would be taken care of during preparation of DPR. 1.7 ESTIMATE OF THE PROJECT COST The project is estimated to cost Rs. 786.89 Cr. including IDC and transmission cost. The preliminary cost estimate of the project has been prepared as per guidelines of CEA/CWC. The breakup of the cost estimate is given below: Civil Work Rs. 435 Crores Electro Mechanical Works Rs. 180 Crores Sub total (Generation) Rs. 615 Crores Transmission Works Rs. 25 Crores Total (Hard Cost) Rs. 640 Crores Rs. 146.89 Crores IDC Grand Total Rs. 786.89 Crores 1.8 FINANCIAL ASPECTS As indicated above, Sippi HE Project with an estimated cost of Rs. 786.89 Crores (including IDC of Rs. 146.89 Crores) and energy generation of 414.09 GWH in 90% dependable year is proposed to be completed in a period of 5 years. The tariff has been worked out considering a debit equity ratio 70:30, 16% rate of return on equity, annual interest rate on loan at 11% and 10% of energy as Free Power to home state available after losses. The tariff has worked out to Rs. 3.84. 1.9 CONCLUSIONS Sippi HE Project involves civil works and can be completed in 5 years out of which 1.5 years required for infrastructure works. The project would afford energy of 414.09 GWH in a 90% dependable year. The cost per MW installed works out to be Rs. 8.19 Crores. SALIENT FEATURES OF SIPPI HE PROJECT 1. Location State Arunachal Pradesh District Upper Siang River Ringong Location of Barrage site Latitude 29°0’50.23”N Longitude 94°48’23.84”E Location of Power House Latitude 29°0’30.06”N Longitude 94°49’8.28”E Nearest big rail head Nagoan (Assam) Nearest Airport Leelabari (North Lakhimpur) 2. Hydrology Catchment area 732 km2 Design flood in 100 yrs 3660 cumecs 3. Diversion Tunnel Diameter & shape 1no 6.5m dia D-shaped Length 600m Diversion discharge 120 cumecs (Non-monsoon) Diversion tunnel one gate (6.5m x 6.5m) 4. Coffer Dam Type Rock fill with central clay core Max. height of u/s coffer dam 10.0m Max. height of d/s coffer dam 5.0m 5. Weir Type Concrete Gravity, Un-gated Weir Weir Crest and Pond Level El + 880.00m River bed level at barrage site El + 860.00m Weir height ( river bed level – 20m Crest level of weir) Length of barrage 120 m Scour sluice: Nos. of size of opening (wxh) 4nos of 4.5 x 4.0 m each Maximum Flood Discharge 3660 Cumecs Maximum Flood lift over crest 6 m U/s Maximum Flood Level EL + 886.00 m T B L EL + 890.0 m 6. Intake Numbers One Invert level El 863M Size of gate 6.0m x 6.0m Design discharge 73.5 cumecs plus 14.7 cumecs provision for silt exclusion. Total 88.20 cumecs 7. De-silting arrangement Nos. type and size of de-silting 3nos. Dufour type each 100m long, 8m basins wide and 12m height Total design discharge in each 30.0 cumecs (including 20% flushing) chamber Particle size to be removed ≥0.2mm 8. Head Race Tunnel Numbers One Size & type 6.0m, D shaped, concrete lined. Design discharge 88.2 cumecs Length 1.5 km Adits 1nos. 4.5m D-shaped 9. Surge shaft Size & type 15m diameter, Restricted orifice Vertical shaft height 30m 10. Pnstock Numbers 3 Type Steel lined Diameter 3.0m Penstock length 200m 11. Power House complex Type Surface Minimum tail water level at outlet 730.0m Turbine axis elevation 730.0m Type of turbine Vertical Francis Generating Units 3 x 32 MW Gross head 150m Rated net head 145m Power house size 70 m x 22 m x 35m 12. TRC Numbers One Size & type Open channel, concrete lined Length 500m 13. Switch Yard Type, size Surface, 100 m x 100 m Power generation Installed capacity 96MW (3x32MW) + 20% COL Energy generation in 90% 414.09 GWH dependable year 14. Cost Estimates & Financial aspects (Rs. In Crores) Civil works Rs.435 Crores Electro Mechanical works Rs.180 Crores Subtotal (Generation) Rs.615 Crores* Transmission Works Rs.25 Crores Total (Hard Cost) Rs.640 Crores IDC Rs.146.89 Crores Grand total Rs.786.89 Crores *Total cost is exclusive of R&R/Land cost CHAPTER – II BACKGROUND INFORMATION Conceptual planning of the project After carrying out site visits and based on the geology of various sites, topography of area etc., the following has been firmed up in the preparation of this PFR. i. Location of Weir: At EL +860 M. river bed level with Crest Level of 880.0 M ii. Location of Powerhouse: At EL +730 M.( Normal TWL) The locations of Weir and power house are preliminary in nature and shall be subject to review at the stage of detailed investigations. > A preliminary conceptual layout & planning of the project has been attempted by the project based on the availability of topo-sheets and Google Maps incorporating weir and Power House locations, HRT alignment and TRC outfall, diversion etc. > Preliminary design feature: Weir: The project is envisaged to have a 20 meter high Un-Gated weir from river bed of about EL ± 860 M. The site has been selected as the valley is narrow and the river bed is geologically sound rock. The length of weir required to dispose the maximum flood discharge of 3660 cumecs is 120 M. The crest level/Pond level is fixed at ± 880 M. The maximum flood level at the weir is EL + 886 M, Considering a free board of 4 M, the T B L is fixed at EL + 890 m. Intake Structure: The Intake Structure is located on the on the right flank of the river. The sill level of the Intake is kept at EL + 863 m.