The Andhra Pradesh Power Generating Company Limited (APGENCO), an undertaking of the Government of Andhra Pradesh, is developing the project.
The project is estimated to cost INR118.81bn ($1.4bn), including price escalation and infrastructure development charges.
APGENCO submitted Terms of Reference (TOR) to the Ministry of Environment, Forest, and Climate Change (MoEF&CC) of the Government of India in April 2019 for getting environmental clearance.
The TOR was granted on June 2019 to conduct Cumulative Environmental Impact Assessment (CEIA) Study for the project.
A draft final CEIA study was prepared and published for the project in November 2022.
According to the study, the plant of the project will have an estimated design energy of 3,502 million units (MU) for a duration of about 8 hours and 10 minutes daily during a year.
In June 2023, the Central Electricity Authority (CEA) approved the Upper Sileru Pumped Storage Project.
Upper Sileru Pumped Storage Project Location
The pumped storage project will be located on Sileru River in Gudem Kotha Veedhi Mandal of district Alluri Sitarama Raju in Andhra Pradesh.
The site is near Sileru village, around 200km from Visakhapatnam.
The project site is accessible via Rajahmundry airport located about 200km from the site and Narsipatnam rail head located about 110km from the site. The site can be reached via a road from Vishakhapatnam to the site.
The total forest and non-forest land required for the project are estimated to be 215.44 hectares (ha) and 117ha respectively.
Upper Sileru Pumped Storage Project Components
The proposed Upper Sileru Pumped Storage Project will have an approach tunnel of about 138m in length to feed the water required to the number three intake tunnel.
The intake tunnel will draw needed water through three headrace tunnels of 12m diameter each. The intake tunnel will be provided with a trash rack and gates.
The three headrace tunnels of about 2,768m in length will be constructed from the downstream of the intake structure to the upstream surge shaft. The distance between each headrace tunnel will be 75m (c/c).
The upstream surge shaft, open from above, will be constructed about 2,768m downstream of the intake structure. The bottom of the shaft is proposed at El 357m, and the top is proposed at El 440m.
From the shaft, nine 6m diameter pressure shafts will feed nine Francis turbine machines of the powerhouse. The nine pumps and turbines will have an installed capacity of 150MW each.
The powerhouse is proposed on the left bank of the Sileru River and above the ground with the deepest excavation level of El 265m, El 330m service bay, and the centre line of the pump or turbine at El 281.50m. It will be located about 358.75m downstream of the upstream surge shaft.
The powerhouse will supply electricity to the pothead yard via bus duct shafts. Transformers will be housed in the transformer hall.
A downstream surge shaft is proposed about 73.5m downstream of the powerhouse. The shaft will receive nine draft tube tunnels and three number of tailrace tunnels will arise from the shaft. El 269m will be the bottom elevation of the surge pool and El 334m will be the upper elevation near the existing ground level.
The three tailrace tunnels about 2,465m in length and 12m in diameter each will be located from the downstream surge shaft to the outlet structure near Donkarayi reservoir with a desirable riverbed availability.
A coffer dam is proposed to separate the construction area from the reservoir or river and construct an intake structure and approach channel in the Guntawada reservoir and outlet structure.
The project will be constructed within 60 months as proposed in the CEIA study.
Upper Sileru Pumped Storage Project Operations
The Upper Sileru Pumped Storage Project will involve the re-utilisation of water of the Guntawada reservoir.
The reservoir will act as the upper reservoir for the project and currently, its water is being used for generating power at the existing hydroelectric power station. It is operating and has a live storage capacity of 3.108 thousand million cubic feet (TMC).
The Donkarayi reservoir near the Donkarayi village will be the lower reservoir for the project and will operate as a peak station. Currently, it is also operating and has a live storage capacity of 13.30 TMC.
Contractor Involved
WAPCOS, a wholly owned central public sector enterprise under the Ministry of Jal Shakti, Government of India, was selected by APGENCO to prepare the CEIA study for the project.
