Sillahalla Pumped Hydro-electric Storage Project (SPHESP)

Why in NEWS ?

• The mountainous Nilgiris district in Tamil Nadu is now witnessing an ecosystem collapse mainly due to extreme weather events. Floods that are happening almost every year are causing major landslides and slope destabilisation. The last remaining wild spaces are shrinking as illegal constructions and large-scale encroachments are turning contributing factors in this damaged Western Ghats stretch.

About

• Among the ecologically fragile areas of the district which are prone to the annual floods and landslides, the Kundah taluk region, located about 24 km from district headquarters at Ooty, is the most vulnerable.
• The extreme precipitation event (2400 mm of rainfall over four days) that happened in August 2019 had caused hundreds of landslides in Kundah watershed region alone. During the 2020 rainy season, 457 people lost their homes in landslides and deluge.
• Kundah village along with Kallakorai, Manjoor, Kattadimattam, Thuthalai, Kanneri, Thangadu, Oranalli, Meekeri, Muthorai Palada and Balocola would be affected in the coming years once the storage reservoir of a controversial mega hydel power project is a reality.
• The power project, which is projected to cost Rs 49.52 billion, is now under implementation and threatening to cause further collapses and destabilisation of the highly vulnerable Western Ghats region
• Other than causing irreparable damage to the flora and fauna of Nilgiris, the project is now being viewed as a major threat in terms of large scale livelihood destruction and rendering of a large number of agrarian families homeless.
• The only temporary reprieve is the Union government’s recent decision to conduct an environmental impact assessment study and public hearings involving locals and environmentalists before allowing the state government to proceed with the project.

Sillahalla Pumped Hydro-electric Storage Project (SPHESP)

• It is located in Nilgiris district of Tamil Nadu.
• It has installed capacity of 1,000 MW with 4 units of size 250MW each.
• Total cost of the project is Rs 4,200 cr (approx)
• It is Pumped Storage Type Project
• The upper dam is located on Sillahalla stream which is tributary of Kundah River.

How does a pumped storage hydropower plant work?

• Here, the turbine acts as a pump, moving water back uphill.
• During periods of high electricity demand, the stored water is released through turbines.
• A pumped-storage plant works much like a conventional hydroelectric station, except the same water can be used over and over again.

Need for the project

1. Tamil Nadu and Tamil Nadu Generation and Distribution Corporation Limited (TANGEDCO), do not have reliable hydro potential of this scale. Hence, Sillahalla Pumped Storage is the only feasible alternative available.
2. In view of mandatory large injection of renewable in to the grid in near future, Tangedco needs advance planning to integrate it and Sillahalla can be useful in this regard.
3. Pumped Storage is the natural battery with longer useful life and environmental friendly proposition of Energy Storage.
4. There is a precedence and current trend in favor of Pumped Storage projects. West Bengal has already constructed Purulia PSP (900 MW) and Turga PSP (1000 MW) is now under pre-construction.

How Project is causing damage?

• The Tamil Nadu Generation and Distribution Corporation Limited (TANGEDCO), the Sillahalla Pumped Storage Hydro-Electric Project (SPSHEP) aims at construction of an upper reservoir measuring more than 260 feet in height in Bembatty village along the Sillahalla stream, a tributary of Kundah River, a major feeder of state’s second- largest river Bhavani. A lower reservoir with more than 350 feet in height will be built further downstream, past the existing Kundah Dam.
• A 2.8 km head race (bringing water to the powerhouse from the upper reservoir) and a 1.56 km-longtail race tunnel (taking water from the powerhouse to the lower reservoir), with a diameter of nearly 10 metres, would be constructed to connect the two dams. Electricity would be generated by pumping water from the lower dam to the upper dam, says the project report.
• The Sillahalla hydroelectric project seeks not only to dam the Sillahalla but also to interconnect the proposed dams with the nearby Avalanche-Emerald Reservoir, which is also located at the same level. The project also includes construction of both a surface storage point and an underground power house.
• As per TANGEDCO’s own estimate, the proposed project will apparently submerge more than 315 hectares of forest, private and government lands once the reservoirs turn fully functional.
• Nearly 800 acres of rich green cover will be submerged in water if the project is implemented fully. In addition, more than 10,000 native people, mainly agrarians, will lose their nature-based livelihoods.
• As per TANGEDCO’s estimates, the project on completion will add 1,000 megawatts to the power grid for use during peak hours in Tamil Nadu, which presently struggles hard to address power deficiency.

Environmental concerns and protests

• With the government announcing the project’s implementation and the TANGEDCO refusing to even acknowledge the environmental and livelihood concerns, a large number of local residents and environmentalists have started sending online petitions in the recent days to the expert appraisal committee (EAC) of Union Ministry of Environment, Forest and Climate Change (MoEF&CC) seeking to reconsider the terms of reference (TOR) clearance for the Sillahalla hydroelectric project.
• In the given situation of environmental decline, it would be disastrous for the entire Nilgiris to undertake construction works of underground tunnels that stretch for kilometres. Such tunnels are already in existence in the case of the Kundah hydel power project which came up years ago. Now, yet another huge tunnel is going to be constructed along with a few minor ones. The tunnel along with two more dams of SPSHEP will further endanger overall safety and environmental sustenance of Nilgiris.
• At present, there are ten dams in the Kundah-Bhavani system and they have caused severe ecological impact in the case of Nilgiris. Now two new dams are being planned on tributaries of the river with significantly lessened water flow.
• On implementation, the dams and the tunnel would influence the ecology and hydrology of the Kundah watersheds. Diverting water from the catchments which witness high rainfall and changing the course of the water flow will further escalate the ecological and hydrological impacts that are already present,” Krishnan pointed out.
• Environmentalists say the area in which the Sillahalla Hydro Project coming up is contiguous to the Silent Valley National Park, the Mukurthi National Park and the Nilgiri forest division. It is widely regarded as a unique biodiversity rich eco-sensitive zone.
• Project site falls within the draft Western Ghats Eco Sensitive Area and the distance from here to Mukurthi National Park would be hardly 3.49 km. The distance to Mudumalai-Mukurthi tiger corridor is just 4.1 km.
• A thorough assessment of the possible impact of the hydroelectric project on the environment of Nilgiris must have been conducted before proceeding with the proposal as the ecology and environment of Nilgiri are very fragile. The project site is situated in an area that is rich in biodiversity and sustains a whole environmental ecosystem.
• The project site is home to endangered species of wildlife including Nilgiri tahr, Nilgiri marten, Nilgiri langur, Nilgiri laughing thrush, Nilgiri pipit, horseshoe pit-viper, rusty spotted cat, leopard cat, mouse deer, barking deer, dholes, leopards and tigers.

Toda Tribe

• Toda Tribe is a pastoral tribe of the Nilgiri Hills of southern India, which will be hugely impacted with the Sillahalla Pumped Hydro-electric Storage Project(SPHESP)
• The Toda language is Dravidian but is the most unusual and different among the languages belonging to the Dravidian family.
• They live in settlements of from three to seven small thatched houses.
• They traditionally trade dairy products, as well as cane and bamboo articles, with the other Nilgiri peoples.
• The traditional Toda dress is a distinctive shawl which is called putukuli. In the Toda language it is called pohor. It enjoys a ‘Geographical Indication Tag’.
• The embroidery is done by Toda women and has distinctive red and black (and occasionally blue) thread work in geometric designs on unbleached white cotton fabric

Nilgiri Biosphere Reserve

• The Nilgiri Biosphere Reserve was the first biosphere reserve in India established in the year 1986.
• It is located in the Western Ghats and includes 2 of the 10 bio-geographical provinces of India.
• Wide ranges of ecosystems and species diversity are found in this region. Thus, it was a natural choice for the premier biosphere reserve of the country.
• The Nilgiri Biosphere Reserve was established mainly to fulfill the following objectives:

1. To conserve insitu genetic diversity of species.
2. To restore degraded ecosystems to their natural conditions
3. To provide baseline data for ecological and environmental research and education
4. To function as an alternate model for sustainable development

• The total area of the Nilgiri Biosphere Reserve is 5,520 sq. km.
• The Nilgiri Biosphere Reserve encompasses parts of Tamilnadu, Kerala and Karnataka.
• The Nilgiri Biosphere Reserve falls under the bio-geographic region of the Malabar rain forest.
• The Mudumalai Wildlife Sanctuary, Wyanaad Wildlife Sanctuary Bandipur National Park, Nagarhole National Park, Mukurthi National Park and Silent Valley are the protected areas present within this reserve.