Nenskra Hydropower Plant Project

The Nenskra HPP powerhouse will house three vertical Pelton turbines of 93 MW capacity each and with 280 MW total installed capacity. Generated power will be transmitted to a Gas Insulated Substation (GIS Substation) and through the transmission line will be connected to the country's power grid.

Water flow of 47.0 m/sec will be transferred through a 15.1 km long and 4.5 m wide headrace tunnel to the turbines. In the close proximity with the HPP powerhouse, the headrace tunnel will branch into three separate penstocks to connect to the turbines. Water is transferred to a tunnel through a water intake located on the left bank of the reservoir creating a 130 m high asphalt faced-rockfill dam. The dam will be raised about 5 km off the village of Tita up the narrow gorge of the Nenskra river creating a live storage of 3,176 million m³. From the reservoir, water is to be supplied into the headrace tunnel. To improve the energy scheme, three low-pressure dams will be constructed in the Nakra river valley. Out of the created reservoir, 45.5 m/sec additional water is to be discharged into the Nenskra reservoir through a transfer tunnel allowing the Nenskra HPP to produce 1,219 GWh yearly.

The powerhouse of Nenskra HPP is planned on the left bank of the Nenskra river on the edge of village Chuberi. The power unit will consist of the HPP powerhouse and near-located GIS substation.

The main structures of the Nenskra dam are to be a 125–130 high and 870 long dam on the upper Nenskra river to create a live storage of 176 million m³ and a reservoir area at supply level of 2.7 km². The dam will capture the flows of the Nenskra river and the adjacent Nakra river upstream of the existing Khudoni HPP reservoir, exploiting the available head of 725 m.[4]

The Nakra Weir is 8.7 m high and 44 m long located on the Nakra river and is built for impoundment and diversion.

The Nakra transfer tunnel connects the Nakra valley with the Nenskra valley and is approximately 12.5 km long by 3.5 m in diameter and will divert water from behind the Nakra weir and into the Nenskra reservoir.

The Nenskra headrace tunnel follows the left bank of the Nenskra valley and is about 15.1 km long by 4.5 m wide. The tunnel connects to the surface penstock upstream of the Powerhouse at a level around 600 m above valley floor level.

The power unit will include the HPP powerhouse, tailrace for discharged water and GIS substation.

Water will be supplied from the intake of the headrace tunnel to the end of the penstock. The penstock starts from the surge, which then transfers into the turbine tunnels. Waste water will be discharged into the Nenskra river by tailrace.

During the operation, 3 units of Pelton turbine type electromechanical plants, each with installed capacity of 93MW will be installed.

To defend from the probable maximum flood, the diversion tunnel dimensions are designed to deal with probable maximum discharge of 1 101 m/sec that is 3.67 times as much as expected discharge of 300 m/sec with the rate of once in 10000 years.

According to the previously drawn up plan the reservoir will capture the flow slowly and gradually (layer by layer). The dam will operate in the natural regime of the river through a bottom outlet to keep the water at the level of 1 370 m.

In 2015, the Nenskra Hydropower Project submitted the final Environmental & Social Impact Assessment Report (ESIA) to the Government of Georgia (GoG) as part of the national environmental permitting process.

The 2015 ESIA report has been prepared by Gamma Consulting Limited, a Georgian consultant, based on field investigations undertaken in 2011 and 2014 and following the public consultations held in May 2015. The Environmental Permit was issued by the Environmental Authorities in October 2015.

Several International Financial Institutions (the Lenders) have been approached to finance the Project. To ensure compliance with their Environmental and Social (E&S) policies, the Lenders recommended that a number of Supplementary E&S Studies be undertaken.

In 2017 the supplementary studies-based report consisting of ten volumes was disclosed to the general public. The report is available at JSC Nenskra Hydro web-site.[5]

Based on the research made JSC Nenskra Hydro has prepared The Environmental and Social Impact management Plan. The plan aims at implementing mitigation measures during the construction and operation in compliance with Georgian legislative requirements and international standards.

Disclosure of the report has started in March 2017. During the disclosure period JSC Nenskra Hydro should introduce the relevant report data to the general public of Georgia, Nenskra and Nakra valleys communities, NGOs, Government of Georgia and other stakeholders.[6]

According to the National Statistics Office of Georgia, JSC Nenskra investment was among the 2015 direct investments Top 10.[7]

The Nenskra HPP Project will create jobs for the local population both during the construction and operation. 100% of unskilled labor will be represented by residents of the Nenskra and Nakra valleys. 75% of partly unskilled labor will be provided by Georgians, out of whom 50% will be residents of Mestia.

In 2016, the project company conducted a study to identify the needs of the local residents. With the study findings and needs of the population in view, the project company launched a community investment program with the following goals:

• create jobs for the local population through support and strengthening of local business
• develop and reinforce the village areas through encouraging of agricultural business and collective farms
• increase involvement of the population into economic and social activities
• contribute to market and touristic business in the Nenskra and Nakra valleys

Some 400 families live in close by villages (Chuberi and Nakra). The majority are Svans, an ethnic subgroup of Georgia's Caucasus mountains with their own language, laws and traditions. The traditions, culture, and identity of the Svans' is rooted in their mountain location. For generations, they have lived in isolation and self-dependence and their livelihoods depend on forestry, grazing and subsistence agriculture.[8] Approximately 28 households will be affected by the project's land acquisition phase, either through permanent loss of land or temporary loss of access to pastures near the dam and reservoir sites.[9]

"[From a] nature preservation point of view, not all of these larger [rivers] like Enguri and smaller rivers like Nenskra and Nakra should be used for hydropower generation." Prof. Dr. Frank Schrader, International Consultant on Hydropower, in his review of the Nenskra ESIA.[10]

The project site was originally proposed to be included within the European system of protected areas as the ‘Svaneti 1’ Emerald site. In January 2016 the Georgian government attempted to exclude all territories to form part of the planned Nenskra project, without providing any evidence that the Nenskra and Nakra valleys are less important in terms of biodiversity than the rest of the Svaneti region. This resulted in a complaint to the Berne Convention on the Conservation of European Wildlife and Natural Habitats for a violation of a number of articles of the convention.[11]

The dam construction will also include constructions of bypass and access roads, high voltage transmission lines and substations. These construction may increase landslides. An indirect result of this project is also the increased chance of flooding because of the mudflows. These mudflows have the potential of blocking the Nakra river, creating flooding upstream. Svaneti is a landslides and mud-flows sensitive area. The local cemetery and agricultural fields of the village of Nakra are regularly flooded by mud-flows. These mudflows have the potential of blocking the Nakra river, creating flooding upstream. Yet according to a review of the Nenskra Environmental and Social Impact Assessment (ESIA), the geologic hazards and potential adverse impacts on locals have not been properly evaluated.[11]