Srinagar, Nov 9 (KNS): The proposed transmission plan for evacuating renewable energy from Ladakh has been revised after the earlier High Voltage Direct Current (HVDC) project was found technically unfeasible due to extreme high-altitude conditions, equipment-related challenges and other technical constraints, according to the minutes of a Special Meeting of the Northern Regional Power Committee (NRPC).

The revised proposal envisages an Extra High Voltage Alternating Current (EHVAC) transmission system for integrating 7.5 GW of renewable energy from Ladakh, comprising 3.75 GW of solar capacity and 3.75 GW of battery energy storage capacity for four hours to support power supply during non-solar hours.

The proposal, discussed at the NRPC meeting held on October 27, carries an estimated cost of Rs 31,427.54 crore and has an implementation timeline of 48 months from the date of award.

The minutes reveal that the original Green Energy Corridor Phase-II proposal, approved by the Union Cabinet in 2023, envisaged evacuation of 13 GW of renewable energy from Ladakh, comprising 9 GW of solar and 4 GW of wind power, supported by a 12 GWh Battery Energy Storage System.

Under the original plan, a 5 GW transmission link was proposed between Pang in Ladakh and Kaithal in Haryana through a Voltage Source Converter-based HVDC system.

However, the bidding process could not be concluded due to design, contractual and technical issues conveyed by original equipment manufacturers to POWERGRID.

The NRPC minutes identify several constraints affecting the proposed HVDC system, including the geographical conditions at Pang, located at an altitude of around 4,700 metres, where temperatures can fall to minus 35 degrees Celsius.

The document states that VSC-HVDC solutions were not available for such high-altitude conditions. It also lists equipment design and performance challenges, high ultraviolet and cosmic radiation levels, weak network strength, transportation and logistical constraints, and additional technical requirements.

Considering these factors, the HVDC scheme was found technically unfeasible for implementation, prompting authorities to explore an alternative EHVAC transmission arrangement.

Under the revised proposal, renewable energy generated in Ladakh would be evacuated from Pang through a transmission network connecting it with the existing Phyang substation in Leh and a proposed substation at Sundernagar in Himachal Pradesh.Click Here To Follow Our WhatsApp Channel

The plan includes a 220 kV single-circuit line between Pang and Phyang, along with two 400 kV double-circuit lines, each approximately 273 kilometres long, between Pang and Sundernagar.

A further 130-kilometre 400 kV double-circuit line is proposed between Sundernagar and Mohali in Punjab.

The revised network is also intended to provide Ladakh with an alternative connection to the national grid, improving the reliability and security of its power supply.

The NRPC minutes point out that Ladakh currently receives power from the national grid through a single link — the Srinagar (Alusteng)-Leh 220 kV single-circuit transmission line of POWERGRID — which feeds substations at Drass, Kargil, Khalasti and Leh (Phyang).

The proposed Pang-Phyang connection would provide dual-source connectivity to Leh, while the Sundernagar network would draw additional grid support through connections with the Parbati and Wangtoo hydropower stations.

The estimated cost of the revised transmission scheme has been divided into two phases. The first phase, involving 2,000 MW transmission capacity, is estimated to cost Rs 25,225.87 crore, while the second phase, involving 1,750 MW, is estimated at Rs 6,201.67 crore.

The minutes state that solar and battery storage capacities would be required to use 100 per cent grid-forming inverters. The proposal also includes nine synchronous condenser units at the Pang pooling station to maintain the required short-circuit level.

During the meeting, the Northern Regional Load Despatch Centre (NRLDC) also called for necessary interaction and resonance studies, citing the proximity of solar plants, grid-forming battery storage systems and transmission-line equipment in a weak grid.

POWERGRID informed the meeting that the required studies would be incorporated into the technical specifications at the time of project award.

The NRPC forum agreed to the revised proposal submitted by CTUIL and recommended the transmission system for integration of 7.5 GW renewable energy from Ladakh to the National Committee on Transmission (NCT).(KNS)