India’s transmission network is growing rapidly to support the increasing power demand and the expanding power generation capacity in the country. Recently, the Central Electricity Authority (CEA) released a key transmission planning study – the draft National Electricity Plan (NEP) for Transmission – which outlines the perspective transmission network plan for the country. It estimates that 123,577 ckt. km of transmission lines and 710,940 MVA of transformation capacity (at 220 kV and above voltage levels) need to be added during the period 2022-27. Besides this, reactive compensation has been recognised as one of the focus areas for maintaining grid stability amidst the growing renewable energy integration. Overall, the expansion and strengthening of transmission systems will entail an estimated investment of Rs 4.75 trillion during 2022-27.
Draft NEP 2023: Transmission system progress and projections
Review of transmission system augmentation programme during 2017-22
During 2017-22, about 88,865 ckt. km of transmission lines and 349,685 MVA of transformation capacity (at 220 kV and above voltage levels) were added. This represents nearly 81 per cent and 91 per cent of the targeted transmission line and transformation capacity additions. There has been a steady growth in transmission systems at the high voltage and inter-regional levels, as well as high-voltage direct current (HVDC) systems. At the interregional level, 37,200 MW of capacity was added at the 220 kV and above level against the target of 43,000 MW, along with 3,819 ckt. km of HVDC transmission lines and 14,000 MW of HVDC bipole capacity. At the 765 kV level, 19,783 ckt. km of transmission lines and 89,700 MVA of transformation capacity were added.
The shortfall in the transmission capacity addition target during 2017-22 can be attributed to issues and challenges faced while implementing projects, including delays in obtaining forest clearances, right-of-way (RoW) constraints, compensation issues, problems in the acquisition of land for substations and contractual issues. Besides this, the Covid 19 pandemic led to delays in project commissioning.
Transmission system requirement during 2022-27
The draft NEP estimates that a transmission line length of 123,577 ckt. km and transformation capacity addition of 710,940 MVA (at 220 kV and above voltage levels) are required during 2022-27. For the inter-state transmission system, 426,675 MVA of transformation capacity and 53,132 ckt. km of transmission line length are required, while at the intrastate level, 284,265 MVA and 70,445 ckt. km are required respectively. At the inter-regional level, by the end of 2026-27, 143,850 MW of transfer capacity will be required, against the aggregate interregional transmission capacity of 112,250 MW in 2021-22.
To provide reactive power support adequate reactive compensation in the form of bus reactors and line reactors (at 765 kV and 400 kV levels), and static compensators (STATCOMs) have been planned. Bus reactors of 51,068 MVAr capacity and line reactors of 57,890 MVAr capacity have been planned for implementation during 2022-27 at investments of Rs 116 billion and Rs 149 billion respectively. Further, dynamic compensation devices such as static VAR compensators (SVCs) and STATCOMs are under implementation at the inter-state transmission system (ISTS) level to provide dynamic stability to the grid in contingency conditions and facilitate fast, robust system response to voltage fluctuations. So far, 12 STATCOMs/SVCs have been commissioned, while 17 are under implementation and two are planned for the ISTS. Meanwhile, at the intra-state level, one STATCOM has been commissioned in Gujarat, while another two STATCOMs are planned in Rajasthan. In addition, there are plans to keep space for the addition of STATCOMs and bus reactors at upcoming substations, especially those associated with renewable energy generation.
In terms of investment requirements, the NEP estimates that an expenditure of Rs 4.76 trillion will be required for the implementation of additional transmission systems (including transmission lines, substations, and reactive compensation systems) during the period 2022-27.
Perspective transmission plan for 2027-32
The NEP has provided tentative estimates for transmission system augmentation during 2027-32, as the location and capacity of the generation plants to be developed during this period are not certain yet. During 2027-32, a tentative transmission line length and transformation capacity addition of 105,000 ckt. km and 595,000 MVA respectively are expected. This estimation is based on peak electricity demand projections and assessments of region-wise generation capacity addition during the period. The transmission schemes primarily involve the evacuation of power from identified hydro and nuclear power projects, potential zones for wind and solar generation projects, and cross-border interconnections.
Transmission plan for the integration of renewable energy sources
As a significant step towards achieving the targeted renewable energy capacity by 2030, the transmission system is expected to evacuate about 537 GW of renewable energy capacity. Projects under various transmission schemes are at different stages of implementation, with some already commissioned, some under construction and others in the bidding process. The CEA’s “Transmission System for Integration of over 500 GW Renewable Energy Capacity by 2030” (December 2022) estimates that 50,890 ckt. km of ISTS transmission line length and 433,575 MVA of substation capacity are required for integrating additional wind and solar capacities by 2030. This would entail an estimated investment of Rs 2,442 billion.
Under the Ministry of Power’s Green Energy Corridors (GEC) scheme, projects for facilitating the evacuation of green energy from renewables-rich states such as Andhra Pradesh, Gujarat, Himachal Pradesh, Karnataka, Maharashtra, Madhya Pradesh, Rajasthan, and Tamil Nadu are being progressively commissioned. While the inter-state component under GEC-I has been commissioned, at the intra-state level, 92 per cent of transmission lines and 94 per cent of transformation capacity have been added as of July 2023. In addition to this, about 19.4 GW of renewable energy capacity is planned to be integrated into the intra-state system under the GEC-II scheme. GEC-II has a total estimated cost of Rs 120.31 billion. Under the GEC-II scheme, an addition of 10,753 ckt. km of transmission lines and 27,546 MVA of substation capacity are targeted. State transmission utilities are currently in the process of tendering projects under the scheme, which is scheduled to be completed by 2025-26.
Growing private sector participation
Following the opening up of the power transmission segment to private players in 2006, their participation in the area has been growing steadily. This has been more pronounced in the past four to five years as more and more projects are now being awarded through the tariff-based competitive bidding (TBCB) route. As of October 2023, a total of 133 ISTS schemes have been identified for implementation through the TBCB route. Of these, 92 ISTS transmission schemes (entailing an estimated cost of Rs 1,237.25 billion) have been awarded through the TBCB route and 41 projects are currently under bidding. In addition, 47 projects have been commissioned and 41 schemes are under implementation. Meanwhile, one project has been cancelled by the Central Electricity Regulatory Commission, and for another project, the transmission service provider has requested for closure. Additionally, the construction of two projects could not commence due to litigation.
At the intra-state level, Uttar Pradesh, Madhya Pradesh and Maharashtra have started the implementation of transmission projects through the TBCB route. Among these, 10 intra-state transmission schemes across the three states, awarded through the TBCB route, have been completed, and seven intra-state transmission projects in Uttar Pradesh, Odisha, West Bengal (Damodar Valley Corporation [DVC]), and Jharkhand (DVC) are under implementation. Other states such as Rajasthan are also planning to implement intra-state transmission projects through the TBCB route.
Conclusion
India’s transmission system has undergone a remarkable transformation over the years. Transmission system planning and operations have been enhanced with the establishment of Central Transmission Utility of India Limited, as well as through the implementation of general network access. Transmission companies are also increasingly embracing state-of-the-art technologies and solutions such as hybrid and digital substations, high-temperature low sag conductors, and monopoles.
That said, there remain several unresolved issues and challenges in the segment that need to be addressed. These include RoW constraints, lack of skilled manpower and limited vendors for key technologies such as HVDC and STATCOMS. At the intra-state level, there is a need for greater focus on network strengthening and expansion to ensure quality power supply. Above all, with the digitalisation of the transmission network and processes, data privacy and cybersecurity will need to be enhanced.
Priyanka Kwatra
