At the 26th Conference of Parties (COP26) of the UN Framework Convention on Climate Change (UNFCCC), India pledged to reach a non-fossil energy capacity of 500 GW by 2030 and meet 50 per cent of its energy requirements from renewable energy by 2030. As of 2021, the installed renewables capacity in India, excluding large hydro, stood at 103 GW. A robust evacuation infrastructure to support the increased renewable energy generation would be key to achieving India’s climate targets. To strengthen the evacuation infrastructure, several transmission projects are being implemented under the green energy corridors (GEC) project, besides setting up of renewable energy zones and new ISTS projects. A look at some of the key developments under these initiatives and the challenges involved…
Green Energy Corridors
GEC I: In 2012, a need was felt to create a dedicated infrastructure for the evacuation and transmission of renewable power in renewables-rich states. The programme is being implemented in two phases. Phase I of the GEC includes intra-state transmission systems implemented by the respective state transmission utilities (STUs) and interstate transmission systems (ISTS) implemented by the Powergrid Corporation of India Limited (Powergrid) or other transmission licensees. Under GEC I, 3,200 ckt km of transmission lines and 17,000 MVA of substations have been commissioned for the evacuation of 6 GW of renewable energy projects in the ISTS scheme. Under the intra-state scheme, 9,767 ckt. km of transmission lines and 22,689 MVA of substations have been planned in eight states for the evacuation of 24 GW of capacity. The Phase I programme is expected to be completed by 2022 (Maharashtra by December 2021, Karnataka by March 2022, and Andhra Pradesh, Gujarat, Himachal Pradesh and Madhya Pradesh by June 2022). As of November 2021, 8,434 ckt km of line length has been constructed and 15,268 MVA of substations have been charged. The total estimated cost of these projects is Rs 101.42 billion, with 40 per cent of the funding (of Rs 40.56 billion) as central grant from the Ministry of New and Renewable Resources (MNRE), 40 per cent loan of Euro 500 from KfW, Germany and 20 per cent as equity from states.
GEC II: In January 2022, The Cabinet Committee on Economic Affairs (CCEA), chaired by the prime minister, approved the GEC II. GEC II has been planned for grid integration of about 20 GW of capacity through the intra-state system. Under this phase, about 10,753 ckt km of transmission lines and 27,546 MVA of substation transformation capacity are expected to be added at the intra-state level in seven states of Gujarat, Himachal Pradesh, Karnataka, Kerala, Rajasthan, Tamil Nadu and Uttar Pradesh. The intra-state transmission system will be built over a five-year period, from 2021-22 to 2025-26, by the respective STUs. The estimated project cost of the scheme is about Rs 120.31 billion, of which the government will contribute 33 per cent (Rs 39.7 billion), as part of the central financial assistance. The balance 67 per cent of the project cost is available as loan from KfW, REC and Power Finance Corporation Limited.
The GEC I scheme also includes the establishment of state-of-the-art renewable energy management centres (REMCs) by Powergrid in renewable-rich states at the regional load despatch centre (RLDC), state load despatch centre (SLDC) and national load despatch center (NLDC) levels. These first-of-their-kind centres in India are equipped with forecasting and scheduling tools and real-time monitoring of generation to address the variability and balancing issues in system operation. Eleven REMCs have been commissioned – NLDC in Delhi, southern region (Tamil Nadu, Andhra Pradesh, Karnataka SLDCs and SRLDC), western region (Gujarat, Maharashtra, Madhya Pradesh SLDCs and WRLDC) and northern region (Rajasthan, SLDCs and NRLDC).
Through these REMCs, 55 GW of renewable energy is being monitored. Further, one additional REMC in South Andaman was commissioned in July 2021 and another in Telangana is currently under implementation by Powergrid.
Renewable energy zones
A comprehensive transmission scheme is also planned for 66.5 GW of renewable energy capacity in the states of Tamil Nadu, Andhra Pradesh, Karnataka, Gujarat, Maharashtra, Rajasthan and Madhya Pradesh. The total cost of setting up transmission infrastructure for 66.5 GW of REZs is estimated to be Rs 432.35 billion. The transmission scheme for REZs is planned to be implemented in two phases. Phase I is expected to entail an investment of Rs 191.6 billion for 29 GW of renewable energy capacity, and Phase II is expected to entail Rs 240.75 billion for 37.5 GW of capacity. As of September 2021, transmission projects worth Rs 202 billion have been awarded so far while projects of around Rs 93 billion have been bid out. The remaining projects are under various stages of planning and discussion.
Dynamic compensation in the form of SVCs and STATCOMs is also being implemented by Powergrid for dynamic control of reactive power in order to maintain the voltage and improve the stability of the grid. Powergrid has commissioned a number of SVCs in the 400 kV grid. Further, one thyristor controller reactor (500 MVAR) is being implemented in Kurukshetra to improve the static as well as dynamic voltage profile of the Kurukshetra high voltage direct current (HVDC) station.
Further, in order to tap the abundantly available renewable energy potential (solar and wind) in Ladakh, the government has announced the development of a solar energy park. For this, feasibility assessment of the transmission system for the evacuation of 10 GW capacity (5 GW each in Pang and Nyoma regions of Leh) has been carried out by Powergrid and is under consideration by the government. The project is proposed to be implemented in two phases, starting with the first phase involving the evacuation of 5 GW of renewable power through the Pang–Kaithal HVDC link along with a 12 GWh battery energy storage system and the second phase involving 5 GW of transfer through the Nyoma-Kashipur HVDC link.
Also, in December 2021, the union minister of power and new and renewable energy approved 23 new ISTS projects with an estimated cost of Rs 158.93 billion. Of these, 13 projects with an estimated cost of Rs 147.66 billion will be developed under tariff-based competitive bidding and 10 projects with an estimated cost of Rs 11.27 billion will be developed under the regulated tariff mechanism. The new transmission projects will facilitate the evacuation of 14 GW of renewable power in Rajasthan, 4.5 GW in Gujarat, 1 GW from the Neemuch Solar Park in Madhya Pradesh, as well as power from feeding areas near Akhnoor and the Jammu region after establishing the Siot substation in Jammu. These projects have been approved after examining the recommendations of the National Committee on Transmission in accordance with the National Tariff Policy, 2016. Under this policy, ISTS projects are to be developed through tariff-based competitive bidding, except for projects that are strategic, time-bound or are meant for technical upgradation.
The way forward
A key challenge has been the slow pace of transmission infrastructure development vis-à-vis the pace of renewable energy project development. As a result, developers often face difficulties in obtaining authorisation for power evacuation, in turn, suffering significant generation losses. This concern is more for new projects that are commissioned.
The technical challenges in renewable energy integration include the intermittency, variability and unpredictability of renewable energy. The lack of flexibility in coal generation plants, voltage ride-through and reactive power management; lack of coordination among state-level transmission planners and central planning agencies; declining system strength; and increasing fluctuations in frequency and voltage levels in certain regions are other technical challenges.
Another key obstacle is that many utility-scale renewable energy projects are planned in remote areas across the country, which makes power transmission cumbersome and expensive. Renewable energy projects in Leh and Kargil have faced such issues. The transmission space has also seen problems related to financing and land acquisition.
On the regulatory side, the absence of market signals for power system flexibility; lack of ancillary services regulations, products and markets in states; low gestation period of renewable energy generation; lack of remuneration for solar and wind curtailment; low strength of the grid (fault level) at the point of renewable energy interconnection; lack of grid codes to support system security; and lack of regulatory frameworks for adequate remuneration of demand response and storage technologies such as batteries are some of the major challenges impacting transmission projects for renewable energy evacuation.
Lastly, for intra-state transmission systems, the issue of delays in commissioning has been rampant. In fact, intra-state transmission has been dubbed as the weakest link in the grid, hampering the uptake of renewables due to the issues surrounding it. Going forward, the development of intra-state transmission systems must match the growing penetration of renewables to achieve last-mile connectivity.