Recently, the planning and execution of transmission infrastructure has taken centre stage with the goal of improving renewable energy evacuation. Under the budget for 2023-24, an interstate transmission system has been proposed for the grid integration of 13 GW of renewable energy from Ladakh at a cost of Rs 207 billion. Further, there have been discussions around laying of underground transmission lines in the Great Indian Bustard (GIB) region. Recently, the Central Electricity Authority (CEA) has released a report, “Transmission System for Integration of over 500 GW RE Capacity by 2030”, planning a transmission system for about 537 GW of renewable energy capacity in major renewable energy potential zones including the Leh renewable energy park in Ladakh; Fatehgarh, Bhadla, and Bikaner in Rajasthan; the Khavda renewable energy park in Gujarat; Anantapur and Kurnool renewable energy zones in Andhra Pradesh; and offshore wind farms in Tamil Nadu and Gujarat.
With the greater focus on the transmission sector, the importance of critical infrastructure in this space has become even more significant, particularly with regard to lines/cables and towers.
Renewable Watch takes stock of the transmission line/cable and tower markets, and recent advancements in the industry…
Market size of transmission towers
According to a Research and Markets report titled “Power Transmission Tower Market Opportunity by 2025, in India, the Middle East, Africa & SAARC Region”, India has emerged as the second largest transmission market after China. India accounts for 15 per cent of the global transmission tower market. Further, India will be consuming 1.8 trillion units by 2025. According to the CII, the Indian government’s vision of a $5 trillion economy will require an estimated investment of Rs 5 trillion in the transmission sector over the next few years. As per the National Infrastructure Pipeline, a capital expenditure of Rs 3,040 billion is expected in the transmission segment from 2020 to 2025.
The transmission tower market exceeded $17 billion in 2021 and is expected to grow over a compound annual growth rate (CAGR) of 4 per cent from 2022 to 2028, according to Global Market Insights (GMI). Furthermore, the market size valuation is expected to reach $24 billion by 2028. Major players operating across the transmission towers market include Utkarsh India Limited, Jyoti Structures Limited, KEC International Limited, Quanta Services, Nexans, Valard Construction, Burns & McDonnell, the PLH Group, Wilson Construction, Power Line Services, the MDU Construction Services Group, Valmont Industries, Sabre Industries, Meyer Utility Structures, Kocaer Steel, Skipper Limited, Ganges Internationale, and ISA.
According to IndustryARC, the transmission tower market size is forecast to reach $3.5 billion by 2027, growing at a CAGR of 7.6 per cent from 2022 to 2027. The top 10 companies in this space, according to IndustryARC, are ABB, the General Electric Energy, Jyoti Structures, KEC International, SAE towers, Alstom, General Cable Corporation, the Weifang Changan Steel Tower Stock Company, Qingdao BST Steel Structure, and MasTec.
Market size of transmission lines
According to Fortune Business Insights (FBI), the global transmission line market is expected to grow from $86.88 billion in 2021 to $138.99 billion in 2028 at a CAGR of 6.9 per cent. The leading players in the global market include Nexans, the Arteche Group, the Prysmian Group, Kiewit, ABB and General Electric. Furthermore, the global high voltage cable market size is projected to reach $54.97 billion by 2026. Meanwhile, the power transmission cables market is expected to grow at a CAGR of 6.8 per cent during 2022-30 to reach $170,280 million, according to Market Research Future.
Underground transmission lines
The laying of underground transmission lines gained traction in 2021 when the Supreme Court ordered the laying of high voltage power lines underground in GIB habitats in Gujarat and Rajasthan. Recently, the CEA suggested that power transmission lines with voltage levels of up to 33 kV passing through the GIB area should be underground. According to the draft Construction of Electric Lines in the GIB Area Regulations, 2023, power transmission lines above the 33 kV voltage level passing through the GIB area should be overhead lines with bird flight diverters. The rules will be applicable to all generating companies, transmission licensees, distribution licensees, central transmission utilities, and state transmission utilities that own, operate and maintain electric lines in the GIB area. According to the release, stakeholders can submit their ideas by March 3, 2023.
In December 2022, the Ministry of Power approved the report of the expert technical committee that was constituted to formulate techno-economic norms for installing transmission systems in potential habitats of the GIB. The report mentioned that undergrounding of transmission lines of 66 kV and above voltage levels is technically unfeasible for the evacuation of bulk power. Such a move would require much longer time for restoration leading to huge generation losses.
In June 2022, technical standards were notified by a special committee constituted by the Supreme Court for bird flight diverters to be installed in priority areas associated with the GIB species. These standards have been notified after consultations with the CEA. As per the recommendations by the committee, parameters like size, colour, operation temperature, grip strength and other construction aspects of the bird diverters must be standardised.
In addition, diverters must be dynamic and should have a warning disc with 2D or 3D design. They should have the necessary clamps and connectors. Utilities should include a mixture of LED and non-LED diverters on their power lines, and at least 20 per cent diverters on a line should be LED type. The diverters must be designed for an effective life period of 15 years and have a warranty period of at least five years.
With the growing demand for power in urban areas and industries, underground cable systems are also being deployed by utilities. Underground cabling provides greater safety against electrocution as compared to overhead cables, requires less right of way (RoW) and is aesthetically better than overhead transmission lines. Even though underground cabling costs are much higher than overhead cables of the same voltage, the high initial cost can be offset by benefits such as safety of citizens, low chances of developing faults and low maintenance costs.
Advancements in cable technology
Cable design and material have evolved over the years with dry extruded cables increasingly replacing wet paper insulated ones. Cross-linked polyethylene (XLPE), high density polyethylene, aerial bunched cables and spacer cable systems are the most commonly used covered cables. Due to the risks associated with bare overhead cables, covered cables such as XLPE, high density polyethylene and aerial bunched cables have gained traction in the market.
There is a new cable type called electron-beam or e-beam cable, which can be used in high temperature applications in the solar, railway and shipping segments. Gas-insulated transmission lines are another form of emerging cable technology. They are a safe and flexible alternative to overhead lines and take up much less space while providing the same power transmission.
Another emerging category of cables is solar cables, which can support the increasing penetration of renewable energy into the grid and high solar power targets. Designed to help evacuate solar energy from PV modules, these cables connect individual modules with the string combiner box. Solar direct current (DC) cables are of two types – module cables or string cables and DC main cable. Solar cables have a high thermal rating to withstand extreme temperatures, and superior abrasion and notch resistance. They can be used across a range of temperatures and are generally laid outside. For solar panels with trackers, the cables need to be flexible as the panels keep moving along with the sun.
The transmission and distribution sector has been a key focus area for the government. In order to achieve round-the-clock power, high voltage transmission lines are being developed. Technologies such as flexible alternating current transmission system (FACTS) and high voltage direct current (HVDC) are helping improve the stability and security of the country’s complex grid system. These technologies reduce transmission losses, optimise the power flow, support the grid integration of intermittent renewable energy sources, and increase transmission capacity and system stability. In tandem with these developments, advancements in cables and conductors can help achieve a seamless high voltage power transmission system.
Advancements in transmission towers
There have been significant improvements in transmission tower designs and these developments have reduced the RoW requirement, minimised the visual impact, enabled faster execution and provided ease of installation. With new designs it has become easier to expand the transmission network to remote areas.
There have also been technology upgrades in tower foundation designs and these are being carried out by utilities via multicircuit multivoltage solutions, wherein the line is upgraded with more than one voltage circuit on the same tower. For voltage upgrade, the line capacity is increased by changing the system voltage from a lower value to a higher value of the line in the same available corridor. The power transfer capacity can be increased by over four times using this technology. Moving forward, there is also a need for utilities to adopt tower designs that can withstand natural disasters such as emergency restoration system towers and monopoles with smaller spans in disaster-prone areas.
The way forward
The government’s target to scale up renewable energy in the coming years by providing incentives to the solar and wind segments is a key demand driver for electrical wires and cables. Further, wiring will be needed to set up charging infrastructure for electric vehicles. Utilities need to not only expand and strengthen transmission networks but also ensure uninterrupted and efficient flow of power by adopting new and emerging technologies. With large-scale projects planned across the country, many of them located in distant regions, there is a rising demand for high capacity transmission infrastructure. The advancements in cables, conductors and transmission towers are expected to help the power sector meet this demand.
By Sarthak Takyar
