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India’s transmission travails

Reg Tucker

India is erecting a $7 billion ‘Green Energy Corridor’, which is aimed at streamlining the constricted evacuation of electricity produced from renewable sources. Sarosh Bana reports.

Apart from problems of fuel linkage, volatile fuel costs and weak incentives, India’s troubled power sector has been hamstrung by a constricted transmission system. Rather belatedly the government is contemplating remedial steps, especially when expanding renewable energy capacities across the country are compelling demand for commensurate and unhindered evacuation of power to the regional and national grids and from renewable generating to renewable deficient states.

According to the Federation of Indian Chambers of Commerce & Industry (FICCI), power generation capacity grew around 50 per cent in the last five years, whereas transmission capacity increased by just about 30 per cent. FICCI attributes this shortfall as a key reason behind the fractured capacity to meet the peak demand for power.

Even the truncated transmission is aggravated by staggering T&D losses, estimated to be as high as 50 per cent in some states, though officially pegged at 23 per cent nationally. These losses are technical, owing to energy dissipated in the conductors and T&D and transformation equipment, and commercial, caused primarily by pilferage, though also by defective meters and erroneous meter reading.

India added 14,661 MW of renewable power capacities over the 11th Plan and is targeting the addition of more than twice that - 29,800 MW - for the 12th Plan period (2012-17) (see tables 1 and 2). The 12th Plan additionally targets 88,537 MW of non-RE power, including 72,340 MW of thermal, 10,897 MW of hydro and 5,300 MW of nuclear. As on 30 June 2014, RE capacities had grown to a cumulative 31,692.14 MW, constituting 12.7 per cent of the country’s overall installed capacity of 249,536 MW (see table 3).

Table 1. Targets set for renewable energy sources and capacities added more 11th Plan, 2007-12 (in MW).
Wind Power10,50010,260
Solar Power-940
Smally Hydro Power (< 25MW)1,4001,419
Bioenergy, including waste to energy2,1002,042
*Renewable Energy Sources  

To cater to the transmission of this surge in renewable energy capacities, the government has planned a transmission network dedicated to renewable power that is characterised by fluctuating generation and unpredictability. Dubbed the ‘Green Energy Corridor Project’, the Rs43,000 crore (US$7 billion) inter-connected high voltage network aims to synchronise electricity produced from renewable sources with conventional power stations in the grid. The whole project has been bifurcated into Inter-State, to be developed by state transmission utilities (STUs), and Intra-State, to be developed by Power Grid Corporation of India Ltd (PGCIL, or PowerGrid), the central transmission utility (CTU) engaged in bulk power transmission. Major Inter-State Transmission Strengthening (ISTS) is part of this plan, to develop high capacity hybrid corridors.


Table 2. Renewable energy source- and year-wise targets set for 12th Plan, 2012-17 (in MW).
Wind Power2,5002,7503,0003,2503,50015,000
Solar Power1,0001,0002,0002,5003,50010,000
Small Hydro3504004004505002,100
Total      29,800

Germany’s KfW Development Bank will lend €1 billion to phase-I of the project, while the United States’ Ex-Im Bank will provide additional funding of US$250 million. Germany, which has expertise in making smart grids, will also provide developmental and technical assistance. “The problem is voltage fluctuation, with conventional grids facing difficulty in absorbing renewable electricity because of its varying voltage and supply,” Michael Steiner, German Ambassador to India, explained. “The planned transmission system will be made dynamic to handle the variations leading to an integrated grid across the nation.”


Table 3. Renewable power capacities as of June 20, 2014 (in MW).
Wind Power21,136.40
Solar Power2,631.93
Small Hydro3,803.68

To separately bolster transmission of conventional power, the Central Electricity Authority (CEA) plans an investment of US$35 billion to augment national grid capacity by 27,350 MW through 90,000 ckm (circuit kilometres) of 765/220 kV lines and 154,000 megavolt ampere (MVA) of sub-station capacity to meet the 12th Plan. Of this, US$19 billion is to come from PowerGrid and the balance US$16 billion from private players.

PowerGrid currently owns and operates 109,536 ckm of transmission lines at 800/765 kV, 400 kV, 220 kV and 132 kV of extra high voltage alternate current (EHVAC) and +500kV high voltage direct current (HVDC) levels and 186 sub-stations. The transformation capacity, as on 31 July 2014, is of 213,504 MVA. The company indicates, “This gigantic transmission network, spread over the length and breadth of the country, is consistently maintained at an availability of over 99 per cent.”

Since the start of the 12th Plan, 1 April 2012, until February 2014, 27,558 ckm of transmission lines were erected, 15,359 ckm of that 400 kV, 4,991 ckm, 765 kV, and 7,208 ckm, 220 kV. “As many as 120 transmission projects have faced delays because of the developer’s inability to acquire land and get timely clearances from all stakeholders,” notes R.N. Nayak, PowerGrid chairman and managing director. “There have been instances of transmission lines being forced to take a different route than planned, resulting in the entire project budget going awry.” He says transmission constraints make it difficult to haul excess power to regions that face shortages.

Mahesh Makhija, director, business development (renewables), CLP India Pvt Ltd, subsidiary of Hong Kong’s CLP Holdings, says the Green Energy Corridor Project is to be developed in three phases and completed by March 2017. “It is designed to haul 42 GW of incremental renewable energy capacity addition by 2016-17, though the actual addition may be much lower, going by the existing rate,” he noted. “If the corridor comes online as per the plan, it will remove all bottlenecks in transmission at the intra- as well as inter-state levels.” Major renewable energy transmission corridors are proposed in the states of Gujarat, Rajasthan, Tamil Nadu and Andhra Pradesh.

Radical changes required

India’s power system is designed round controllable conventional sources of energy generation, limiting operational flexibility. According to Makhija, the intermittent generation of renewable energy sources requires radical changes in the power system like separate connectivity standards, dedicated teams in the existing load dispatch centres (LDCs) to manage generation and dispatch, promotion of peak and ancillary generation sources, and suitable safeguards such as frequency controllers, reactive power compensators, harmonic protectors, and over current relays.

“Most of these measures have been the backbone of European transmission systems that operate at combined wind and solar penetration of over 25 to 30 per cent,” Makhija explains. The CEA is contemplating regulations on technical standards and grid connection, as present regulations on grid connectivity do not cover Distributed Generation and Renewables (DGR) to accommodate small sub-33 kV generators.

Ajay K. Goel, CEO of Bangalore-based Tata Power Solar, says the prevailing grid that is meant to haul huge power volumes from conventional sources has to accommodate DGR as well. “Storage systems are required to take care of uncertainties in this category of generation sources,” he explained. “These may not only be pumped storage plants, but also battery storage systems in conjunction with the inverter system for ac grid.”

Goel adds that these systems necessitate the development of smart, or intelligent, grid that is controlled by the application of extensive information and communication technologies. The prevailing distribution system that carries power in one direction may require to be bi-directional to transfer power in the reverse direction, too — for instance, from roof-top solar PV generation from customers with proper metering.

Makhija believes that while renewable sources cannot match the reliability of conventional fuels, they can fit in rather efficiently in a well-planned system. For instance, European countries handle the variability of renewable energy sources through co-ordinated generation planning and sophisticated forecasting tools and system operation techniques. In the Indian context, managing renewable energy variability is no different than managing consumer demand that keeps varying throughout the day and also during the seasons.

Terming evacuation a major challenge for wind project developers in the country, Makhija cites project delay due to unavailability of grid network around wind farm sites that are generally located in remote areas. “Despite policy provisions for ensuring grid connectivity to renewable energy projects, utilities have been reluctant to develop transmission lines for them due to the low utilisation of renewables during the lean period and to delays in securing budget approvals from the government,” he explains. “These developers generally create the evacuation infrastructure themselves, right from building a pooling sub-station near their wind farms, laying transmission lines from these sub-stations to the nearest grid sub-stations, and at times also strengthening the inter-connecting grid sub-stations and larger grid networks, as well as laying high voltage transmission lines upto 150 to 200 km.”

Clearance for this is required from the STU, which analyses the load flow to determine the voltage level for inter-connection with the grid sub-station, depending upon the project capacity. Approval may be conditional upon creation of transmission lines to the grid sub-station and/or strengthening of the existing grid sub-station. The governing framework for system operations are the state and national grid codes, which elaborate on the functions included in grid operations such as scheduling, dispatch, metering, and balancing and control.

According to Makhija, wind energy surplus states such as Tamil Nadu and Rajasthan have done little to strengthen the existing grid or create additional evacuation infrastructure. The Indian Wind Energy Association estimates losses of 2,200 million units (40 per cent of total annual generation) in Tamil Nadu alone during the high wind season in 2013 due to evacuation constraints and backdown carried out by the utility.

Importance of investment

With an investment of about $1 billion, CLP India is the largest investor in India’s wind sector, having built up a portfolio of 12 wind farms of a cumulative capacity of 1,051 MW. It will be investing an additional $1 billion to $1.2 billion to raise the total capacity to 2,000 MW by the end of 2016.

Ashish Rajvanshi, principal, and Raghav Iyer, senior associate (engagement manager), Booz & Co (India) Pvt Ltd, now part of PricewaterhouseCoopers (PwC) and renamed ‘Strategy &’, point out that traditional grids cannot forecast and bear the fluctuating load brought about by renewable energy sources. The analysts believe this can cause load imbalance, putting grid stability at risk.

Rajvanshi indicates that while on paper, renewable projects in India are to be provided evacuation, grid sections have needed to be occasionally shut down to ensure grid stability. “The existence of the REC (renewable energy certificate) market ensures that renewable energy generators can be in any part of the country and yet benefit from utilities that need to purchase their share of RECs to comply with the central mandate,” he explained.

Ramesh Kymal, chairman and managing director, Gamesa Wind Turbine Pvt Ltd, the India subsidiary of Spain’s Gamesa Corporación Tecnológica SA, also believes that the concept of ‘base load’ - the unvarying load which occurs almost the whole day on the power plant – is alien to renewable generation because of its intermittent nature, though wind power has the ability to meet peak power demand.

“In recent years, the plant load factor (PLF) of wind power has doubled to 25 to 30 per cent, primarily due to the new generation large-capacity turbines and efficient wind park management strategies,” he stated. “Wind power is already competitive with new conventional power in some of the Indian states and may become further competitive on issues like fuel availability and incremental cost of imported fuel.” According to Kymal, modern-day wind farms have grown in capacities of over 100 MW and with power from them being hauled at 132 kV and above renders it easier to synchronise them with the 132 kV lines of STUs.

Kymal indicates that though issues of land availability and grid infrastructure are more or less universal for the wind industry, a comprehensive long-term policy framework in Europe has ensured a common grid on the continent to be shared by power deficit and surplus countries. “Particularly in India, the availability of attractive finance mechanisms and competitive interest rates for wind power projects are specific to certain locations,” he noted. “In the proposed green energy corridor, however, estimates have been made for renewable energy additions upto 2030, with sub-intervals at the end of the 12th, 13th, 14th and 15th Plans.”

Bikesh Ogra, president, Solar, Sterling & Wilson, says that while the unpredictability in renewable energy generation is a concern, it can be addressed by investing in smart grid technology that synchronises all sources of power. “Renewable power is inevitable, particularly in a country like India where supply side factors impede the meeting of peak power requirements and where power deficit widens to over 10 per cent during summer,” he stated. “With the reduction in solar power tariffs to about Rs7-8 (11.6 to 13.2 cents) per kWh, grid parity will be likely by 2017.”

Ogra maintains that as state electricity boards are in heavy losses due to generous government subsidies in electricity prices, they prefer load shedding to buying all the electricity generated and are too cash-strapped to improve current grids and build new ones. The green energy corridor, according to Ogra, will tackle the intermittency and variability of grid-connected renewable generation through strong grid inter-connections, flexible generation, ancillary services and reserves for supply-balancing, demand side management, storage for load balancing, renewable energy management centres (REMCs) equipped with advanced forecasting and communications tools, synchrophasor technology - PMUs/WAMS (phasor measurement units/wide area measurement systems) – on pooling stations and inter-connection with the centralised control centre through fibre optic communications for real time information, monitoring and control.

Amit Kumar, executive director, Energy & Utilities, PwC Pvt. Ltd, notes that evacuation was difficult for projects with no clearly identified beneficiaries or bulk power transmission agreements as that made it hard for transmission utilities to plan for and invest in augmenting associated transmission systems.


Sarosh Bana is the executive editor of Business India. He also serves as Renewable Energy Focus magazine's India correspondent.

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30 December 2014
Excellent article. Congratulations Reg Tucker.
Here are problems of evacuation of power from Renewables in Tamil Nadu.

Variability in wind power generation poses greater challenge to the grid stability. Due to seasonal generation from wind power the state is not able to utilize its transmission infrastructure effectively and during high wind season the transmission line are congested and subsequently there are problems of voltage stability and power quality. For Example most of the generation from wind farms in Tamil Nadu takes place in tirunaveli and mokundal region and power is evacuated to nearby 230 KV or 400 KV substations. During monsoon season most of the hydro plants also run at full capacity and the demand of electricity to the agriculture consumers become insignificant, this becomes challenge to the system operators to evacuate power from the substations of this grid as the existing transmission lines become overloaded and southern grid is not synchronized with northern grid, which leads to backing down of wind power plants in this region, Even though there is electricity demand in other regions of the country. The states suffers already from power shortages of about 1700-3700 MW. There is also load shedding to the HT consumers of the order of 40% on base demand which effects the productivity of consumers. In order to handle power crisis in the state, government has introduced one day power holiday to all HT and LT consumers and also peak power restriction measures.
This is not a new issue that suddenly popped up, however grid integration has been very well handled in countries such as Germany, Denmark and Spain and the wind penetration in this countries is over 50% of their installed capacity. There is no single solution to address the grid integration issues, however the overall system should have balancing power capacities, short term forecasting and scheduling, demand response, pumped hydro and interconnection with other regions at a high voltage levels so that, regional exchanges of power can take place the electricity to longer distances
In an interview with Intersolar India, Gaurav Sood, Managing Director,Solairedirect India has highlighted the challenge faced by its solar plant in Bap, Rajasthan. He says
” The (solar) plant has been performing well overall. Unfortunately, all the plants connected to the Bap Grid Substation (GSS) have been asked to reduce their input into the GSS by about 15% from 10am to 1pm. This reduction is applicable till date and is causing loss to us but till date the GSS hasn’t given any specific date by when their internal problem will be sorted so that we could pump 100% of our output. If we neutralize the effect of this de-rating, then the plant is performing slightly above the P(50) levels, in line with our projections.”

Poor evacuation infrastructure
“The development of wind power generation in India has been fairly unplanned so far, which has led to power evacuation and infrastructure bottlenecks. To utilize wind energy effectively, planning of evacuation infrastructure should go hand-in-hand with identification and approval of the resource. The implementation of smart grid technology and investment in power storage are also crucial to counter off-peak power generation and improve power quality.
“As soon as the Centre for Wind Energy Technology identifies or approves a wind zone, planning around evacuation must be undertaken by the evacuation utilities. Quite often, wind power projects tend to be located in remote areas where grid network is poor and this necessitates investment into evacuation network which developers are generally willing to undertake,” notes Makhija.
However, there is no effective cost recovery mechanism in place for this part of development, he stresses. “The transmission utilities and the regulators must recognize the efforts and investment involved in developing the evacuation infrastructure and provide for suitable cost recovery mechanism in the tariff.”
- See more at:
As someone suggested,” It is opined that the
wind generator has to adopt the mantra of “Predict-Plan-Participate” as a means to address
for the challenges brought in Integration of Renewable to Grid.”.

Here is an Excellent presentation:
Grid Integration of Renewables, K.V.S. Baba, General Manager, National Load Despatch Centre:
In the light of these problems,” India is erecting a $7 billion ‘Green Energy Corridor’, which is aimed at streamlining the constricted evacuation of electricity produced from renewable sources” is most welcome.
Dr.A.Jagadeesh Nellore(AP),India
Renewable energy Expert

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