Transmission companies have not been able to seamlessly integrate renewable energy into the grid. They are also unable to reimburse investment on transmission evacuation. Umesh Agrawal, Associate Director Energy, Utilities & Mining, PwC tells RAHUL KAMAT these anomalies will hinder the large scale development of renewable generation projects.
The grid must maintain and control generation in a way in which it can instantaneously ramp up and down in response to changes in load. How far have we come in India? An instantaneous ramp up and ramp down is not practical as the majority of generation being thermal in the country, has constraints on the ramping rates (MW/Hour up or down). However, with appropriate ramping, rates of various stations´ response to the LDC instructions needs to be prompt to safeguard the Grid from failures or blackouts. Further, the FGMO needs to be activated for all the generating stations. Presently, there might be a record of compliance to both of these, but there is a need to test-check each of the generating stations from time to time. Without a test check or an audit, the control of generation on real time basis would not be evident.
Maintaining grid reliability requires precise synchronisation of voltage and current. How reliable is India´s current grid mechanism? The voltage and current stability is the most critical parameter for stable and reliable grid operation. The monitoring of these parameters had been a challenge for the transmission companies in the country. Phasor Monitoring Units (PMU) have been piloted in the country. These are devices that provide synchronised measurements of real time phasors of voltage and current. Due to the high cost of PMUs, the installation of these have been undertaken only at strategic locations. These kind of technological advancements need to be taken up in the future which would enable the system operation in a reliable manner.
The massive grid failure that happened in 2012 was a result of mismanagement on the part of regional load despatch centres. Has this issue been addressed? The grid failure which had occurred on 30th July 2012 and 31st July 2012 had brought out the critical issues and bottlenecks in the transmission system operation. The critical issues which were identified by the ´Enquiry Committee on Grid disturbance in Northern Region´ are depleted system with a number of transmission lines taken under planned/forced outage, huge overdrawls by some constituent states, inappropriate reduction of overdrawls inspite of NRLDC´s instruction to SLDCs, protection systems that didn´t trip due to conditions such as load encroachment, absence of FGMO controls being activated in several generating stations, etc. Therefore, the remedy for above critical issues would be either technological solutions or disciplinary solutions. The best technological solutions may be adopted for which activities would have been already been underway and the results would likely be evident in the coming years. However, on the disciplinary issues strict measures need to be implemented, with the autonomy of the SLDCs being the first priority. The Pradhan Committee report issued in August 2008 had stressed the ring fencing of the SLDCs for their functional autonomy. But till date this recommendation has been hardly implemented in most of the States.
It is said that the Northern Grid will take longer to restart operations in the case of a widespread outage because it is largely dependent on thermal power supply. Is there any way this anomaly can be overcome? The constituents of the Northern region grid have power sourcing majorly from thermal generating plants. Approximately 70 per cent is from thermal, 20 per cent from hydro and balance from other sources. Further, the major generating sources are not located evenly across the region, with major thermal power stations located at the south eastern parts and hydro generating stations located at the north western parts. The generating sources are located at extreme ends whereas load centers are majorly at the central part of the region. The anomaly in terms of dependence on the thermal energy and existence of hydro energy at extreme ends are due to constraints of resource availability at certain locations only. This anomaly can be overcome only by developing and implementing various restoration strategies. The build down (sequential restoration) strategy and build up (parallel restoration) are talked about for restoration adopted by the load dispatch centers. The factors such as creation of more sub-systems, power system islands, integration of renewable plants, etc. need to be assessed for effective restoration.
Existence of procedure or logic for restoration of power systems and coordination of each person involved are very critical to quick restoration of power systems during grid failure. A standard operating procedure for restoration and a chain of command needs to be pre-specified by the respective organisations responsible. The Central Electricity Authority, the respective Regional Load Dispatch Centers (RLDCs) and Regional Power Committees (RPCs) have already been performing these tasks. Thus, the restoration exercise is governed by the CEA (Grid Standards) Regulations, 2010 and the procedures laid down by the respective RLDCs.
Have there been issues concerning the quality of power supplied through the National Grid? Are there any fluctuations in power quality? There have been instances of overloading of transmission corridors and power swing in case of faults/failures in the Grid. However, from the quality perspective hardly any records are available in the public domain. Rather, the quality issues have been observed in the distribution networks across many State utility networks owing to lower voltages, fluctuating current, etc. Wherever there are such issues of quality the relevant authorities need to invest in the network and sub-stations. The CTU has been investing appropriately to ensure capacity augmentations to meet the increasing demand and generation. Some States with positive future outlook have been investing in the infrastructure, but investment in infrastructure in many States has been a concern.
What are the last-mile connectivity issues that India´s National Grid faces? The RE development has ushered in a large requirement of transmission network to fulfill the last mile connectivity to these RE generation plants. Majority of the RE generation developers have preferred to invest in their own transmission evacuation system to connect to the nearest Grid. However, there are a large number of RE generation developers who have neither been granted connectivity to the grid by the respective transmission companies nor have they invested in their own transmission evacuation systems.
These upcoming generation plants are in limbo. Further, there are some States which have come up with policy incentives for providing reimbursements on the transmission evacuation from RE generation plants. In this scheme, the investments made by the RE generation developer is reimbursed by the State Government and/or State Transmission Company and/or State Renewable Development Agencies. There are instances of delay or no reimbursement of these investments to the RE generation developers. These instances will hinder large scale development of RE projects.
How difficult is it to integrate renewable energy into our grid? Renewable energy plants do have a difficulty in forecasting or predicting the generation schedule with accuracy. The scheduling and dispatch planned by SLDCs becomes very difficult resulting in large deviations. The CERC (IEGC) Regulations, 2010 stipulate forecasting of generation from renewable sources to an extent of 70 per cent accuracy. The deviation to the extent of 30 per cent is taken care through the Renewable Regulatory Fund (RRF) mechanism in the above IEGC. Deviation beyond 30 per cent attracts a penal charge of Renewable Regulatory Charge specified by IEGC. RE generators should adopt new technologies for forecasting generation to enable to qualify under the allowable deviation limits. Network specifications need to be implemented by many RE generators. There is a long way to go before the integration of renewable energy to the grid is made a success story.
I wish to start pvc / pp electric wire unit in Delhi. What kind of information I can get if I subscribe for your magazine
Pls invite me all auction in gujarat
we are doing business developing for solar power ,thermal power , customer supporting and we have 45 mw splar power on hand needs investors.....
pls call +910842559230