11 minutes reading time (2263 words)

Behind the scenes of the PM’s ‘lights-out’ call success

India's Prime Minister Narendra Modi's nine-minute lights-out call was met with resounding support on April 5, 2020, without disrupting the electricity grid in India. The PM had urged Indian citizens to switch off lights at their homes and light up candles, lamps, and mobile phones in a display of solidarity and the country's 'collective resolve' to defeat coronavirus.

While there were apprehensions about negative impact on the grid due to the sudden drop and spurt in demand leading up to the event, the Indian power utilities along with national and state load despatchcentres ensured grid operations remained smooth and uninterrupted throughout the country.

So, how did India's grid successfully manage a load drop of 31 GW on the night of April 5, for nine minutes? Netra Walawalkar spoke with B B Mehta,Chief Engineer, SLDC at Gujarat Energy Transmission Corp Ltd (GETCO) to understand what went behind the scenes in managing this unprecedented event successfully.

Can you share how the load despatch prepared for and coordinated the event? What were some of the planning and projections around the event? 

It was a great event. Grid operators are habituated to managing such grid vulnerability on a day-to-day basis. However, the challenge here was that it was a pan-India event. It was going to be held across India at the same time, so it was important to have meticulous planning.It was a large-scale distributed operation but in one way it was integrated also.

Electricity is a concurrent subject in our country; it is not only looked after by the States but also the Central government. All the States were working in a low demand scenario since the lockdown was announced in the country. The general power requirement of the country has fallen by 40 to 50 percent and amid that there was a massive event. To cope up with that contingency we did a detailed analysis with different stakeholders in the power sector.

As you may know, electricity cannot be stored so we need to generate just the amount we want to use and if there is excess then we have to switch off the generation or reduce it. For that, we need to have a response time of the generator which is analogous with the goal given by the PM. So, the fast ramping or fast response devices in the generation segment is hydro and gas power plant and others, so that they have been called upon couple of hours before the announcement of the program and they were to act as per the plan. They were informed that there needs to be lesser gap between the power that is being generated and demanded either on the plus side or the minus side. So, we had a detailed meeting with our generation stations, with regional despatchcentres, then we had national meetings by the POSOCO and SLDCs. All the SLDCs connected through video conferencing, and statistical details were prepared and shared.

Initially with respect to Gujarat we submitted a drop of 12,500 MW but our regional load and national drop came around 700 MW to 800 MW only. By and large there was an idea that there will be load drop of 12,500 MW, but we probably misjudged for when it took place, we had around 31,000 MW load drop.

With respect to preparation, we identified the teams that would do each operation, we put experts on those teams and at the power stations and sub-stations. Our protection team was on its toes, for voltage control our sub-SLDC was informed on time and with that level of precise planning we were ready to meet the challenge on April 5.

BB Mehta

How exactly was the operation managed during the nine-minute event on April 5? 

It was very precisely planned as to who will contribute to the management of the grid variation. Say, the grid is having some base-load and there was some delta factor which is going to vary during the nine-minute window, which plant will play role to control that dynamic, so hydro stations were informed and put on mark an hour before the start of the event. They were operating at a megawatt level as per what was planned by the regional load despatchcentre and as soon as the load started to fall, they promptly responded by reducing their generation so as to have the net balance remain as is. As soon as the load dropped, the frequency shot up to some 50-point level but by that time the generation was drastically reduced to ensure it does not go beyond the limit.

Further, once the event was over, instructions were passed as to who will pick up how much generation to ensure there is no hue-and-cry over any imbalance or mismatch. They acted promptly and it was a seamless transfer of information. Overall, it was a very tightly integrated approach and there were no more deviations beyond the standards and the
grid code, and we could manage in time.

This planned event is unprecedented in the history of power grid, what are some of the learnings from this event?

An important lesson is that our action plan for mitigating these contingencies should be more precise. We should have more detailed study of the load and the component because we anticipated 12,500 MW drop but it went up to 31,000 MW. Further, we had a strict advisory from the government that other States should not face any problems because of us, so we had to doubly back up.

We could curtail wind generation when frequency crossed about 50.2, it was about 600 MW wind generation immediately shut off and it was planned, advanced intimation was given to the wind generation station and they immediately operated it on just one call. We had taken the help of agriculture load too; some of the [agriculture] load was going to switch off just before 21:00 hours on the day of the event so as to have more inertia on the load of the demand. Some of the agriculture power which was scheduled to start after 21:00 hours, was done in advance. We told farmers they will get power half an hour early so that there is less load drop from the grid point of view and overall grid management will become easier.

Another learning is that we should take help of these dynamics. This may not be available to distribution companies serving only urban cities like Delhi or Mumbai but for large State Discoms this was one of the good opportunities. We still need to have more flexible generation at our disposal in case such contingency arises in the future.

Since 2011 the Regulatory Commission has talked about tightening the frequency band but there has been no firm step taken in this regard, what are your comments on that. 

No, they have tightened the band a little but ultimately frequency is a benchmark which indicates the balance between the generation and load.

Today, what happens is that the load is not in my control, everyone is free and flexible to use power as per his convenience, so requirement of power is not in the hands of the grid control operator anymore. It seems to have declined over the last decade as the portfolio of renewable has increased. What has happened is there is limited control of renewable as we do not know how much of the renewable will be harnessed. Now, there is some forecast regulation but that regulation itself has a lot of loopholes. Say, there is percentage error formula which does not match with the conventional power percentage error formula. There is already an open band with respect to Gujarat, where for up to 12 percent deviation there is zero penalty. So, if I have 8000 MW portfolio of renewables to manage but I cannot vary more than 250 MW that is one of my boundaries, that is also one of the regulation.

There is huge mismatch between the regulations being planned. They may have the idea to give incentives and promote renewables, but electricity generation from renewables follows a set of laws and that from conventional is governed by a different set of laws. Therefore, with respect to the management of the grid, our rules should be analogous with each other, while amount of penalty can be different. One more thing, we knew that promoting a type of generation say renewable, is going to have huge vulnerability, variability, or uncertainty but we are not planning any balancing mechanism and we are asking grid to do plus-and-minus 250 MW at SLDC-level.

Frankly, we have planned 175 GW, but we never plan any gigawatts for balancing. Now, they are planning 450 GW, but I do not see any associate planning for balancing. If you know you are planning something intermittent or variable, but are not planning to counterbalance that type of source, that will create a lot of problems with respect to the grid operation. Therefore, administratively, at the policymaking level we need to take a call to ensure we have homogeneous synchronous planning, regulations and policy that supports grid operations in the true spirit.

Unfortunately, due to the lockdown the demand has fallen, but renewable or wind remains as it is. One other important thing was real market operations date, it has been delayed by two months, it was supposed to be started by April 1, and I am surprised as to why that has happened.

The real market operations date is now postponed to June 1, and Discoms and generators will get one more avenue of managing their schedule with real-time market starting and that will help managing charges and penalty, but how do you see the role of energy storage in grid management? 

Energy management and energy storage is the need of the time. I already mentioned that we have missed the bus planning about storage and balancing device. We need to take a call on promoting storage.

Today, suppose someone wants to plan a 10 MW storage he has to think about CAPEX, as soon as he is the member of the grid he has to pay the transmission charges, who will bear that cost? These are some of the problems that need to be addressed.

Some of the storage mechanism, which is already with us, like pumped storage hydro station probably pan-India more than 4000 MW pumped storage hydro stations which are constructed, technically tested, but not in operation due to administrative or small technical issues. So, people are talking storage but are not taking actions, there is still no roadmap that is being prepared.

What are your thoughts on battery energy storage systems? 

I think somebody has to take the call. If you remember the history or solar, Gujarat during 2008-09 invited and paid `15 tariff for the solar. Similarly, if we want to grow towards a new technology, somebody has to pay the high cost todayonly then research can take place, industry will take shape, and someone will come with a much lower tariff. Pan-India I do not think we have more than 100-200 MW of storage solutions in service or under construction. That is to say, we have a 3000 MW grid and we do not even have a 300 MW storage solution under implementation. Thus, someone has to take a call. If required viability gap fund can be utilized, but we need it.

Storage in lieu of the penalty of renewable; my point is why do we have that 'penalty thinking'. My thinking is storage in lieu of balancing the dispatch of the renewable, if you think and talk in that sense then there will a huge quantum and balancing requirement will be justified, and the course can be determined later.

Today, every State regulator is first keen to know what is the penalty of renewable and whether the storage solution fits in or not, so the RE developer is happy to bear the penalty and not go for storage. That is not the system need; it is a commerce/economic requirement.

My requirement is very simple, if I have variation of wind, a 1000 MW every day, almost 250 days in a year then I need to have at least 300 MW of storage then I can mitigate something. But then, people start asking how much penalty it can raise? How much impact on your grid? I say, if 1000 MW variation is already there then we should at least have 1/3rd of that for balancing and to keep it operational wherever the support is required it should be granted.

Large transmission projects have huge impact on the tariff of the distribution company, whether the project is taken up by the CTO or the STO but that is being granted because it is essential for transmission of power from one place to another. My plea is that balancing is also an important element of the grid to maintain the grid discipline and to operate grid within the desirable hygiene.

Lastly, the event was a great challenge for us, but it was a large distributed operation with one integrated theme: let us all control the grid. And, we have all been successful.

This section regularly features interviews transcribed from the Emerging Tech Radio (ETR) podcasts. The interviews are conducted by Netra Walawalkar who is also the Publisher of ETN. ETR is the radio arm of IESA's media endeavors

Netra Walawalkar Publisher ETN
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