LIVE _ Integration of Renewable Energy into the Indian Grid

Sir, we are live now. Please start.

Uh thank you very much. Uh a very good evening to all listeners NPTEL learners.

My name is Mahendra Kumar. I'm working

as an additional chief manager in projects and business development division of NLC India Limited. For the next 1 hour, I'm going to discuss I'm going to deliver a lecture on the integration of

renewable energy into the Indian grid under the topic. And

prior to starting my lecture, a brief about my organization. NLC India Limited is a Navratna central public sector undertaking under the administrative control of Ministry of Coal. It's the

first central public sector undertaking having capacity renewable capacity connected to the grid over and above 1 gigawatt. And

it is the first organization to establish a battery energy storage system. Uh coupled with a renewable

system. Uh coupled with a renewable energy generation source to smoothen the power output into the grid. And with

this brief, let us go into the deliberations on today's topic.

We are going to deliberate onto this five major topics today.

Uh renewable energy, what is renewable energy, and what are its unique characteristics? Why it becomes so

characteristics? Why it becomes so unique you need to talk about integration? Have you not even in the

integration? Have you not even in the earlier years when thermal energy was integrated, when hydro energy was integrated, there was no such topics of integration issues with the grid. So, a

little understanding on that. And Indian

grid, in what way the Indian operating grid is unique and is it ready to accept the pumping of renewable energy inside it? And the challenges, real challenges

it? And the challenges, real challenges in the integration, and the options available, and the future that is awaiting the sector, which would which paves way for a budding engineers or

research scholars to work on those areas, prospective areas, which are of the need for the country.

Renewable energy generation has become the talk of the town.

Post Paris climate summit, as per United Nations Framework Convention on Climate Change, change, UNFCCC, India has committed some

goals, of which the most important was to have a 30% installed capacity of energy generation based on non-fossil fuel-based

generation.

India is so comfortable until that point of time with coal-based energy generation. Because around 80% of energy

generation. Because around 80% of energy generated energy generated was through the thermal-based systems, and we had got so many number of advancements, efficiencies have been

consistently improved, the grid was so comfortable.

But post 2016, there has been too much impetus on development of renewable energy owing to environment concern and for having a sustainable development

coupled with energy security.

And across the globe, there was too much of efforts. Few countries have crossed a

of efforts. Few countries have crossed a a great achievements. While European

countries have done well, India by that time was so primitive, now is the fastest developing in terms of renewable energy.

And it has aligned itself towards the global uh pathway, and has set a target

of 450 GW. In terms of MW, it is 450,000 MW of renewable energy capacity to achieved by the year 2030.

For your understanding, the present day the entire grid installed capacity is only 3 lakh 80,000. But in the next 9 years, we

lakh 80,000. But in the next 9 years, we are aiming to establish renewable energy generation sources capacity sources for

4 lakh 50,000 MW of energy. So, when

such a large-scale penetration of a unique kind of energy into the grid requires lot of innovations.

Some disruptive non-conventional changes are expected. Why? Because of the nature of

expected. Why? Because of the nature of renewable energy sources which cannot which don't act as a base load as of now, but a day is expected that they are

going to give energy as base load, but those are in future. But this

penetration, it has got a it has got a future, you have got a target which requires detailed analysis.

And that detailed analysis is going to come in the coming part.

Renewable energy. By the term, what is renewable energy?

Two things can be used to define it.

One, it is clean.

Two, it is replenishable. You don't

annihilate something.

You don't exhaust something.

Which is a natural source which comes again and again and again. So, clean and replenishable non-depletable is the two three characteristics which

is speak about the renewable. While all

other sources are depleting, maybe your fossil, it's highly depleting. Maybe

your nuclear, depleting. While these

source of energy don't deplete, they keep on they are in existence um non-partic- of time. So, it will be

on existence. Some sources of renewable

on existence. Some sources of renewable energy are hydro, wind, solar, biomass, geothermal, ocean energy. We have got

large number of sources of renewable energy, but in Indian context we do not have hydro large hydropower plants are not brought under renewable energy

sources in India. They are earmarked as hydro a separate category.

Small hydro plants less than 25 MW capacity is being taken as renewable energy sources.

And wind and solar are predominant.

Wind India is bestowed with uh wind rich sites.

So, we have got uh some um developed wind generation sources.

Solar, India being a tropical country has got good potential for development of solar energy, and we still have good amount of solar capacity installed as of

now. Biomass, agricultural land has got

now. Biomass, agricultural land has got a good source for biomass. Geothermal,

ocean energy uh don't uh fare well in Indian context, but those are available in other nations where they've got the potential. So, these are some sources of

potential. So, these are some sources of renewable energy. In particular in

renewable energy. In particular in Indian context, wind and solar gains utmost importance, and it it gets our

attention.

Renewable energy generation sources has got the following challenges. Has got

the following characteristics which pose as a challenge to the operating grid system.

Say, it is clean, it is non-depletable, but the challenges are it is intermittent.

By the word intermittent, it is not continuous. It operates for a specific

continuous. It operates for a specific period of time in a day. Maybe 8 hours in some locations which has got some good solar radiation, maybe 10 hours.

And variability, solar comes with that character, variability.

As far as variability is concerned, this particular source of a renewable energy comes for a season. Say, June, July,

August are normally you'll get wind generation more. After

the during November, December, the same source which was running at its rated capacity will will be idle.

So, your demand or your generation happens only for a period. We call it as 3 to 4 months. There after it goes to zero times. So, it has got it has got a

zero times. So, it has got it has got a character which is not consistent with your demand. Your demand never changes

your demand. Your demand never changes that way. Your demand is 365 days, 24

that way. Your demand is 365 days, 24 hours a day.

Point number two, uncertain. As a matter of fact, we do not have control over the natural parameters. Either it be the

natural parameters. Either it be the sun's glow, cloud passage, or wind speed. You don't have a control over it.

speed. You don't have a control over it.

It is hard to forecast. It is tied to meteorological forecast. It does not

meteorological forecast. It does not support grid security. See, for example, our grid at times requires little less power, at times it requires more power because of demand that is being

happening there. This you don't have a

happening there. This you don't have a control over it. Whereas in thermal power plants, based on your need, you can actually control it. You'll be able to generate little more, or you'll be able to generate comfortably less if

your power is not required. That is one important challenge associated with the renewable energy sources.

Locational dependence. See,

even though tropical country, we have potential, solar potential rich in deserts, and wind potential rich in offshore locations.

But your load centers are not there.

Your load centers are not there in deserts. Your load centers are located

deserts. Your load centers are located somewhere nearer to urban locations.

So, hence your generation will be at one point while your necessity will be at another point which is which necessarily not be very close. It would be It may be far long off. So, these renewable energy

sources are location dependent unlike your conventional source of generation.

You can't neither transfer the raw material or your source of energy generation. You'll have to establish

generation. You'll have to establish compulsively there where in conventional systems you get you got option of establishing power plants at load centers where it is actually required.

Non-synchronous technology.

This renewable energy sources are connected to the grid to the consumer we'll take it as through power electronics rather than

any rotating equipments. Solar energy

photovoltaics receives sunlight, converts it into electricity, and this electricity is in DC form while your grid operates on AC. This DC is going to

be converted into your in your inverter based on power electronics then connect.

Similarly, wind turbines operating on variable speed where your variable speed AC is converted to DC then again DC is converted to AC and pumped in because of

quality issues. So, it is

quality issues. So, it is non-synchronous technology unlike where your thermal power plants your turbine runs and your generator coupled with that based on frequency we have certain

technologies associated with governing frequency governing mode of operation.

In case if your frequency rises above your set value 50 you your turbine automatically unloads. In case your

automatically unloads. In case your frequency goes little below than the set value 49.9 your turbine your turbine based available steam can little generate more

based on limitations. A lot of factors are there, but it responds to the grid requirements. We call it as grid

requirements. We call it as grid services. Neither your solar can

services. Neither your solar can respond, nor your wind can respond. It

is entirely out of your control. It

depends only on the nature. So, such is what is your renewable energy is. I told

you wind generation is based on season. Say, may it be June, July,

season. Say, may it be June, July, August, our wind generation based on months for one particular year is shown here.

April, it is less. But, when you see it in June, July, August, you find peak generation happening there. The same goes to zero by

there. The same goes to zero by December. November, December, January,

December. November, December, January, February. So, this becomes a

February. So, this becomes a non-reliable source of energy generation. Non-reliable source of

generation. Non-reliable source of energy generation because you can't depend 100% on the source of generation.

This is the way how a wind turbo generator works.

Coming to the solar generation, I have told you it is coupled with intermittency.

Intermittency on a day's generation, I had marked it for every 15 minutes how a solar power generator, PV-based power generation works.

If you see, the generation starts by 6:45 or 7:00.

It comes down by 18:15, 6:15 in the evening.

Does your grid requirement or does anyone works on this necessity? No, we

have a very flat or we have requirements around the 24 hours. Not only that, see the profile of generation. For every 15

minutes, the generation goes up and down because of climatic changes, cloud movements, wind, dust. Lot of things are there. Temperature rise, lot of

there. Temperature rise, lot of parameters are there. You do not have a control over these parameters. You can

neither tweak it to smoothen it, or you can tweak it to up it. Nothing can be done. So, that is the one which I've

done. So, that is the one which I've been saying.

Uncertainty. I told you you have no powers over to uh dictate what would be your generation by this time.

Because it depends on so many number of factors. If you take it as a wind power,

factors. If you take it as a wind power, it depends on humidity, rain, ambient temperature, dust concentration. Lot

many factors come into role on its generation characteristics, on its generation characteristics. Similarly,

generation characteristics. Similarly, solar power generation depends on cloud movement, on dust concentration, rain, because it it has an impact on the

temperature of the module, solar PV modules. If the temperature of solar PV

modules. If the temperature of solar PV modules is less, relatively less, the generation will be more. If the

temperature of solar PV module raises, the generation of solar PV module gets reduced. So, you have a kind of

gets reduced. So, you have a kind of uncertain situation about about your generation. You do not have a control or

generation. You do not have a control or kind of ability to predict and tell that this would be my generation this time.

Which is actually very much required for a safe and stable grid operation.

Solar Atlas. I told you it is location dependent. It is not the same

dependent. It is not the same everywhere. It is not the same

everywhere. It is not the same everywhere. It varies from place to

everywhere. It varies from place to place, location to location. Even in

India, even though it's a tropical country, it you're in a mid-range, mid-generation range. Where your

mid-generation range. Where your capacity, your generation can be around 16 lakh units for 1 MW a year on an average. Some locations in Rajasthan

average. Some locations in Rajasthan desert offers you a little around 20 lakh units. It depends on

lakh units. It depends on uh it depends on the irradiation factors.

And so, uh establishing a project at the particular location is economically viable, but at a locations where it is generating 16 lakh units are lesser than that

may not be a viable option because it would affect your economics. The plant

economics will be seriously dented. So,

it is to show that plants based on solar if established a high potential zone, your economics will support you. In

place of low low generation low solar potential, you'll be getting lesser generation which will directly

impact on your economics. Fine. Wind

potential similar way is a different across the globe or even I would say in the state of Tamil Nadu, we have got certain locations which has

got average wind speed more than six 6.5 m per second. Normally in the passes available with the Western Ghats. Um

Muppandal Shengottai Kayathar similarly in Gulf of Kutch. There are certain areas where

Kutch. There are certain areas where your average wind speeds are so high, so establishing a project there gives you best results and best generation while

at other locations, um nowadays technology is being brought by the wind turbo generators to reap even at the slower speed at the very lower speed. Um

but even then your economics you generate less your economics because you have put in some amount of money you'll have to break even that that doesn't happen actually. So, locational

happen actually. So, locational dependent. Non-synchronous technology.

dependent. Non-synchronous technology.

So, we do not have a rotating equipment in solar power plants.

Can it be taken as a supporting factor or a negative factor because rotating equipment basically solicits higher maintenance cost. But here even though

maintenance cost. But here even though you don't have it, you will not be you cannot support during grid requirements.

Point number two. Through only power electronics we call it as a support our during black start operation, this renewable energy sources cannot be a dependable source unlike

conventional plants which can be used for whenever a grid is blacked out it that can be used as that. So, these are connected through power electronics and not through mechanical systems and other

things. So, that's what we had been

things. So, that's what we had been discussing about the renewable energy sources. So, we have come to a

sources. So, we have come to a little bit of understanding on the renewable energy sources. Clean,

non-depletable, but intermittent, non-synchronous seasonal variability are all there. Fine.

all there. Fine.

How about our Indian grid? Because we

are talking about connecting this renewable source to the Indian grid.

We'll see how the grid What is the characteristics of our Indian grid? Our grid is so unique with the two peaks and two lows

on the same day. It is not normally a flat curve.

Normally, no grid will be in a flat position, but ours is too unique to It's unique. You could see this is an actual

unique. You could see this is an actual demand that was met for the day, 30th December 2020.

Why that particular day? That is the day by when which we achieved the highest demand highest demand for any one particular day until this date.

Approximately more by 180 180 gigawatt 180,000 megawatt was achieved on that day. We have two peaks and two lows.

day. We have two peaks and two lows.

Normally, yearly morning low somewhere around 4:00 it will go to rock bottom or to a little bottom. By 10:00 9:00 to 11:00 it will reach one peak. Then

again, it will settle down by 3:00 to 4:00 5:00. It reaches again a peak

4:00 5:00. It reaches again a peak during 7:00 in the evening.

Your demand your necessity your need is not a flat one.

Or not a particular graph which is suitable for renewables because as solar which runs for 300 days generates its peak by at 12:00 to 2:00. By the time

your grid requirement comes down. It

doesn't generate by 7:00 but your requirement is too high by evening 7:00 evening peak.

So variation. When it is wind for the three seasons June, July, August no doubt it will give a real flat a little lower during daytime otherwise it's a

real flat. But solar 300 days morning

real flat. But solar 300 days morning peak it rises and reduces not matching with the actual demand that is persisting in our Indian grid.

And it is also not sure say this is the way the demand was met with various generation sources because we have we have thermal, we have nuclear, we have

hydro, we have wind, we have solar.

Solar the yellow line shows it starts from 7:00 and gets done by 6:00. It's

it's portion is very less because you need to compare with the right hand side generation megawatt 100 megawatt.

While thermal acts as the base and contributes to the major portion of energy requirement energy requirement.

All other sources contribute only little very small portion when compared with the 100% requirement of an Indian grid.

Wind contribution was less hydro acted as a cushion. The blue line which has got one peak then comes down and again

takes another peak acted as a cushion for accommodating this solar generation.

But India being an agricultural country you cannot expect this always because hydro plants based on reservoirs reservoir discharge based on

agricultural requirements also. Always

you can't discharge as you like or you always you can't stop when you don't want to do it. It is an interlinked parameter. It is not a standalone

parameter. It is not a standalone parameter.

So, this is the way how that particular demand on that particular day was met with various sources.

In terms of contribution, the brown which shows uh or an orange like thing, the thermal contributed the biggest.

While the yellow is for your solar for a very small point. The green is for wind, again a very small point. Hydro acted as a cushion. This is just to show

a cushion. This is just to show presently that thermal acts as a base load today.

As of now.

And solar is just contributing a very little now.

And the variation that has that has happened on the grid on that particular day, you could see

a variation of 60,000 MW has happened in the grid. From the morning low

the grid. From the morning low by over 9:00, 9:48, it has it has ramped up 60,000 MW. Too

much of variation was seen on that particular day. To that

extent your grid requirement, your demand requirement is on a single day, there is a plus or minus 60,000 MW requirement is there, which is so unique

when compared with other countries and which is so unique when in terms of renewable energy generation is concerned because you need to accommodate it there.

And to that extent there is variation and on that particular day, 75% or 77%

of energy required was met through your base load plants, coal and lignite.

While your renewable energy sources, wind and solar contributed only 10% of it, 10% of it.

And this is not to show that this is the way your grid operates. You cannot say always will this be 60 gigawatt plus or minus? No, we are subject to too many

minus? No, we are subject to too many number of changes. I would again show you a plot for the latest 11th March 2021 and nearer flat and nearer flat

where the difference between the low and the peak is not too high. So, that's

what what we are telling, our grid requirements are so unique when compared with other nations, other global nations requirements. Maybe flat at relatively

requirements. Maybe flat at relatively flat at sometimes, maybe having a steep rise of 60 gigawatt the change is required. And here if you see again, the

required. And here if you see again, the same solar hydro acted as on on that particular day, the hydro acted as a cushion for taking the taking the

generation for accommodating the generation that happens to come from solar.

And again, the percentage of wind was a very very low, very low on that day, while thermal as usual was contributing the major portion in the grid.

On that day, the largest deviation was 32 gigawatt or 32,000 megawatt. On 30th

December, it was 60,000 megawatt. On

this day, it is 32,000 megawatt. So, our

grid is so season dependent, our generation is season dependent, grid is grid demand is season dependent. So, that is what we

season dependent. So, that is what we try to emphasize. All along, what has been done? What has been done and to

been done? What has been done and to what extent has the renewable energy in terms of energy?

We don't speak in terms of installed capacity. Installed capacity is

capacity. Installed capacity is different. Today, of the installed

different. Today, of the installed capacity of 382,000 megawatt in total, Indian grid comprises

of 382,000 megawatt, we approximately have 92,000 megawatt of renewable energy sources. 41,000

sources. 41,000 megawatt of solar, 39,000 megawatt of wind and others contribute to 92,000.

But in terms of generic generation that doesn't reflect because thermal plants operate at a higher output 85% plant load factor while renewables such

as solar act at only 19% capacity utilization factor or wind act at 27% they generate very less when compared to thermal. So on on when I

assume for that particular 2021 year every month conventional sources of contributed to this extent and only approximately 10% of energy, this is in

terms of energy million units, has been contributed by renewables in blue. So

for every month approximately 10% of the energy generated is through your renewable energy sources. It is just very very very little when compared to

the actual junk of requirement.

What is the projection? Integration so

now as of now it seems that it has been perfectly integrated that are hydro systems that are that are taking now fine. We have our own projections where

fine. We have our own projections where we are going to see. I told you 450 gigawatt or 450,000 by 2030 is being

planned. Our capacity addition has been

planned. Our capacity addition has been projected this way that in another less than 2 years by 2022 December we need to

reach a renewable energy capacity of 175,000 megawatt from the present 90,000

megawatt. This is old figure 92,000 is

megawatt. This is old figure 92,000 is the present one. So 175,000

megawatt of renewable energy is to be reached. I have told you the

reached. I have told you the characteristics of the source as well as the grid but you will you will have to go by approximately you have to increase

it to 36%.

By 2030 you need to achieve 435 435,000 MW of renewable energy, which is actually 53%.

And by 2040, as per a study of Government of India, you have to go up to 597,000 MW.

So, it is not with the present 24% where the grid is to some extent comfortable.

We have challenges, but we are adopting or we are we are accustoming it to that, but your share is expected to increase in the days to come, thereby

the challenges are also expected to increase.

Fine, this is a split up of what that is going to form part of this particular generation. Of all the sources of

generation. Of all the sources of energy, solar is expected to swell to a larger extent to swell to a very larger extent, and

it is expected to reach 360,000 67,000 MW by 2040, 280,000 by 2030. Sorry, it

must have been 100,000 by 2022 and 60,000 by wind. So, that is the way these two sources are expected to grow in the days to come.

So, yes, this is the breakup for the next to 2022 December. 100,000 MW 100,000 MW of

2022 December. 100,000 MW 100,000 MW of solar energy generation is expected to come. What is the present generation? It

come. What is the present generation? It

is approximately 41,000. You still have to achieve 60,000 MW within a period of around less than 20 months time. Actions are

underway. Government is floating a lot of tenders for establishment of solar pass associated with so many number of schemes, but the target is too high. You

need to double, you need to 1.5 150% swelling is expected. Wind from the present 39,000 MW, you need to further add 20,000 MW to reach 60,000 MW. Hydro

small hydro 10,000 and 5,000. This is

what is the target that has been set by government of India for December 2022 as per MNRE.

And challenges in RE integration. Yes, we

need to achieve it and what are the challenges?

One side, we have an unpredictable, uncontrollable generation. On the other side, we have

generation. On the other side, we have an incalculable demand.

So, either way, we are compelled to have challenges. On one side, we are not able

challenges. On one side, we are not able to perfectly predict our demand. On the

other side, we do not have a perfect we do have a uncontrolled generation source. But, these two has to be brought

source. But, these two has to be brought in line, has to be smoothly integrated.

What are the major challenges? See,

earlier, our grid was a very conservative controlled grid. During

independence, it was purely hydro stations. And thereafter, thermal picked

stations. And thereafter, thermal picked up because of larger developments that happened in rank and your thermal power plant technology, that slowly started dominating and went off

well. And until 5 years back, it was

well. And until 5 years back, it was doing extraordinarily well. But, now it it has come it is supposed to give way for renewable energy sources. So,

first point is unmatched generation.

When does a peak a normal peak occurs on a day? On two times, morning 10, evening

a day? On two times, morning 10, evening 7:00. And the major source of renewable

7:00. And the major source of renewable energy generation, that's renewable solar, is not available by 7:00. It is

on no day it is going to be available.

So, what to do? It is one point. Point

number two, non-responding non-responsiveness. See, we are coming

non-responsiveness. See, we are coming to a particular place where for demand, for production or consumption, your generation should respond. To what extent you respond, you

respond. To what extent you respond, you become so cost effective, you become so good. But as a matter of fact, source

good. But as a matter of fact, source nature dependent. And you have a

nature dependent. And you have a compelling factor must run status for renewable energy sources is what is being mandated by government of India. Until otherwise, if

a grid demands for security reasons, you can curtail any solar or wind generation. Otherwise, nobody can

generation. Otherwise, nobody can curtail wind solar generation. But this

gentle source of this renewable energy source is not responsive for the grid needs. Again challenge. Whenever there

needs. Again challenge. Whenever there

is supposed to be some curtailment, it will keep on generating. Whenever you

need to have some requirement, it will just go on because it doesn't have control over it. Must run status. As I

told you, economics.

If you start because nowadays that's renewable energy sources are being having ultra low tariff and having a very narrow margins. So again,

curtailment or stopping of production will have one more cascading effect in economics and will have a demotivating effect on establishment. So must run status. Cost perspective. See, renewable

status. Cost perspective. See, renewable

projects are land intensive. Unlike

conventional projects, there is a thumb rule where 1 MW of thermal generation requires 0.5 acres.

Whereas 1 MW of solar plant initially required 5 acres, now due to technological developments, they are reaching to 3.8 to 4 acres per MW. You

work out for 100 MW, it is 50 50 acres per thermal. It is 550 acres or 400

per thermal. It is 550 acres or 400 acres per solar. Land intensive. Okay,

that is okay. In terms of generation, while 1 MW of thermal generates 87 lakhs of units in a year. I'm speaking about a year. 85% it would generate. Whereas a

year. 85% it would generate. Whereas a

solar will generate somewhere around 16 lakh units. We call it as low CUF, low

lakh units. We call it as low CUF, low capacity utilization factor and high transmission cost because it will be located somewhere. It is not at pitted,

located somewhere. It is not at pitted, it is not at what we call it as load centers. It will be somewhere. It you'll

centers. It will be somewhere. It you'll

have to transmit the power that is generated. So, high cost associated with

generated. So, high cost associated with the transmission aspects related with RE sources. So, these are all some major

RE sources. So, these are all some major challenges that are in that are enforced into the system by the renewable energy sources. Now, we'll

come to the options point. Okay, we have got

options point. Okay, we have got challenges. We want What are the options

challenges. We want What are the options that needs to be developed well because what are the global best practices that have made because Germany is one country

which on one particular day has met its entire requirement through renewable sources for a period of time.

When that is possible by one particular country, why not us? Why not us? What

did they do and what is on cards for us?

What are the available proven integration base? We call it as we have

integration base? We call it as we have got forces four points here.

Wider balancing area.

Wider balancing area. Say, sun solar starts sun rises in the east and sets in west.

Sun on a particular region shines for a particular time, then it moves to another portion, then it moves to another portion. When it moves, there comes 7:00. So, when you have a wider

comes 7:00. So, when you have a wider balancing area, your demand and your generation can be shifted. One

particular location where there is demand and one particular location where there is demand and where generation, if you couple it, you can you can say I told you by evening

12:00 to 2:00, you'll get the best generation for solar. Find out where it is required by that time. Move it and you transport it, you get an option because you don't want to curtail and

you just shell it, then again by the time there generation could be more when your are is high, just move it back. So,

that way when wider balancing area is a low cost methodology available for integration. Regionally you should be

integration. Regionally you should be spread across your system grid system should be spread across.

Point number one. Point number two.

Energy storage system. A costly affair presently. The levelest cost of energy

presently. The levelest cost of energy storage hovers somewhere around 6 rupees to 8 rupees uh through battery. Because

that's a one proven technology and one promising technology in the days to come where our optimal energy mix recommends 27,000 MW capacity battery energy

storage system to be in place in the Indian grid by 2030.

But costly. But costly. Because it's a chemical storage system. You peak

saving. During 12:00, 11:00 to 3:00, whatever you generate, you capture in a chemical storage system. You discharge

it start discharging maybe 5:00 to 8:00.

You take it, discharge it. But coupled

with um round the cycle efficiency. See, you

give 100 units to a battery, you don't get back 100 units. You'll be getting somewhere around 80 units or 85 units.

And life of the battery, cost associated because every 5 to 10 years you'll have to replace it. Lot of challenges. But it

is one option because we'll have to choose something because it depends upon the cost economics. When you work it on a holistic manner, if it is it is agreeable, we'll just give it we'll just make it.

Flexible systems. What do you mean by flexible systems? What people have done

flexible systems? What people have done the way the conventional operating systems, not just the hydro, also the thermal system to just flex

itself.

We do have a common term of going your 55% of the operating capacity. If your

plant is 100 MW, when you don't require power in the grid, you are supposed to go to 55 MW generation.

We flux the conventional systems. That flexing has to be improved. As of now, now our grid is connected with

um a considerable portion of old age plants making it difficult to flex it too much.

So, the day will come when you are able will be able to flex it little more.

You'll be able to go up to 55%.

While foreign countries, European countries in particular, had one kind of flexibility where they just don't uh flex their thermal systems. They use the steam generated from the thermal system

for district heating. So, they don't have any problem. They'll still operate at 60% while their production of electricity will be 10%. The remaining

50% goes to district heating. That

opportunity is not available in the Indian context, but still we'll have to bring in systems which can go up to 55% of its operating capacity and still be stable and supply and support the grid

services. A little more penetration of

services. A little more penetration of gas-based power systems. Gas turbines.

Presently, the capital cost of gas-based plants is too high even though the cost of gas is sliding down, but the capital cost of 10 crore rupees per megawatt is

too high. But anyway, the days will come

too high. But anyway, the days will come when we have flexible thermal generation systems into the grid. That is one way how you'll be able to accommodate it.

And the final one and a promising one, a very low-cost um opportunity available way is forecasting and scheduling. Even though

regulatory framework has paved a way for forecasting and scheduling renewable energy sources, we will have to still mature. Because uh in most of the states

mature. Because uh in most of the states it is yet to take off, you will have to tell what would be the generation from your solar plant tomorrow?

By this time. Every 15 minutes block you need to you need to spell out. Not just

for solar, your wind has to be spelt out and there is if it is error if your absolute error is within 10% no problem.

Beyond 10% it depends on state to state.

In certain states they charge 25 paise, 50 paise, 1 rupee. So, they are bringing in the science of forecasting and scheduling because it is the cheapest

available way for properly planning your generation and you can spell out by this time if you are if your grid don't request it, where can it be pumped? Can

be easily planned. These are the four mature areas that are being that was followed by the global best country practices, best

practices.

Fine. We'll deliberate in detail our wider balancing area. Say you have intermittency and variability, but once you have a very large balancing area

Indian grid has got the credit of the largest synchronous grid. See it

forms it was it is five parts. Southern

grid, Western grid, Northern grid, Eastern grid, Northeastern grid. There

are five grids. So, of which they are interconnected. It's a national grid,

interconnected. It's a national grid, but the transmission capability or we call it as inter-regional transfer

capability as of now is only 120 gigawatt or 118 gigawatt if I'm right.

This is constrained. This is

constrained. Why? As I told you locational dependent. The Southern grid

locational dependent. The Southern grid is rich in renewables. Karnataka, Tamil

Nadu, Andhra. Good in wind, good in solar. Gujarat, Rajasthan. Good in wind,

solar. Gujarat, Rajasthan. Good in wind, good in solar.

And you need to connect it well with other grids such that whatever generated should go. In June, July, August, if you

should go. In June, July, August, if you see, there'll be huge wind generation from Gujarat and Karnataka, Tamil Nadu.

You need to take it. When it is only it you can take it only when it is fully connected. When you say that all

fully connected. When you say that all your power can be transported out because naturally northeastern or northern grid doesn't have as such huge generation of renewable energy sources.

So, this will actually give a large There is an opportunity. You need to strengthen the grid system so that your balancing areas Whenever southern grid

generates, you give it to northern grid.

Whenever northern grid generates with idle power, take it here. And this has to be done in a through but actions are happening.

This will happen. This will happen.

European countries, German can transfer power to neighboring countries.

Czech or to France. To that extent they are well connected. They call it as a European grid and northern countries grid. When we also have a better

grid. When we also have a better relationship with neighboring countries, when we get connected that way, we'll still get an opportunity of achieving better economics and better

balancing.

That is transmission network better transmission network has to be done and is being done. Every month, every year, the interregional transfer capacity is keeping on increasing. When that comes

in, this balancing will be easier task.

Next, storage system. Yes, we call it as peak. Peak happening between 11:00 to

peak. Peak happening between 11:00 to 3:00. So, you need to take it, shave it,

3:00. So, you need to take it, shave it, take it to your real requirement. Or we

also have another technology called as pumped storage system in hydro plants.

But it hydro is related with agricultural system. So, to

agricultural system. So, to So, to make any changes in that is a That's quite complicated. That's quite

complicated. So, pumped storage system, even though is the best reliable, dependable storage system, implementation in Indian context has got certain limitations. Battery

energy storage system, again, the levelest cost of energy storage is hovering around 6 to 8 rupees. In the

days to come, when lithium batteries dominate and when this matures because of technological developments, and that should when it comes down, definitely it

will help us. There is one more opportunity in in energy storage systems, utilization of electric vehicles.

Say, Government of India has got a plan to bring in 30% electric mobility into the Indian roads by 2030.

They are going to have high energy intense batteries.

We'll incentivize them. Say, when you charge your car at this point of time, you'll be given a electricity at this rate. When you

discharge, provided if you don't require power, if you are discharging it, you'll be given an incentive of this. Rather

than the grid on its own building battery energy storage system, we'll we'll accustom ourselves with the available available system, where electric

vehicles they will add do this purpose of energy storage for us. We'll

incentivize them through some kind of some kind of regulations. That That

gives you a better opportunity for storage systems. And flexible system, say, there are two parts. One is the demand, the other one is the generation. Even in

demand, we must be in a position to shed non-critical loads, or we must be in a position to plan that this act happens at a particular point of time. It is not

that you work on your own. Based on grid systems, through Now, even nowadays we have got five slots, wherein evening peak, morning peak, the tariffs are hiked. So, that is one step towards it.

hiked. So, that is one step towards it.

So, you should be plan in advance where you need to take this activity, high energy intense activity. Generation, you

are bringing down you your systems will be brought the newer thermal power stations will be capable of operating at 50 to 55% of the rated capacity on requirements. Coupled with ramping

requirements. Coupled with ramping requirements, 60 gigawatt is on one particular day from 3:00 to 10:00, you need to ramp it up.

Meet that ramping capability to the systems the newer thermal conventional systems which are coming on board are being designed. The older systems which

being designed. The older systems which were developed during 1970s and 80s are retiring now. When those get phased out,

retiring now. When those get phased out, this system will help us in better flexing the system. Forecasting, as I told you, prediction,

uh permits, say, various sciences are being used, statistical sciences and numerical weather prediction, something like finite element analysis on a three-dimensional part. We have six

three-dimensional part. We have six parameters that will be solved for its actual factors. Hybridizing both of

actual factors. Hybridizing both of these things, numerical weather prediction coupled with statistical approach with the meteorological data, they get the past 10-15 years and they

take certain parameters on this year.

They couple it, they work it out, they write some algorithms and they predict what would be the solar irradiation or the wind velocity on this particular date. If this is the radiation and if

date. If this is the radiation and if this is the wind velocity, what is your solar generation and wind generation is being worked out. So, that, if being

done with some kind of accuracy, will make your generation profitable.

Not only it will help you to accommodate, it will help you make it profitable because you know that by this time I'm going to generate this much of power, you can go for power trading.

Say, I'll be generating this whoever wants because they do day ahead market.

So, you can just commit, you can give and make money out of it because requirement based on requirements, your profit is your tariffs are hovering somewhere from 7 rupees to 3 rupees. So,

you can make money out of it through forecasting and scheduling.

So, uh this is going to dominate.

Furthermore, furthermore, apart from those technologies which we have discussed, flexibility in thermal generation.

Somewhere if some innovations are brought that not just a steam from a thermal power plant is used only for power generation, may also for some kind

of process. So, based on requirements,

of process. So, based on requirements, you can shift this way that way. If to

that kind some innovations are brought into the system, there will be better uh benefits. There will be better benefits

benefits. There will be better benefits for the grid and for the Indian system power power sector because that is what is being done in German. They take 50% for district cooling. So, naturally they

have they their boilers are so safe, they do wonders there. That is one major area where innovations can bring in and can happen and will be really

good for the integration of RE sources.

Investment in solar. Say,

to what extent you can maximize the generation. It depends on too much of

generation. It depends on too much of investments in solar. See, the

technology is developing very rapidly.

For a single single panel which was generating only 270 Wp earlier, now has started generating 340 Wp and it is expected

that is going to reach 630 Wp and 1,000 Wp is in papers. Lot of technological changes are happening. So, if lot of investments are made in solar, now again

it is being made and if performance or efficiency of the modules are being increased, that would in help in some way help the existing system to respond to requirements. You can curtail because

to requirements. You can curtail because you made two efficient solar systems so that you can have overcapacity. Uh based

on overcapacity, you'll run it uh if if your system is still capable of running at 100 MW, you'll run it 80 MW.

Any grid requirement, you go to 100 MW.

If any grid requirement, you go to 60 MW when your system is so efficient. Now,

you are not possible to do it because your margins are so low.

Hybridization, that is one again technology which is expected to dominate the days to come.

See, renewable is required.

Not through other means. You hybridize

the available renewable energy sources, solar and wind.

Both are complementary in nature. Both

are complementary in nature.

Uh complementary in the sense, if you see the generation profile of wind in daytime, it will have a small sag by which when solar will be peaking out.

When you couple these things, when you put one upon the other, you could find a little uh flatter. It's not a flat, but to some extent um uh smoothed in the curve. And the

utilization of the transmission system will also be better if you couple both these things. And that will also pave

these things. And that will also pave some way for smoother um coupling of integration of renewable energy sources. Storage options, for

energy sources. Storage options, for sure, is any kind of storage options. I

was discussing only the battery chemical energy storage systems, but systems are also available, mechanical storage system, gravity power house. Uh articles

are cropping out with mechanical uh storage system, not flywheel, but gravity-based storage systems, which also offer a kind of option. An

innovation there could help in further integration of renewable energy smoothly into the uh grid.

See, coming to the uh summary point of all our discussions, absorption or your integration of renewable energy

is imminent. And there was some

is imminent. And there was some restrictions there in the market sighting so many reasons that how could this variable non-dependable source of

energy could replace my requirement. But

now it is made very clear thermal has to pave its way for renewable energy generation. No doubt over it.

generation. No doubt over it.

Now having accepted that initially which was obstructed now we'll have to look out for ways how we can make this happen. Now how we can make this happen.

happen. Now how we can make this happen.

So uh uh our sector which was considered monopolistic or is a sector which was considered to have a very high entry

barrier now has opened ways. Now it is highly liberalized the power sector is highly liberalized. You know way to and

highly liberalized. You know way to and economic flexible power generation will be the future. Not the conventional my generation is so rigid, I can't change,

I can't curtail, or I can't do this. The

days are gone. A flexible power generation will be the future for the country to to move in a sustainable manner because fossil fuels are depleting or hurting

the environment. Only this can to some

the environment. Only this can to some extent mitigate the damages that has been caused due to renewable energy sources. So before concluding

sources. So before concluding I would rather have the live sheets which has been shared for

question answer. Um

question answer. Um The first question is what are renewable energy sources? Hope I had

energy sources? Hope I had did the I've discussed on this.

Non-depletable. The first question is non-depletable uh and uh clean clean source of energy is

renewables. How did India How is it

renewables. How did India How is it going to benefit India? Uh to be very true, uh the thermal power plants, the

emissions, and coupled with One point is that can give you a clean source of energy. Point number two, in terms of

energy. Point number two, in terms of economics, too. The average power tariff

economics, too. The average power tariff of thermal energy sources is uh approximately 3 to 4 rupees or some newer plants are 5 rupees. But this

uh renewable power uh comes at 1 rupee 99 paisa, 2 rupees, and it is uh highly benefiting the economics. But it will sustain. It is now it is so sweet. We'll

sustain. It is now it is so sweet. We'll

have to wait and see how it is going to be uh uh going to uh thing.

Uh is 2020 um solar energy will be a bright scope?

Yes. To be very true, the target for 2022 December is uh uh question from Mr. Gaurav Aggarwal.

The target for solar energy in the Indian grid is 1 lakh megawatt. The

present capacity is 41,000 megawatt. You

need to add in another 20 months, less than 20 months, you need to add another 60,000 megawatt. Be it be project

60,000 megawatt. Be it be project execution. Be it be project uh operation

execution. Be it be project uh operation and maintenance.

This field is a real promising field for engineers in the days to come. Thermal

is giving way to renewables, in particular to solar. So, naturally,

you'll have to uh there is high high uh scope for um career in RE.

Are we going to hybrid power system?

Uh um Listen about Fine. Next question.

Um How to set up a startup in solar energy and how to get government support? See,

considering the maturity of solar, the government has slowly withdrawn the incentives that were given initially to

motivate it. So, as of now, it is that

motivate it. So, as of now, it is that it is as a startup, rooftop solar which was envisaged to

contribute 40% of the target has not taken up well. Has

not taken up well.

To be very frank, ground mounted grid connected as connected as taken off well and is doing well.

Startup in rooftop, a wide opportunity is there. A wide opportunity is there

is there. A wide opportunity is there and that can be looked into and that can help in startups. And

renewable sources um non EN candidate, okay. Will I receive?

Okay.

Um fine.

Uh What is grid tied inverter? How it's

different from other inverter? See,

uh grid tied inverters are used in solar PV power plants. While in other inverters, what we use here is batteries based inverters. Here grid tied

based inverters. Here grid tied inverters takes a reference takes a reference from the grid and generates a sinusoidal wave in in in correlation

with that and pumps the the power from solar DC side to the grid. Whereas in battery, that is

grid. Whereas in battery, that is different which is being used for internal thing. Here it takes a

internal thing. Here it takes a reference, there it doesn't take a reference, it just works internally.

And another question, uh integration file, uh Indian grid. How to Okay. Uh

Thermal power plants still form the base load of our national grid, whereas solar and wind form uh part of peak load.

When can a nation completely stop using thermal power plants? Uh

can we extend um virtual power plant completely?

Fine. See,

um thermal power plants are presently the base load plants.

We anticipate to penetrate 25% of energy requirement only through wind and solar by 2030.

And this may be revised to further, but as of now, from the present 10% energy pumping in terms of energy, I'm speaking, not in terms of capacity, in

terms of energy, it is only 25%. It

would stay it would take Even as per our projections, there will be a small portion of thermal power plants available in the grid even by 2040.

Because we still have our plants getting commissioned 1 year 2 year back. There

is good capacity that has been commissioned. That would live until at

commissioned. That would live until at least for 25 years. So, the complete phase out of thermal power plants would take good amount of time while

it is on the path. Maybe by 2045.

It is not clear, but one day it will happen happen.

And the second question from Mr. Prasanna Kumar is are offshore wind farms required for our nation?

Should India invest on them? What is

your opinion? See, the one only advantage with offshore wind power plants is higher generation compared

with the onshore.

The generation is high.

Point number two, say when this plant generates 27% in onshore, offshore generates 40 to 50%.

The concept of variability to some extent is nullified there. That is very good for Indian context. Studies have

been made by authorities for wind for feasibility report of establishing offshore wind plants in Gulf of Kutch as well as some locations

in Tamil Nadu near Kanyakumari.

Results are promising. But those are high capex because we normally have a initial entry barrier into technology.

We need to study from the Scandinavian countries of German has got approximately 40 gigawatt of offshore wind wind capacity. 40,000 MW.

Comfortably doing, performance is good.

So India too has potential and can be taped tapped should be tapped because renewable energy we want some flatter some smoother source of energy

generation. Offshore offers a good

generation. Offshore offers a good a good option for flat generation.

Um reactive power demand cannot be met.

True. And that is that is one the power quality issues associated with renewable energy sources are high.

Workings are on there. Harmonics,

voltage surge sink and other reactive power issues, fault current issues are there. As of

now since this forms a very low percentage of penetration, it is in a manageable form. But when it increases

manageable form. But when it increases beyond a particular point, there will have to be large scale corrective measures or large scale efforts needs to be taken by the grid

operators to take care of the power quality issues arising out of renewable energy sources.

Uh fine. Okay. Okay.

How grid can be controlled and troubleshooting carried out? See, um we have as of now uh load dispatch centers.

We have uh regional load dispatch centers. As I

still told you, five grids. And we have a national load dispatch center, which is the national authority.

This regional dispatch centers communicates with the state load dispatch centers. Every

dispatch centers. Every uh the grid is being operated this way.

Every state has its own state load dispatch centers. They take generate

dispatch centers. They take generate They monitor generation. They balance

this way. That power is taken from which which particular transmission system power flows from where from where to where. They take about it. And this uh

where. They take about it. And this uh state load dispatch center has sub state load dispatch centers based on requirement.

And now uh it is uh they have gone with one concept of demand curtailment, too.

How can it be controlled? It can be better controlled. They have control

better controlled. They have control over generators as well as control over the consumers. The

the consumers. The the demand side also. So, it is easy for them if any untoward say if the frequency is going low,

they'll cut the particular demand demand uh the area which is consuming more. On the other hand, if the

more. On the other hand, if the frequency is going more, they'll say generator to to stop. And they are themselves now working about a particular area where the load dispatch

centers will have the control of solar inverters and wind turbo generator inverters. They will curtail, not the

inverters. They will curtail, not the operator the generator who is sitting in his control room. The load dispatch centers can have the control over switching on and switching off.

To that extent, they will they are going to take the control from the operators for efficient operation.

Uh source wise Okay, integration of renewable into the integrated grid.

Uh participate Okay.

Uh is sufficient because number of industry during pandemic shutdown demand may be different and a Uh is data is sufficient because number of industrial units during pandemic are shutdown and demand

may be different. True. True. Uh but uh it is told that uh is this particular pandemic situation is dependable source of related to a

generation other things. Uh we too expected a slowdown in consumption.

No, consumption has not uh drastically reduced. It has shifted from one location to other location. We

basically have domestic, agricultural, industrial commercial.

And when there is some uh reduction in industrial load, there has been substantial increase in domestic load.

And to some extent, the grid has seen the peak only during 31st December 2020.

Now it is uh smoothing slowly, but it has seen its peak only during this period during this period. And uh who says it is a dependable uh renewable energy uh is not theory it's actually

parallel with theories, right?

Okay. Can you please send me the MATLAB files on this for studying and start research purpose as a grid by Yes.

Uh okay. What all efforts have been raised uh solutions for Can I uh how student join this organization for learning become part of this good project.

Um fine. Uh

What about nuclear power plant? Will it

meet the demands? See, nuclear power plants have a must run status and whatever that are on cards will come and there is no major thrust from the

government for the newer capacity addition through nuclear source. That is

saturated. They are must run plants. You

cannot curtail generation from them or you can't give any schedules to them.

Whatever they generate, they'll pump it into the grid and they are supposed to agree for that. And they cannot be formed either as one particular source that could help us to meet our demand.

It is only the renewable energy sources which is expected to meet the demands.

Is expected to what kind of research is expected in wind energy generation to meet the

present demand in India? Yes, presently

wind sector is working on one particular area.

Point number one, how to generate from low wind potential sites.

Say, 4.5 m/s average wind velocity is the cut off speed previously. Now they

are thinking of technology where lesser wind speeds too should be used to tap and used for power generation. One

point. Point number two, repowering.

Say, wind rich sites have been established with low capacity plants.

On the present day context, when 500 kW was there, that was a good plant, but now it is construed to be a a lesser capacity plant. So, now they are

capacity plant. So, now they are thinking about say in in Germany, there is around 11 MW plants are available. So, now we only

have two to three MW plant. So, that

they are thinking about raising the capacity. So, that is all about the

capacity. So, that is all about the questions that have been raised on the on the particular thing. Now, I hand over the session to

NPTEL moderator. Thank you very much,

NPTEL moderator. Thank you very much, sir. Thank you for the participants for

sir. Thank you for the participants for having been patiently heard this session. Thank you.

session. Thank you.

Yes, sir. Thank you so much for the session, sir. It's

session, sir. It's a lot of responses from Thanks.

Thank you.