Hello, welcome to the second lecture sequence of the first week of the NPTEL course on an introduction to programming through C++. I am Abhiram Ranidhi and the reading for this lecture sequence is chapter 2 of the textbook. So in this lecture, we are going to ask some basic questions, really one basic question and provide some very high level answers to it. So basically the question is how can a computer do so many things? It can search for information, predict weather, process pictures, pledges. In this lecture, we want to provide some high level answers, not detailed answers but sort of just to make things plausible. So all these tasks seem too difficult and too unbelievable. So we are going to provide you just the small amount of information which will make them seem a little bit more understandable. So the answers are going to be of the following kind, we are going to argue, we are going to propose really not a detailed argument, we are going to propose that most real life problems can be viewed as mathematical problems or problems on numbers. And a computer can be made to solve mathematical problems. Well, this statement is a little misleading because a computer does what it is told. So if we can solve that mathematical problem, then we can tell the computer go ahead and solve it. So in that sense, a computer is good at solving math problems. So these high level answers we are going to provide and the hope is that these high level answers will give you enough background for whatever happens later in the course. So here is what we will do. We will see how to express real life problems as numerical problems. So we will take examples of feature processing, predicting the weather and processing text or language. Then I will talk about algorithms and programs. Then I will tell you how a computer really does all these things. So this will be a really whirlwind introduction to digital circuits. So a topic which can take courses in electrical engineering. But we are going to again go through it at a very high level. So I will tell you how a digital circuit works, how numbers are represented using electrical quantities. I will tell you what the parts of a computer are and I will tell you the notion of a machine language program and compilation. So all these things together will be background material for what happens later in the course. So let me start with this question. So you see this colorful picture in front and if I ask you what is in this picture, you could tell me right away that there is a chameleon. By the way, this is taken from a Wikipedia page. Now we would like a computer also to do it and in fact today computers can do it. A computer will tell you that there is a chameleon. How does a computer do this? Well for that we need to know how to represent pictures using numbers. So I am going to start off with black and white pictures. So how do you represent black and white pictures using numbers? Suppose I have a 10 centimeter by 10 centimeter picture. So I am going to divide it into tiny squares. So each square says 0.1 millimeter by 0.1 millimeter. So the side length is 10 centimeter and the side length of the small square is 0.1 millimeter. So really there are 1000 squares on each side. So 1000 by 1000 that is the total number of squares or 1 million squares or pixels are there. Now if one of those million squares is mostly white, we are going to represent that whiteness as a 0. If it is mostly black, we will represent it as a 1. So for 1000 by 1000 squares picture, we will have a million numbers. So we will have a sequence of million numbers which will represent that picture. Here is an example. So that smiley face on top of that I have put smaller squares and as you can see say a square over here, square somewhere over here is mostly white so I get a 0 over here. Whereas this square is mostly black and so I get a 1 over here and so in this manner I have put 1s and 0s. So this is going to be a representation of this picture. Now I would like to note this representation is not perfect. So really if you give me this, I will be able to say that look the picture could be something like this as well and this is not really the same as this picture but it is close enough and in fact you can observe that if I make the square smaller and smaller, I will get a better and better representation of this picture. So if instead of having 1000 by 1000 pixels, I divide it into a million by million pixels then I will get a nearly perfect representation. In fact it turns out that really 1000 by 1000 is not bad. Your screen, this screen for example is probably having something like 3000 by 2000 or something like that and yet you cannot make, you cannot make out that it is made up of small squares. Then other things are also possible. So a square may not be completely white or completely black. So there may be some gray levels. So instead of using 0 or 1, you could also use the number 00.1, 0.2 and so on. So you might have different gray levels, so numbers to represent different gray levels. So your numbers are not just 0s and 1s. So it is not just sequence of 0s and 1s but a sequence of 1 of 10 numbers whatever or whatever 11 numbers. What if you have color? Well colors can be broken down. So a picture now is going to be made up of 3 sequences, a sequence for the red component, a sequence for the blue component and a sequence for the green component. The actual color is made up by adding these components. So that is how a picture is represented. Now what can we do with such pictures? Well we can ask questions like is there a chameleon in it or what is in it? So typically what do these problems look like?  So there are a million numbers 0 and 1 and these pixels are given to us in top to bottom left to right order. So these are representing a 10 centimeter by 10 centimeter black picture given in left to right top to bottom order like the way you would write text on that page. Now instead of worrying about chameleons let me pose a very trivial not even a problem which might be of interest to a child but a really really trivial problem. What is the problem? Is there a vertical line in this picture? So let me draw it here is my picture and suppose there is a line in it so I am asking is there a vertical line that is all that I am asking. So what do you do with such a question? How do you represent this question using numbers? So you have to ask what property does the sequence need to have if it is to contain a vertical line? Well if I take this picture and convert it into numbers what is going to happen? So I am going to get lots of zeros but suddenly there might be a 1 again lots of zeros then lots of zeros over here then there is a 1 in the same column lots of zeros 1 in the same column zeros here zeros here and maybe all zeros here. So the point is that there is a 1 for some rows some consecutive rows of some column. So can I describe what pattern this sequence of zeros and ones is going to possess? Well here is the pattern suppose the first one is in the ith position where is the next one going to be? Well how many steps are you going to go from here to here?  Remember that the zeros and ones are given to you in the top to bottom left to right top to bottom order. So if an 1 occurs in the ith position then next one will appear in the i plus thousandth position because there are because this distance is 1000. The 1 after that will appear in i plus 2000 position i plus 3000 position and so on. So in fact that is exactly the pattern. So there are going to be 1s in position i, i plus 1000, i plus 2000 and so on for some i. So at this point we have described what it means in mathematical terms for there to be a vertical line. Is there a vertical line is as good as saying does the sequence p of 1s and zeros satisfies this property that for some i there are 1s in positions i, i plus 1000, i plus 2000 a few such entries. Now how do you solve this problem? So this problem is actually quite easy you can try out different values of i. So you can check is there is this pattern valid for i equal to 0. If it is valid for i equal to 0 that is as good as saying that there is a pattern right here that there is a line right here. So this effectively for different values of i will give you different lines and then if you find that is for some values of i this pattern is actually there then you can claim yes there is I have found a vertical line. Now the question does this picture contain a chameleon? In principle is identical okay why again you have to you need to identify a set of properties that the sequence of numbers representing the picture must satisfy in order for the picture to contain a chameleon. These properties will be really complicated but some properties will have to be identified there is no escaping this step then you will have to decide how do I check whether these properties are satisfied. Again this is a difficult mathematical problem but it can be solved okay and in principle it is the same problem that we saw that problem was a trivial problem but again for the vertical line but again the problem was similar in principle that you needed to identify a set of properties and you needed a procedure for checking whether the pictures satisfied those properties. So in practice this requires enormous ingenuity and but people have displayed that enormous ingenuity. In fact this is the main concern of a deep subject called computer vision. We are certainly not going to study computer vision in this course but all that I wanted to point out to you was how basically that subject works that subject works by representing pictures in terms of zeros and ones by associating a property that that sequence of numbers has to have if it is to contain a certain object and designing computations which will decide whether that property is satisfied by a given picture. Let us turn to one more interesting problem you hear the weather report and you may wonder how do they do that. So here is what happens again at a very very high somewhat superficial level. So they divide the surface of the earth into small regions just like you divide a picture into pixels and for each region you are going to have variables say P i, T i and H i which represent the pressure, temperature and humidity in that region. Now we know enough physics to say if you tell me the pressure, temperature and humidity in a certain region and not just in a certain region but the regions nearby so adjacent regions or regions which are not too far something like that then I can calculate by using laws of physics which are mathematical in nature what the future temperature pressure and humidity are going to be. So if we measure the current pressure, humidity and temperature then we can calculate what happens say 1 second from now on but then we can calculate 2 seconds, 3 seconds and we can eventually calculate what will happen tomorrow. Now I have greatly simplified what is actually going on but what is going on is in essence this. So we are using physics we are talking about values of things like pressure, temperature, humidity and we are using laws of physics to say how they are going to change and this requires lots of computations but that is what computers are for. Then like picture processing if we make those regions smaller and smaller then we will get better accuracy why because if a region is large then it does not make sense to ask what is the temperature in that region because in one part of the region the temperature might be high in another part the temperature might be low but if the region is really tiny then you can say oh roughly it is the same temperature in that entire region just like picture processing. So if you make the region smaller then that means you are actually having to do more calculations but again as I said that is what computers are for. Computers can also process language of course they can do searches and you might be wondering how do they do that. Well here is a very simple scheme again this is this is too simple lot more sophisticated things happen but let me just tell you one plausible idea. So first we begin by defining a code for representing letters and the code that is commonly used is the so called ASCII code which stands for American Standard Code for Information Interchange. In this code the little a letter is represented by the number 97 the little b is represented by 98 the little c by 99 and so on so consecutive numbers are given for consecutive letters lower case letters and similarly some numbers are given for uppercase letters as well and not only letters but symbols say the equality symbol has an ASCII code digits also have ASCII codes so 9 as a number is different from 9 as a symbol that you see on the screen and the space character also has an ASCII code. So what is a word? A word can be thought simply as a sequence of ASCII codes for the letters in that word. So computer for example can be represented by the ASCII code for c o m p u t e r. If you check 99 is the code for c in fact it is the next code after 98 which we said is the code for b. So clearly it is the code for c but if you check the rest of the numbers are in fact consistent with this idea and they are in fact the codes that are used in ASCII. So a computer is a sequence of numbers what is the sentence or a paragraph well they are simply larger sequences. Now you can ask does the word computer occur in a certain paragraph what is that question? That question is simply the question does a certain sequence of numbers occur inside another sequence of numbers that is it. So if you can answer queries like this very quickly you can do searching for words in books or web pages or whatever you have. So here are some thought exercises that I would like you to do. So these are these are mental exercises I just want you to think about it because these are the kinds of questions we are going to ask later on and later on we will try to have very precise answers. So for example we talked about how do you represent how do you represent the fact that a certain picture has a vertical line well in a similar manner I would like you to think about what patterns of 1's and 0's would correspond to a plus of any size being present at the center of an otherwise white picture. Another question that I would like you to think about is suppose you are given a sentence in a language you cannot understand but you are given a sky course would you still be able to count the number of words in the sentence. So could you express this as a question on a sequence of the sequences of numbers representing the sky course of the different characters. How will you represent chess playing as a question on numbers or how will you represent a chess position for example. So once you can express a chess position as a number then you have a foot in the door to say to asking questions about what is the next good move what does it mean for the white rook to capture a certain pawn or something like that when can a rook capture a pawn. Those questions will start becoming amenable to analysis once you first decide what does it mean to represent a chess position. So what have we discussed we have said that questions about pictures whether documents can be converted to questions about properties of number sequences and these are just examples. The implication is that basically any question we should check whether it can be converted to a question about numbers and that is when we can solve those questions on a computer. But answering these questions requires solving interesting math problems so it does require a lot of ingenuity. So we will stop here and take a break.


Hey, guys. It's Andy. This is going to be a video that literally will change your life. How? I'm going to teach you eight different ways on how to bump a customer $500 a month. This is a video, if you're ready to elevate your game, go to the next level in life and triple your income, you don't want to miss it. This is going to be a live training, it's going to be freaking nuts. I can't wait to see you. All right, guys. Check it out. It's Andy. So this is going to be a webinar training video. I want you to understand this. 99% of the videos that I put out on YouTube, they're basically value building, free content. I give you a quick objection, show you how to overcome it, boom. This is actually a webinar. It's going to be a training that I want you to join. I want to explain this to you. Let me tell you what it is first. I want to tell you how you can join. So a big deal to me is the Master Closer Seminar. The Master Closer Seminar is a seminar where we train right here in my conference room and have 80 people each month fly in and train with me and I teach them how to close any deal, any time, any place, anywhere. Not only close it, but close it for all the money, okay? A Master Closer Seminar is $997. You can wipe your butt with that. When I teach you how to make $250, $350 grand a year, guess what? It's worth it. Most people go to college, spend $50,000 to learn how to make $50,000. For $1,000 bucks, I teach people how to make $300,000 plus a year. My last year selling cars, I made $700 grand. I want to explain this to you. This is going to be a webinar on one way to raise your income $100,000 a year. So take wherever you are right now, don't care if you're making $300,000 or if you're making $30,000 a year. I can raise your income $100,000 a year. How? By simply learning the eight ways. Right here, this is what this video is about. The eight ways that I have never taught before, not all at once, on how to bump a customer $500 a month. Now, I put out an older YouTube video on how to bump customers, how to maybe negotiate as you're navigating through payment objections. This is going to be a webinar that basically shows you when a customer says, I want to be at $300 a month. If your manager was to put out a pencil or a proposal at $800, I am going to show you eight ways to get from here to there and close them. This webinar, there is a link below in the description box, it's real simple. You click on it, we're only taking 200 people. So this webinar is going to be on August 10th. When it's on August 10th, you're physically going to see that, look, you're going to log in probably around 9 p.m., Central Standard Time, and you're going to join the Zoom meeting and it's all going to be recorded for you. But me and you are going to be able to talk back and forth to each other. I'm going to say, all right guys, a guy's trading this car, he's buying this, by the way, I'm also going to show you how to do it with and without a trade-in. So you're going to see two different ways, but I'm going to show you eight ways on how to take that customer from $300 to $800 a month. If you right now could learn how to bump somebody $500 a month, how much money would you be worth? You'd be worth a ton of money, why? Because you would never miss a car deal again. There's two important things to this training, okay? Number one is how to have bullet-proof, fearless confidence while negotiating. When you join me on the Zoom meeting, you're going to have that. And then number two, you're going to have the answers to the test, no matter what objection they throw at you, no matter what the scenario looks like. You're going to have eight ways to go. You're going to have your armor on to say, I understand, let me show you how affordable your new vehicle is. Boom. You're going to go right into it and you are going to close them. Three of these ways I have never taught before on YouTube, never, okay? A couple of them I've dabbled into the first five. But the last three are lethal. There is one of them that I've never taught nor in a Master Closer seminar or on YouTube. It's a graph that I teach. It is wicked. I went in on a car deal the other day and I was in a dealership and there was a GM and he said, hey, Andy, I've had three managers in on this lady. She's at $750 a month on a big lifted diesel. We need her to be at $950. The deal is making $8,000 or they cut the eight grand out and they shake her hand at the $750. And I went in and I used this payment graph close that I've never talked to anybody that is literally wicked that I'm going to be teaching during the Zoom meeting. And I walk in within three minutes. I close her up at $950 a month, shake her hand. She's happy as heck. Okay, guys. So this is the one time where you can join with me in this training live. And remember, if you can't make it, no big deal. Every single person that signs up, the 200 people that sign up for the Zoom meeting, every single one of them will get a recording of this video.  I don't know if I can make it then. Cool. No big deal. You're going to get the recording to your email so you can physically watch this 100 times over on eight ways how to bump a customer $500 a month.  And if you want to become the best automotive salesperson in the car business and become the best closer in the world, you're not going to want to miss this training. Guys, click on the link below. Join me now. I can't wait to see you in the live training. Get ready to be blown away.


The urban heat island effect is caused by the built environment, which can lead to increased surface temperatures during extreme heat events. This study examined how different types of land use affect surface temperature, as well as how concentrated areas of certain land uses can increase the severity of the effect. It was found that commercial and industrial land uses had higher surface temperatures than parks and recreation land uses, while water bodies had the lowest surface temperatures. Additionally, higher concentrations of either of these land uses resulted in even higher surface temperatures. To address this issue, the authors recommend that municipalities develop policies and regulations targeting problematic land uses to reduce the effects of the urban heat island effect.


So, we come to the end of the course, we have looked at various aspects related to energy, the energy resources and the way to do economic calculations and the environmental impact. In all of this we have done a number of tools and techniques, we have also looked at different ways in which one can do the analysis, we have also looked at the qualitative perspective and try to put everything together. So, in this last module, I would like to discuss with you what will be the future of energy systems. So, as we have seen in the past, there have been many changes in the energy systems. And we talk in terms of the transitions that have been made in the energy systems. And we are also going to look at what are the future energy systems going to look like, what are the transitions that we are going through, what are the drivers of those transitions and whether it is in India or in the world, what kind of challenges and opportunities do future energy systems throw up. So, just before we look at the future, let us look at some things from the past. Let us look at some what do we mean by a transition. Now, as we know an energy system transition often involves not just the transition in the technology, but it also has impacts in the society at large. So, just to give you an example of a transition that has already happened in the past is a transport transition. So, this is an image which is of quite a famous image, it is an image of a street in New York in Manhattan, it is one of the busiest streets in New York. And this is an in 1900s, if you look at this image, you can see that in this image, all of these each of these vehicles are all horse driven cars. And this is this was the predominant form of transport. In this, there is only one, let me just show you this, there is only one IC engine, it is this is the petrol driven car, there is one car in all of this and the rest of it is all horse driven and this is just April 1900. The same street in Manhattan, 10 years later a little more than that 1913 March and you can see over here, all of these are most of them are Ford T's, these are the IC engine driven petrol driven cars and on one corner, you can see there is one horse driven cart in this. So, you can see a transition where a rapid transition has happened over a period of a decade, there has been a shift in the private transport from horse driven cars to IC engine driven petrol driven engine driven cars and we now are looking at similar kinds of transitions where we are going from off from petrol and diesel based IC engines, maybe to electric vehicles, maybe to biofuel fired vehicles, maybe to hydrogen fuel fired vehicles. So, let us look at in what were the transitions in the past. So in India and many other countries of the world, we have made a transition from traditional fuels to modern commercial fuels, mainly fossil, we have also had significant investment in large centralized energy supply and distribution infrastructure and centralized interconnected electricity grid which is there, now it connects all parts of our country and every single village is now connected to that grid. We have a large hydro and coal based thermal power plants and the focus had always been on supply growth, most of this growth happened through public sector and government investments. What are now the drivers for the energy transitions going into the future? The first most important driver is the challenge of climate change where we are trying to now maintain the global temperature rise less than 2 degrees or preferably less than 1.5 degrees. All countries have made commitments in Paris and then there is a global move away from fossil fuels. Today, 70-80% of the energy sources are from fossil and so the transition has to be away from fossil to renewables and maybe some amount of nuclear. We have also seen one of the biggest drivers has been there have been significant drops in the prices of solar PV and wind, there has also been reduction in prices of shale oil and natural gas with the result that several countries which were oil importers have become oil exporters. In the Indian context, we had success in public procurement of LEDs of fans and they have been rapid decline in prices and this has resulted in us believing that this could be a model by which we can try and spur growth where we can ensure volumes and reduce prices and make things affordable. And there is also a big disruptive change in terms of internet of things where there are technology developments where we can have intelligent sensors and control at relatively low costs and this can result in actually having a large number of distributed systems which are controlled, managed, monitored. So these are essentially the drivers for the energy transitions going into the future. We should remember that the energy sector if we want to make changes in the sector we will be changing lifestyles, we will be changing businesses. Some businesses will there will be disruptions, some of the existing businesses will start make will disappear and this will obviously mean some implications of costs and some implications in terms of there will be losers and gainers and so we need to think in terms of this transition being less painful and so to give you an idea of these transitions and possible futures we will take some of the salient features from the world energy outlook. The world energy outlook is produced by the international energy agency every year and I am going to show you some slides from the IEA's World Energy Outlook 2019. So the first slide that you can see here shows the change in energy demand. Now these are based on the IEA's projections, the change in energy demand and average annual GDP growth rate by region. In this there are two scenarios, there is a stated policy scenario which means that we start with whatever are the existing policies that the countries and the regions have stated and then there is another scenario which is an aggressive scenario which is a sustainable policies scenario. So in the stated policies scenario based on the existing policies of the different countries if we look at the change in energy demand over the time period 2018 to 2040 this is a report in 2019. So 2018 is the base year and we are looking forward to about couple of decades further which is 2040 and we can see very clearly in this there is coal, oil, gas and low carbon sources and you can see that there is a reduction in the coal and oil in almost in the European Union and in the United States and in Japan. However in most of the developing countries including India, Africa, Middle East, Southeast Asia these are going to increase. The overall MTOE you can see that in the world the growth is propelled by the additional demand required by China, India, Africa and some amount from Southeast Asia and Middle East. These countries the US and European Union have sort of plateaued and their growth is going to they will not contribute to increases. However, there all the existing base they start off from a very high base and we also if you look at the growth rates in this case this report uses us slightly a growth rate slightly higher than 5%, 6% growth rate for India and slightly lower growth rate for China, Africa and you can see there are positive growth rates for Japan, US and EU but the energy requirement most of these cases have declined significantly. In the Indian context there is a significant projected increase and the economic growth in the developing economies if you see the growth rates are much faster, higher than the growth rates of the developed countries and this will result in an increase in the overall energy requirement of the world and so clearly the centres of demand have shifted and the growth is all in the developing countries and the focus then is on how the developing countries will make the transition, make the growth and provide the energy services that we need for development yet try to do this sustainably and that is a big challenge. So if we look at it the IEA basically says there are no single or simple solutions to reach the sustainable energy goals. We start with first that if you look at the current trend in terms of the emissions from 2010 to 2018 and you project that into the future this is the trajectory that we have if you see this is the growth trajectory of the CO2 emissions. Now if we try to see if we can have a variety of different options with the stated policy scenario we can we still have a we will go below the current trends because of the policies that we have put in place for the national development commitments of Paris and the local national commitments and but in order to go to the sustainable development scenario we have to go much much below this and this is the biggest challenge. If we look at it these are some of the possibilities we can do this through a combination of energy efficiency renewables and then fuel switches and carbon capture and utilization. So this is on an overall macro scale and you can see this is the kind of pathway which is required this is the projected current trend if the policies that we have put in place work then we can go down by so much even then it the CO2 emissions would increase but if you want to really make it sustainable we have to go for aggressive efficiency renewables and fuel switch and CCS. If you look at this this is now broken down into different sub components and the report the IEA report gives details about how these could be achieved. So there is there are a host of different policies and technologies that can be adopted in every sector to keep the climate targets within reach and to look at a 1.5 degrees stabilization and so this is sort of a time frame till 2050 where these options can help us reach sustainable energy goals and this is not going to be just renewables or just efficiency it is a whole combination of different things. In the stated policy scenario you can see that different countries will have different proportions of share in the new capacity additions and you can see in this you can see in the Indian context significant amount of share from renewables both wind PV and hydro and then you can see that the largest chunk more than 60 to 70 percent of the new additions will all be renewables and this is based on the projections. This is similar kinds of details are there for most of the other countries of the world and so that is an interesting kind of trend that we need to keep in mind. The other issue which is there is that what is the carbon dioxide intensity of the electricity generation and if you look at India we are one of the relatively higher CO2 per kilowatt hour and we can see that over time we expect that to be going down in the stated policy scenario it can go down by about a factor of 2 so we can go down to about 400 and in the sustainable development scenario we can see that we have to go down even more and less than 200 and so based on this this also shows us the dimensions and the total amount of emissions which are there in each of these countries. So the sustainable development scenario of course results in a far lower carbon intensity of the electricity sector. Now this is that will also affect the transition which we talked of if you are going to move from IC engines to electric vehicles the CO2 savings will depend on what is the carbon intensity of the electricity sector. The other issue which will be there is that today a large part of our energy comes from coal and in India this is particularly true. So what would happen is that we are trying to see the reducing CO2 emissions from the existing coal fired capacity and you can see that in the stated policy scenario this is the amount of reduction which will be there and then in the sustainable development scenario which would be even higher. So some of this would be where we would retire the existing plants, existing plants earlier and then we can also rework the plants or retrofit them to make them, cofit them with CCS, convert them into combination of hybrids with renewables and these are some of the issues. So the coal sector will be in deep transition and many of the existing plants would actually have to be phased out or modified. The growth of the other issue which will be there is that if you look at the electricity demand there is a significant growth in the electricity demand and of course in the stated policy scenario it will go by about 200% of its existing value in the sustainable development scenario because of efficiency this is going to be lower but even then there is a reasonable amount of growth. There will be because we are having a higher share of renewables there will be a need for flexibility in the system and that flexibility of the system will mean that because we will have variable renewables in our supply we should be able to quickly ramp up, ramp down, shut down certain plants and be able to adjust and these flexibility would mean that we would need to invest in either demand side management or storage and that might add also to the costs. Now let us look at the electric vehicles and let us look at the comparison of electric vehicles with the IC engine vehicles. So if we look at this you can see that these red dots are the current emissions of IC engine vehicles in different countries and you can see the Indian IC engine vehicle per kilometer are roughly about 150 grams of CO2 per kilometer and with the improvements in the IC engine vehicles this is where that can go. In the case of electric vehicles currently depending on the electricity mix of the grid the CO2 emissions are actually slightly higher than the IC engine vehicles and that is an interesting kind of point to think about. Of course, when we talk of shifting from IC engines to electric vehicles this will definitely reduce the local emissions, but on the global emissions the reduction or non reduction depends on the intensity electric intensity of the carbon intensity of the electricity mix. And since Indian the Indian electricity sector is predominantly based on coal this results in this factor. In the future of course, depending on how the mix changes it can actually go with the sustainable development scenario it would be much lower than this, but this transition comparison between IC engine and electric vehicle depends very significantly on the electricity mix and need not necessarily this transition need not necessarily increase result in a reduction in the CO2 emissions. So, that is the point to be noted that today if we look at this it might actually result in a slight increase in the CO2 emissions, but with the grid becoming more renewable in future that would not be an issue. In the stated policy scenario for different countries you can see in 2018 this is the overall in the total primary energy demand we see that in India about a little less than 20 percent is from renewables this includes large hydro in 2040 that could be more than 40 percent of the total. Of course, this is one particular scenario which has been developed by the IEA there could be other scenarios you can even think in terms of 100 percent renewable scenario. Now one of the issues in this is that in the grid when we look at the grid over a period of time what would happen is the CO2 intensity of the grid would keep changing and that will depend on essentially the if we have a large amount of renewables as is projected to happen in the future with solar PV during the sunshine hours the CO2 intensity of the grid would be actually quite low and you can see the different kinds of shapes of the grid for India and Europe the CO2 intensity versus time. So depending on at what time you are looking at the CO2 intensity would be different. Let me illustrate this issue of what happens when we have a high renewable penetration in the electricity sector. So we start with the projections from NITI IO as part of its energy plan you can see that there is a projection for 2040 business as usual scenario and ambitious scenario with a significant amount of renewables. So what we did was we took a made a simple aggregate model where we looked at a base year the year for which we have all the data where we had the load profiles we also had data on the wind variability the wind at different times of the different hours of the day and different seasons and the similarly solar insulation we also had existing installed capacities by different categories coal, hydro and solar, wind and then using this we then projected for target year with some growth rate took the load profile and projected it demand growth rates solar and wind capacity growth rates hydro and nuclear installed capacity growth rates and variability in the demand. With all of this we then and the kind of constraints which are there we obtain the future demand for different days by hours daily monthly and seasonal and then we tried to allocate based on the capacity based on thermal hydro and renewables tried to fill the load curve so that the hydro actually met all the sudden requirements to all the ramping as far as possible whenever we need fast ramping up or down that would be allocated hydro for those parts then we based on this we found out after removing hydro and solar and wind what is the residual load curve which has to be met by the thermal generators then we saw what is the ramp rate and is it possible for the thermal generators to be able to meet those ramp rates within calculated the cost of electricity the PLF the ramp rates emissions and then we also found out the necessity of storage. So, we will just illustrate this in terms of we projected from the existing curve the demand curve for the country as a whole in January 2040 this is for a typical day and we have it R by R based on this then we looked at this is what hydro could do and then this there was a we subtracted the PV and the wind and then we got the residual so this is the different filled up load curves and based on this we then got that this is the amount of this is the requirement from the rest of the system from the thermal generation and we can see based on this we can look at the slope of this and that gives us the ramp rate and this so that will give us what is the kind of ramp rates which we are getting and this was about the order of 30 gigawatt per hour and we can see what it means also on a plant by plant basis when we look at this if we increase the share of solar and wind we get to a point where the solar the solar and wind that is generated the electricity generated from solar and wind is more than the electricity required during that time period and so then this becomes negative this area under the curve if we share that is the requirement for storage so as we go further and further we can see how much every additional unit on solar and wind has to actually go through storage before it is used in some other section so this is giving us the final renewable generation the generation by different sources and this kind of analysis can help us see that as we go for more than this 35% 40% a certain percentage by generation then every single amount of every megawatt hour of electricity additionally that is generated from PV has to go through storage and then be used at some other time period and so that will depend on what is the cost of storage and even with pump hydro it adds to another 5 rupees or 6 rupees per kilowatt hour and so that will in that is one of the challenges when we think in terms of going for large scale 100% renewable schedules we will also need to look at variability on a short time frame and that has certain issues suddenly if we had cloud cover say in certain regions the PV output may drop we need to be able to have other sources which can quickly ramp up and meet that requirement and so the rules of the game for the electricity power sector will completely change and this is something where there are lots of there is a lot of scope for doing research and finding optimal solutions. Another issue which we should think about when we talk about the transitions when we started the solar mission India was a net exporter of PV but today what has happened is that we are importing a large part more than 80% of our modules are imported and most of it is imported from China. So this has some just to give you an idea model manufacturing capacity in 2016 was about 5300 megawatts which was operational out of a 6800 megawatt installed actual production was only an average of 1330 megawatts so it is a very low capacity utilization because we are unable to compete with some of these large Chinese companies 88% of our domestic supply is imported and 84% is from China and this also accounts for a very large amount of import bill similar things are there for this at the cell level. So when we think in terms of future transitions we need to be able to see what are the things that we can do in terms of technology to try and see that in India we are able to make and we are able to compete and we have the technology and we are providing the supply and it helps our economy and we get also the jobs and the economic benefits out of this. Most of our renewable strategy has been with the large centralized mode it is possible of course to think in terms of small decentralized energy and one of the things which can be done is we can think of each house as a presumer where it generates its own energy and maybe supplies additional energy back to the grid. So we have this whole concept of passive houses and zero energy buildings and energy plus buildings and if we do this then we can actually transform the way our energy sector looks because we can have a large number of small houses which are presumers which are also producing their own energy also supplying to the grid and the grid is there as a backup. We had an interesting initiative from our students where the students participated in the solar deca-cloth and this is our student team, team Shunna it was the first Indian team in the solar deca-cloth finals and the challenge in the solar deca-cloth is to design fabricate and implement a completely fully functional solar house running only on solar energy. So this house that you see here is a 680 square foot house with 5 kilowatt of PV on top, some solar thermal on top, phase change materials and this was designed and the building was fabricated in the IIT campus. It was dismantled, shipped and rebuilt on Versailles in France in 2014 June and then this was during the competition, it was shipped back and it has been rebuilt on the IIT campus as a demo building. The focus here is first to design it so that the energy intensity is low, use passive concepts, reduce the total requirement for energy then provide renewables on top and these can be done in a way where they could be cost effective and we can reduce the operating energy of the building. Similar kind of concept this is a larger one which was our team in the solar deca-cloth China, this is a 1800 square foot house G plus 1 and in this we also had the requirement of charging an electric vehicle to meet the transport requirements and these you can see are the images of the student teams which were available. So, one of the possible things is that we may move away from the large centralized energy systems to a hybrid with distributed energy systems backed up by a grid which provides reliability and supply. The current systems and trends seem to be in favor of large continuing the large centralization with for instance we have a solar power plant which is almost 700 megawatts at one place. We have large areas of land under solar PV and because from a business point of view it is much easier to do this on a centralized fashion. However, it is possible that if the incentive structure and the technologies work in a way where we can go for a large number of small distributed systems rooftop systems integrated and along with maybe electric vehicles and public transport the energy systems that we can see in the future can be quite different. We can look at almost every industry or every product that we make and it should be possible to make these products with much less energy and also possible to make them with almost zero carbon footprint and that could be another part of the transition. So, we are looking at transitions in the electricity sector, we can look at transitions in the transport sector. It is going mainly going to be electric vehicles, hydrogen vehicles, biofuel vehicles, public transport, biking and walking and trying to redesign the buildings, cities, workspaces and then the transitions in cooking we are going to go from solid fuels which have been used traditionally to modern renewables and we may have LPG and modern renewables as part of it. And then the transitions in the industry where we try to make the industrial products where they are using less energy, redesign them and combine them with zero carbon and carbon capture and storage. There are many different ways in which technologies can evolve and we have seen in literature a large number of possibilities in terms of different scenarios. Energy systems are linked very clearly with development and with the society and all these transitions involve some amount of costs, some amount of penalties and problems for individuals and the winners and losers may also be different. In all of this, it is also likely that there will be a need for some behavioural change. We may need to do things differently in order to ensure that our futures are sustainable and that we can actually continue to provide energy access reliably and provide the energy services that are required to maintain the future of our generation and future generations. So, in all of this as we saw, there are many dimensions of sustainability. There is the issue of centralised versus decentralised. We know that energy transitions are imminent. We need to assess the impacts of these transitions in terms of equity, that means equality in equality, income, quality of life and all of this gives opportunities for technology development, R&D jobs, alternate strategies, innovation and as we saw, this is a socio-technical problem. The standard assets which are there for instance, coal-based power plants may cause regional imbalances, may result in jobs lost and we need to work this out and work out solutions that make these transitions manageable and also ensure that we are able to go through in terms of looking at not going beyond the climate change tipping point. So, with this we come to the close of this course. Please feel free to look at all the references and if you have any queries, please do post them on the forum and we hope that you have enjoyed and learnt about the tools and techniques needed to analyse energy systems and we hope that you will be using these in your professional career and in terms of looking at different policies and different energy systems and development of energy systems. Thank you.