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Hello there, last several classes we have been discussing solar energy in considerable detail, we looked at solar energy in various ways we could use it photo-thermal, photovoltaic and photo-catalysis. Those were the three major ways in which we considered using it. So, we sort of, that was the extent of the discussion we wanted to have on solar energy. The new topic we start today is on wind energy. This is the other major way in which we are trying to you know use renewable source of energy for applications in the human context. Now, I must also tell you that you know something that we discussed right in one of our early classes that even though there is so much effort in all these directions in solar energy in terms of windmill etcetera, the real penetration they have made so far into the overall global scheme of things is still quite low. I mean we are still looking only at 1, 2, 3 per cent you know a small percentage of you know penetration of these kinds of technologies into the actual supply process which is what is supplying you know our electricity to our homes, to our offices, to our workplaces and so on. So, there is still a long way to go, but still given the various options that are available solar energy is considered extremely clean, wind energy is also considered extremely clean. In a sense, wind energy is a different way in which we are capturing solar energy. as you are aware you know sunlight comes down on us and heats the earth and it is not uniform. We have you know heating at various places occurring to differing degrees. So, there is the temperature difference across the planet, maybe minor temperature differences, but still significant enough temperature differences. So, we have you know the entire weather system is fueled by this energy that comes in from the sun. So, if we had no energy from the sun and we had you know we were it was a cold place everything would be rather relatively quiet because we have this daily incoming energy from the sun and the fact that the earth rotates and so many other things factors which contribute to each other in this manner. We have a very active weather system. We have a lot of you know the movement of clouds, you have a lot of evaporation, cloud formation, movement of clouds, rain, you have wind movement, you have movement of water, a lot of stuff is happening on the planet as a direct result of the sunlight that is coming in on us every day. So, in some ways, as I said the wind energy it is an indirect way in which we are using solar energy because that is what is causing the wind to begin with. And this itself constitutes only about say 1 or 2 per cent of the solar energy. The solar energy that comes in only a small percentage of it is you know involved in that those percentages may vary based on what all is being considered, but its relatively a very small percentage which participates in this weather phenomenon that we see. So, today in the way the world is progressing, the wind technology is being actively pursued by several countries, it is still not uniformly being pursued across the world. We will see, we will look at that information today. In our class, we are going to do an overview in this class of this wind energy area and then subsequent classes, of course, get into considerable detail of specific aspects associated with it. So, today as I said internationally there is a lot of interest in it, there are specific companies that have you know grown up in this area and lot of effort has been made to capture wind energy. So, many places certainly, many places in India, it is a common sight these days to see windmills to see what are called as wind farms because they have several of these windmills or wind turbines arranged in some periodic manner, some known some pattern they arrange it there and capture the wind energy. So, that is the context in which we will look at things. So in fact, even the photograph you see here is from one of the IIT campuses, at IIT Palakkad, their current temporary campus that they are in has this structure that you see here. Although the photograph is you know as is out there I particularly like it because it shows you everything it shows you the nature that we are trying to protect, it shows you the wind turbine that is out there and of course, it shows you all the transmission lines which is a key aspect of this technology. You need all of those things to be there for us to utilize this process. And as I said this is there all over the world. I mean you see it many places, now increasingly it is visible you drive on many highways, you go to various cities somewhere you will see dotted on the skyline you will see these wind turbines increasingly becoming present. It is considered an immaculate form of energy because there is nothing we are doing there, we just have a fan that is you know we are not burning anything there we just leave this object out there which is the wind turbine and the wind does everything else the wind moves it rotates the turbine, you will generate electricity and use. There is still it is not that it is, it has got no issues it is got some issues, but in the grand scheme of the issues that are being faced by you know the energy sector, I would say relatively these are mild issues. So, there is no sign you know chemical pollution during the manufacturing process although they are looking at you know composite materials that are being used for those turbines there are the current blades that are being used are all composite type of blades. So, there is some you know polymer processing that is being done for that. No doubt I mean so, we have to look at how clean that process is so that is something that I mean in the grand scheme of things you may want to analyze that whatnot. But once it is out there it is just generating electricity based on wind, the few things that sometimes people grumble about with wind technology is in terms of it's you know cleanliness or friendliness are 2 or 3 things, a lot of times the local population somehow do not like the sight of these things you know it just, it is in some ways maybe they think it is an eyesore I mean they do not want to see they do not want to wake up every day and see this huge set of structures blocking their view. So, it does block your view even if you are used to nature you are just seeing you know things around you then this is not something many people feel comfortable about even though actually, it is not doing any harm, it is just sitting there kind of thing you just put these structures there and a continuously moving, so sometimes that causes unease to a lot of people they keep seeing this thing rotating and rotating and rotating they do not feel comfortable about it. I mean if you are driving through we just go past it, but if you are there and every time you look up you see this huge thing rotating in front of you it is not something that many of us are comfortable with. It also makes a slight amount of noise and it is a very kind of a periodic noise because it is not like a, unlike a fan in your house which is going at very high rpm, this is a much lower rpm. So, you stand there and even keep hearing this noise, “woosh, woosh”, like that no noise to keep on coming and it is a kind of a periodic noise with enough gap in between those woosh noises that if you are there you will it will keep on disturbing you. So, you are trying to do something your mind gets stuck in this noise which keeps on coming and it may affect people’s ability to sleep if they are staying relatively close by because you keep on getting it they just nonstop it keeps coming. It is sort of like you know a dripping tap, if you have a tap dripping in your house sometimes that bothers you, you cannot you know do anything because that noise of that drop repeatedly falling in the bucket or on the floor really affects your ability to sleep to concentrate and so on and that varies from person to person. Some people are you know they do not care that noise is there if they just can put it out in the background and forget about it and continue to do their things. The number of other people is sensitive to that, they find that very difficult. So, there are issues like this. here is also some criticism that people make saying that these rotating windmills can impact migratory birds. migratory birds can get hit and killed by these windmills and those incidents are true they do happen. Again you have to look at the broader picture there are various reasons both manmade and natural by which the birds get impacted in that scale of things again this is not considered as a large enough impact, although ideally, we want to keep that impact to zero. So, that issue is also there. So, these are the kinds of you know issues that we are looking at as you know, in you know a broad spectrum of things that you have to look at when you step back and look at the technology because once you get close to the technology, it all always looks good you say oh this is nice, this is nice, this is nice and that will always be the case. But you have to step back to see this grand scheme of you know what are all the things that it is doing and what is the impact. There is, there are claims that it up affects you know radar signals and so on. So, many many other things are there, but those are all perhaps not as critical to us as a general user. But, there are also many positives and that is the reason why we want to look at it. (Refer Slide Time: 09:13) So, our learning objectives for this class are to them; to understand the pattern of usage of wind energy internationally and to also understand the pattern of usage of wind energy in India. So, where are we internationally concerning usage of wind energy and even within India what are you know the pattern of usage? Also, we would like to become associated or aware of you know geographical issues associated with wind energy water sort of concepts we have to keep in mind etcetera and also become aware of different types of windmills. So, perhaps you know I think especially the point number 4, I may discuss in greater detail, will some of these points we will discuss in greater detail some of them will discuss in less detail in this class, if necessary we will elaborate in another class. So, this is the general idea of what we are looking at. (Refer Slide Time: 10:10) So if you start by looking historically, first of all, this term windmill, these guys we hear this word the usage of the wind turbine. So, we tend to see in the news wind turbines, we do not necessarily hear the term windmill, but that is a matter of choice of what you are trying to convey. I think in the general public’s perception they are essentially the same. I mean you see something out there which is rotating and that rotating movement is caused due to wind and because it is rotating something useful is being done. So, that is a general idea. So, in the olden days historically if you see this has been used for a couple of different applications. The first was you know sort of for these two applications, for grinding grains and pumping water. So, they were also considered as you know grinding mills kind of is the kind of idea that they had. The nice thing about this first two applications is that you know especially in these areas where the windmill was operating you just did not have to do much I mean once you set this up the wind would keep on doing its thing and you just have to you know to feed the stock that needed to be ground,, and you will just keep grinding it and even water pumping. There are places where you know if you have some reservoir from which you want to pump water out using a windmill. Because this thing is just continuously operating you have to switch it off at times if you do not switch it off it will just empty the water I mean it will just pull out all the water and throw it out. So, you have to keep that in mind because it is just quietly running continuously. In our homes when we put pumps to pump up water from you know sump underground to the tank above, because we are using electricity and you know we are you know conscious of those things we go and switch off the pump and there is an overhead tank we want to make sure that it does not overflow we go switch off the pump. If you just have a windmill to do that and people can install small windmills on top of their house which will do this pumping at least from the underground water some it will take it to the overhead tank without having to use any electricity. If you just leave it on it will just pump the water out, I mean all the water out and you may just overflow the tank up there if that tank on top of your houses has a lower capacity than the underground sump which is most likely the case then you will just empty the tank you will empty the sump and there will be nothing left you will be just overflowing water out the top. So, you have to be out because it is free you just let it run and then it will just do its thing. So, you have to be aware that it operates that way and you should be you know ready to switch it off, so to speak or stop it put a brake on it and halt it. So, this is what it had been used for historically. More recently, of course, it has been used for generating electricity and that is why it is called the wind turbine because eventually we have some generator there and then you are generating electricity. So, in our context largely we are looking at the electricity generation part of it, although emotionally you could use it for any of these other purposes also so that is always possible. So, that is the wind turbine and these are the historical ways in which it has been used and with that, as our background, we will keep moving forward. (Refer Slide Time: 13:24) So, what are some general requirements? So, some general requirements for setting up this kind of a facility, I mean you may think you can set it up anywhere yes indeed you can set it up anywhere it will work with differing levels of effectiveness. So, there may be locations where it just comes very very minimally effective. So, it depends on you know if you want to get serious about it you have to look at the cost-benefit analysis right. So, you have put some cost to set up some infrastructure what is the benefit you are getting from it. So, from a purely economic sense that is the way you would look at it of course, from an environmental sense you have to look at the cost part of the equation as well as the benefit of the part of the equation is a much more elaborate manner. I think that is the key when people say it you are ignoring environmental considerations that is basically what they are saying. When you write the cost-benefit kind of analysis if you do not put the cost to those things that are environmentally bad then basically you are not doing a proper analysis that is really what it means. So, in the cost-benefit analysis, you have to put in the idea that you know this is the cost reporting of this wind turbine or windmill what is the benefit that I am getting out of it or what is the benefit that society is getting from it. So, this is the thing you have to keep in mind. Therefore, you need to set up this windmill in such a way that it works well, if it does not work very well then you are not getting enough benefit out of it then for the amount you are spent on it you are not really, the local people maybe yourself or the people around you who are depending on the windmill are not getting the benefit of the wind. Generally speaking, this is the kind of number that people quote that you would like to set it up in locations where there are at least 16 kilometres per hour winds on average. There is going to be significant variation through the day significant variation through seasons etcetera, on average we were we would like to have at least 16 kilometres per hour winds. Also generally the preference is to put it up in locations where there is less likelihood of strong bursts of wind happening all of a sudden. So, there are many geographical locations for a variety of reasons, you will have a situation where the wind is relatively calm and then all of a sudden you will have a huge gust of wind for a significant period and then again it will stop and so these things are possible based on the geography of the location. So, at least you have to be aware of it, you have to know how to handle it, but those are not the best places to sight the wind turbine. And finally, of course, you need access to transmission capacity because that is how you will get the power generated there to either the local houses nearby or two even if you are going to put it on the grid and then transmit it to some distance then you need access to that transmission capacity. So, generally in a more you know systematic way of going about doing this they will look at all this analysis, they spend more than a year analyzing the wind patterns at a given location before deciding whether this is location is good enough to set up windmills because it is a fair amount of investment in the infrastructure and they would like to set it up in such a way that it benefits everybody. So, a significant amount of site you know analysis is it done before this windmill gets sighted allocated, all right. (Refer Slide Time: 16:29) So, if you look at international usage of wind energy and this is based on total installed capacity in 2015. So, these numbers keep changing in fact, especially with wind energy this number is changing pretty dramatically and I am going to show you some data concerning that, but so, we look at this, we will we have to keep in mind that this is data to 2015, so with every year, things might change. About one-third is in China. So, China uses one-third of as setting up. I mean if you look at you know the total capacity or that is being generated a total no power that is being generated one-third of the power is being generated by wind plants sitting in China. Of course, this is free I mean when the wind energy is free. So, nothing prevents anybody else from also setting up wind plants, but China has made a major push in that direction they have significantly invested in setting up wind plants. So, some of the largest wind plants are all sitting in China, I mean they have you know systematically done this and. So, they have several such wind plants that have been put in place. The next is the United States, then you get Germany and we are here we are fourth we are not too bad we have our approach to doing things we do not force-fit solutions. So, we have you know a certain system we follow to come up with to decide whether we are going to do something and then go about doing it etcetera. We are right now the fourth largest such in terms of wind power capacity and wind power generation. I would also add that we are amongst the general if you look at the growth of wind energy, we are one of those countries where the growth is very significant. So, that is a very positive thing. The government is you know actively trying to get more wind energy you know farms setup and harvest the wind energy. So, this is being actively done in India and so our growth rate is relatively good in this sector. So, that is something that I know we can feel good about because that is the right direction we feel that that is one right direction to move in terms of energy usage. And then you have Spain, you have the United Kingdom then Canada. So, you can see that you know these are also significant countries, but they are all also I mean in a sense a little bit low on the in capturing of wind energy and then you see this few more countries here. So, we are already 4th, 5th, 6th, 7th, 8th. So, about 10 countries are listed here and then the rest of the world. So, you can see it is a very disparate distribution, possibly a lot of places in the world could benefit from wind energy and you know once you set up this windmill you can get a lot of energy because at the end of the day you anyway have to set up some plant to generate electricity right. So, you instead of generated putting a coal plant there you can put a windmill there if you can compare the economics of it. Of course, people will put some you know amount associated with it and so you have to do an economic analysis to figure out what works there, but that economy should you know ideally also take into account the environmental considerations. So, if you look at it the rest of the world is only 14 per cent. So, we are doing almost half as much as the rest of the world I mean in that sense. So, to speak and China is doing more than the rest of the world in terms of at least what we are describing here as the rest of the world. Of course, these are all also the other countries are also part of rest of the world, but what is being clubbed here in the 14 per cent is a significantly small percentage of the capacity so to speak. And the total that is being generated is about half a million megawatts right. So, half a million megawatts is being generated as of 2017. So, that is what is being generated by all the countries around the world and one-third of that is being generated in China. So, this is the current status. Of course, this is the source of the data which I have re-plotted here, but the data is available in that source you can go and take a look. So, significant, the point you see here is that the significant variation across the country. So, it has got a lot to do with the policy in that country. So, nothing because the wind is just there I mean it is not that unlike coal or oil or something which you have to import from somebody this you do not have to import, it is right there in your country. So, it is only a question of the policy in the country whether you want to go in that direction whether you see a long term that this is the right direction to go in and therefore, you encourage companies to you know set up these wind plants which are, who are willing to do so, and then find the locations assist them in setting it up etcetera. So, it is more a policy-oriented issue rather than anything else unlike you know fossil fuels. Fossil fuels we know geographically they are in some locations you have to buy only from those people. So, it comes with some other baggage, here that baggage is not there it is truly you know just like solar energy sunlight. Solar energy also you can say it is not uniform across the world because you will have places where you are having less sunlight you are having more sunlight all those things are there, but generally, the wind is there all over the place I mean it is just a matter of locating the right place. So, it is much more equitable across all the countries and so, you can utilize it. So, this spirit that you see internationally is significantly tied to the policies in these countries. So, that is what I would highlight. (Refer Slide Time: 21:56) Even within India, you can see that different states have made significantly different participation in this wind form process. Interestingly the number one state leading this effort is Tamil Nadu. So, they have done a great job in setting up these wind farms in the state it is the number one state in the setting up of these wind plants if you see. It is significantly more than even the number two Maharashtra is at 17 per cent, Gujarat is 15. So, these are the four major states Tamil Nadu, Maharashtra, Gujarat and Rajasthan. So, these are the four major states that have significantly put in efforts in the area of wind energy. Then you, of course, you have Karnataka, Madhya Pradesh and Andhra Pradesh at the other others are relatively small. So, in this, in the scale of this diagram it is showing up at 0 per cent, but that is it means it is significantly less than 1 per cent that is really what we are looking at. So, you can see here 1 2 3 4 5 6 and 7. So, 7 states more or less are doing the much of the wind energy sector as you know a sector that is generating power for any use it is distributed across these 7 states even here you can there is this place called Muppandal, Muppandal windfarm. So, if you go to the southernmost part of India which is, of course, the Kanyakumari, close to Kanyakumari there is a small village called Muppandal. And there is the largest such wind farm that has been set up which is a 1500 megawatt capacity wind form. It is a very interesting place because it is a very small village actually and it was quite an impoverished village, but this farm has helped the local people, this wind farm because it is generating electricity and supplying to the grid. It happens to be a hilly region there and there are strong gusts of wind which go through the mountain passes. So, you have strong winds going through mountain passes and that therefore, it becomes an ideal place to set up these wind turbines. Those of you who have travelled to Thirupathi also will see you these wind turbines dotted on those hills. So, many of those places you know as you gain in altitude you get the strong winds blowing in different directions. It is also very historic place this Muppandal, I mean it is associated with an ancient Tamil poet Avvaiyar, and she is supposed to have been at this place and she is supposed to have worked very nicely with 3 different what shall I say kingdoms that were there then, three different kings and dynasties that were there at that point the Cholas, the Charis and Pandyas. And I mean just oh just out of historical you know relevance she had managed to get all 3 of them to attend some event and they had set up pandals for from on behalf of each of them. And since there were 3 such kingdoms, there were 3 such pandals and hence the name Muppandal, the mu stands for three and the pandals, are the pandals that they put in place. So, that is just you know interesting historical take on the place, but it is now famous for this you know a wind farm that is set up there, you see this in them you know I guess sort of in the middle of nowhere you have this wind farm and that has contributed significantly to the overall generation. You can see here 32,000 megawatts as of 2016 that is what India is generating as of now, 32,000 megawatts and out of this you know almost thirty per cent is there in Tamilnadu. So, Tamilnadu has a significant contribution to this activity. And the government is actively trying to push this to about say 60,000, about 60,000 megawatts by 2022. So, at least there is some intention to push it to almost double this in the next 6 years or something. So, these are all I would say you know heading in the right direction from the perspective of you know making ourselves environmentally friendly and therefore, it is very nice and welcome sign to see. (Refer Slide Time: 26:13) So, if you see here, this is a trend which I thought I should show you because this is also true internationally. You can see here from 2006 to 2016. So, that is about 10 year period during which this was this must have been about 7500 megawatts from there we have gone to about 32,000 megawatts. So, that is what that is about more than 4 times increase. So, four and a half times, so a 450 per cent increase in capacity in 10 years. So, that is very significant. Almost if you look at all the technologies that are out there which are being you know deployed into the public domain for people to use from the perspective of inner energy usage, this is a sector which has grown very significantly. Roughly even, in India, if you see here roughly you will see about you know something like 15 per cent, 20 per cent, 30 per cent growth from year to year. So, for example, you see here this is about this is also about 27,000 something and this is 32,000. So, you have grown by about 5000 in the space of one year 5000 megawatts in the space of 1 year with a value of about you know, so about just under 20 per cent, just under 20 per cent is the kind of growth that we are seeing here and this is true internationally also. Even internationally if you look at the various countries who are trying to push this technology forward many of them are pushing in this in this kind of percentage 15-20 per cent growth. So, for any industrial sector to be moving in this manner where it is growing by 15-20 per cent every year it is a very promising sign I mean for that industry it is a very promising sign. So, all the capacity is built correspondingly and that is a great sign to have. So, that is what we are looking at. (Refer Slide Time: 28:06) In terms of types of windmills, we will as I said you know maybe examine this even more as we go forward, but here itself we would I would like to share with you some ideas related to these types of windmills. So, broadly there are two types, the first one is listed here, the horizontal axis wind turbine and as you make as you can guess maybe the other one is the vertical axis wind turbine. So, very briefly it would look something like this, we would have some kind of a tower, some tall tower and then on that, we would have some structure, from this you would have a shaft that comes out and that is your horizontal axis, horizontal axis. So, something that is out there and then from this you has the blades. So, this is how this would be set up. (Refer Slide Time: 28:36) So, you would have wind coming in this way. So, the wind is coming horizontally and then this turbine keeps rotating and then generates electricity. So, this is the general layout of a horizontal axis. So, this axis is horizontal and that is what they are referring to as the horizontal axis wind turbine. Maybe the name does not seem significant to you, but when you look at the advantages and disadvantages you will understand what we are talking about. So, the first advantage is that what I marked in green are the advantages the tall towers enabl