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Module 1: Renewable and Non-Renewable Economics Resources

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Biomass and Materials

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We come to now another energy source which is in the Indian context quite important, it is biomass. (Refer Slide Time: 21:46) And biomass could be an agricultural residue, crop residues, it could be wasting which are there and cattle dung and then this biomass of a variety of such biomass is available. There are many different processes and process roots for the conversion of this biomass. (Refer Slide Time: 22:14) When we try to map this biomass each of the biomass has the depending on the ash contained and the moisture contained, you have a certain energy content of the fuel and you can see that in all of this has the energy contained between we are talking between 12 to 19 megajoules per kg. Remember that we were comparing this with when we talk of oil it is about we are talking of 40 megajoules, coal is about half of that but it is the reasonable source, so it is slightly lower than the energy contained in coal but it is something which is abandoned and of course in some cases, they already have alternative uses, it is being used biomass is being used as fodder for cattle, it is being used as feedstock, it is being used hatching for houses. So we have to see whether the bottom of the supply and demand and we have to also look at if you talking about animal dung, we look at how do we collect it, how do we process it but we can estimate an all of this when we look at getting the estimates of this, this is, these are now stocks, so we will have to have distributed ways of making this calculation. When we do these calculations, we would need to look at, for instance, we know in different regions of the country or regions of the world what is the wheat production, rice production and based on that, and based on the production we can find out per ton of product. (Refer Slide Time: 23:58) How many tons of residues are produced and we can multiply that, we can take the yield in terms of how much area under plantation, what is the yield multiply that by the residue ratio and then we will get the amount of residue, we can get the energy content of the residue. Also depending on the growing season and the harvesting season, the residues will be available at a particular point of time. So, one of the recent controversies and which has been in the news is has been about the pollution in many of our cities including Delhi and the problem with the air quality has been blamed on the stubble burning which is happening in Haryana, in Punjab and the crop residues and the stubble and it is possible of course to gasify it use it for and we have to work out the things. So, this is the kind of potential. (Refer Slide Time: 24:58) So, in all of this, you can take the rice again the quantity of residue, the residue ratio and the residue energy. So that is how we can calculate the biomass. (Refer Slide Time: 25:07) In the case of biomass, there are different possible processes there are thermochemical processes where we can look at if its combustion just like we have in a power plant the ranking cycle power plant, we burn coal and then we get steam and then we use that steam to run a turbine. In this case, we can take biomass, we can take biogas, we can take rice husk, we can burn it generates steam, generate power. The efficiencies are slightly lower than that of a coal-based power plant but it could be also co-fired you can have coal plus some biomass and the other route is instead of combusting it completely we can gasify that means we add less air so that it is partially gasified, it is gasified and you get carbon monoxide and hydrogen which is the producer gas. And that producer gas than can be used to can run an engine, a diesel engine or a dual fuel engine or a dedicated producer gas engine or we can pressure it and use it for a gas turbine. Most of our Indian experience has been with atmospheric gasification and we have been using that gasified output for heating thermal or for running an engine and generating power, shaft work. We can also think in terms of using this biomass for pyrolysis and getting liquid fuels, so this is thermal chemical, the rates of reaction are higher these are all chemical reactions biochemical is where we let now the microbes do the work for us, in the case of digestion, anaerobic digestion we get biogas, it settles down and we get biogas and we also get slurry and we can use this also for fermentation get ethanol, you can have oil extraction and you can have biodiesel then biofuel. (Refer Slide Time: 27:08) In the GEA and in this special report on renewables you can find all this again in terms of different biomass feedstocks, different kinds of conversion routes and different outputs in terms of heat too, heat or power or liquid fuels or gaseous fuels, so there are many different things which are possible. (Refer Slide Time: 27:34) In the case of biomass, the issues are that if we want to dedicate some land for biomass production, if you want to dedicate some land for biomass production then ue of food versus fuel and we can if we on the other hand if we just use the resources the waste which is coming from the animals or wastes which are coming from the harvest and then we can lookat these has alternative use, then we can look at the surplus which is there for energy conversion and then look at the end-user. If we are doing dedicate plantation there is a fossil, there is food versus fuel and that is a problem we need to see we also need to see if we are getting biofuels what is the amount of energy that we are putting in, into creating that biofuel. So, in a later lecture, we will talk aboutnet energy analysis and we will see how this looks. (Refer Slide Time: 28:45) So, when we look at biomass plantation, with the different kinds of fields this is the kind of yields which are available in different parts of the world and this has given this has again beingclassified in terms of the technical potential of biomass. (Refer Slide Time: 29:01) The problem in the case of biomass is that aggregation and creating a number for the country, a number for the world is a difficult exercise and its subject to many uncertainties, this is a localissue and we need to identify locally the supply-demand and the maps. In the case, of bioenergy this supply curve which is being drawn in the GEA if you see, this supply curve gives you at different we can go up to an 80 EJ/year at about 6 $/GJ. Biomass can bereasonably cost-effective there is an issue of as we said the use of land, use of water and we have to look at it in terms of the sustainability but biomass bioenergy systems have not been growing at the rate at which PV and wind have been growing. Bioenergy systems have the added advantage that most of the technology and most of the generate local employment and these are something where we think in the future that there will be much more in terms of potential. (Refer Slide Time: 30:15) In Europe, there have been some estimates of the kind of form different kinds of there are again there are different technologies for conversion. The first generation, second generation and with genetic engineering we are looking at different kinds of conversion routes. In all of this, we have to look at the overall sustainability in terms of energy as well as other issues in terms of land and water. But this is some of the things which are there. (Refer Slide Time: 30:44) And this is an aggregate supply curve with municipal solid waste, animal waste, crop residues. So, if we combine all of this you can see the this is an image which is there from the global energy assessment which talks about electricity, heat and primary energy and talks about the exajoules available, we can see that in the case of renewables we are not constraint by the potential, there is a significant amount of potential, this may be distributed we have to see how and where we can do it in terms of cost affecting methods. When you analyze any particular location, we can find out what are the local resources in terms of renewables whether it is solar or wind and then identify for the demand how much you can require, we can then look at the cost-effectiveness of such things. Now one of the key things when we talk of renewables situation and when we are looking at large scale renewables is that we have to match the supply and the demand. And matching the supply and the demand means that we will look at solar the solar supply is starting from letting us say 6 o clock or 7 o clock in the morning and going up to 5 or 6 in the evening. When you are demand is in the night and we are looking at the commercial load and the lighting load coming in from 6 in the evening till about 10 or 11 in the night where we will have a high demand we need to then slower the energy which is coming in from solar and then use that energy in the night. This involves an additional cost and the total amount of storage that we have installed for the energy sector is not even 1 per cent of the total energy that we supply and this is also there are many different storage options and this is, of course, another topic. (Refer Slide Time: 32:47) But when we look at you can look at the economics of different kinds of storage, it could be large scale storage it could be distributed storage and when we talk in terms of storage large scale storage it is mostly we are looking at you know today the most cost-effective large-scale storage is the pumped hydro. Where we look at hydro having a low reservoir and a high reservoir and you pump the energy from the low reservoir to the high reservoir even that today, at today’s price is that cost you another 5 rupees per kilowatt-hour. So, this is going to be an issue when we talk in terms of high renewables. The matching of supply and demand we try to see so far in the electricity grid we were looking at thermal and hydro scheduling. Now when you have renewables we have thermal, hydro, solar, wind scheduling mostly today to encourage renewables when we supply renewables we consider them as must run that means when the PV generates we try to use it when the wind generates we try to use it, this will result as we saw in some cases in the backing down of thermal power. So, when we look at future demand and we have high renewables. What we do is we take that future demand to subtract from it the renewable share and then see thenet energy which has to be met by the fossil and this leads to what is known as that California duck curve, so we have to see whether or not the supply system can meet that and this involves, so at a system level when we talk of high renewable energy penetration we have to plan our systems differently. (Refer Slide Time: 34:37) In the GEA, as well as in the special report on renewables, there are some supply curves given for renewables and you can look at this in a little bit more detail. So, to sum up, we have looked at today we have looked at the different methods of assessing renewable energy resources, we saw these resources are distributed and depending on the type of resource we would map the distribution of the supply, we would also see how it would vary over the day and the season. Whether it is the wind, whether it is solar or it is the tidal OTEC or the biomass we have seendifferent ways to estimate and look at the potential. Today these renewables are relatively small but they are going to be an increasing part of our energy mix and when we look at a particular application we need to estimate what is the technical potential and the economic potential and then design our systems for that. With this we will close our chapter on renewables, we will also now look at what is the situation in terms of materials that we need for the renewable sector. We have already looked at energy resources and we saw that we have stocks, fossil fuels and we have flowed renewable energy. We saw that there is sufficient renewable energy to meet our requirement. Now the question is we have sufficient renewable energy to meet our requirement but each of these renewable energy sources needs technologies, those technologies materials, do we have enough materials to meet the energy requirements or will end up in problem-related to materials. (Refer Slide Time: 00:56)So, the question that we would, the issues that we would like to address, one is will we run out of materials? Can we create a closed-loop materials system? Which renewable energy materials will be constrained and what will be the impact? You are not going to completely answer all these questions but we will look at how we can analyze this and what are the typical types of material and how they are looking at it. (Refer Slide Time: 01:31) So, if we look at the materials, we find that of the significant amount of our CO2 emissions are accounted for by some of the most energy-intensive and carbon-intensive materials. If you look at materials we are looking at steel, we look at cement, we look at aluminium, paper, plastic and these accounts for the largest chunk of the carbon emissions it's about 10 Gigatons of CO2 out of the total 28 Gigatons of CO2 in a particular area I think it is 2008. And this is from the paper by Allwood you can look at this paper for more details. (Refer Slide Time: 02:17) So, if we look at the periodic table which I am sure all of you are familiar with you have studied it at some point of time either in your school or our college and you can see that there are several of these materials including some of these rare earth and some of now these materials which are being become important for batteries, for storage, for photovoltaic you have this whole set of material which are coming in for the photovoltaic, for the lead-acid batteries, cadmium telluride thin you have the other chromium, nickel, cobalt. Then you have lithium, then you have these materials which are used for hydrogen storage and many of these materials involve our located in some regions and a few countries and they also involve a significant amount of energy used in their extraction. So, when we look at materials, we can think in terms of material efficiency and this is from the paper by Allwood, We can try and design so that we use fewer materials. So, we can this is called dematerialization. (Refer Slide Time: 03:39) You know look at your cellphone or look at your motor see how much steel and how much metal is going into it, see if you can have the same functionality using less metal, we can also replace the substitute, energy-intensive materials by less energy-intensive materials. Materials that are less carbon intensity, so this that is we can do dematerialization, we can do light-weighting and now with nanotechnology, we have the advantage that we can have designed a material which has the properties that we require. For instance, it is being told that if you look at Eiffel tower and you look at the weight of the Eiffel tower today if you have designer steel which nano-composites and engineer steel you can we could reduce the quantity of steel that is required with the same strength and we can get a much more lightweight Eiffel tower using fewer materials. (Refer Slide Time: 04:55) In general, when we look at the production of a material we can look at the production going to the and you have them at each stage of the production there would be some scrap we can recycle that scrap that when we look at the demand and then the after the post demand when it is used it can be recycled then some part of it, so we can try to see if we can have this entire thing as an entire loop as a loop which is closed and we use relatively less amount of virgin material and we can try and recycle at each of these stages. (Refer Slide Time: 05:40) If we look at the global materials used you will see that energy-intensive materials account for about 50% of the industrial energy used, cement steel, paper, chemical, fertilizers and also the interesting thing is that most of these now these materials are being consumed by the developing countries, there are much higher growth rates in the developing countries. (Refer Slide Time: 6:10) We have if we look at any of these materials we can plot. If you look at let us say steel used per person and we look at the status of the country in terms of GDP per capita or GDP per person. You find that this increases with income to a point where it stabilizes and then maybe declined, this is something like the, this is called the KUZNETS curve, so most of the developing countries are at this stage where there is this growth, developed countries have already gone where you have already produced all the steel you have of your infrastructure is already created. You have the number of cars and the k of things which are there and then the number of it starts declining and so that is the kind of I will just show you some of these trends.(Refer Slide Time: 07:24) So, if you look at steel we see different countries North America, Europe, you can see China and Indian over here and you can see that this is corresponding to something like we go to a stagnation level which is of the order of about 450 kg/person/year. So, it is an apparent consumption as a function of income high growth rates for developing countries and it goes to saturation, there is an implication on the global energy used. (Refer Slide Time: 07:54) The similar thing you can see for instance for cement, you can look at the kind of different levels at which you have these developing countries, which are growing in these cases it is more or less saturating of course it is saturating at different kind of levels. (Refer Slide Time: 08:11) And this is sort of global demand normalize you can see that there is overall growth. (Refer Slide Time: 08:18) Ashby has come up with this scientist in UK whose created this kind of design plots and this these design plots are extremely interesting in terms of when you look at a particular characteristic, for instance, you look at Young’s modulus energy per meter cube and if that is the requirement which is for a particular application and we are choosing between the metals, polymers, ceramics and you have the embodied energy, which is the total energy required to create that material and to extract it and to make it available from nature per cubic meter. So, based on this we can use with this we can decide between different materials and see what is the implication when we are making a particular choice in terms of what is the amount of energy that is being used. So, this could be used and we can have similar kinds of lots giving the carbon intensity of these. (Refer Slide Time: 09:33) This is another plot which is will be talking about the strength and the strength in terms and the embodied energy. So, these are interesting design age which can be used for us to choose less energy-intensive materials and less carbon-intensive materials for a particular application. (Refer Slide Time: 09:48) And so, you know we will when we talk about embodied energy and we do the lifecycle we will look at this is little more in detail but one can look at different types of elements and see what kind of energy is embodied and what kind of efficiency is there. So in general what has happened is that one expects that with materials as the demand increases and if the inmost of the material we are looking at a finite stock, so these are the stocks but then there are possibilities of substitutes and with technology improvement it is possible that we can have less use of the material but in general what one expects is that materials will, we will run out of materials and so there was this debate and you can see this there is a very interesting bet which was there in the literature. (Refer Slide Time: 10:58) And you can see in science in 19, there is a general article published by Professor Julian Simon in 1980 and he felt that planets resources are not finite, there has been ecologists and environmentalists were saying that we need to look at material getting over we need to look at resources and he said that planets resources are not finite, (Refer Slide Time: 11:36) On the other side of the bet were Malthusians, Paul Ehrlich, John Harte and John Holdren and they have been saying that we have one world, one earth and finite resources and we need to conserve and use our resources efficiently. (Refer Slide Time: 11:49) So, Simon challenges through an open challenge saying that if the scarcity is due to population growth and the prices of all-natural resources grain, oil, timber, metal should rise at any future date and he said that he is willing to bet anyone because he believes that technology and human innovations are such that there is no scarcity caused by human efforts and he said that he was willing to bet anyone that prices would decline at any future date. And he made an offer that any natural resources can be picked at any future date. So, when this challenge was issued Paul Ehrlich and John Harte and John Holdren took up the challenge. (Refer Slide Time: 12:56) Ehrlich, John Holdren, John Harte accepted the challenge in October 1980 and the choose the following materials. Chrome, copper, nickel, tin and tungsten and they bet a token amount of 200 dollars each at 1980 prices on these 5, so a total of 1000 $ and the idea was that in 1980 at 1000 $ they bought a certain amount of this and idea was the future date of 1990 was picked and it was said that whether these would the value would be more than 1000 $ or less than 1000 $? If this was more than 1000 $ then Simon lost the bet and Simon has to pay that difference to them, if the prices declined if it is less than 1000 $ they have lost t e bet and they have to pay Simon. So, what did you think happened? In this particular case, Ehrlich, John Holdren and John Harte lost the bet. (Refer Slide Time: 14:05) And you can see this, these are the commodities which were mentioned, you can see that this was the in the 1980 and even you can look at 1990 you find that actually, the prices went down. (Refer Slide Time: 14:26) So, essentially what happened is that you can see that this is what happened in 1980, this is the situation in 1990 and so with result that they this, of course, this did not prove it because this goes through ups and downs and there was an economists article recently which said that just so happened that he was unlucky to choose the years if it had been some other years then this would bet the kind of situation. But the fact remains that overall there are 2 trains which are there, one is that there is a problem in terms of scarcity but also with technological innovation and volumes the cost reduction are there, so over a long period we have seen very significant reductions in the cost of materials. (Refer Slide Time: 15:23) So, you can see for instance if you look at copper, the real price of copper has been going down and so it is not clear there is an issue of scarcity but there is also innovation and possibility of technological improvements and so when we talk in terms of materials we have to be aware of scarcities in the short term. But it is not completely apparent that this will necessarily result in extremely high prices, there could backstop technologies another available option. So, for all these materials we can use the same static R by P ratio or we can use something like the Hubbert’s curve if you want to estimate periods. In many of these cases, these are all these price trends. In many of the cases, if you see we can look at what kind of where is the distribution of this materials, so sometimes regionally some countries have for instance if you look at lithium it is only available in a few countries of the world. (Refer Slide Time: 16:32) So, the control of these materials and this could involve getting an advantage and then they are taken industry and development may be affected by it. So, we need to look at substitutes, so with this, we have seen we have got a quick introduction to the kind of materials that are used for the energy sector. We looked at over with development that material used per capita will increase and then saturate and maybe then decline and then there could be possibilities in terms of substitution by more energy-efficient and low carbon materials and then we can look at it is not essential that scarcity of materials always increases the price, the historical trend shows that there is also scope for innovation and technology improvements where prices may decline with time. With this we end the portion on materials for those who are interested there are more details in some of these papers you can look at the GEA, you can look at the papers by Allwood and about the bet you can look at John Tierney original article in New York Times which gives you about the Betting on the Planet. In the next session we will start with looking at the historical way of the mine managers problem, if you own a mine how much of that mine should you allow to be used every year and we will cast this as an optimization problem and see how a resource, a coal or oil or gas how it should be mined and distributed over future generations, thank you.