 we talked about batteries most of these many of these are now where you have prototypes they are commercial. We want to look at an early stage calculation and how the energy analysis can be used to actually compare between different options. So we talked about hydrogen and the only way we can think in terms of making hydrogen viable is if we can make it from renewable sources. The current methods of hydrogen production typically most of it 90% of hydrogen production comes from natural gas from steam methane reforming. One can also have coal gasification and electrolysis. Mostly it is based on fossil fuels which is not sustainable from the overall viewpoint. So we need to look at hydrogen production from renewable energy sources like wind solar biomass and this study that we are going to talk to you about is to look at biological methods of hydrogen production. These are still at the laboratory scale and where you can operate at ambient temperatures and pressures. They are expected to be less energy intensive and they have a variety of feedstocks as carbon source like sugars, lignocellulose material, wastewater and there are several reactions there are substrates and bacteria. So you have basically the biological feedstock something like C6H12O6 with water giving you hydrogen CO2 and then another compound. So this is the hydrogen that we would separate and use and we would like to this you can see this is a slightly old paper it is in 2008 with comparison of bio hydrogen production processes. So what we said is all these processes today are still at the laboratory scale. Based on what has been done in the laboratory scale and the performance can we assess and see whether these are likely to be viable and how do they compare from an energy or a net energy point of view. So we would like to calculate the NER and see if those NERs are greater than one. And in order to do that so the production at commercial level not reported, pretreatment methods and hydrogen production depends on the feedstock which feedstock is viable which is not, which process is viable which is not. So the analysis of different feedstocks and processes is necessary before we invest in scaling up the process and this is a methodology that we have used we have shown we are looking at biomass to hydrogen there are thermo chemical methods pyrolysis and gasification larger scale. We are here we are looking at biological processes biophotolysis dark fermentation photo fermentation I am not going to go into the details of the process I am just going to illustrate for you the methodology and some of the results and those who are interested can look at the paper and associated papers and this can be an area where still this is an area where there is a scope for doing active research. So we look at four different processes dark fermentation photo fermentation two stage fermentation biocatalyzed electrolysis and will take an input feedstock of sugarcane juice. So the functional unit that we have defined is 1 kg of hydrogen to be produced at 25 degrees centigrade temperature and 1 atmosphere pressure. We compare this with a base case of steam methane reforming with natural gas and we would like to calculate one to couple of things one is what is the net energy ratio output by the non-renewable energy input the NER should be greater than one also what is the kg of CO2 equivalent per kg of hydrogen and then the energy efficiency we have used the LCA software CIMA Pro but we can also do this just using our own calculations. And the heat which is being used in the processing we need to produce steam we use diesel with 90% combustion efficiency for the electricity we use the Indian electricity mix and this is the kind of mix and we said that biomass derived CO2 is 100% carbon closure so 0 CO2 impact and we look at natural gas and bag gas as the residue this is the electricity supply mix that has been assumed in this case. There are different kinds of for steam methane reforming as the base case we use natural gas coal and these are all the different kinds of inputs which are used for the net energy analysis of hydrogen from steam methane reforming which is used as a base case for comparison with these options. This one was the dark fermentation in the case of photo fermentation we have the sugar cane mill to get bag gas then we get photo fermentation which goes to the anaerobic disaster to produce methane and the photo fermentation output is separated using pressure swing adsorption and use so we get hydrogen. In each of these processes there is some energy input which we quantify. In the third process that we have is the two stage fermentation process where again we have milling and bag gas we have dark fermentation as well as photo fermentation and then you have the anaerobic digester for methane and pressure swing adsorption for hydrogen. The next process is with bio catalyzed electrolysis where we have an anode and a cathode and bacteria where you have this small this is where you have the electrolysis and hydrogen is being produced and these are the input data in terms of the electricity used in the sugar cane crash crashing and the production in the dark fermentation photo fermentation methane to CO2 ratio the recovery in the PSA compressor needs a electricity input. So we have the isothermal efficiency and then we have the loading of the bio catalyzed electrolysis based on this we build up for each of the process mass and energy balances. I am not going to go into details of this you can look at the details in the paper and essentially what happens is that for each of these the sugar cane input, electricity input, the ammonia, platinum, the outputs which are there and for each of these processes we create the inventories in terms of masses and then we also create the energy content and then the case one the final results without byproduct with byproduct of course it looks much better. You can see that in all these cases the CO2 emissions kg CO2 per kg of hydrogen that we have is significantly lower in all the bio catalyzed in the bio hydrogen processes and it turns out that the two stage process seems to be the best in terms of the CO2 emissions. Similarly, if you look at the non renewable energy used photo fermentation and two stage process look to be similar while bio catalyzed electrolysis uses much more in terms of the energy. So this gives us a way a direction in terms of how to move forward in terms of processes within the process we can again use it if we can have a process model and we can use it to make the comparison between making a viable process and making a process which can then go to the next stage where you can do the economics. This has been this is these are a series of charts which have been used by Ashby which has been proposed by UK researcher Ashby and this is reported in Alvo Detal. You can see essentially the idea is that when we choose materials we often do that based on a particular application we choose from a particular set of materials and people often historically use a particular set of materials but for some properties it is possible to have a whole host of materials. So for instance if you look at ceramics metals polymers and we look at let us say the property that we are interested in is a Young's modulus. So you can have for a given Young's modulus a whole set of different materials between metals and ceramics and different materials have different amounts of embodied energy. Similarly, we can also draw this in terms of embodied CO2. So we can actually choose a material that uses less energy or less GHG equivalent emissions and this could be a basis for looking at sustainable design for the future. And this is just to illustrate this is another parameter when we look at strength and so one can actually create these kind of curves and can these can aid the designer in terms of choice of different kinds of materials. And we are now in a in the area where we actually have nanotechnology and we are creating designer materials. So this can be even more useful because we can actually look at materials with a particular capability which has a low energy footprint low carbon footprint. So with this I would like to just give you the last example where we are talking of sustainability analysis where we are looking at combining all of this the LCA the thermodynamic analysis technology a techno economic analysis we would like to screen different kinds of technologies and compare them and see what are the prospects for future and this can help us in decision on investment. So we looked at in the case of life cycle assessment these two criteria we will look at the cumulative energy demand and the carbon emission footprint and in thermodynamic analysis we can look at the energy efficiency the exergy efficiency exergy is basically the second law of using the second law where we convert everything into work equivalent which is exergy and then we can look at the primary energy consumption per kg we can look at the current cost future cost and bottom up cost. So we will take an example this is from a PhD thesis done recently by one of our students where we looked at the possibility of using for zinc which we manufacture currently using an industrial process using fossil fuels how can we make the zinc manufacture process sustainable. So we have a whole host of different options where we make it zero carbon and we would like to compare this. So one of the processes that we are looking at is a solar-carbomothermal reduction where we start with zinc oxide and the carbon source which could be biomass or coal we have this reaction which is essentially zinc oxide plus carbon giving us zinc plus CO and this is a carbothermal reaction which we are carrying out at high temperatures we generate those temperatures by getting solar thermal concentrated heat and there has been this reactor which has been there for carbothermal reaction of zinc 300 kilowatt reactor compound parabolic collectors and this has been done in Israel. You can see here that on the ground you have these helostats which are focusing on to a reactor and this is a beam down reactor which again focuses these translates it to a mirror and this goes to a reactor which is here and this is getting very high temperatures and you can have you can concentrate it. This is one reactor which has actually been built and some performance data is available. We took that performance data and tried to analyze what does this process mean if we wanted to implement this process to manufacture zinc how would it look like in terms of the energy and the carbon and this is how we calculate this. So essentially what happens is you can look at the multiplicity of processes. We can have either keep the process as it is zinc oxide leaching, electrovining using metal and we can look at creating these the electricity that we are using and the heat that we are using get it from renewables that means photovoltaics or CSP. So there is one possibility which with the baseline example is grid hydro metallurgy where you get grid electricity or we could have the solar giving you PV electricity and then running the PV hydro metallurgy or we can have solar thermal CSP, CSP hydro metallurgy and get zinc and carbon monoxide or we can do the carbothermal, the thermochemical and the whole host of different technology routes. In each of these we then identified and designed the reactors and the systems to produce a certain amount of zinc annually and then made this comparison and I am going to show you just the final results. When we did this we then calculated we developed a sort of Sankey or an energy balance diagram which shows you the different kinds of where all other energy flows and the overall kinds of losses and the final output. So based on this we can see that the energy efficiency as compared this solar carbothermal and grid power when we look at solar carbothermal and the PV for the auxiliary load we can have an option of PV CSP and grid hydro metallurgy. So you can see that PV and hydro the at the pilot scale if we one looks at it the PV and hydro metallurgy the existing process and making it PV seems to be better in terms of an energy efficiency view point and however from a CO2 view point when we look at the life cycle assessment from the cumulative energy demand CED and the CEF you can see very clearly that with grid electricity this is the mega joules per kg of zinc that we are getting and with PV we can this reduces very significantly and CSP also this reduces if we can get the thermo chemical road with biomass then we can actually get somewhat nearer the PV though it is still a little higher than the PV. However on the CO2 basis you can see very clearly that if we compare a thermo chemical process with biomass thermo chemical process with biomass then it is possible to actually go ahead and make the thermo chemical process with the PV for the auxiliary and the thermo chemical process turns out to be better than the PV hydro metallurgy option. So this shows us that it is possible to actually go ahead and we can look at a new renewable based process for zinc and it is possible actually that we can modify all the industrial processes so that they become zero carbon. There are multiplicity of different possibilities in terms of roots and when we do the initial pilots and the experiments one can actually use net energy and life cycle analysis and the carbon footprint as a basis for making this comparison. Now what does it look like in terms of economics now interestingly of course when we look at economics these all these roots that we talk of are much costlier today they are costlier by a factor of 10 but it is possible with technology development and volumes that these costs we can go down significantly in the future. And so for instance if we look at it the solar carbothermal with biomass which is the root that we are looking at is depending on the way you do the estimates about 1000 to 2000 dollars per ton as compared to the grid hydro metallurgy commercial one which is of the order of 300 dollars per ton. Of course this is at the pilot scale if we make this at the commercial scale and we expect the kind of cost reductions that are possible then we can actually go ahead and get in that same range. So it is possible that we can do this kind of a cost reductions. So now when you look at net energy analysis life cycle analysis life cycle analysis gives us a way in which we can look at over the entire life cycle the environmental impacts and the energy impacts. Net energy analysis at times what happens is specially in the case of new technologies and when we are looking at going from the research and the lab scale to the pilot scale or pilot scale to the before commercialization it is very difficult to estimate what would be the cost. In the situation where you have limited information about the cost and there are only one or two companies which are exploring this it is important to look at how does a new technology look at from the point of view of the overall energy that is input is the NER greater than 1 what is it look like in terms of the CO2 impact. So these are additional tools and techniques available to you which you can use along with the economic calculation and the emission calculations and that can help in sort of screening and deciding where it can go. In some cases if you find that the ratios the energy numbers and the cost numbers are almost similar then it is likely that there is no not much scope for reduction or it needs major breakthroughs. In the cases where you find that the energy inputs are much lower but the costs are at a higher factor it means that with technology development and commercialization it is possible that that technology may actually yield better results. So an energy net energy analysis can help and direct some of the choices of new materials new processes and this is something which has been used but not used as much as it could be and this is something which I hope you will use when you analyze different energy systems and you especially look at new things coming out to see that they are viable from an overall energy point of view. With this we will close with this module and we will go to the next module which will be on energy policies and how we can do policy analysis.