 I'm going to be showing examples that are published by many different groups in a different organization. So I want to be clear at the outset that although I told you guys this compilation that's all to discuss today, a lot of the work that we'll see, a lot of the results that we're going to see are coming from other researchers and other organizations as well that can work from just that pure standard. So energy systems analysis is a very flexible term. You can imagine a lot of things falling into that umbrella. So I wanted to just wet our appetite by measuring some concrete things that we're going to come across during our talk. So one question, one somebody might be interested in, would be which produces more emissions, combustion of traditional biomass, agriculture, forestry, or fossil fuels? Right, we're also thinking about climate, which of those is bigger is more important. Each of them has challenges that you're thinking that are unique to that kind of mitigation. What about the energy spend that we need to make in order to get useful energy to run our economy? And which technologies have which characteristics within that question, right? So coal-fired versus photovoltaic energy. What's the energy spend for one versus the other? And how should that inform our thinking about choosing between these two or many other possibilities? This is the first year now that fuel cell vehicles are available. Passing through fuel cell vehicles are available for purchase to consumers. Pretty exciting from a technology standpoint. Is it a win for the environment? I'd sort of like to think so. But one vehicle is part of a very complex technological ecosystem. How should we think about that question? Absolutely. So with those things we look forward to, let me now dive in more systematically. So there are many flavors of energy systems analysis. We're not going to talk about ice cream, but this is going to illustrate there are many flavors of energy systems analysis. And so I'm going to start by operating a taxonomy of energy systems analysis, which aligns well with our work at GSAP, just at the starting point. So one type of energy systems analysis is compiling information about energy infrastructure, whatever you think it really is. What I mean is stocks and flows of energy, right? From the 50,000 foot view, where is the energy coming from? Where is it going? Where is it converting between one form and another? Where do the energy service sectors fit into the larger economy to provide energy to buildings and provide energy transportation? Now there's a different kind of question, which is more granular than the first. And I want to think about two different technologies or a range of different technological options, such as for generating electricity. How do I think about the costs and benefits associated with different options requiring the same energy service? What are the trade-offs involved? Maybe one is more efficient, but the other has more toxic affluence in its manufacture, all kinds of questions like that. And this gets to some very practical on-the-ground quality questions when somebody is thinking about what kind of biofuel and systems to establish or self-generations and systems to establish, right? What should we say? What are we battling? And then getting even more down to the ground level, looking at one specific technology. If I have a previous research chemist and I was doing an electronic catalysis research and you probably just came from yourself and others, how should I think about a catalysis researcher, the relationship between a technical improved and unwinded wireless and the potential for the impact on the large energy system, right? What's the connection between specific technological advances and the dynamics of our larger energy system with respect to climate or energy availability? So I will show some examples for all of these three characteristics, right? Starting from the high level to the low level. I see a hand in. I should have mentioned at the outset. Let me mention a couple of things. First of all, the slides that I'm showing you today once I toss them off a little bit will be online and available to everybody. Second thing is I'm going to ask, if it's okay with everybody, to hold your questions to the end or forward to them and there is time dedicated at the end. I have about 60 slides and if we're pushing the hour, I will skip to make sure that we have time for questions. So one other thing we should mention by way of introduction is who does energy systems analysis? What is this meduous thing which happens out there in the somewhere? For you, you may be sitting at those similar places and I'll remember, but it's worth remarking. This is, by the way, a representative list about the comprehensive or exhaustive list. So one sort of organization that does energy systems analysis are our national labs here in the United States and other countries as well. So firstly, lab across the bay has quite a substantial program. Argon lab has done a lot of work in fuels and managed the Greek model, which gives an analysis resource for biofuels and other things like that. Embrel is the science of this field. That's a national real-life energy laboratory in Colorado. Academic organizations, such as B.Sanford, the False Fair Institute in Switzerland, Princeton, and many other academic research programs that often complement the science and engineering research going on at those state institutions. Non-governmental or semi-governmental organizations, well, I should say non-governmental. The U.S. Energy Information Administration, as well as the IEA, which is an OACD organization, put out very substantial volumes of information that contribute to our knowledge base. And finally, large energy companies, especially oil majors, produce many of them annual forecasts and statistical compilations that, again, there's a wealth of data and the challenges in my experience is often sort of through finding information, useful information in the area. So here are at least four classes of organizations which do some form of energy systems analysis. So back to this economy, this is going to serve an outline for us. So we'll start by looking at a couple of high-level examples and then move toward the technology side as we go along. So I'll remark on sort of characteristic toolkits that are involved for each of the scale of the energy system for now. And these high-level compilations basically rely on statistical data, collecting a lot of data from a lot of places, aligning it and providing it as a useful format. So this is a chart that many of you may have seen. Livermore Lab, not far from here, has for many years compiled what's called a STANFI diagram that illustrates energy flow that's specific to the United States and it attracts the, what I call it, I call it energy vectors. What form is it empty in when it comes into our economy and what sector does it go to? And they, more or less, this will be break out the electricity sector in that block at the top. So if we want kind of a snapshot and let me just make this explicit here that the width of each of these hands is proportional to the quantity of energy flowing along that. So this gives us a really visually acceptable snapshot of where the energy is coming from in our country, where it's going, how much goes through the electricity sector. And one thing that I find interesting is over here on this side, they break out explicitly at the end here, energy services versus rejected energy. What is rejected energy? Technology, a version of technology with a less than 100% efficiency at LR, of course. And there's some loss over rejected energy. So keep in mind, we've always discussed that there's more rejected energy traveling for our economy than there is energy that goes to providing useful services when it should take place in this chart. The IEA also has a resource of energy flow diagram, thank you diagram. Now, they take a worldwide scope and so this is a resource by which I'm not actually following this at the time but I have a couple of snapshots. But I want to share with you that it's a pretty cool dynamic web resource and it shows a very similar plot to what we just saw, country by country. Or I think they might have continents, but they have OECD versus non-OECD. They have time-resolved data and so you can actually watch how that thank you diagram evolved over one or two decades. Let's... So here's an example. I know that this text is small and I'll try to draw out some highlights just by way of illustration to highlight what available in this resource. So here's the IEA national-level thank you diagram for India. And so here at the left are the energy energy inputs and here at the right are the destination sectors for various problems in India. So what's going on in India? Well, they import a lot of oil. Wow. They import a lot of oil much more than they produce in that sector. That's interesting. How does that affect the way that they think about how they want their energy sectors to evolve? And how does that affect their relations and the resource quality? And that's simply an import sum. There is no growing economy. They need to achieve energy with a health impact on sourcing so much of their electricity from coal. That probably plays into a lot of things by now in India. A lot of bio or waste products, okay, so a lot of people in India live in developing world conditions in traditional and agrarian societies. Those are a lot of traditional biomats, biomat cookstones, that sort of thing. And let's see what's happening over on the right side. So industry and transport are smaller than other. I'm going to guess that other is probably domestic home services or what happened. But again, cooking at home. Let's look at the contrast. So here's the IEA diagram for the US. We just saw the little more summary with this place that on a visually consistent comparison for us. So how does this compare? Well, the US imports approximately equal quantities of energy terms of imported oil and domestically produced oil, excuse me. And we produce a ton of coal and export very, sorry, import very little. We've got a lot of gas production of course. This has been a big story the last few years. This is not a presence in a significant way in India's energy resource. So that's a big story. And one interesting contrast in India is that we put a very large portion of our energy into transportation much more than industry. So I believe with that as one example of the comparison of what you can draw, which is static in 2014. Again, there's time resolved data and regional sector data as well. Now GSAP several years ago produced another way of looking at energy flows worldwide, looking at not energy to say, but something called energy which some of you may be familiar and is typically characterized as the useful component of energy. What does that mean? It's thinking about the useful work that can be obtained when a resource is out of equilibrium with its environment and it comes into equilibrium with its environment. The way I think about this, the mental picture in my head is that if I have a large boulder at 5,000 feet there's a lot of potential energy there, but it's on a plateau that feels on a plateau of 4,000 feet. So the useful energy that can be extracted with our environment is what I get when it comes down to 1,000 feet, not 5,000 feet of people. So what we're really interested in when we're checking our energy resources is the work that we want our energy vectors to use in our economy. So this is a very detailed resource that I know the text is very small but I want to give you a sense of first of all the information, the granularity of the information that's available here and then some of the high level insight. So where is the useful energy coming from in our society? So as per decision the width of the path is proportional to the magnitude of the resource. So there are basically two types of path. One is human-appropriated plants, one is agriculture and forestry and the other three separate ones for three years of fossil path today. And so we see if you kind of the number is a little bit more energy flowing through our global energy system from fossil resources than there are from forestry and agriculture. So one interesting thing about that is of course it's all, all of our energy resources are ultimately solar resources. It's just that in the case of our fossil resources, they've accumulated over a very long period of time and we're drawing them down very quickly relative to the quantity of time that it takes to accumulate them. So we're getting a lot more energy from dense accumulated energy resources than we are from forestry and agriculture. So those are renewable resources, right? And so this point is sort of an extended discussion about peak oil and how we should be thinking about managing our resources and with respect to the sustainability of our society. And this is a helpful look at the relative values of those. So this is the seven half of that diagram this is the interest of completeness. My energy is ultimately destroyed as we use it to do work and so where the energy destroyed on a worldwide basis. A lot of it goes to the world of fossil work, much of it goes to the gas and many others. These charts are already on the GCEP website and everybody would like to have a look. GCEP have also compiled a worldwide carbon flow accounting. So, well, first of all, livermore lab does it for the US. So here's the livermore lab flow chart. So visually very similar but of course, there's no stop coming from zero carbon energy sources, right? There's no carbon coming from solar. There's no carbon coming from wind. I actually wanted to say about that but that's good enough for a first pass. How much of our carbon emissions is not going to be like this exactly? It turns out to be something like 40% if you didn't know that and you need to get the answer quickly. livermore lab has the chart that will allow you to be productive and it's first level so that's how it comes. So here's a big way that we get to this very well. What about worldwide global carbon flow? So again, a lot of detail but again, looking at the fact has almost as much carbon emissions come from the agriculture and forestry and from the farm. So if you're interested about, if you're interested in worldwide carbon emissions and if you're interested in sort of a really high level strategic approach to mitigation then this shows that there's not a lot of fossil fuel. And that of course is a lot of geographic resolution. A header to name where there are fossil fuel heavy emissions and where there are biomass emissions. But this gives us a high level look. Okay, so that's it for my quick touch on high level stuff. Now I want to talk a little bit about comparing different technology alternatives that offer the same energy service. And I will look at two tools and the tool kit and the first is that energy analysis. This is then a focus of GSATS for the last several years and first I want to give you a visual orientation so I'm going to concrete examples to get a pretty good visceral sense of what the energy analysis is all about and then carry that forward to look at some technology. So let me share with you one way of thinking about an energy conversion process and this conversion, I think that's one of the most important to be the higher oil industry that's going to be charging my batteries and storing energy. But no matter what the process is there's always going to be some fuel stock energy coming in right? If I'm pumping oil that's cutely down and I'm pulling it out and that's going to be like there's current coming from the wallet and then there's some energy to the consumer to find some immediate next use. And so thinking about the battery because the ratio of these two obviously is huge. There's also some external energy input in order to enable that resource, right? So an oil reduction is one of the steps, right? And we have to service that with a lot of fuels like battery doesn't have a time to factor this out. Factoring that fact we can have energy input as well as purely inputs but also factor in the stream to energy requirements. And there's some energy consumed by the process sometimes useful to have this explicitly denoted in our analysis of the process. But let's make this concrete. Here's an example that we're all familiar with in my personal opinion. What's the process that provides transportation and if we need to get more detail it would be very specific, right? It provides transportation at a time that I want to work with in this country, right? It's always available to me and it has particular characteristics of power to do with life, right? So it has five possibilities. But it requires an energy input. We're all familiar with the energy input from the investment is gas. Okay. How do we think about the external energy input? Manufacturing? Manufacturing. So it's an, I'm going to narrow it down to a scenario, right? I'm going to narrow it down to a scenario, right? I'm going to go into my driving and I need to go get some fuel. I'm going to let the needle like hard to do as it does. So what's the energy input? You know that? You really need to drive to the transition. Okay. You want to drive to transition. And so we're going to hold that car in line. Well, remember, what is it we want to do in the car? We want to hold the car. We want to look at the facts and have fun. We want to do more mundane things like groceries and necessities like that. So where is that, where is that energy coming from, right? So to allow it to supply the fuel as noted, it's coming from what's already available in that system, right? In this car, the system is putting out the energy which always could be useful energy but I'm using some of my gas to drive to the rapeseed and I'm not using it but grocery store or some of these. So we can describe this as energy that's diverted from economically productive uses. Probably speaking, you can think now about a larger system, right? Instead of just one car that's providing money, a larger system of technologies or information people pursuing different objectives and they require aggregate energy to put them into forms and so we're familiar with these, right? It's typically possible sources and our environment is personal and just as in the more specific example of the car energy used were required to go get those and so those are the things like what a fuel service it is or transporting more around the world or running mine shafts or what are the big figures of all the different mines at home. So of all of the energy that's outputted from our side-wide, tunnel-wide energy sources in all of the parts we're in some of it goes just to keep the energy extraction process going. So the question in it that I want to point out, if you want to do fun things and cool things or interesting things, things that are not because of the functioning gallery but things that we associate with a high quality of life like going to a sports game and football helmets or being spent at high universities doing things that don't go along to deceive myself and then immediately write on how hard it's to form this is in a sense a larger society that has the energy served by the energy ecosystem to enable that. So the question that that might be asked is what are the direct and indirect energy inputs that are required to produce the energy because from our previous example we hear what we know is that if we could take a small slice of our energy services that we're on and recycle that back into continuing energy extraction, first of all if we have a stable system we might be able to keep up the gap and secondly we'll have a lot of people who do things like building and teach courses and go for heights and play sports games but what would happen if the proportion of the energy that we need to recycle continuously and to extract more energy through larger energy, right? What happens when the proportion for end uses that are desirable to us shrinks and the characteristic signature of merit for thinking about that is energy return on this VROI and the idea here is that if I have a, I can get a lot of energy out for both of the energy in that I'm doing pretty well, right? I don't care why it's good and we can know right away that energy batteries that power our society, fossil fuels are particularly energy debt and I've been into the past 150 years we've been able to build an economic and industrial social infrastructure that benefits from their college VROI so there is here at Stanford is one place where there's been some sort of great charitable systematic analysis on packing what and what those numbers look like, how to do this systematically and this might be interesting and interesting and a little bit of a structure to have if we think that might be an additional level we have to choose among different technology options going forward so Adam Brands, here at Stanford Down and Wigdale previously at GSAP produced one such example and so this is looking at a processing state which is what we're finding in the United States so as we saw a couple of times ago there's some energy input at the in this side and then there's some net component output at the outside there's some external energy that's here to fund that component and then there's some inefficiency so what should we what should we take away from this one a little bit well I think it's fair to say this is one component of the total oil extraction and production process we want to think about total ERI of extracting from the well one end and delivering to the gas station the other end this is an important part so I'm going to jump to the punchline which is to look at some ERI values for different fossil energy resources so this is the plot from this analysis of oil and gas worldwide and then make an ERI of 20 that is for every 100 energy invested in oil and gas extraction and production delivery we get 20 minutes of energy that's pretty good I'll take it this analysis also has values for coal, tar sands, oil, scale these are all from biohands there's a good place to note that there that there are there's variants and the assessments that are made and so the first one I'm going to review is not the correct one you'll see that there are ERI bars in the analysis and we'll see the moment in the example of some more variants one other interesting note for the top of this particular assessment is that by some data analysis ERI values for specific categories of ERI resources are defined so this is for global oil and gas an assessment that's just for Canadian oil and gas in the orange and in the blue oil, gas and tar sands so I say that it's not to show you that the verdict is quite long and we're heading into the ground but to show you that this is a discussion of I'm interested in reporters and I think it can be just why and what it would be if everyone has that ultimate energy output to final demand available for us to continue running for as high as we're accustomed to so I mentioned earlier that when motivation for this kind of system analysis might be the technology for this so let's turn to the same framework around now to look at energy generation so again, you guys saw the expert this by now how should we look at this data set and think about the energy return ratios so what do I what do I determine whether you can input the output is that efficient well the answer the suggestion is inefficient my suggestion is going to be we can determine in a value the efficiency of the process and indeed we see that for those who can't see at the input side there are 100 units of energy in the output here there are about 16 units of energy so in the 860% it's pretty low so let's go and think about fossil conversion but for anybody who works in portable tanks 15% I mean it's not all the way outside of this but that information is encoded that it's here at this time ok so here is another set of numbers and so what further information about this system do we obtain by these numbers the extra energy input into the system this is the over the top in the rule encircles all of the energy inputs that we have to go factory transporting materials to build the solar cells to transport those cells to install them these are the energy inputs from the rest of the ecosystem in order to be enabled ok so this is the EROI this is the energy return sorry these are the the ratio of each two is the EROI if you read the papers the value gets to about 400 energy for us all of the extra energy input so 60 micro you do about an EROI of 4 for so in this analysis again I know that that's simply very from one analysis to another but here's one way to make very visually explicit and very technically highly resolved way where the energy costs are in producing our energy I think you can also think of that as a hot spot approach and I would see another analysis to take that approach if you're thinking I want my energy production to be more energy efficient I would want to break down the state of the process so here is a compilation of EROIs for renewable generation also some gas and coal which is to give you a snapshot of one analysis so I wouldn't take these of the absolute value of the fossil but the trends are broadly similar to one analysis so the next gas and coal often aren't too far apart solar is often much lower when it's usually higher than solar and hydro and nuclear I have not followed the EROI sessions of all products but you'll see that this particular analysis is interested in determining the impact of firming renewables with storage under EROI their answer I do have an analysis in a few slides so to report that analysis I made a meta-analysis of the literature on the EROI of PV and wind these are these figures EROI figures so he found a PV of around 10 roughly and for wind around 90 roughly the last two guys are using EROI models to go but the qualitative trend is somewhere in a higher EROI than PV again you'll see here that there's a lot of scattering so there's some ground-level takeaways here about the EROI of wind and the never trust the signal output we believe that there everything that we've just been seeing in the last few slides is a static analysis taking on what snaps out of one point in time making a PV cell or many other technologies very energy-conservative process and in particular for a technology like PV that doesn't require any operation but the energy cost is front depending on how much you get before you get any benefit from the PV cell you're spending basically all the energy you're ever going to have to potentially the manufacturing cell and if you want to have a roughly growing industry that energy spend you might add up very quickly you might add up more quickly and the energy benefit that you get from your PV installation so here's a dynamic net energy analysis of the PV industry McDale's work here and the schematic is here there's a lot of energy spent a lot of energy spent in the industry in order to get out and running because we've got production miles to go and more gradually and the energy spend more gradually the energy output from all those installations will gradually accumulate and so as we're integrating over time both the deficit and the credits how does it balance out should we be concerned about whether the PV industry is sucking away energy from the rest of our the rest of our ecosystem the short answer to that is no other way than working and this just sketches out some of the ways that we quantify it so at a certain point the energy spend to continue building production lines is matched by the energy output from the facilities so that's a great even here and then at a certain point the cumulative quantities of the energy output that the curve across the industry will become cumulatively that energy producer as well as an entertaining energy producer so here's just some data showing up to 211 showing that PV is rapidly growing the rapidly growing industry fragmented energy costs the question is relevant for PV and here's a way for us to think about this graph okay so this is a space in which the green area indicates that you're an energy surplus region the red area indicates that you're an investment and what are some of the factors that determine where you are at a given point in time one is what is the growth rate of the industry what is the energy subsidy that is pulling from the rest of the economy another is what's the capacity factor in the PV systems, right? the higher the capacity factor the more energy is productive and another is what's the energy cost of PV that you're building the lower the cost per unit generation capacity the longer the payback the more the mean this question might be so I'll show you the same space now with one specific technology plotted it's CADTEL and this is a time course so going back for not quite a decade initially the industry the CADTEL industry was in a positive net energy region they ran up a lot of energy expenditure to expand production but as that additional capacity came online the growth rate was modded to not then it came back into the net energy production factor now why won't these traces all work the same with different technologies from a technical side the reason is that they have different energy intensities to build upon a lot of capacity and also they have thrown at different rates so here's the courses for different technologies crystalline silicon represents the light share of uninstalled capacity and we can see that for most of the last decade it's been pretty close to the rate you can find and at least at the time of 12 multi-crystalline silicon is starting to come back to the net positive other than the energy character so the takeaway from mixed study is that we are just about at rate even right now and he anticipated that cumulative investment would be paid off by cumulative production in the early 2020 but it was a I think it's a very thorough analysis which points towards one of the possible wings of that energy analysis just to think about the extent to which one sector of our energy structure is subsidizing another sector of our energy structure whether that happens as a good thing or something to be concerned about for the right reason here then other sectors of our energy structure are subsidizing the community in the long run and the positive character in the long run the community is now an entry rate service we can use the same amount of the framework to think about energy storage which is another energy service thinking about high levels of renewable energy so just as we can find energy return on investment as a ratio of the total energy output to the total energy input for a particular process or economy so to a storage we're going to think about the total energy just passed from a particular storage installation and compare that to the embodied energy to a manufacturing and install that storage unit and so on the bar we're working on this this is as the energy storage on investment so I'll do the UROI so I can keep up the line and one might just be interesting well because there are a lot of different energy storage technologies out there in discussion okay not a lot of points but if you're aware there are a number of battery chemistries and other non chemical technologies under development so it's an interesting point in time for airwise install which is broadly socially beneficial so here is a summary of both Charlie's work and my work on hydrogen thinking about energy storage and it's just a bar plot of the UROI bags of a number of different technologies on the left in the ground are geologic technology so this is compressed air energy storage a couple of example gas for energy output and palm pilot stores they don't bring that down but these are very high energy storage on investment ratio so here we have in the blue are various batteries lithium ion batteries on the left sodium sulfur vanadium redox batteries lithium bromine batteries and lead acid batteries and we can see that first of all they're all a lot more than the geologic storage and second of all they are now in equal in terms of thinking about energy and then there's the medicinal analysis thinking about what hydrogen is in the budget you use you have grid electricity if you have a generation coming from a wind farm or a solar farm or a large storage that's kind of the beach case that's thinking about all of these technologies and so if you want to do that in hydrogen you would put the electricity into an electrolyzer to generate capture or store the hydrogen keep it there until you get the real fuel cells other things are more easy to think about hydrogen but we were thinking about just in terms of a grid storage source so in terms of the energy input and the hardware we need to do that that's favorable in terms of energy now some of you may already know that the amount of efficiency of the process of hydrogen is quite low lower I think than any of your patterns here so here you have this situation where one energy energy return matrix seems to favor some to take that technology and a different energy return matrix is a good place for me to point out I'm going to go away from this thinking as a result of my talk that these are tools that we should use between one rather than the other these are information inputs to put together on a panel of available information and the way any decision maker will obey when he gets to invest or quantitatively about this particular use case of capturing open generation if I don't have any storage should my wind farm consider so much power and I don't have a trailer so this would be happening at least up until very recently in Texas where it was a lot of capacity and the higher the concentration of these interventions were different levels the more of an issue this would be because we spent money and we could build a generating resource in the last few months so alternatively we build a storage resource they capture it over generation at a later point in time that has the benefit of capturing all the generation but it has the downside for additional energy costs to the back so how do we think about those two here is a space in which I'm looking at the aggregate EROI of a storage enabled mini grid so not just the generation itself not just a high EROI wind power say so the energy costs to build wind turbines and the battery and total energy output from the main turbine directly to the grid and to the battery and use that to determine a system-wide EROI and that is plotted here against the proportion of total generation which is diverged through the battery so maybe 25% of my wind farm output over the course of the year would otherwise be failed it's only 10% I hope that but the when I plot these grid EROI in this space they look different for different technologies because different technologies and storage technologies have different EROI ratio and the EROI of the generating resource and the ESOI of a storage resource and the efficiency of the battery and the fortunately all interact together to produce different curves and one of the takeaways is that although hydrogen has a pretty low relative efficiency it has a high ESOI and in this storage enabled grid it looks just as good as any of the battery technologies on an EROI basis so again I'm just thinking not about any financial investors thinking about husbanding our side energy resources in terms of running our society in exchange for our industry's investment in building wind farm or other energy so these two lines up here are pumped high relative to that air which is what's on the air time ESOI ratio but if you're now choosing between if you're in a place where those are not you've got to be available for or call mountain for the reservoir so if you're in a place where you don't have those things and you can build a concrete path where you're going to put there you're going to be in redox or in ion or hydrogen people with hydrogen say low efficiency is not good for us and they might be right but it might also be useful to know especially if you're a public agency to know that on an energy basis that's not the problem that you get from this kind of analysis and the final thing to note is that as we saw on the earlier slide the EROIs fossil energy resources like Foil and Gap are somewhere around 20 or 30 so if I can build hydrogen or about maybe we got static and a couple of the wind then I'm somewhere around 25% that version but I'm still getting a better EROI because it's a science, total energy investment to produce that electricity than if I were using coal, fire or gas so that's a takeaway storage technology with a low efficiency with a high EROI might still yield a benefit to us when thinking about the overall energy resources and this approach and the analysis and the configuration is what highlights that so now let me just here talk about another item in the toolkit called life cycle assessment which some of you may already be familiar and either the post-causing of net energy analysis or the umbrella discipline of net energy analysis is not that clear but a pretty similar intuition that you have to consider the entire life cycle of a product or of providing a service in order to think thoroughly and critically about how it compares to other options so the first thing to say about LCA is the life cycle assessment is that it encompasses at least in principle all stages of providing service or building a product so here's a graphic thinking about building a product starting with materials extracted how to iron it or to do extract to make the steel that went into your automobile or into the steel that you've mounted the fields on manufacturing processes many are not specialty types but some notably are fine refining particular other material metals that might be electrochemical couples and batteries to do another silicon refining is very interesting distribution transportation of course what's the use phase impact of my particular technology if we're thinking about electricity generation so full fire power plant is going to have continuous inputs of an energy resource for society in order to produce the output PV system is going to be different so PV is going to have essentially no contribution to total impact from the use phase and here I'm reflecting small contributions just washing off the panel and then end of life management and the other thing to say about LCA is that it's codified and standardized discipline and process and so there is at least in principle a standard to aspire to reference to in terms of whether you've done a full LCA and what the best practice is about but LCA's are valuable also to improve it so as my energy analysis LCA studies might have different system boundaries similarly scope studies might come out with different results it just can only do them only because they had different fields to start with and they spoke with manufacturers and so I've been saying what I'm going to say in my big way is to be a critical consumer of this information if you're reading newspaper or online the information is important but so I have to think about what's coming from and how it will develop so let's get concrete here again thinking again about personal transportation so we are all familiar with gasoline vehicles and it's kind of exciting that that might not be the baseline by the time my kids are our licensing age we drive at least now in our house so how should we think about which is cleaner, which is overall beneficial for the environment gasoline or electricity maybe some of you have considered this already any thoughts? typical literature says it depends on where your electricity comes from or it's full generated or more carbon free generation so it depends on where the electricity comes from is that going to be a dominant impact it may be it is but it has a contending approach it depends on the impact you you guys mainly you know let's look at one particular study okay so this is not a meta analysis but again for lots of purposes to see what the literature looks like when we try to drill down on that in these questions so here's a recent LCA in a very well-known history of the journal that's asking exactly this question trying to parse out the impact of gasoline powered versus electricity powered transportation excuse me but I was a bit cryptic, DWP is global warming potential which is one of probably about 12 or 14 impact categories that were assessed in this study we're only going to look at two, don't worry but this is one that everybody is familiar with and can relate to so here at the bottom ICEV is internal question engine vehicle so there are two scenarios that they analyze and there's nothing about gasoline vehicles or diesel vehicles and then the top four rows are various electric vehicle scenarios and they are distinguished by two factors one is the particular battery chemistry involved so they have iron phosphate batteries and nickel cobalt manganese batteries two different widely explored chemistry for batteries, both they matter and also by the electricity source that was previously suggested and I think it's this coal natural gas and the Europe-wide agreement and then of course the contribution to global warming potential is broken out by different by different phases of the life cycle in particular of the manufacturer so they're breaking out the other power trains in one category separate from matter and we can see so one could take away is that in all of these cases the fuel or electricity the energy input to operate the vehicle don't have any impact and so that is exactly to the gentleman's comment earlier that it depends on the electricity comes from but in a sense it doesn't depend that much right it's all bad, either you're burning gas and you have distributive CO2 emissions that are being applied or you're burning a fossil fuel and so you have somewhat lower emissions at a centralized location now there's some reason to think that a centralized location is better because then you can do a lot more with carbon capture and a much more concentrated stream and that can get you to this qualitative comparison among the cost and benefit to different technology options but so one takeaway from this might be that battery vehicles have slightly lower emissions than internal combustion vehicles with non coal electricity only if you're burning coal to get electricity then you don't have a win in terms of emissions so what about another impact category same study, same set of scenarios thinking about human toxicity and this is an interesting category I'm trying to contemplate because it's often one where consumers that is not realized by the first world consumers of the products that we're thinking about there's a lot of offshorings of manufacturing or international sourcing and the places where the resource that's needed is richer or labor costs are lower and that also means offshoring various impacts sometimes emissions impacts and sometimes human toxicity impacts no distractions for a great example so how does that play out for these six scenarios two combustion vehicle scenarios and four battery vehicle scenarios looks like the human toxicity impacts of the battery vehicles are much more severe what are these two components of the bars it's the battery and the other power train components so I would anticipate that if you or I sat down to go through in detail the findings and go through the literature upstream we find the metals extracted from the battery bubbles is a significant component of this of this battery impact specific to the battery but I'll leave that to you when you need to do the homework and then the this study also finds that the fuel excuse me, the electricity generation for these for the battery sources has much higher human toxicity impacts so it was like they're saying that centralized fossil generation electricity has a higher impact than the stupid gas so the battery vehicles have much higher health impacts so what is that, what's the simple answer using this data to think about battery versus combustion vehicles there's no simple answer, it's a panel of data and depending on which criteria are most important to your locality or your national economy or your emissions transportation goals you might take different conclusions from this panel of information oh, but batteries aren't the only next generation propulsion technology on my line for small parts of the vehicle, right? I previously mentioned hydrogen so let's add hydrogen to this, so what is that? any guesses? battery's better battery's better and why, what caused you to anticipate that? what's the efficiency yeah, so I previously mentioned the context of stationery and conversion that the round trip efficiency is converted from electricity to hydrogen to electricity, it's very low and that's pretty bad in stationery and electricity storage context compared to battery levels so this is just the same point now on transportation so I think it would be a similar answer depending on where the hydrogen is very cool yeah so I love the idea that hydrogen is a carbon free fuel because it's just like looking at a vessel or a leaf that says zero emissions vehicle or a golf cart, right? zero emissions vehicle well, yes but it could be a zero emissions vehicle if not going there so yeah it's exactly the same point you can slide behind it if you follow the energy upstream you can draw suitably wise yeah taking a properly large system so a different study tried to do exactly that again one study this is not my definitive meta-analysis and so here they're I specifically mentioned here that they're looking at kilograms of CO2 equivalent per vehicle kilometer, that's the impact category that we're looking at what are the scenarios, we have combustion engine vehicles down here with different fuels, we have hybrid electric vehicles we're included in this particular analysis a battery vehicle scenario and at the very top is the hydrogen scenario and the key thing here again back into your comment is the source of the hydrogen so most hydrogen that's used today that is not used as part of the integrated industrial process, as you may know is from steam methane reforming but SMR is steam methane reforming because we're getting our hydrogen from a fossil fuel and that's a pretty emission defensive actually if hydrogen sounds great and it could be great to contact because you can appeal it by electrolyzing water so if you have steam electricity and you're splitting water then you have a pretty low emissions overall but today that's not how we're getting our hydrogen so what this is pointing out is that if we're going to build a deploy hydrogen vehicles in our existing energy infrastructure then the impacts might not do what you think they are right? so the takeaway here is that hydrogen powered vehicles have higher emissions probably have higher emissions if you're using steam and methane reforming so again in this scenario we've got clean electricity to do steam hydrogen generation that would be really exciting because our present economic conditions for a different hydrogen generation are a lot more complicated than that let me just check my time okay so I'll just make a quick remark here that some people have pointed out that or positive that there might be systems leveled benefits to a hydrogen infrastructure that extend beyond just the vehicle operation and the experience of the drive and those would include things like having a storage system which would be used to capture over generation or buffer over generation that you might want to use as a storage system even for your electricity because hydrogen storage has a much lower self discharge rate than many batteries okay that's cool, it can attract these technical characteristics and you can also drive them as a combustion fuel you can feed it into the natural gas grid and that is now being done actively in Germany especially up to a certain relatively low percentage, I think it's around 5% so maybe that's a useful care person to have maybe that allows you to reduce your natural gas combustion, now hydrogen of course is not going to produce any CO2 emissions whenever, and that's a good thing so DSAP was fortunate to host a visiting student earlier this year and Marcus and he and I together worked out an analysis of this question using a highly detailed optimization model and so if there's interest after it I'm happy to come back to this but I want to respect it once time and just cut to the one of the takeaways which is that if you have a choice between introducing battery electric vehicles into your community or fuel cell electric vehicles into your community one which does not have any attended hydrogen infrastructure and one which would have hydrogen infrastructure and if all of your hydrogen is going to come from solar powered electrolysis PV is providing electricity to generate hydrogen then in this specific scenario that it's more cost effective to reduce your communities overall emissions with battery vehicles then it feels okay but as I said this is a highly detailed scenario with a lot of inputs and a very specific scenario and so if you are a planner or a technical consultant this might be the scenario that is relevant for you or the scenario that is relevant for you might be quite different from this this is looking at one certain product community that does not exchange hydrogen with neighboring communities and we made an effort to integrate consensus forecasts about technology costs and fuel costs into our analysis but you know if there are errors on that and there are different scenarios how it might free out under future trends so now I want to turn to the last incarnation of energy systems analysis that we're thinking about in detail and that is thinking about the impact of some specific technical advance and some specific technical application on a larger energy ecosystem which that technology is a part or might be a part of the future so I have a couple of examples about that so one topic of broad interest as you all probably heard already today is solar fuels the idea that we would like to take energy from the sun we would like to take carbon from some suitable source like a biomass, maybe a capture plant or a gas and use some particular technological pathway to reduce hydrocarbon fuels which are useful to us and which are particularly familiar to our existing energy industry which uses liquid hydrocarbon fuel and of course we're always thinking this indicates what nature does it doesn't have a much slower rate than what we would like to do and so here on the bottom first of all, it visually makes the case about why we want to do this but we really want to have finite, stable, sustainable liquid fuels infrastructure we need to do more or less by just describing we have to be taking as much carbon out of the atmosphere as we are putting back in through combustion in some fashion if we can take the carbon out of the atmosphere and put it into the fuel that's fine, we still oppose the loop so we get that technology would allow us to get to the virtual cycle which sequesters for some period of time carbon from the air as organic and how to grow so we can think about doing it in a non-biological fashion which my research background was discussing earlier so two quick projects of this kind one is a prototype device that uses solar hydrogen which was developed by Lawrence Berkeley lab as part of the DOE joint kind of artificial photosynthesis they actually built the prototype and I saw it sitting on the desk it was not this big of putting in the right absorbers and the right catalyst layers and closing it into like gas management a fluid flow system that they could put this on and make hydrogen so they've done this on like 10 centimeters square yeah and the whole effort of that project is to prove that now as much as possible small scale because people would be necessarily very large scale but how good your catalyst has to be if you want to get as much energy out in the hydrogen you produce as you put in to make the device in the first place so this is again thinking about energy payback you want it seems like a reasonable starting point to at least say that I want my EROI to be one maybe I'm going to subsidize an end factor of this kind of technology up to some point to get it running but ultimately you want to have a steady state contribution of a technology like this for energy infrastructure that has to at least break even on energy so how good the catalyst has to be in order to get into that break even so this is the analysis that was from this particular study in one of that part of the overlay and this is a variable state that looks at two characteristics of the device one is it's operating life time longevity in years it's going to operate for 10 years 25 years that would be awesome how long it has to operate if I want it to break even on energy well that's not the only factor another factor would be the efficiency with which it produces hydrogen from the side this is often called the solar to hydrogen efficiency or SDH efficiency and so this is an analysis that varies those two characteristics holding everything up to constant and find the contour line to the right of which you can break even on energy to the left of the two arms so if bad traffic doesn't go to zero that's alright I know the authors don't like them they go down to 5 years of operating life time here so let's say the device is only going to last for 5 years maybe I'm actually going to know that how efficient does it have to be it has to be about 5% efficient 5 years and it's not 5% efficient then it hasn't broken even on energy maybe it's only I know it's only 3% efficient but when it's part of my lifetime testing what number do I need to look for I need to look for about 5,000 years of lifetime just to break even on efficiency if I can do better than that contour line that I'm in that positive territory that's a good thing that's what I just said alright now a moment ago I was talking about liquid fuels it may indeed not be very useful for one of our future energy systems but we certainly know how to work with liquid fuels so here's another vision more specifically for liquid fuels there's a project of mine that I have ongoing so does this look like a good idea or does this not look like a good idea I think it sounds nice when I describe CO2 out of the air and chemically reducing it to provide us with a liquid fuel that it ultimately met zero emissions yes, no but what more do you have to know in order to make a judgment or are you already confident on where to go please, good idea okay we have one vote for yes two for yes three, four I have four for yes five for yes what's the energy required to make that fuel okay I request for more information what's the energy required to make the fuel alright, so we need more information I've got two comments what is it cost what is it cost coming for gallon equivalent cost for gallon equivalent alright, there's a business man over here there are no, nothing's going to have to run investment so we need him on board any other thoughts how much energy does CO2 out of the atmosphere I like your question information, what is the energy cost for capturing the CO2 which is the chemical feedstock for this process so I only have one thought on this in order to be kind to all of us but the slide shows the first cut of my analysis which seeks to provide the information that was asked for what is the cost of the CO2 capture how much energy is required to carry out this and so by way of changes on the way to change this question of the dollar cost for gallon and gasoline equivalent I will suggest that a good starting point is to ask what is the energy input that we need to get some well-defined quantity of fuel output and that is my framework, right, and we then can do the test in economics on the particular system that we're hypothesizing so let me give you a quick tour of this what am I trying first of all we already have methanol today this is not a process to get methanol we already have a way to get methanol and we already have a way to get electricity without capturing carbon so my future scenario is a scenario in which we have coal-fired electricity we capture from the power plant's loop to get a sufficiently pure CO2 feedstock stream and put that into a reactor with a low carbon electricity in the presence of protons and get our product out to the other side so is that a good idea or not my first counter-question is how does it compare to what we're doing already okay so I'm going to suggest that before we decide yes it's a good idea we should find out what the carbon emissions is about this process, right the whole point, the part of the point is to pull carbon out of the air at least at the same rate of output if there are upstream emissions in any direction which far outweighs the benefit that I would get by substituting a zero carbon methanol for carbon-intensive methanol then all the rest doesn't matter and it's not a win, okay so my question for us all is what are the requirements in particular on the catalyst the electric chemical, the electric catalyst to at least raise the heat on the carbon so that's what this plot parses out and this so first the yellow contour on each of these is the yellow band that yellow band is the red one if you might guess it means good then that right so this shows me some region in the technology variable state where what I have to do if I want to be doing okay on emissions if I want to at least be doing the incumbent process emission intensity and let me not really know that I strive to use a consistent comparison in comparison on the one hand the electricity and the methanol in the advanced case on the other hand the emissions from the electricity that's so far with no catalyst and the methanol which we produce today mostly in the natural gas case plot so I'm trying to apples to apples so I want you to know that one of the four variables I'm looking at the electronic efficiency with which the electropalus uses my process electricity to reduce my CO2 to methanol I'm looking at the atom yield the efficiency with which my reactor takes every atom of carbon that comes in and turns it around to methanol might not be very efficient doing that might be a lot of CO I'm looking at the catalyst over potential this is a measure of the thermodynamic efficiency of the catalyst no catalyst is perfectly thermodynamically efficient there's always some heat loss so even though the reversal potential is 500 or something the operating potential might be 700 or 800 that delta is the over potential and I'm looking at the energy intensity of CO2 capture right to that point earlier so I have it so I've included three different scenarios for that and so I put the box on the slide yeah okay so one thing to say is that the rate even line is at relatively low values of electronic efficiency and atom efficiency so when I talk to electrochemist working here I have it on CO2 reduction and I say oh 220% nobody says oh my god we're never going to get there I say okay that seems like something that research might be able to do okay research is a future unknown nobody really knows but I think that this kind of analysis should be useful to us in thinking critically about which research program to pursue do we have a chance of success or not that's one of the good information another good information is just where we are now so I don't I'm still looking for information on the atom efficiency of catalysts that view this particular reaction but the faraday efficiencies are widely reported and they're often in the 10 to 30% written or optimized energy scale up on this is a strictly research stage right now but part of my objective is to provide an animal framework with which to think about again which are the pathways which technology pathways we should be pursuing to the extent that we can at an early stage of development and okay I'll hold it there and I'll let you guys bring it back to the question so that's my tour through different domains of energy systems a quick wrap okay what was our toolkit, statistical compilation give us kind of a 50,000 foot view on what's going on in energy flows and it might be useful to us in thinking about where a particular technology that I mentioned that I'm interested in fits into the national or global scale of energy flows or carbon flows we talked about that energy analysis thinking about what is the proportion of total energy in that I can return not just to it to continue to extract energy resource but to do things that we want to do and we talked about what's like assessment which is a pretty powerful tool it's also a specific example of that but again I'm one of the critical consumers of the information and either let's like we'll study or in the energy study and some of the specific insights that we came across worldwide fossil fuels contribute slightly more emissions than the bio-nations a very high level of insight it's not going to tell you anything about what the state of California should do or the nation of global warming should do that kind of information okay we saw that wind power has a higher zero i than tg that's a qualitative and consensus trend although different analysts have an absolute value for those two zero i values and we saw that battery vehicles at least by according to the studies that we examined have a slightly lower life cycle of emissions than gasoline when they're using non-full electricity but the fuel cells as exciting as technology is probably have a normal advantage over gasoline unless we're using real hydrogen that's not exactly correct and then we saw a couple examples of trying to connect a specific characteristic of a specific technical system to a larger energy dynamics in the case of solar hydrogen we saw that 5 is an efficiency sorry I wrote a 10-year university 5 years you need to have 5-year lifetime in order to get your payback so that's me we have time for questions now please feel free to be especially at any point so when you did your ero-line analysis if you're looking for something like Tardis energy put a certain amount of energy in to get a gallon of fuel out you burn it and then it's gone but if you're looking for something like a PV system you create that PV system and you put it in the field and that PV system is generating energy each year so when you calculate ero-line PV you include the lifetime energy output yes so the this is what should be done for any analysis either a ero-line or a life cycle more broadly for a generating technology that has no continuous impacts there is a remark earlier that's not front impacts and the case of solar energy is quite large because of the current and current and so yes the energy spend is any more times over the generating lifetime of the device than that okay so if you discount out of this on the platform that the question has been around in that energy discussion should be practice energy discounting in the way that you practice currently or financially discounting and so I was thinking that the next did not that it would happen double-check to be absolutely short and in general we do not okay but PV comes out at four then even if you look at the lifetime energy okay and then just one related question let me just add that I want to note that I know at least one manufacturer that will disagree with that value and will note probably correctly that ero-line and PV have been increasing in recent years so why was the hydrogen efficiency not included in the ero-line because it would seem to me that it should be included not with knock hydrogen down but it was included so let me first note and maybe it's a little bit clearer for you that those two technologies provide two different energy services if I understand your question correctly I think you were asking about hydrogen storage scenario you know storing hydrogen energy so the question there is what is the energy standard to build the device and how much how much energy will I get out of it and in that case I assume the particular particular use case of the one from a particular slide I'll bring in a particular title and the short answer is to your question on PV is that the energy spends in the hydrogen case with every unit I've left with the output is relatively low compared to batteries because the batteries you mean you do a lot of refining of semi-specialty metals in order to build the battery in hydrogen you're not you have to build the electrolyte in the QSL and those are power components in the energy components if we want to use store life energy just a big steel can which is relatively speaking energetically inexpensive compared to batteries why is it not getting the idea of efficiency efficiency is like 25% because it has because it has a long life time part of it but the energy components just a steel can now I assume that my analysis is that you will be replacing the pan-fuel cell in time to time because the lifetime of the pan-fuel cell is shorter than the last time of the steel type of stores you know David if you are denominating by power in and power out because then you are looking at them perhaps the more energy-intensive component of the system that I described so you are looking at the energy storage that is a steel can compared to a lithium system with specialty types of apparatus okay so questions you talked about when having to reject some of the energy that it makes I assume for your analysis you assume that wind doesn't do that so it has an ideal capacity factor same with PV and same for natural gas like a lot of natural gas turbines have been spinning down to accommodate more PV wind on the grid so what were the capacity factors you assume for PV wind natural gas in your return on energy yeah so I cannot speak of fossil fuels because I was not involved in developing the studies for the fossil fuels there are certainly studies out there that can help you go back in terms of in terms of mixing out the PV he assumes I believe with something in the range of 20% capacity and his analysis that was the dynamic he was looking at some worldwide statistics and I have some data from my backup and in terms of the wind I think I use a pretty optimistic capacity factor for wind something like 25% and for each source you assume that the grid could take whatever it was made within a capacity factor it doesn't have to periodically shut down due to changes in load I did not integrate that resolution of grid operating dynamics in a study that I was looking at with the Cretalins analysis I assume my assumption was that we want to capture all the wind energy and I can strain the system to capture everything and if the grid wasn't going to take it then we'll capture and so that then determines the capacity of the storage system I understand I think I assume that I want to have three days to buffer and then just to challenge maybe one of your final assumptions you compare the battery electric vehicles to the fuel cell vehicles I just encourage you to do an analysis for the fuel cell with carbon capture on steam muffin reforming to see if that changes the conclusion any because if you believe that one paper you showed the vehicle footprint was higher for the battery electric vehicle than the fuel cell vehicle so the thing that was tipping the scale so to speak was the emissions associated with the fuel production there's a way to perhaps address that and carbon capture hydrogen production can be a little bit less daunting than from some other source yeah so I think glad that you raised that and there's for any conference study like this of course one has to do scenarios I mean of course there's somebody out there studying not mine but I read it with interest and I appreciate that in any study like this one has to study the science just because it makes your final conclusions slide yeah I think it's fair enough to add that the absence of CCS is a great point and I would love to learn actually more about capture from hydrogen production okay have you looked at shape oil from shale? I have not but others have let me use this story so Adam Grant here at Stanford it is more than that with an eye and I'm not going to speak in his stead really other than to say I think I can say generally with confidence that no actually I'm not sure fossil is out by my domain okay so tar sands come in at a lower year wide than conventional gas and coal and and boy it's not going to take you long to find studies literature on the energy returns of shale gas or more of the less likely impact as it's getting so complicated lately and we can do a search right here after we finish up if you want I happen to be able to do that for this one C and G L and D for ICB C and D L and D and look at how there's activities, search activities going on all over the world well I'll give you my own personal just not L and C not GSEP speaking and not the sort of original like the search activities around what research we should be doing because my impressions now are that as I noted I think a few minutes ago with centralized combustion you at least have a place of chance you give it part of the passive life of change right so the CO2 concentration in the power plant flew with something like 15% as compared to the CO2 60% so if you think the part of the sustainability technology portfolio should be capture and sequestration or capture and recycling then you may as well bias and favor of that and try to shift emissions into concentrated point sources so how does that work with the transportation no matter what your carbon fuel is for transportation it's going to be distributed much harder to capture so I find the belief in the interaction of thinking more about concentrated of CO2 for as long as we have to have CO2 emissions and I think my view for others a lot of people see a highly electrified future for life being vehicles and I know many people see a CND future for having to be tracking remediation something else something else but when I think about these things that's how I think about it look at hydrogen so here's what I know so far is that you take a big hit on compression to localify and I think also on elaboration so I don't know I mean look the automakers have come out with high pressure gaseous storage so far and they're initial at the initial production and NOAA is a very active research area and would enter that discussion with a strong cautionary attitude for the energy cost of the phase conversion I don't know if my answer is that's the question I'd be asking Yeah, I'm not a a fan of analysis I'm not a fluidist person and people are smarter than I thinking about the fundamental science of this conversion and future research is not normal so I would inspect the board and see what their challenges are For the last years I've been seeing popular media reports which are new to me that there are a lot greater emissions from natural gas drilling and extraction and transportation than I previously believed to exist to such an extent that some people are saying that natural gas is a dirtier fuel in terms of greenhouse gas potential than coal burn I assume that academics have been doing this for years before the popular test picked it up Is that already baked into your analysis of the energy and the greenhouse gas emissions of natural gas or is that something that needs more research to be really understood Too quick notice by way of the intro my understanding is that the recent discussions that I was after this issue have been simulated largely recently published research on this issue and there are other people I know who have been doing work and others elsewhere and so I think that some of the fundamental underlying analysis of the discussion has actually been quite recent and so is that consideration based on the number that I have shown the short answer I think is no so I again I'm not focusing on not so much fossil energy I'm interested in how we can compare the fossil and the various methods I get my information from credible sources I hope such as I've shown to you today but the barcloth that I showed at least one of them from 2014 was the other one so those predates the last few months of discussion about feasible emissions and they certainly will impact the global warming potential how they will impact the energy return on investment is a different question I get things when it comes to questions whether you are counting the methane resource that doesn't escape as part of the initial feedstock so maybe it will alter the ROI value my guess standing on one foot as it were is that the speculative emissions are very significant while we believe they are very significant in global warming my guess is that they are relatively significant as a proportion of total energy total methane extracted from the ground which means that the ROI doesn't change much for methane impact though but again it's just highlight that we need to have a thinking cap on when comparing different characteristics about the same energy system we might not care about the impact on the ROI but we really think we should care about the global warming impact in terms of transportation I don't think there was much methane involved in the scenario although as we noted the hydrogen, the one case for hydrogen production was from steam methane reforming so yes if you want to really throw you could have a look at the methane production of the literally upstream from the hydrogen I don't think it's a question the same issue would be true with the use of hydrogen hydrogen is very critical to keep hydrogen in storage I've read it can you read it? yeah I've read it very little about this search and I don't have to go find those papers I didn't even answer I don't have any questions under an ideal scenario with the larger vehicle i.e. completely charged from solar r will finally get into a point where the carbon intensity of the global warming in fact is now substantially reduced i.e. one example of the batteries probably need to be replaced real near 10 the amount of solar that you're going to have to make the carbon footprint of installing that solar you can recover that in the 10 years that you then need to run and replace the batteries if you look at it in that sort of scenario as opposed to just gas or coal I have not can't right now think a report that I've read that has tried to be convoluted which is exactly what you're thinking about it I would say so I think your question is what if you take into account the full life cycle of the vehicle including the battery capacity is it preferable to have solar or electric battery levels in terms of emissions to have our existing Japanese but with the fuel source that is as low carbon as you can inject the fuel source i.e. all solar or solar energy so here's how I would think about that so let's assume that all of our feedstock electricity production is going to go to zero approximately zero on the left just to find out the body is to playing field for the moment in order to draw out that we still are going to have impacts from from energy and the body carbon and so this is what you're getting at when you're pointing out the possibility of battery presence so the energy even though that person was truly truly truly carbon free the carbon footprint and energy spend would never decline to zero it might get quite a lot lower and I think it's fair for us to consider that to be a big win compared to where we are now and yeah I think in my thought the fabric is not a perfectionist so if we can install a ton of utility cfc and use that to drive our lease yes let's do it at the same time that we're looking for battery couples that have lower upstream emissions of the modern energy one other thing to keep track of it can't be nicer if we got to the point about energy infrastructure but this was the main issue there are different energy vectors of different quality right if I if I have pd on my rooftop I can use that to charge my car that's good but if I want to buy a car that's made partly of steel maybe not very much because maybe at least if I use a higher light weight that's good and has a battery in it which requires suitably refined what the chemical couples those are high temperature processes pd is not going to get in a high temperature process so so one might say that the energy vector that I need for transportation the most intense one that I require is electricity not high-grade properties that's good pd helps me there but it's not going to help me to run my and it's not going to help me to run my lithium and so so there's a certain unsubstitutability that basically the energy system and it doesn't bother us to be used to it but if we want to think about reconfiguring our energy structure that may become important at some point and another example of this is what I alluded to earlier right the electricity but it might be great if you like the transportation and you can pursue it but for marine and aviation and military they're going to continue to eat high-density hydrocarbon fuel so we like to buy what we can and we deal with the best under different you know how that is all I see some of the paper on biofuels that show net removal of CO2 for the environment if a couple of us carbon capture can you talk to how that could play out on some of your analysis in terms of comparing biofuels with no advanced internal combustion engines versus battery electric vehicles and fuel cell vehicles let me first know that my thoughts on the model are expected in time I think the stage is open and now I'm very happy to talk with anybody who would like to stay thank you for treating me in touch at any time and I'll have to thank you