Sustainable engineering

Transcription

What is sustainability? Sustainable -- Is it this fire? I think we understand that any one thing in isolation we could live with. It could even be a good thing. But sustainability, of course, is about what we all do, the choices we all make, collectively. It's about how many Earths it would take if everybody in North America-if everybody in the world -lived at the same standard of living that I do if everybody built a fire like this. And that's what makes sustainability especially challenging. It's about what we all do together and it's about collective action. So we talk about the challenges of sustainability, the challenges about us all working together. What do we really mean? I think there's three main points. The first boils down to value. Look at this guitar over here -- what's its value? what's its value to you? Maybe you don't play the guitar so it has no value to you. If you gave me a thousand dollars would I give you that guitar? This guitar has been with me for about twenty years, so I'd probably keep the guitar even if you give me a thousand dollars. I paid four hundred dollars for that guitar back in 1991. If you bought a similar guitar today would it costs more? Would cost less? Values change over time. Values are different to different people. You think about the difficulties valuing that guitar over here... and let's extend that analogy to what's around us. You know, what's the value of this wood? What's the value of the trees? What's the value of a stable climate? These are tricky questions. And different people are going to have different answers. And if we think that maybe the air is not being taken care of, or the climate isn't being taken care of, or the water isn't being taken care of the way we want it to be, then we can ask the question why doesn't the market take care of it? And, well, that's a very common question to ask. Why doesn't the market take care of the environment? Well, the market is just us. It's a reflection of our values. So the market sets prices and people set values. And the values we place on the environment are something we learn about in school. It's not the sort of everyday decision that we make that we don't think twice about. If I'm going to go out to dinner with my wife and to take a night off we might decide to go to downtown Ann Arbor, go to a nice restaurant. Maybe we're going to spend sixty dollars on dinner Or on another night, we're in a hurry and we throw something in the microwave and barely spend anything on dinner, maybe even skip the meal. These types of decisions come very naturally, very instinctually. But, if i'm going to ride my bike to work for a commute, I'm going to live in a certain area that allows me to do that... well, these are very heady decisions. There are trade-offs associated with those decisions and decisions about carbon dioxide and climate, these are things you learn about the school. Who would have ever imagined being born and expecting that the gas you exhale, CO2, would somehow lead to a warmer planet? Obviously it's not because of people exhaling -- it's about fires like this and maybe nine billion people making fires like this metaphorically of course, with their cars, with the electricity they use, etc. The values we place on the environment are something we learn about school. It's something that we need to be educated about and it means that it's a challenge to address these questions, these sustainability questions. The third area is about the distribution of cost versus benefits. When I decide to build this fire you can see the emissions coming from the fire. These are emissions that everybody shares. Nobody's bottling these emissions up and bringing them and putting them back in my house for me and my wife and my children to enjoy all by ourselves. They're shared. And we tend to act differently in groups when we share things than when we own them individually. So for instance, imagine yourself being on a ranch -- you on a ranch. And you have cattle on your ranch. Just picture for a moment how many cattle are out there on your ranch. Are there shoulder to shoulder to shoulder cattle? Well if they could be, you'd make more money. But of course you're imagining that they're spread out because they each need pasture. So you have in your mind automatically figured the optimal number of cattle for your ranch. When now imagine, instead of that plot of land being just yours, it's shared by ten neighbors. Do you imagine the same amount of cattle being out there being shared? Of course not. Everybody brings their own cattle and next thing you know, the areas is over grazed. This is what's called the tragedy of the commons. We tend to act differently when we share things than when we own them individually. Imagine that you're going out to lunch with a group of people. There are two things on the menu: There's hamburger and there's pheasant. Hamburger cost $5 and pheasant costs $105. And everybody's paying their own way and you know, if you're a college student, somebody fresh out of school, you're probably getting the hamburger because you can't afford the pheasant. Everybody's paying their own way. Well let's change the nature of the game a little bit: Let's add up the bill and divide by the number of people there. You think some people are getting pheasant now? We tend to make different decisions in groups than we do as individuals. Again, nobody's bottling up the emissions from this fire and just putting them back into my house for me and my wife my children to enjoy later. The emissions are being shared. So I maybe feel differently about this fire than I would if this fire were in the house. This is the challenge of sustainability. It's about what we do in groups relative to what we do as individuals. So if we act differently in groups than we do as individuals we have to question how we treat things we might share -- the air, the water the land. We share these resources. Because we share them we may just like the pheasant, just like the cattle, we may tend to over-consume them. And that's the challenge of sustainability. So while climate change was a story about what we know and what we don't know, air pollution is really a story about what we can see and what we can't see. One of the big differences between climate change in air pollution in general is that, you would be hard-pressed to imagine that say fifty thousand people last year died prematurely from climate change in the U.S. Or that in Europe, maybe three hundred thousand people died prematurely due to climate change, or around the world, two million people die prematurely due to climate change. Hard to imagine that that actually happened but, with air pollution that's actually the story. And air pollution comes in many many different forms. Particulate matter is one of the most obvious forms that we can actually see. The effects of particulate matter may range from the benign to the dangerous. From the benign side, you might notice a fresh layer of snow in your backyard becomes dirty looking after a few days. Or in this area you might notice the ability after a few days to swipe your finger on a window sill or on a railing and you notice it's rather dusty and that dust probably came from the air. The effect of that might be asthma in kids. It might be premature mortality in adults. And these are things we can see. Smog is another form of pollution that we can see. You might think of a brown soupy air. I'll never forget the first time I visited my folks after they move to Orange county in California. I looked around on the first day and I thought the surroundings just looked like another suburban area. Then it happened a rain that night, it was rather unusual for the area. The next day, suddenly you can see Los Angeles and you can see the mountains. That's obviously air pollution. Smog is an air pollutant that comes from tail pipes, it comes from re-fueling your car at the gas station You might smell some of that -- it's called volatile organic compounds -- as you fill up your tank. Or lighter fluid from your barbeque or paint fumes. These fumes combined with products of combustion, from industrial processes, from traffic, and create this smog. A large component of that smog is ozone that actually something we can't see, but also photochemical oxidants, those are the constituents of smog that we can see. And smog can be very harmful as well. Some of the effects might be benign. You go out for a run, and you notice your chest is somewhat tight after you go for the run. Of course, smog can lead to cardiovascular stress as well and premature mortality So of course ozone is one of the constituents of smog we can't see. There other pollutants we can't see. Carbon monoxide is one that we might be familiar with. We all know not to run the engine of our car in the garage with the door shut because carbon monoxide actually competes with oxygen for sites and hemoglobin reducing oxygen distribution in the body and can lead to a form of suffocation. So we've talked about air pollutants that we can see and those we can't see. It gets really interesting where the two come together. We could think about sulfur dioxide. So sulfur being emitted from from combustion or industrial processes. Sulfur dioxide is actually fairly toxic. It's toxic to people, it's toxic to vegetation When sulfur dioxide actually combines with particulate matter, you end up seeing cardiovascular stress, you see hospital beds getting pretty busy when you get the combination of those two pollutants coming together. So the typical solution to the sulfur dioxide issue is actually to raise smokestacks. So you see very tall smokestacks. The old phrase says 'dilution is the solution to pollution.' So if you raise stacks high enough you won't notice the sulfur dioxide on the ground, and that's true But what happens over time is that sulfur dioxide become sulfate, SO4, and sulphuric acid and that's where the acid rain issue comes from. So that acid rain is a little bit less of a human health issue than it is an issue for agriculture, it's certainly an issue for forests, it's an issue for for lake. Acid rain can travel over a very large distances The sulfur emissions from detroit might affect lakes in the northeast at reducing their ph and affecting fish life in those regions. So sulfur dioxide becomes acid rain due to these tall stacks. So the solution the sulfur dioxide was to raise the stacks and that obviously puts sulfur dioxide high in the atmosphere. But you don't need tall stacks to get pollutants high up in the atmosphere. So very stable molecules CFC's, which you might have heard of, get high up into the stratosphere even -- about forty thousand feet -- due to their stability. CFC's come from refrigerants and they were actually a solution to a problem as well. Back in the 1930's refrigerants used to be explosive or smelly, harmful, dangerous. CFC's were a solution by being very stable, inexpensive, their molecules allowed refrigeration to become far more widespread. But of course as these molecules got into the sky it turned out to be so stable that they would end up in the stratosphere. There, they actually deplete ozone. And the problem with that, of course, while we don't like ozone on the ground is a constituent of smog -- it's harmful to people, and to agriculture and forests -- up in the stratosphere it actually protects us from UV rays protecting us from skin cancer and protecting agriculture from UV as well So CFC's are an example of the solution to one problem causing another problem. Now there actually is a happy ending with CFC's. This is one of the examples where society has gotten together and has actually banned the use of CFC's and are a trajectory to eliminate the emission of ozone-depleting chemicals. And, it would be wonderful to imagine another clean air act in the future that actually eliminates things like smog, eliminates sulfur compounds and the other air pollutants that we've talked about carbon monoxide, etc. Engineers can do a lot to eliminate air pollution from engineering decisions from design as we're gonna talk about a little bit later. Air pollution is, thankfully, one of those problems that can largely be reversible. Air is very abundant, so if we simply stop emitting the pollutants, over time the air will be clean again. And even that ozone hole, due to those chlorofluorocarbons or CFC's, is beginning to repair itself. There are other issues like climate change that are much more difficult to reverse or as we're going to see when we go up river on the Huron water pollution and water resources, this is a much more difficult problem to simply reverse. So we moved upstream from Detroit now to the banks of the beautiful Huron river. A place adjacent to the Great Lakes that have twenty one percent of the world's fresh water, at least surface water. And it's a place where we don't usually think about water scarcity Even in North America we've got about well let's say about eight percent of the world's population and we have about say fifteen percent of the world's freshwater that's both surface water and groundwater but I think we all know that the story isn't just about quantity and we can think about whether we'd let our kids swim in this water or whether we'd let them drink it or eat the fish out of it. This begs some questions about what is the quality of our water. It begs questions about what we're doing to protect our water resources for today and for future generations. We think about sustainability wasn't long ago when we talked about rivers being on fire in the nineteen-sixties sewage in our Great Lakes and clearly we've come a long way in those dimensions. But it's a question, you know, what quality of water do we need? What quantity of water do we need and not every place in the world is as well-endowed as we are with respect to the quantity of fresh water. We don't have to go much farther than the Southwest where not long ago they were talking up pumping water from the great Lakes just to have the availability. And there's a nexus between water quality and quality, it doesn't take a lot of pollution to foul up a water that is scarce right? Dilution is the solution to pollution. We've got pollution, just add water and eventually it'll be dilute enough. Well that's certainly not going to do in places where water is scarce and here in the U.S. we have technology in engineered systems that are in place to protect our water resources in the quality, but not everywhere in the world though. And we can look at a place like Asia where maybe they have thirty percent of the world's freshwater and sixty percent of people. So places of high population density, places with a lot of industrial development and without the engineered controls that we might see here in North America. So what does sustainability mean for water? It means access, not just the physical availability but high-quality water and a water that people have economic access to. And so we think about the water that's just around us it's probably cheaper to simply protect what we have than to develop new technologies to reclaim water that we've already spent and polluted. So materials are really a story about now versus later. We have enough materials today to keep the economy running, as the population grows it might be a bit more of an issue. But we have economics to take care of us in large measure. As we run scarce on some materials we tend to look for more sources of materials, we tend to find them. Even in the case of oil where we're consuming so much oil everyday we tend to go explore and find some more of it. So as the price goes up we go out, we look for new sources, the price comes back down. Now when things truly become scarce the price goes up stays up, then engineers are pretty good at finding alternatives. So sustainability when it comes to materials isn't just about running out of stuff actually the issue is much more complex, it's about economics how much do the materials cost? It's about going out and finding more materials. And just because the material might be available on earth doesn't mean it's available to us as engineers It's maybe located in a part of the world where we don't have access to it and we certainly know that materials have been a source of conflict around the world whether it's oil in the Middle East or it's maybe it's water in Africa. There have been conflicts over materials over the ages. So we can talk about oil today or we could talk about conflicts over water today, lithium of the future, we talk about electric vehicles and there's a question about where the future of lithium is going to come from and whether there might be conflicts over that. So we can talk about now versus later, we can also talk about here versus there. We can talk about the toxicology of materials as well. We're surrounded by toxic materials even in our cars and they've been reports on lead, antimony, bromine in our vehicles or pesticides. There's a concept called body burden where you can basically take a sample of your hair they can take samples of breast milk they find all kinds of toxic materials in the human body. The question is whether that's going to be an issue or not. Known toxics, if you take lead, of course we know that's particularly toxic but the question is what are the effects and in what doses and that's largely an unknown. So when we think about materials we can think about their availability, we can think about their toxicology, we can think about whether we have access to those materials, we can think about price and we should also think about where where we put materials at the end of their life. Nobody wants that landfill in their backyard. So siting of new landfills is an issue. We can't recycle everything, we can't remanufacturer everything today so we have continuing needs for landfills. Those landfills tend to be put in those regions that tend to be economically disadvantaged. Those areas that tend to be poor. We think about recycling, a lot of the electronics recycling we see circuit boards being shipped overseas low-income countries where they actually need the money a lot of those materials being recycled and then shipped back over to the industrialized countries, are used over there. So when it comes to materials it's not just about running out of stuff, there are all these other issues that we need to consider. So we started off talking about the challenge of sustainability when we have shared resources. We tend to think differently in groups as we do as individuals and we went through some of the challenges. We talked about air pollution, we talked about water pollution, we talked about climate change, we talked about materials and moving forward now the good news is that we've got solutions to all of these problems. Engineering, engineering design can address each one of these issues. Materials, conservation, recycling, re-manufacturing, solutions for air pollution, solutions for water pollution, hopefully as we move forward we'll have a chance to discuss these solutions that are going on in engineering colleges all around the country and all around the globe. So the challenge is less about the availability of technology to solve some of the problems we talked about and a lot more to do with what happens when the rest of the world begins to develop in the way that we have here in the United States. So if you ever stopped to wonder if everybody in the world lived at the standard of living that we do here in the United States, how many planets of resources that might take? I stopped to do that about ten years ago and actually you can do that yourself, there are websites where you can make these calculations like myfootprint.org or what have you. But when I went and did this calculation I was surprised to learn that if everybody in the world lived at the standard of living that I do, it would take about six planets of resources and that's actually a pretty typical number. If you look at the average U.S. citizen, that's about right. So we took some action. We began to use less energy, turn the thermostat down, drive less, maybe ride my bike to work, eat less, etc. And a few months ago I actually went and made that calculation again and I was very pleased to find out that that burden if everybody in the world lived at our current level of resource consumption would be about three planets so we basically cut our burden or our footprint in half. When I began to dig into the calculations, why exactly that was, I was actually surprised to learn it had very little to do with flying less and driving less, although those things helped. What really made the difference is the fact that our family expanded. We went from two people in our family to five people in family. We now have two daughters a son that weren't in the previous calculation, and so our load, our burden, our resource consumption hasn't increased very much but the family expanded and therefore we went from about six planets to under three. Now naturally these kids are gonna grow up they're gonna have footprints of their own and that actually begs the question: what happens when the rest of the world begins to develop? We've seen population growth is actually rather robust right now. When I was born there were about four billion people on the planet. Now there are about seven billion. And we're on our way to about nine billion. In the mean time we see that not everybody of course lives at the standard of living that we do here in the U.S. So the last time the United Nations development program did an analysis, about twenty percent of the world's population was found to use about ninety percent of the resources. The bottom ten, twenty percent of the economic ladder were actually using only about one percent of the resources. So when we think about it, the reason things are sustainable for the moment are that not everybody in the world lives at the standard of living that we do. So the question is then when the rest of the world develops and aims to achieve the standard of living that we have here in the United States, what's gonna happen? And we can do some simple math to show that actually the current path that were on is not sustainable. There are about three hundred million people in the United States. Now if the average U.S. citizen requires six planets of resources, if everybody lived at that standard of living, we can do some simple math. And instead of six planets let's just say it's three planets it'll make the math a little bit easier. So there's three hundred million people in the U.S. and if everybody lived at the U.S. standard of living it would require three planets of resources so that's one planet per hundred million people. As we look at population growth, let's just look over the last year or so. It's now two 2012, over the last year the world's population has grown by about a hundred million people, so clearly we're not on a sustainable trajectory. Again we come back to the good news. We've got the technology to reduce our resource consumption, to reduce our pollution per unit of goods and services we produce. So we can break down the sustainability challenge into this simple equation, I equals P times A times T. So the I here is the environmental impact these are the challenges we were talking about the air pollution, the water pollution, climate change, materials consumption, those are all impacts and it doesn't matter which impact or all of them that we're talking about, that impact is equal to the population times affluence. Now affluence, we can talk about that in terms of being gross domestic product per person. You see if I talk about gross domestic product per person and multiply that by population, I've essentially got gross domestic product there. Now the third letter is technology, and we can talk about that as being the environmental impact per unit of goods and services that we produce. So we can talk about the environmental impact per GDP, so if we multiply population times gross domestic product per person times environmental impact per unit GDP environmental impact equals environmental impact. This is sometimes called the IPAT equation. Now let's look at what this equation means. We've talked about population and the fact that it's increasing, and we've talked about the affluence, not just today around the world but in the future as well. And this is a term obviously we would like to see increasing. So we multiply p times a we know that we're going to have an increasing amount of impact. So if we want to address these sustainability challenges, really it's about t. It's about technology. It's about the environmental impact per unit of goods and services we produce. That's a technology question. We have technology to reduce those environmental impacts. But it's not just a technology question, it is the degree to which that technology is deployed. We have solar panels, we have windmills, we've got electric cars, the question is really about why we don't use them. And so it's not just about designing the technology but getting that technology into practice. And getting that technology in practice is an economic question, it's a social question and it's an environmental question, which is why we often called this a triple bottom-line. It's about environment, it's about people, and it's about the economy. so we'll call that the triple bottom line. You know back in the seventies and eighties who used to think well we've got an environmental problem let's let the environmental engineers take care of it. They will clean up the smokestacks they'll clean up the pipes going into the river and everything will be okay. We realized in the nineties that maybe ben franklin was right, you know, an ounce of prevention may be worth a pound of cure. So we thought about pollution prevention, let's get the manufacturing engineers involved to prevent the pollution in the first place. Then win the two thousands we realized, you know would be a lot easier to prevent pollution if we designed the products to avoid the pollution in the first place. So we got into design for a time. Here in two thousand ten and beyond we're thinking about sustainability, we're thinking about sustainable enterprise not just the design of the technology but the deployment of technology and the regulatory systems and policies that can make that technology profitable. So when we think about sustainable design we think about enterprise, we are thinking about triumphs. Sustainable design triumphs. Avoiding traps, avoiding tradeoffs and working our way towards triumphs, as we're gonna talk about here moving forward. Traps, trade-offs, and triumphs are really all-around us. Let's start by talking about what a trap is. A trap is a design or a system that is marketed or presented as being sustainable or good for the environment but it's not really good for the environment at all. One example that comes to mind might be the example of ethanol based fuels for vehicles. Ethanol when it comes from corn actually requires as much energy if not more to produce than your gallon of gasoline and with respect to greenhouse gas emissions it's basically a wash or it could even be more than a gallon gasoline. So when it comes to ethanol it's all about where you get that ethanol from. So a triumph works for the triple bottom-line, so it's some design, a product, an innovation, a service that works for business, it works for the environment, it works for people. So examples of this might be a flat screen monitor. You may remember the old days when we had cathode-ray tubes on our desks with our computers and nobody seemed to want them but there was no alternative. When you actually look at that technology it was very energy consuming, it was full of toxic materials. Then these flat-panel displays came around and suddenly these monitors had a lot lower burden with respect to their toxics, a lot less energy consumption, and they took off in the market. So it was a product that people actually wanted that was good for the environment in so many ways. Then of course we realized that they're affordable and we could use more space on our computer desktops and next thing you know, there's two or three screens on our desks. And that's actually the danger of a triumph, is over-consumption. So you've got a product, people want it, it's good for the environment, and the next thing you know it's being over-consumed. So while we look for triumphs in sustainable design there's always that danger that it's over-consumed or it's a victim of its own success. So we think about other potential triumphs like LED lighting, which is coming online. Today, an LED lightbulb might cost you 20 dollars. ten years maybe it costs less than a regular lightbulb or at least in that ballpark. When that happens given their efficiency you'll have a solution that's good for economics, it would be good for the environment due to its increased efficiency its ability to light large spaces with very little energy and it would be good for people too because people want lighting. It's been said that we might have a lot more lighting in the world if it were more efficient and more cost-effective. So thinking about triumphs then, we could ask what other types of technologies would fit into that category. We talk about solar, we talk about wind, today these aren't exactly triumphs, they certainly haven't replaced fossil fuels to a great extent they've been heavily subsidized. The hope is that as we use more of these technologies they will become more affordable, they will take off. We started off by talking about ethanol as a trap and as we think about solar, we think about wind we think about the need for renewable electricity systems, there's a question about whether cellulosic ethanol, a new form, not ethanol based on corn but ethanol based on switchgrass or other types of woody products that are generally waste today. And if we could develop that technology where these waste biomass, cellulosic biomass could actually be converted into electricity at an affordable rate we'd likely have a triumph coming down the road. So cellulosic biomass is an example of a closed loop system, if you think about growing switch grass, that switchgrass needs carbon from the atmosphere so it pulls carbon out of the atmosphere and becomes a fuel and then we burn it and it goes back in the atmosphere. Closed-loop technologies actually have significant promise as triumphs. It's not just in the fuel sector, you think about closed-loop manufacturing, remanufacturing, you think about cell phones from the 1990's, they weren't quite cell phones, they were suitcase phones and brick phones and satellite phones, and those technologies now have become so miniaturized that they really can't get much smaller. You don't want a cell phone smaller than the size of your hand for instance. What it does is create an opportunity if the technology were there or the systems were there if the supply chain incentives were there, you can imagine a phone that you actually keep over multiple generations but after your contract expires or even sooner if the technology is available. Just open it up change the processor, maybe change the screen, maybe change the battery and you can actually conserve a lot of material, a lot of the manufacturing burden that went into that phone. So closed-loop manufacturing is another example of a potential triumph down the road. Thinking about materials, it surprises people to think about aluminum as not being as recycled as generally perceived, so what I mean is, we think of our beverage cans as being made out of aluminum, we recycle that. But actually it turns out if you look at aluminum it's only used in the economy about three times before it ends up in a landfill or somehow leaking out of the economy. So we can think about closed-loop material systems, more advanced recycling, so if we have a aluminum intensive vehicle that gets very good fuel economy because it's light, you know, today if you have an aluminum intensive and you scrap it at the end of its life, basically that aluminum is going to be downgraded, maybe it's going to become a casting for an engine. After that it might escape the economy or it might end up in a product before it escapes the economy. But in a future world where the incentives exist, a triumph might be an example of being able to convert a body-light aluminum intensive vehicle into another aluminum intensive vehicle. Where the cost lines up, the material lines up so of course aluminum has a very significant greenhouse gas footprint, an electricity footprint to create, so if you could close the loop on that material cycle it would go a long way towards reducing environmental burden both in production and in the use phase of a vehicle, given the lightweight potential of aluminum and the strength of the material. garden Another thing is that a triumph doesn't need to be a product. Like I mentioned it could be a service, it could be a policy. Think about a regulation that might allow businesses, power utilities to internalize some costs of greenhouse gas emissions for instance, pollutant emissions, mercury emissions, what have you. And that sounds like increased cost but there's some operating costs benefits to renewable technologies so if you think about solar electricity, once you've got it in place and the sun is shining, the operating costs can be fairly low. The same goes for wind. There are maintenance costs of course but it's not like you have fuel costs. So a policy that might encourage in a smart way a renewable electricity future might also classify as a triumph. One of the interesting things about traps, trade-offs, and triumphs is that they're dynamic. Definitions change over time, technologies change over time and what might be a trap at one point might be a triumph at a later point. That's a song called going through the motions by a band called The Miracles of Life and I think the idea of going to the motions is the crux of the sustainability challenge. So when we think about going to the motions and sustainability the real question for us is whether we're going to keep doing things the way we are, or whether we're going to use our engineering talents to make a better life not only for ourselves but for future generations so they're not at risk of not being able to live at the standards that that we live today. That they have access to resources, material resources climate resources, air, water, with the same ease that we do today. So really what it means is for the mechanical engineering it means thinking about the types of energy systems, mobility systems that we have today but re-envisioning them. Thinking system-wide, thinking about our friends on central campus and what they can bring to the table and not just to have the technology but the context of the technology. If it's mobility maybe it's not just about the cars but it's about transportation, it's about multiple modes, it's about the future of our cities. If it's civil engineering maybe we're thinking about buildings and their place. Thinking about much smarter buildings that use energy much more efficiently, that recover the water that those facilities use. If it's industrial processing and waste water treatment maybe it's future system or we can take wastewater and treat that waste water in a way that not only cleans the water but it also produces energy and produces fertilizer. If it's the chemical engineer it's new ways of producing energy carriers and batteries that will allow us to store energy from renewable sources in times like night where we may not have that solar energy available to us, the wind isn't blowing. If it's the computer scientist it's the software and applications that enable all that. If it's the electrical engineer it's about that computer that really doesn't require that much energy, server farms that are really running lean. And it goes on and on from there. Engineering is about technology and sustainability is about technology so we as engineers not only have to design that technology but to do that with an eye for what society really needs not just today but in the future.