The Exchanges

Q So how much energy are we talking about? Of all of the energy that we use, like, how much of that is going toward moving water, cleaning water, doing something to water?

A If you look at the United States as an example, we use about a hundred quads of energy, a hundred quadrillion BTU of energy. BTU is a British thermal unit of energy. About 13% of that energy is for water and steam. So it's not zero, but it's not half. It's a sixth or something like that, a seventh. And a third of that, like Four percent of national energy consumption is just water heating in our homes, in our businesses, just to get water to a comfortable temperature for our long hot showers or for washing dishes and clothes, and that's a lot of energy. That four percent of national energy consumption in water heating is bigger than what Switzerland and Sweden use for all purposes combined in a year. So just imagine, like, two rich countries are using less energy Combined over a year than we use just for water heating. So that's one example. And that's really the direct use of energy for water, including the treatment and the chilling and everything else. That's also including the steam for industry, but it is not including the energy going to make steam in the power sector, which is about a third or more of our energy consumption. It's like a third of our energy consumption in the United States just goes to boil water to make steam in power plants.

AI assessment note: “About 13% of that energy is for water and steam.”

Q I mean, we're going to come back to all the risks and what we're seeing in the news right now, because we're currently in a kind of a global drought that is exposing a bunch of these challenges, but since you allude to that one in particular, can you be more specific? Like, what's actually happening Uh, where do we have rivers causing barges not be able to deliver coal?

A Well, it seems like we have drought everywhere, just everywhere, but right now in Germany and with the Rhine, and also in China, we have rivers so low that barges either can't carry a full load of coal, or they can't carry coal at all. Like, just there's not enough water for the ships to move. And these coal plants in the old days maybe stored 60 days worth of coal on site. These days they store like 15 to 30 days. And so they don't have a lot of backup, but the rivers stay low for months at a time, which is starting to happen. And so today it feels like Germany and China is where the news is, but that happened in the Mississippi River in the United States not that long ago either. So we have plenty of examples from around the world on that.

AI assessment note: “right now in Germany and with the Rhine, and also in China”

Q All right, so I just want to double click on that for 1:02. You're saying that the amount of water that we withdraw and use to cool power plants exceeds the amount of water that we use, for example, to drink and shower and all this other stuff?

A By far. Yeah, the amount of water we withdraw to drink and shower is a few percent. It's not a big deal at all. The biggest users are really power plants and agriculture, at least in terms of withdrawals, the amount of water we withdraw. Now, the difference is, for the water we drink, we've consumed it, like, we use it and it goes somewhere else, and in agriculture, it consumes the water. With the power sector, it mostly does not consume the water. It takes the water from the lake or river, it uses it to cool the power plant, and then mostly returns the water. Now, if it's a cooling tower, it actually evaporates the water, goes to the atmosphere, it comes down as rain a few states over or in a different country, depending on where you are. But that power plant usage of water for cooling exceeds the amount of water withdrawn every day, For agriculture. And then municipalities are third on the list. Those are the cities that water we use for drinking and washing. If you look at consumption, how much water is consumed, agriculture is the biggest consumer, and then cities, then the power sector. So you kind of have to look at it based on how much water is used versus how much is actually consumed.

AI assessment note: “By far. Yeah, the amount of water we withdraw to drink and shower is a few percent.”

Q So one thing I've seen a little bit of your analysis on, which I think is interesting, is if you think about food as a form of energy, as you just described, and sort of contextualize it relative to the other types of energy that we think about that power our society, like, how efficient, how good is food an energy carrier, source of energy?

A Food itself can be a very energy-dense carrier. Material, especially like the lipids and fats are kind of the same energy density as fossil fuels, which is really incredible. And so they like butter and the fatty part of a steak and that kind of thing. Proteins have less energy density and carbohydrates have the lowest energy density, which is kind of ironic because we think of carbohydrates as a way to get too much energy that makes us fat and that kind of thing. But in terms of energy density, the mega joules or kilojoules per kilogram, the lipids are fossil fuels, you think about it. And the proteins are pretty good and then the carbohydrates are Less energy dense, but they, they carry this energy, but most importantly, they carry the energy in a form that our bodies can digest, and we can convert that energy into, say, glycogen or stored sugar in our muscles or other energy we have in our body. The gasoline and methane, other energy forms we like for our engines, our body can't ingest and use, so the food we ingest is really energy in a form we can use.

AI assessment note: “lipids and fats are kind of the same energy density as fossil fuels”

Q mentioned it originally when you talk through all the things that we do at the end, is the food waste. How do you think about food waste as it really, I mean, obviously food waste, there's lots of problems with it, right? Food waste becomes, if it biodegrades, it becomes methane. It emits, you know, a powerful greenhouse gas. From an energy perspective, how do you think about food waste?

A Food waste is a big issue for all these reasons. It takes up space in the landfill. It generates greenhouse gases. It also wasted the energy that was used to grow it, and that food waste number is something like 30 to 50% of the edible food in the United States is thrown away. Typical numbers say 40%. Similar numbers in, say, the UK and other rich countries, so there's an incredible amount of food waste, and it's certainly a problem at the end of life when it decomposes and make methane, but I think of all the energy that went into growing this food that we don't eat, and we don't eat edible food sometimes because we don't feel like it, or it's ugly fruit. There are these, like, ugly Fruit and vegetable campaigns. Like, go ahead and eat the ugly tomatoes. They still taste good, and they're still healthy, and this kind of thing. So there's a lot of energy embedded in that food waste, and reducing food waste would be a very good thing for us to do, because it would avoid all those environmental impacts. And I would say also that food waste happens in a different stage of the supply chain in the United States compared to, say, a poorer country. So in the United States, we have a very robust cold chain, which is good news, but that means we're wasting the food on our plate. Like, we're over-serving at these all-you-can-eat buffets, then we just don't eat it, or We don't take a home…

AI assessment note: “I think of all the energy that went into growing this food that we don't eat”

Q Waste products from the production of edible food Whether that be corn stover or something else, that actually we might as well do something with because it's a waste product otherwise, and if it has value as an energy source or in a different context as a source of biogenic CO₂, then great, right? But, but separate the waste product from the primary purpose of the crop. Is that right?

A That's exactly right. Yeah, and there's a lot of waste streams in agriculture, and especially things like Manure and crop waste and things like that. Well, let's use that. Some of that crop waste is used as a soil amendment to keep the dirt from floating away or running off, that kind of thing. But we have especially hundreds of millions of tons of manure that we could turn into biomethane as opposed to just leaving it as an environmental hotspot, a liability. So there are these waste streams. We might as well use that in a way that helps us avoid other energy or reduce emissions elsewhere. So I really like that. But growing food for the purpose of energy gives me all sorts of discomfort. I should have said, I should have said, gives me all sorts of indigestion. That was the obvious pun, right?

AI assessment note: “That's exactly right. Yeah, and there's a lot of waste streams in agriculture”

Q energy-water nexus, with the food-energy nexus, we're going to talk about all the ways that we use energy for food, and then all the ways that we use food for energy, and then we're going to talk about the Nexus between those two and how it's changing. So let's start with how we use energy for food. How, first of all, how much energy do we use to produce food?

A It's a big number in the United States. It's about 10%. Different people do the analysis and come up with anywhere between like eight and 15% of national annual energy consumption is for the food system. And for the food system, I'm including at the field, agriculture and the agrochemicals that go there, the diesel for the machines, the propane for drying the crops, Then you use diesel to transport the crops to a milling location or a factory where there's processing and grinding, and then it might go to a refrigerated warehouse, then it's delivered to a grocery store, then we pick it up in our gasoline car, and then we cook it with natural gas or electricity, then we dispose of the food waste, and if you add up all the energy embedded in the chemicals, like the pesticides and fertilizers, as well as the fuels to operate the crops, not even including the solar energy, like just the, the sort of man-made fuels or the man-refined fuels, That go into the system, it's about 10%. So it's a big number. And 10% of that, or one percent, is in the food itself. So the food we need to ingest in the United States is about one quad of energy a year, and we consume about a hundred quads of energy over the course of a year. One quad of that is in the food we eat, but there's another, say, nine quads of energy to grow and reap and harvest and improve and cook and process and dispose of that fo…

AI assessment note: “anywhere between like eight and 15% of national annual energy consumption is for the food system.”

Q Do you think, just to put it simply, at the highest level, as a society, should we be ever using edible plants, corn, soy, palm oil, should, should we ever be using any of that for the purpose of energy? As opposed to as the, for the purpose of food.

A So, in my opinion, no. I don't think we should be using edible food for modern fuels. I think we have other options. Using the waste streams gives me no heartburn. We should totally do that. But I don't like the idea that we're using corn that could feed a lot of people to power up inefficient trucks. Like, we could probably achieve the same savings just by making those trucks more efficient, or driving smaller cars, or driving less often. Like, there are other ways to displace 10% of our gasoline consumption, which is about where we are with corn-based ethanol. So the goal is to displace 10% of gasoline. Let's use those other techniques rather than using food. It really makes me nervous. That doesn't mean alcohol fuels don't have some value. They have some value to increase sort of the performance of the engine. You can get higher compression ratios, you can get less pollution, this kind of thing. So there are some benefits, but if we believe electric motors are going to displace those gasoline engines anyway, what's the point? So I'm really critical of using food for fuel that way when we have so many other options. And United States efficiency is a great starting place.

AI assessment note: “So, in my opinion, no. I don't think we should be using edible food”

Q Good point. Um, all right, so let's just talk about the ways in which this nexus between food and energy is changing. Obviously, maybe the biggest, highest level one is climate change itself. So what do we know about the ways in which climate change will, will affect the food energy nexus, or either is affecting it today, or will affect it as, as climate change worsens?

A Climate change really is a challenge for agriculture productivity. Above a certain temperature, photosynthesis really drops in efficiency, so that's one challenge. The droughts and floods either wash off the soils or hamper the ability for the crops to grow in the first place. We're having massive agricultural losses in Texas right now from the heat wave and drought. They can't get the feed for the cattle, so they take cattle to market before they're at full weight, so they get less money. Like, it's a huge problem to agriculture how hot it is today. And then you also have different pests have Three reproductive life cycles in a summer instead of two so they can eat the crops or sort of cause other problems. So there's a lot of challenges to agriculture from climate change directly just on crop productivity and health of the ecosystem and that kind of thing. You might get some improved agricultural opportunity in northern climates. So maybe for a while we'll see improved agricultural outputs in Canada, but then those will be offset as well later on. So there's some, you know, disbenefit in certain latitudes and benefit in other latitudes. But more harm than good overall from climate change itself. But then you have these other steps of the system. You might need to air condition more of the crops to keep them from spoiling. The heat accelerates spoiling, so we're spending more …

AI assessment note: “we'll spend more energy to overcome the consequences of climate change”

Q see out in the future? So let's start with that first point. So you've framed it in a way that I like, which is there are a bunch of ways in which we use energy for water, and there are a bunch of ways in which we use water for energy. So let's take those in order. So first, what are the ways in which we use energy for water?

A The, that's a great way to think about is this nexus means we're using one for the other, and it's both ways, and so we get We start with an inventory, so to speak, of what are the different ways they're, they're related to each other, and then we can think in the future, what does this mean moving forward? We use energy for water in a variety of ways. We use it to pump water, usually uphill, out of a river or lake or a well or whatever, wherever it is, water tends to fall by gravity to lower elevations, and we tend to live at higher elevations, even if it's just a few feet, and so we have to use energy to lift it to where we are. And that's one of the first and most important uses of energy for water. But we also use energy to treat the water, to pump it long distances, to chill it, pressurize it, refrigerate it, deionize it, you name it. We use water in a lot of ways, and we need the water to be at a very particular quality and a particular quantity at a particular place at a particular time. And that means we use energy to get it there. In the old days, it might be a person pulling a bucket and a rope from a well or a horse Turning a circle to elevate water with scoops out of a river or an Archimedes screw or something like that that is raising the water. And today it's big electric pumps that are massive that require a lot of power just to lift the water. And then all those…

AI assessment note: “We use energy for water in a variety of ways. We use it to pump”

Q What about different types of food? So, for example, obviously there are other emissions-related reasons why For example, we might want to eat less beef, just because of the emissions in the, in the cattle world. But maybe not specific to beef, you know, are there big differences in terms of the energy intensity, the energy embedded in different types of food, or at least categories you think about?

A Absolutely. And when we think about, like, systemic changes, which was your sort of question, where you think, okay, what can we do? Well, reducing waste, we talked about, is a very big one. Changing what we eat, or how much we eat of it, also is very important. The transportation miles Tends to get the most attention, but actually is not as important. A great study came out of Carnegie Mellon, uh, over a decade ago, looking at sort of these food miles, and they're, the conclusion they had was that food choices, meaning the diet selection, what we eat, how much we eat of it, is much more important than the number of miles the food moves, which is kind of interesting, and that's not obvious for a variety of reasons, and that's one reason we have, like, fruits that are always in season. We get them from somewhere, but if they're moved by ship, it's not that big a deal. In these grains and fruits and vegetables tend to be much less energy intensive than the proteins, the animal proteins, and so probably at least in the United States, we eat a lot of beef, we eat a lot of meats, and I'm a beef eater, and I really like eating beef. We could all probably stand to eat a little less protein, and that would be less impactful. The good news of the meat world is that we tend to waste less meat because it's so expensive. We tend to waste other things that are Sort of, uh, less expensive fr…

AI assessment note: “grains and fruits and vegetables tend to be much less energy intensive than the proteins”

Q worse as bad as energy is as a market to try to build something in and scale something fast and get past regulatory hurdles and all that water seems to be on a whole other level. And I've never totally understood how it ended up being that way. Like, why don't we have markets for water? Why don't we have data? For water and we do for energy. What's different?

A It's a great question, and I don't really know the answer other than our history was complex with how water was allocated, and there's two different types of water, first of all, to keep in mind. One is the surface water, the lakes and the rivers, the water on the surface, and then the groundwater, the water below ground in the aquifers and places that we can't see very easily, and I want to say some of it came from just the fact that we couldn't see the water below ground very well. We're kind of blind to the water, and so the laws are Mysterious in places like Texas where they treat the water below ground as part of the occult or something like that. So it was regulated in very funny ways. It was allocated to farmers and agriculture, then cities next, and then industry comes along later and says, hey, we want the water too. It's just so locked up with these water rights where people were given the water or assigned the water a hundred years ago before we anticipated what the future would be, and so now it's hard to get that water released, and it's only really possible if you have a real crisis. In Australia, they found a way to create markets for water and water innovation because they had such a severe drought about a decade ago. They had these tragedies. It was just a disaster of like a farmer a week committing suicide because their crops wouldn't grow, which is horrible. …

AI assessment note: “It's just so locked up with these water rights where people were given the water”

Q be amortized over the production of the facility and so on. One of the applications that people talk about when they're sort of thinking 2030 years out into the future for nuclear fusion is just massive nuclear fusion to run massive desalination plants and produce a ton of potable water. Is that like a horizon you can envision, or do you think that there's a reason that doesn't make sense?

A Yes and no. So if we had unlimited, really affordable energy, we would use it for high value purposes, and one of the high value purposes is to get water, primarily for irrigation, for food, but also for drinking and for all our uses at home. But that water ends up being expensive, so we probably wouldn't want to use that water just for golf courses or for our lawns. So there might be some sorting and stacking of what our water priorities are, and we don't have to wait for the far future for desalination. It's already happening today in Israel and In parts of California, and inland Texas, and Israel, and Australia. So places that are water scarce already do some desalination. Even if the electricity is not cheap, just because they need the water so badly. So for your basic human needs, it doesn't matter the price. But for the luxurious needs, it does matter the price. And so if you need water to drink, you'll pay whatever it takes, because you'll die without it. But maybe for your lawn or your swimming pool, you'll be more mindful and thoughtful about that price. If we have fusion or whatever it is that gives us more energy at a lower price, then we might have more luxurious uses. Now, I wouldn't call this luxurious, but restoring the ecosystem would be a pretty good Purpose of water. And so we could think about getting water and recharging aquifers, or putting water and ecosys…

AI assessment note: “Yes and no. So if we had unlimited, really affordable energy”

Q What about, um, I guess here's a different way to ask this question. Of the energy that we use to move water around, is it mostly electricity, or is it thermal energy?

A It's great, and I didn't really answer the question of how we use energy to prove the water system. We use water to improve the efficiency of energy, but we use energy to improve the quality of the water and the quantity. We can use energy to get more water from deeper water tables, from a deeper well. We can move that water longer distances. It might be dry in Phoenix, but wet Somewhere else a few seats over. We can maybe pump the water there. We can desalinate the water. Maybe we have abundant salt water if you're near an ocean or something, and you can use that energy to get it to the right quality for drinking. So there's a lot of inputs where it's really good for us. The energy in gives us better water, and the water in gives us better energy. So that's kind of the good news on that is better availability, better reliability designed the right way, better throughput.

AI assessment note: “I didn't really answer the question of how we use energy”