A (5:27)

I'm looking up what weighs. Oh, here we go. A Mac, a 13 inch MacBook Air weighs about a little more than a kilogram. So.

B (5:40)

So your laptop. Yeah. If you want to throw your laptop over a meter, accelerating at a pace of 1 meter per second squared, that's about a joule. That's. That's about a joule in one step. It's not a huge unit of energy. We obviously, like you're moving your body around, right. It weighs a little bit more than a kilogram. At least mine does. And you're moving around, accelerating all over the place. Walking around like that is using up energy on a regular basis. So joules are pretty small. And, and that's important because a joule, a watt, which is actually a unit of power, not a unit of energy, is described as a joule per second. So if energy is a quantity, it's something that we're consuming or producing or transporting or converting, then power is the rate at which we're doing that. So it, if I have a. If I'm consuming a joule of energy in a second, that rate of consumption is 1 watt. One analogy for that is like a bathtub, right? Like the amount of water in the tub, the volume of water, that's the energy, and the size of the faucet, or the rate at which the faucet is adding water to your tub. That's power.

A (6:46)

I'm raising my hand.

B (6:46)

Does that make any sense? Yeah. Okay. Robinson has a question. Yes, Robinson.

A (6:50)

Okay, so I have a few questions. The first is I just want to. I think it is kind of important to establish, like energy here, the joule, what that changes about a substance. And I realize this is like high school physics. Physics 101 is the acceleration, not the velocity. Like, we sometimes think of energy as a property of velocity, but it's actually the ability to change velocity. That is what energy does, right?

B (7:16)

Yeah, that's right. You think about the kind of basic Newtonian mechanics, right? If you're. If you have an object in a vacuum with no friction. Right. Or no forces working against it, it will continue at the same velocity and the same trajectory. Fore. Right. And so what it requires energy is to change that direction or velocity, which requires acceleration or the application of force to some mass.

A (7:38)

You just kind of said this, but like, what is the difference between energy and power.

B (7:43)

Yeah. So energy is the actual thing that. It's the quantity of the thing that's doing work. Right. So it's the amount of fuel we burned or the number of calories we had to eat to run our bodies over the course of a day, or the amount of electricity we had to generate to run our lights or our computer. Power is the rate at which that energy is consumed or supplied or transported or transformed. And so it is not itself a unit of quantity. You don't use power, you use energy. Power is the rate at which you're using energy. So again, it's how quickly the bathtub is filling up or draining, not the quantity of water in the bathtub. So a watt is the basic unit for the SI unit for power, which is going to be equal to energy divided by time energy over some period of time. So power, energy and time are fundamentally related in that way. Energy is equal to power times time. So when we talk about electricity units of energy, we usually use the term watt hours instead of joules. That's a watt of power sustained over an hour. That's the quantity of energy that would be delivered over an hour if we were sustaining it at a rate of 1 watt. So energy equals power times time, power equals energy divided by time. And then I guess time is energy divided by power, if you want to think about it that way.

A (9:01)

So a watt is not specific to electricity. A watt we could actually talk about for any kind of energy. It's just the fact that you could even describe your car motor.

B (9:12)

Yeah. And in fact, in Europe, they do that. They don't use horsepower. That's another unit of power. It's kind of a weird one when you think about it. Right. Like, what is a horsepower? In the US we, and in the UK we, it's power, so.

A (9:25)

Yeah, exactly. There's no confusion about this horse. How big a horse?

B (9:30)

I have questions about this horse. And in Europe, you'll often actually see the motors, the engine power rated in kilowatts, which is your maximum power output from that. That motor. Obviously, when we switch to electric motors, that makes a lot more sense too, because now we're even talking about electrical power. And when we talk about, like, power plants having a number of watts or kilowatts or megawatts or gigawatts, that's usually the maximum power output that plant can deliver. Right. So it's a rated power or maximum power, and it doesn't necessarily produce at that maximum power all the time. Right. Think about a wind farm that's varying in its output with the wind or solar with the sun, or even a nuclear plant that has to shut down for maintenance. And so if you want to understand how much energy a power plant produces, you have to know the power at which it's producing integrated over time, or what we call the capacity factor, which is the average power of that plant over a given amount of time.

A (10:25)

I want to go there in a second, but first I want to make sure I understand something correctly, which is as an energy reporter, or as a person who reads energy documents and reads energy stories, reads heat map. There's a discussion both of kilowatts, but really of kilowatt hours. And am I right to understand that one watt if one watt times one second equals one joule, Right, That's. That's correct. Right. That's like.

B (10:54)

Yes, that's correct.

A (10:55)

A kilowatt hour is a. Even though it sounds like a chunky unit, and sometimes I feel like it's a bit of a weird unit to throw around, it is the same. It's measuring the same kind of thing that joules are measuring. In other words, when I throw my laptop 1 meter and that distance at 1 meter for a second. Right, that's actually the thing we're measuring by saying that I've just expended one joule of energy is the same ultimate substance that we're measuring when we say a solar farm put out 60 kilowatt hours.

B (11:31)

Yeah, that's right. And that's worth pausing on because again, this is why energy is so slippery a concept, because it can come in so many different forms, and we often use different units when we're talking about a different form. So when it's electricity, we often. We talk about kilowatt hours or megawatt hours. We should pause and say a kilowatt is a thousand watts, right? So a kilowatt hours. A thousand watt hours. So we got all these prefixes too. But, you know, you could. So we've talked about defining energy in physical terms, right? Displacing a kilowatt over a meter at some. At a meter per second squared of acceleration. But you can also think about it in heat terms. So, you know, heating up a body of water or heating up a room, right? That's going to require energy to do that, right? Energy coming out of your furnace or your fireplace or whatever else. And we often have different units for that, too. So calories are the standard unit in SI terms. Whereas we also often talk about British thermal units or BTUs in energy world. This is an imperial unit that we rarely use outside of the U.S. those units are defined in terms of the amount of heat required to usually to heat up some unit of water. So, for example, a calorie is defined as the amount of heat required to raise the temperature of a liter of water by 1 degree Celsius. And that's the kilocalorie. That's the big calorie. The small calories or gram calories is 1 millimeter of water raised by 1 centimeter. So that's the other way we can think about it as like a heat flux. Right? That's what a lot of our energy goes to combustion. Right. To generate heat and then do something with that heat. So that's another way to get a physical intuition for energy. But then often we use different terms. Energy, of course, can also be contained in the chemical bonds of certain things. That's what we're combusting. We're breaking up the chemical bonds of wood or coal or natural gas. And so then we also talk about the heat content of, or energy content of those fuels. And you can use joules for that. You can use BTUs, you can use calories, you could use megawatt hours or kilowatt hours. Or in many cases, they use physical units to describe different types of fuels as well. So you might hear things like barrels of oil or millions of tons of coal. Those all have to be standardized units of energy as well, which just adds to the confusion.

A (13:38)

So one calorie, one kilocalorie, I believe is 4,186 joules.

B (13:48)

Yeah, of course, you can do that mental math in your head, right?

A (13:50)

I do it all the time. So I think what's interesting here is that, you know, the hu. If you think about a standard, this isn't quite standard anymore, but if you think about people eating 2,000 calories a day, that means the human body's expending like 8.3 million joules a day.

B (14:09)

Yeah, 8.3 megajoules, I think.

A (14:13)

Yeah, exactly. That's 2.3 kilowatt hours. So does that mean actually people use more? How many. What's a household use of kilowatt hour? Like one point something?

B (14:24)

No. So a typical household in the US and this would be less if you're in Europe or somewhere else, consumes a little bit over a kilowatt of average power. So that's the average rate at which they're consuming electricity. Now, of course, it goes up and down as you turn off on and off devices. Right.

A (14:39)

If I turn it on, that's about 24 kilowatt hours hours a day.

B (14:41)

Right. So that. Exactly. So that's a little over 24 kilowatt hours a day.

A (14:45)

So a family of three.

B (14:47)

Yeah. So According to the US Energy Information Administration, the average US household consumes about 10,500 kilowatt hours of electricity a year. So that's about 28, 29 kilowatt hours a day, or about 1.2 kilowatts average over the course of the day.

A (15:04)

Well, I'm now just thinking about, you know, the average diet for a person.

B (15:08)

Right.

A (15:08)

Is 2500 kilocalories, which is. Yeah. About 2.5 kilowatt hours. So what.

B (15:15)

Yeah, that's a good. That's a good.

A (15:17)

Weird house is using 10 times as much energy as your body is at any through the day.

B (15:22)

And that's just the electricity. Yeah, that's just the electricity part of the energy, too. If you're driving to work in a car that's not electric, you're not. That's not counted in that energy consumption that you're. Then you're consuming the energy in your gasoline. If you're heating your home with natural gas. Right. That's not counted there too. But yeah, to give a sense of scale, I like that one. One human is 2.4 kilowatt hours or something like that. 4 kilowatt hours is the amount of energy you'd need to run a window AC unit of a half a watt, half a kilowatt for eight hours. So you want to cool yourself for eight hours a night while you're sleeping. That is 4 kilowatt hours. So usually we're thinking about most things we're doing that are like major energy users are in the kilowatt hour scale.

A (16:02)

I like this because I think. I mean, there's a certain element to where this is getting a little matrixy, where we talk about humans producing kilowatt hours of electricity. But no, I like this because it makes sense. Right. I have one more question, which is in energy writing and energy reporting, I think there's often. It's very common, simply, frankly, in writing, to avoid echoes, to avoid repetition, to vary. Referring to energy as power or referring to it as energy, do you think that's okay? Do you think that's forgivable? Or are there moments where we're writing about power that we should be sure to call it power? In moments we're writing about energy because I think, especially writing about the power grid, referring to electricity, energy and power Those things are basically treated as interchangeable, even though from a physics perspective, they aren't.

B (16:53)

As we've talked about here, the way we experience the grid is in terms of energy, right? It's in terms of the amount of energy we're using over some to do something useful. So I would recommend generally reporting it in those terms, in energy terms. And that's just because the rate at which we consume energy or the power varies dramatically, as we were talking about, over the course of a day. Do I have my EV charger on or off? Do I have my air conditioner on or off? Like, these cause huge swings in the rate at which we're actually consuming that energy or the power rate. And that's also true on the generator side, too. You think about particularly, we're talking about reporting the size of an offshore wind farm or a solar farm plant. You usually will hear that expressed in terms of its maximum rated power output. It's a 300 megawatt wind farm, for example. That's the maximum it can produce, or the maximum power rate at which it can produce. But it doesn't sustain at that rate all the time. And so the average power rate is much lower than that. And that's where this capacity factor concept comes in, which is basically the average power rate divided by the maximum possible. So if we say a wind farm has a capacity factor of 50%, then that 300 megawatt wind farm, that's 300 megawatts of maximum power, is varying around between zero and 300. On an average, it's producing energy at a rate of 150megawatts. Even a nuclear plant isn't running constantly. That's as close as you get to an equivalence between a power rating and an energy output, because it runs 90% of the time. But even there, the nuclear plant turns off for 12 weeks every 18 months to refuel, and so it's not producing all the time either. So I would probably counsel describing things in energy terms for the most part, because that's what we actually experience as heat or as acceleration of mass or other things that we can feel in our daily lives.

A (18:38)

Let's talk about scale for a second. So in writing about electricity, and I'm writing about renewable specifically, you encounter these kind of like big units, right? You encounter watts, but you really encounter kilowatts, megawatts, gigawatts, and then at the scale of national systems, terawatts. And for ease of use, these energy units are almost always followed up by, and this is the number of households it powers, right. This is the number of average households, it's going to power. But the thing is, when you start digging under the surface, there's a huge amount of variance in those household terms. And I think it really obfuscates how people understand the energy system, the power grid. So like how much are these units? If we want to switch to a unit first and a watt first way of thinking about renewables and thinking about the electric, thinking about electricity, how big is a kilowatt, how big is a megawatt? What is the right comparisons to hold in our head for those that don't require just converting to like, oh, this is 10,000 households and this is a million households.

B (19:43)

Yeah. So again, if you're thinking in watts, you're talking about power. And so there again it's like, are you trying to describe an instantaneous power, a maximum power, an average power? Those are all different things. I think the key thing is if you're talking about power, you got to start with what am I actually trying to describe? And if I'm not actually trying to describe a unit of power, I'm actually trying to describe a unit of energy, which is like how much energy households use, then we probably shouldn't be using watts, we should be using watt hours or their equivalent. So that's my first point. Second though, let's talk about scale.

A (20:16)

Yeah, yeah.

B (20:18)

So to follow my own advice, let's start with the energy units first. And you'll get the relationship here between energy and power to some degree in this explanation. So if I'm talking about the amount of energy that a computer, a laptop or a light uses over an hour, for example, that's the scale of like tens of watt hours. So a 10 or 15 watt LED bulb, that's the maximum power it's consuming when it's on. So if you have a 10 watt bulb on for an hour, that's 10 watt hours. The draw of a typical laptop. If you look on the back, it's, let me see what mine is. It looks like my laptop is rated at 60, 60ish watts of power draw. So if it's on and I'm computing at its maximum power draw for an hour, then I'm used 60 watt hours. Personal electronics lights, those are on the scale of watt hours per hour. You know, so I'm, you know, if I'm using it for days or weeks, then it might grow to a kilowatt hour. But if I'm thinking about kind of the near term use over a period of hours of a Laptop, cell phone, or an LED light. Those are in the scale of watt hours. If we're talking about other larger consumers of electricity, or again the scale of annual of daily use of a human, then we're at the scale of kilowatt hours or thousand watt hours. So like you said, a human uses roughly 2.5 kilowatt hours of food a day. If you're running your air conditioning unit over the course of the day, that's going to be in singles to tens of kilowatt hours. Your solar panels on your roof are usually on the scale of 5 to 10 kilowatts of maximum capacity. And so they produce 25% on average. Maybe they're producing 4 kilowatt hours per hour on average and 7 kilowatt hours per hour and the sun is up. Something like that. And your chargers as well, your EV charger is also on the scale of several kilowatts also.

A (22:15)

Do you want to build critical skills that are transforming the clean energy sector? Then discover the Yale Clean and Equitable Energy Development Online Certificate program from our sponsor, the Yale center for Business and the Environment. This fully online 5 month program is designed for working professionals who want to build projects that serve both people and the planet. You'll dive into energy fundamentals, project finance, and key phases of development and operations while learning how to center community engagement. In just five hours a week, you'll learn from leading experts, develop practitioners practical skills and gain actionable insights. By engaging in video lectures, live sessions and a real world group project, Yale ensures you have the expertise to advance clean energy solutions that benefit communities and drive economic resilience. Are you ready to elevate your career and make a difference? Then Visit cbey yale.edu to learn more and enroll in the Clean and Equitable Energy development program. That's CBey Yale. EDU or check out the show notes for more. One reason load growth has come back right is because through the 2000 teens, at least this is my understanding, you should correct me if this is wrong, but through the 2000 teens, we were basically increasing the efficiency of the power grid at the same time that we were adding new demand to the power grid. And we were increasing the efficiency because we were replacing the stock of incandescent light bulbs with LED light bulbs. Basically like that was the biggest story in electricity demand. And if just to go back to your units, like if you think about how much power an incandescent light bulb draws, it's like 60 watts. And now as you were saying, it's 60 to 100 and now, as you were saying, an LED light bulb draws like 10. Like that's where the demand growth went during the 2000 teens. And the fact that we've now basically finished converting, you know, most light bulbs in the United States to LEDs and but are still adding new capacity, like, no wonder demand growth is back. Anyway, I just wanted to interject that because it was really, I think it's evocative of how like we're talking about 50 watts per light bulb, which is a lot, but also how these small, relatively small differences in power units add up to massive utility scale decision making. Anyway, though, as you were saying, Ev, it drives a kilowatt.

B (24:37)

Yeah, yeah. EVs are the scale of kilowatts. Yeah, no, that's helpful, I think, to remember. And it's interesting because of course, electricity was first used for lighting. That was its first application way back when. And now it's interesting that like lighting has become so efficient that it's such a tiny sliver of the overall, you know, electricity usage nationally now and so many other things. Air conditioning and increasingly EVs and heat pumps and data centers and computing and everything else are the big drivers. So, yeah, a couple other things that maybe are to give us again on like a household scale that we're used to interacting with. I mean, one would be a tank of gasoline in your car, right. In your conventional car. So a gallon of Gasoline contains about 40 and a half kilowatt hours, 40.5 kilowatt hours. So 1 gallon of gasoline is on that scale of a couple gallons of gasoline, I guess are on that scale of like average household electricity use over the course of a day. Now, of course, you can't turn gasoline directly into electricity at a one for one conversion ratio. Right. You got to use a diesel generator, which itself is only maybe 30% efficient. So it actually takes a lot more than that. And that's also partly why electric motors are so much more efficient, right? Taking the energy in your battery and converting them into traction in your cars because there's already electro electricity. You don't have to combust anything to make heat and then drive motion and then turn that motion into power in your wheels. Right?

A (25:56)

There's a lot less heat loss.

B (25:58)

Yeah, yeah, tons less. Yeah, exactly. So an internal combustion car is maybe a third as efficient as a, you know, electric vehicle. So, yeah, tank of gas, 10 gallon tank of gas, 400ish kilowatt hours. That's actually quite a lot. This is why fossil fuels are so amazing. You can fill 10 gallons of gasoline and have an enormous amount of energy from a kind of personals perspective.

A (26:18)

Right. I mean, it is actually like when you fill up your car's gas tank, let's say it's 8 to 12 gallons.

B (26:23)

If you relatively, it's a lot, several.

A (26:26)

Hundred kilowatt hours, that's your weekly or even more than week's worth of household electricity use.

B (26:32)

Right. And also, I should think about it, it's about a week's worth of commuting too, Right. You don't use up your full gas tank in a day usually. Unless you're a Uber driver perhaps. Yeah. So anyway, so now we're, yeah, we're in like weekly scale consumption. Now we're talking about megawatt hours, whether that's your commute energy usage or your household energy electricity usage. Then when we talk about gigawatt hours, now we're starting to talk about power plant scale, right. Or data center scale or industrial facility scale. A large nuclear reactor is typically on the scale of about a gigawatt or a billion watts. It's a million kilowatt hours or kilowatts. So a gigawatt scale power plant, again producing for an hour would produce 1 gigawatt hour of electricity. So when we're in that scale of gigawatt hours, we're talking about the output, sort of the hour by hour output of a large power plant or a large data center or something of that scale. Those are going to be in your gigawatt hour terms. And then you indicated earlier terawatts, that's the next scale up. 3,000 gigawatt hours is a terawatt hour. Now we're talking about the scale of like annual production for a power plant or annual consumption for a state or data center or something like that. Those are going to be in the scale of hundreds of terawatt hours. And nationally we consume about 4 TB,200 TJ of electricity annually in the US today. So there's. Now we're in the thousand terawatt hour scale. Now we're talking about national annual electricity usage.

A (27:58)

I think you skipped directly from megawatts from kilowatts to megawatts. But can you briefly talk about megawatts?

B (28:04)

Yeah, megawatt is 1,000 kilowatts. So a megawatt hour is 1,000 kilowatt hours as well. And then that's again the scale of your weekly electricity consumption in your home or your weekly consumption of gasoline for your commute or maybe several weeks renewables.

A (28:20)

I mean, I feel like when we talk about solar farms, we're usually talking about in the world of megawatts. So that's true.

B (28:27)

Most power plants are smaller than a gigawatt. A nuclear plant is big. Most power plants are several tens to hundreds of megawatts scale production. So if they're producing for an hour, then you're in the tens to hundreds of megawatt hours range. But if they're producing for a year, you're more like terawatt hours.

A (28:43)

I just want to stick in megawatts for a second because it's actually when we talk about renewables and when we talk about renewable sized addition to the power grid, we tend to be in megawatts. Only when you talk about these giant generating sites like Vogel units 3 and 4 are each, I believe, more than a gigawatt. They're like 1.2 gigawatts or something. You talk about these massive, massive new nuclear power plants, then we're talking about gigawatts. But mostly in the world of when we talk about adding new power demand, especially from renewables, it tends to be in megawatt hour world. And so just for instance, a technology that we don't hear very much about anymore, concentrated solar thermal. But that if you've ever flown across the country, I'm just thinking about this because I think it's evocative. When you fly across the country, there are two big concentrated solar plants. These are the mirrors that point at the single tower and then boil things. And when birds fly across, they instantly get incinerated. But anyway, Ivampa, this famous concentrated solar thermal plant that went up early in the Obama administration and is going to close actually next year. That is 392megawatts.

B (29:55)

Yeah. You would see this out your window if you're flying from.

A (29:58)

Exactly.

B (29:59)

That's why Los Angeles, over towards Las Vegas and beyond.

A (30:03)

Exactly. We've had folks from Fervo Energy, the advanced geothermal company, on this podcast. They're working on applying, as we've discussed then, Fervo is the company, one of the several companies that's working on applying fracking techniques to generating clean electricity through drilling new geothermal wells. Cape Station in Beaver County, Utah, their big demonstration project. That's 400 megawatts. When it's fully built out, that's going to be 400 megawatts. When it's fully built out. Empire Wind, which is the big equinor offshore wind project in New York state, is 810megawatts. And so just to give you a sense, what is the Average combined cycle gas.

B (30:43)

A couple hundred megawatts.

A (30:44)

A couple hundred megawatts. So just to be clear, like when we talk about power plants, normally we're in this world of talking about megawatts anyway though.

B (30:51)

Yeah. Or hundreds of megawatts.

A (30:53)

Or hundreds of megawatts.

B (30:54)

Or another perspective is Princeton University has a gas turbine here that we use to generate some electricity as well as use the waste heat for heating and cooling in the campus. We're going to shut that down soon and replace it with our ground source geothermal project. But that's a 15 megawatt turbine. So for the scale of a single campus, you might have a tens of megawatt scale facility. The data centers, like the big exascale data centers, we're talking about like giant ones, those are usually in the hundreds of megawatts to even gigawatt scale facilities. Now that we're talking about some building out 3, 4, 5 gigawatt scale campuses for data centers. So that's pretty wild. The other way to think about a gigawatt, I usually think of it in terms of if again, if it's a gigawatt of average consumption, that's like 800,000 homes. So if you assume two people per home on average, that's like a city of one and a half million people scale. So a gigawatt is a city scale of consumption or production on average, which starts to give you the sale of these data centers. Right. If it's a gigawatt scale data center, we're talking about like plopping down another one and a half million people's worth of electricity use with one of those facilities. That's big.

A (32:03)

How do you convert? You just kind of did it off the cuff. But often when you see these megawatt gigawatt numbers, they're immediately followed by a conversion to homes. And I think when you've been paying any attention to this, you realize that these conversions could be like, are especially in PR documents, are like so off the cuff, they're like not comparable at all. What do you think is the best?

B (32:24)

There's some embedded assumptions in there.

A (32:26)

Yes, exactly. And they also vary a lot by region where like Texas homes use a lot more electricity than homes in the Northeast.

B (32:35)

Yeah, so there's a couple of kind of embedded assumptions there. The most important of which is the average power output of the facility versus its maximum and then what you assume for how much electricity a household uses. So let's take the Empire Wind project. You said it was 810 megawatts. That's its maximum capacity. Assume it's about a 50% capacity factor. That's a good average power output ratio for a wind farm. So you know, wind farms in the Great Plains states onshore, they might be approaching 50% capacity factor. Offshore wind, maybe they're in that range 40 to 50%. So let's say 50% round numbers. That means it's generating 405 megawatts of power on average. That's pretty big. That's a couple of combined cycle power plants worth all the time cranking out power 24,7. So that's a fairly big amount of energy from that wind farm. But then if we, then we have to assume that the average consumption of a household, which according to EIA nationally is about 1.2 kilowatts. So I take that 405 megawatts, that's 405,000 kilowatts of average power output. If I assume the average home uses 1.2 kilowatts per hour, then that's about 337,000 homes. Call it 340,000 in round numbers or 330,000. That's the kind of conversion that's being done behind the scenes when someone is reporting the number of households. And of course, it depends. If I change that capacity factor to 40%, I get more like 270,000 households, not 340. If I take maybe a more New York specific household electricity consumption rate, which might be different from the national average, I'm going to get a totally different number too. So that's where it gets a little tricky, is what are you embedding in there? And I think the best thing to do is just get a feel for the round numbers here. Right? We're talking about Empire Wind is several hundred thousand homes. That's the scale at which it produces. And that's probably as accurate as we can get in these kinds of conversions.

A (34:37)

Can I ask one more question, which is, are homes even the right way to think about this? We always convert to homes. But like people don't only use electricity at homes. Businesses use electricity, industrial facilities use electricity. So what's the breakdown of where US power demand goes to? Homes versus businesses versus let's say industrial uses.

B (35:01)

So it looks like just over a bit over a third of US electricity production goes to residential usage. As of 2022, it was 3.38.4% of US electricity sales were to households. Residential consumption, that's about equal in size. About 35% went to commercial buildings, offices and other commercial spaces, and about 26% went to industry. So think of it as like a quarter going to industry if we all switch to EVs. Maybe that's not true. I was going to say, I think maybe the share of consumption from industry and commercial properties is going to go up over time more rapidly than households because of the efficiency gains. But maybe that's not true anymore. We've tapped out the lighting efficiency improvements like you said, and if we all convert to electric heating and EVs, then actually residential consumption could grow quite significantly. So I guess if you're thinking about what's the largest user today, it is the largest sector is residential consumption. So maybe households are the right number to think of. I'm not sure what else we could use EVs. That would be the other. As more and more people start to switch to EVs, maybe we'll start to say this will power however many million EVs for a week or commutes for a week or something like that. That could be the next intuitive thing that we might switch to.

A (36:17)

One more question, which is that people, what this all means, and I just want to make sure is that when you're looking at, say, what energy use is for a geographic area or for a system, you have to be careful between maximum use, average use. You said this at the beginning, but I want to draw it out between maximum use, average use and annual use. Because all of those, if I'm understanding correctly, will be in watt hour, whether it's megawatt or gigawatt. And you just have to be careful that you don't allide them. I was looking up because I was curious. The New York City subway system uses 3,500 megawatt hours annually. So what is that? 3.5 gigawatts hours annually.

B (36:54)

So that would be like three and a half nuclear reactors producing continuously for or seven natural gas power plants, or seven to ten natural gas power plants producing continuously. That's a lot of electricity.

A (37:05)

That's a lot of electricity.

B (37:07)

If you think in the household too. It's interesting to break down like the biggest users. And I think you guys did a good job in your decarbonize your life guide that everybody should check out at heatmap, pointing out that there are just a few really large consumers of electricity in a typical home. That is space heating and cooling. That's the biggest one by far. Coming in at about a quarter that size or maybe a third is water heating, if you have an electric water heater. And then even smaller than that is refrigerators. Beyond that, everything else is very small unless you have an ev, which would be on the scale of your heating and cooling, too. Lighting used to be part of that equation, but it's not anymore as we talked about because of the growth of LEDs.

A (37:48)

I learned a lot from this.

B (37:49)

It's interesting to do this without my lecture slides with a microphone instead. Hopefully that was somewhat helpful.

A (37:56)

That was great. This concludes our first session of Shift Key summer school. We'll be back in the second session with an introduction to how power plants work. We're going to go through the history of electricity, starting with coal to the modern day. Describe how each kind of power plant work. We're going to keep building your understanding of the grid. I'm like, delighted we're doing this, Jesse. I have already learned so much from this hour. If you hated this, we'll be back with a regular episode of Shift Key. Sooner than you think. Thanks as always, for listening. Shift Key is a production of Heatmap News. Our editors are Ghislaine Goodman and Nico Lauricella. Multimedia editing. Auto engineering is by Jacob Lambert and by Nick Woodbury. Our music is by Adam Kramlau. Hope you're having a great summer and see you next week.