Net-Zero Energy Skyscrapers: A Tall Order


What does it mean for a building to be net-zero energy? What does passive solar mean? What techniques can architects use to reduce energy consumption? Join the conversation with Jonathan, Joe and Lauren.

Male Speaker 1: Brought to you by Toyota. Let's go places. Welcome to Forward Thinking.

Jonathan: Welcome to Forward Thinking. I'm Jonathan Strickland.

Lauren: I'm Lauren Vogelbaum.

Joe: And I'm Joe McCormick.

Jonathan: And today we wanted to talk a bit about really energy efficient buildings; buildings that are so energy efficient that they actually don't, either they do not draw any energy from the power grid at all -

Lauren: Net zero.

Jonathan: Net zero, or maybe they draw energy from the power grid, but they also put energy back in, still being net zero, or they're just very very low energy, so they draw a little bit from the grid but not a lot, or they're even energy positive, which means they just feed energy back into the power grid. And we wanted to talk about what it takes to make a building do that, and what it would take to make a really big building do that, because it's one thing to design a residential home that can be net zero energy compliant, right? That's one thing, but to design a skyscraper that can do it, that has a completely different set of challenges that get much more complex, and so we wanted to kind of talk about this whole idea and why we should even consider it in the first place. So really, the net zero thing is pretty self-explanatory.

I mean, you could at least imagine one in theory. You could imagine that, let's say that you have a farm house that's on essentially a plane, and you get lots of sunlight, generally speaking, throughout the year, and you also have some good winds that go through the area, so maybe with wind turbines and solar panels, and with a very good design of your house, you might be -

Lauren: To collect the sunlight appropriately at different times of the day.

Jonathan: Right, and we'll get into all of that in a minute. That sort of stuff might allow you to be self-sufficient. In fact, you could, theoretically, have a building that's so self-sufficient it doesn't even connect to a power grid.

Joe: That's off the grid.

Jonathan: Yes, you're off the grid. Granted, you're still being tracked, because someone's always looking for you. No, I'm just kidding. Just kidding.

Joe: So, we've heard of houses like this. Your house ahs a nuclear reactor inside or it has whatever, it has solar panels.

Jonathan: A team of hamsters running in wheels generating electricity.

Joe: Yeah, whatever it is that makes this house self-sufficient, but you mentioned bigger buildings. Have we ever heard of a truly truly energy self-sufficient, a net zero high rise; the large kind of building you'd see in a city?

Jonathan: All right, there's supposedly some. I say supposedly because it's difficult to actually confirm.

Joe: Well let us suppose. Tell us about it.

Jonathan: All right, so there's a building called the Pearl River Tower, in Guangzhou, China, and this tower is 71 stories tall, so I think that counts as skyscraper. 71 stories tall.

Joe: Does that count as skyscraper? What's the qualification?

Jonathan: I believe so. You would think that it would have to.

Joe: Well, it's at least a high rise.

Lauren: Right, at the very least.

Jonathan: At 70 stories, I think I'm willing to call it a skyscraper. Of course, I live in Atlanta, where a 70-story building would be enormous. In fact, we only have a couple that reach that high. Anyway, it's like the fourth tallest building in Guangzhou, and somewhere in the 20s for all of China. It's 2.3 million square feet of space, and it's an office building, so there's no residential in here as far as I can tell, it's all offices. And it's supposedly net zero. I say supposedly because I don't have -

Lauren: You haven't checked it out personally?

Jonathan: Well yeah, I don't have any way of specifically going there and seeing it and making sure that in fact -

Lauren: And the numbers on it, the engineers have an interest in making it sound as good as possible, of course.

Joe: Well, we don't want to cast doubts upon them, but we should, yes.

Lauren: Oh, I'm sure they're fine upstanding citizens, but I -

Jonathan: Well they do have an interest.

Joe: Good point though.

Jonathan: The point being that we cannot confirm, we can only take in the data that is available from the people who built the thing, and there's no way that you can say that that's unbiased. By its very nature it's biased. It may still be correct, but it is biased.

Joe: Right, wait a second here. So a 70 plus story building that doesn't use any more energy than it makes? How is that possible?

Jonathan: All right, assuming that in fact that claim is true, here's how they did it. First of all, it was designed by two American architects, Gordan Gill and Adrian D. Smith. Actually, I'm assuming they're American. I know that they designed it in Chicago. The building itself was completed in late 2011 early 2012, and the way that they generate energy is through several different methods. They use something called "passive solar power". Actually, they call it "sunlight harvesting." That's how they refer to it on their website. But they also use wind turbines. They have two large sections of the building where it's designed to channel wind through these sections and wind turbines are in them.

Joe: Oh, so it's like a jet engine for your building.

Jonathan: Kind of, yeah. If you were to look at the building face on, you would see that there are two levels within this building. So the building is in three big sections, right? So you see floors where obviously office space exists, and there's a chunk of floors and then there's this weird level and then there's another chunk of floors and then another weird level, and then another chunk of floors. Those two weird levels are actually the wind turbine levels, and they're channeling the wind through, so the other thing is that if you were to look at the building in profile, the outward facing walls would look kind of curved from floor to floor, because it's actually channeling the wind through those turbines.

They also have photovoltaic cells, also known as solar panels, and they used stuff like raised floor ventilation and radiant heating and cooling ceilings to help control the temperature inside the building to reduce the need for using energy to run the hvac system. So that's how this building supposedly operates. It also makes it really easy to get all that sunlight because, from the pictures I saw, it's the only really tall building in its area. There aren't any other neighboring skyscrapers butting up against this thing.

Lauren: Right, which has to make it immensely easier to A.) Catch that wind and B.) Catch the sunlight.

Jonathan: Right. Harvesting the sunlight is a lot easier when you don't have another enormous building casting a shadow on you. So, that's generally how it's done, and of course that's kind of how all net zero buildings work to some extent. There is an effort of actual energy production, as well as energy conservation that's going on

Joe: So, let's look at some of those features individually and see what they take. Now, I imagine everybody's heard of solar panels and wind turbines. Probably a lot of people aren't familiar with passive solar.

Jonathan: Right, yes. So, a solar panel would be an active solar system, because you're actually actively grabbing that solar energy and converting it into electricity. What is passive solar?

Joe: Passive solar is a design issue. It's hard to just add it on to a building the way you might be able to - so, take your average skyscraper that already exists. You could stick solar panels all over it if you wanted. That's a feasible upgrade. The passive solar is a design issue from the ground floor, and it means that essentially the building is constructed in a way to make perfect use of natural sunlight. And a lot of this just comes down to heating and cooling. I looked up - the U.S. Department of Energy says that the average home's utility bill in America, 54 percent of that is just heating and cooling. Heating and cooling is a huge amount of the power we use in our buildings and infrastructure, because we like to be comfortable, right?

Jonathan: I like my building cave cold.

Joe: Right, so we could wave our hands at that, but I don't know if I could sit in an office sweaty and get my work done.

Lauren: And still be productive, sure.

Jonathan: I have. I don't recommend it.

Joe: Yeah, it's difficult. So we like to be comfortable, we keep our buildings at a nice temperature, but this is really really costly, if you're constantly pumping in cold air, pumping in hot air, in order to do it. Passive solar design allows you to do this with natural angles of light from the sun. So what it has to do with is how you orient the building, for one thing. The building is built in such a way with the passage of the sun and different seasons in mind, so it's built with side facing windows that are designed to allow sunlight in in the winter to naturally heat all the rooms, and designed so as to block the sun in the summer.

Jonathan: And this is because the sun itself passes in a different arc depending upon the season because of the tilt of the Earth. Keeping in mind, of course, we're talking about rotation of the Earth and the tilt of the Earth, not the actual passage of the sun.

Lauren: Right, important point.

Jonathan: It does mean, however, that there are times, you've probably noticed this, where there's certain times of the year where at a particular time of day, sunlight just streams in through a window and blinds you and you just can't get anything done so you have to move to some other part of the house or close a blind or something. But other parts of the year, during that same time of day, everything's fine, you don't have sunlight coming in through that window. Same sort of thing, except you're designing an entire building around that, so that in the winter the sunlight comes in, it hits surfaces that are designed to absorb as much heat as possible and radiate that heat out throughout the day. So that way during the winter months when it's cooler, the sunlight is actually warming the interior of your house and it's staying warm longer than it would if it were made out of some other material. So the material itself has to be good at absorbing that energy, and then radiating it out over time.

Joe: Another issue is just simple insulation. Anybody who, if you've owned a home or anything like that, you know that insulation makes a huge difference in your energy costs.

Lauren: Oh yeah, yeah, it's all the glass panels, floor to ceiling kind of glass panels, that we have on our current building, actually, that we're sitting in right now, are gorgeous, but how energy efficient are they?

Joe: Yeah, we don't know. They probably lose a lot of heat.

Jonathan: You definitely want your building to be weather tight. That's kind of the way that the industry talks about it, and that will allow you to save a lot on your energy bills. So a lot of these things we're talking about are things that, at least to some extent, existing buildings can do, but like you were saying, Joe, you can't take full advantage of it unless you're planning it from the very beginning.

Lauren: Right. It's harder to rotate a building after you've already set it up.

Joe: We can put it up on stilts and turn the lazy susan.

Jonathan: Sadly it's not quite like Sim City where you just pick this up and move it over here. Yeah, and also, it's easier to do on a smaller scale than on a large scale like a skyscraper. Especially if you're talking about the dense urban population where you've got lots of skyscrapers together. That might mean that you don't get, even if you were to build it from the ground up, you might not get full sunlight all day long because of the way the other buildings are.

Lauren: You might only be able to have one of these in every three or four city blocks or something for them all to be as efficient as possible.

Joe: Right, well, you mentioned the Pearl River Tower. You said it was the only building around.

Jonathan: According to the pictures I've seen, yeah, there are no other skyscrapers that are immediately adjacent to it, so it looks like it gets the full benefit of sunlight from where it is right now.

Joe: So that would automatically kind of cut back on some of the advantages if you couldn't build it close to other buildings, right? And another challenge that we can think about with net zero or at least low energy skyscrapers or high rises is, you've got to offset those costs you do incur. So you can use passive solar to control your climate, but you've still got to turn on the toaster and plug in your laptop and stuff like that. Where does that energy come from?

Jonathan: So you need to have some sort of energy creation. A generator is what you need. You need some form of generation to create the electricity you need to run the stuff in your building.

Joe: Right, so if you don't have a fusion reactor in your building, you're going to have -

Jonathan: Right. If you do have a fusion reactor in your building, please let us know, because I would love to see that. But, chances are you don't, so how do you generate that electricity? And really you're talking, one of the other goals, we didn't really mention it, but one of the other goals for a net zero energy building is to reduce or eliminate greenhouse gas emissions, which means that you can't just fill up generators full of gasoline and crank them up and use that as the way to generate electricity. You need to find a way to generate it that's clean, and so that's where the photovoltaic cells and the wind turbines come into play, to harness the natural energies as much as possible. But again, when you're talking about a building, that's challenging.

Lauren: Right, right, there's only so much you can do with wind turbines and a study in 2009 found that, by far, wind turbines are more efficient cost wise than photovoltaics for doing this kind of thing. They compared, for a mixed use community of about 1600 people, this was a study done by the Pacific Northwest National Lab, they compared five different scenarios for this and they found that even in a city like Phoenix that has a relatively low amount of wind and a relatively high amount of sunlight, that yeah, a wind farm would win.

Jonathan: And also, Joe, you were pointing out earlier when we were talking before the podcast that it really depends upon the ratio between the sides of the building that face the sun and the top of the building.

Joe: Right. Both of these things, whether it's wind or solar, they need some sort of freedom of access. Especially solar needs direct access to the sunlight. Wind, I'd imagine, I actually don't know, and this would be interesting to find out, but do you get more wind if there's less other skyscraper around you, or if you're within a city skyline does that cut down on your access to wind?

Jonathan: It actually just depends upon the geography, because you can have what becomes a wind tunnel, depending upon - there's certain parts of Atlanta, by the way, this is incredibly obvious. You might walk down one street and you think, "That's a nice breeze." You walk between the buildings on Peachtree Street near the Fox Theater, and then suddenly you are holding on for dear life.

Joe: Oh yeah, sometimes I'm driving home and I think I'm going to get sucked up in a cyclone. My car shakes.

Jonathan: Right, and then there's the ruby slippers that you wear all the time. It explains a lot, Joe. But the point being that yes, the idea that even if you were to coat the entire side of a building with some form of solar panel, they've talked about films that could be used to coat different surfaces that could act as a photovoltaic cell, let's say that we get to that point where we can do that. You still are limited by the fact that that side of the building is only going to be exposed to the sun during part of the day. So part of the day it's going to have a lot of sunlight hitting it. The top of the building is going to have sunlight hitting it for most of the day, but if you've built a very tall but relatively skinny building, in the sense that when you get to the roof, you only have a small percentage of - the square footage of the roof is only a tiny fraction of what the sides are, that's not an efficient way to generate energy.

Joe: Right. The taller you go, you're increasing the ratio of your energy needs to your ability to harvest solar energy.

Jonathan: Exactly, and tall buildings like, the hvac system that we were talking about. Assuming that of course the passive solar approach does not completely eliminate the hvac requirements, and really if we're talking about a realistic skyscraper, I can't imagine a scenario where passive solar takes care of all of that.

Joe: You could force it to, I guess. You could just not build an hvac system.

Jonathan: Yeah, people are just going to have to shiver and sweat depending upon the time of year, or in Atlanta, depending upon the day, since we seem to be going through winter, summer, and spring, simultaneously this year.

Lauren: This week.

Jonathan: This week, yeah. So in that case, you're talking about, the more floors you have, the greater the amount of energy you need to maintain the climate as well, so again, the bigger you get, the higher your footprint, or the deeper your footprint, is going to go, I guess we could say, if we're going to use that metaphor. So that makes it a challenge.

Lauren: Also, does it depend on, you know, you mentioned that this Chinese building was an office space. Is it going to take a lot more energy cost for a community, for a living community?

Jonathan: I would imagine that it probably would because if you're talking about an office space, one of the things you would do to help limit the energy is you essentially say, "At X time, this office building is essentially closed, and you can still be here."

Lauren: But without lights.

Jonathan: Right, you may not have electricity or heat or air conditioning, but you could still be here. Whereas of course if it's residential -

Joe: Oxygen.

Jonathan: I don't think it's gotten quite that bad, but yeah, if you, for residential, clearly you would need to have access to all of those things all the time.

Lauren: Plus, more people shower, I would say, at home than they do in their offices.

Jonathan: Maybe you. You have obviously not seen the shower on this floor, or the shower at my home, for that matter.

Joe: It's a talent only shower, we have no ideas, only Jonathan gets access.

Jonathan: Well, you know, there are benefits that go with the job. But, yeah, so there are some challenges here. In fact, we cannot really say for certain if a high rise, like a skyscraper, could really be a net zero energy building, if we're talking about in the middle of an urban space. It would be an incredible challenge. Maybe we could find more efficient ways to generate electricity through things like wind power or solar power and that would help, but you're still talking about a huge energy need. Another thing we could do, looking at energy conservation, so cutting down on things like vampire power, standby power. Essentially that's when you have your computer turned off but it's plugged in and it's still pulling some power from the building. If you were able to eliminate that and have the switches where, when you turn the switch off, that's it, no more power is going through there, that would help.

Lauren: Right, or the per capita water use in America is something like 660,000 gallons per family per year, and that's an enormous amount. That's almost twice the global average.

Jonathan: Yeah, so cutting down on that would help a great deal as well. So, I think it definitely would be a huge challenge and possibly even an impossible one right now, with today's technology. That's not to say that we would not some day find a way to achieve this. At any rate, going through this would mean reducing our energy consumption, which is a good thing.

Joe: I mean, whether or not we believe the claims about this building in China, we do know that now we can create what are called low-energy buildings. It's definitely feasible to create a building that, though it might not completely break even, it uses very little of the grid.

Lauren: Right. Even 50 percent less is a pretty terrific amount when you go for a couple of years.

Jonathan: And there are some buildings out there, they're usually smaller one, that they take some energy from the grid, but then they may generate energy throughout parts of the year, and actually sell energy back to the grid. So ultimately, if you look at the receipt at the end of the year, you might say, "Oh, well this building ultimately breaks even," even though during parts of the year it has to consume energy from the grid. So there are those options as well. And of course, maybe one day we'll reach a point where this won't be as big a priority, for instance, maybe if we somehow crack that fusion problem.

Lauren: We all have Mr. Fusions in our kitchen.

Jonathan: Yeah, we've got an energy surplus at that point, and if you have an energy surplus then these considerations are no longer really important. Now, I would stress that a lot of the things that go into this design process are beneficial in other ways, besides the fact that they help cut down on our energy consumption, they also cut down on greenhouse gas emissions, which also then means that we have less of an impact on climate change, so there are other reasons to pursue these technologies besides just cutting down energy.

Joe: Well, there's no reason to put all our eggs in one basket.

Jonathan: Right, but I'm saying even if we get to the day where fusion is completely possible, which, I hope that day comes; I just don't see it happening tomorrow. But if it happens maybe ten years from now or 20 years from now, I still think that the design principles of the net zero energy buildings are important for us to consider for the other benefits besides energy consumption. So, that's the answer I give to people who think that they say, "Oh, well, don't worry, because technology is going to solve our energy problem so we shouldn't have to worry about this at all." My response is, "No, we should definitely look into this, because it means that we come up with new ideas that help the world, even if the energy consumption angle goes out the window."

Joe: Well, I love to speculate about technology as much as anybody, but it's really easy when you're not the one making it.

Lauren: Sure, I'm not working on the fusion problem, personally, so.

Jonathan: It's way easier. No, I'm working on -

Joe: So, we want to keep our feet on the ground.

Jonathan: Yes, yes. The only reason I say all that is because I know people. I actually know people in my life who have the attitude of, "That's not worth worrying about because someone smarter than I am is working on it."

Lauren: Right, no, just throw that McDonald's wrapper right at that baby deer's head. It's fine. It's going to be okay. Someone else will take care of it.

Jonathan: Technology, a robot will come along and pick up both the baby deer and the wrapper, use plasmafication to turn them into useful energy, and Bambi and your fast food will power your home for the next three hours. I know people who think like that.

Joe: And you can eat all the ice cream you want.

Jonathan: There are people who think like that, and my perspective is that that is not necessarily a responsible philosophy, the idea that, "Oh, we don't have to worry about it today because tomorrow we'll solve the problem." Well, the only way that works is if we actually work on solving the problem. That's my point. I know that we talk a lot, especially in this episode, about the challenges that we face, but honestly, if there's one thing I think human beings have proven themselves capable of doing, it's meeting challenges that previous generations thought as being impassible. There was just no way we were going to get around it, get over it, get through it, and yet time and time again, we have found ways to fix problems that people thought were unsolvable.

Joe: Oh, of course. Every cool thing we've ever done was deemed impossible.

Jonathan: Right, and so I really do think that knowing what the challenges are, that's definitely important, but don't give up thinking that those challenges are hard barriers that we'll never get through. That just means that we need to rise to the occasion, is ultimately what I think. So guys, if you are interested in these sort of topics, these futuristic topics, then we highly recommend you get in touch with us. You can follow us on Facebook, you can follow us on Twitter, you can follow us on Google Plus, you can go to the blogs That actually has links to all the things I mentioned. You can find the various links to the videos, the podcast that you're listening to now, if you want to listen to some older podcasts and you don't have time to download them, you can listen to them directly on the website. We have lots of information there and we want you to be part of this conversation. Let us know what's exciting to you and we will make sure that we incorporate that into our future discussions. We really look forward to hearing from you, and we will talk to you again really soon.

Male Speaker 1: For more on this topic and the future of technology, visit Brought to you by Toyota. Let's go places.

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Duration: 26 minutes

Topics in this Podcast: solar energy, sustainability, wind energy