The tradeoffs of building green
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0:01 - 0:04First of all, I'm a geek.
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0:04 - 0:06I'm an organic food-eating,
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0:06 - 0:09carbon footprint-minimizing, robotic surgery geek.
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0:09 - 0:12And I really want to build green,
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0:12 - 0:14but I'm very suspicious
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0:14 - 0:16of all of these well-meaning articles,
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0:16 - 0:18people long on moral authority
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0:18 - 0:20and short on data,
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0:20 - 0:22telling me how to do these kinds of things.
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0:22 - 0:24And so I have to figure this out for myself.
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0:24 - 0:27For example: Is this evil?
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0:27 - 0:30I have dropped a blob of organic yogurt
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0:30 - 0:32from happy self-actualized local cows
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0:32 - 0:34on my counter top,
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0:34 - 0:37and I grab a paper towel and I want to wipe it up.
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0:37 - 0:40But can I use a paper towel? (Laughter)
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0:40 - 0:43The answer to this can be found in embodied energy.
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0:43 - 0:45This is the amount of energy that goes into
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0:45 - 0:47any paper towel or embodied water,
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0:47 - 0:49and every time I use a paper towel,
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0:49 - 0:51I am using this much
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0:51 - 0:53virtual energy and water.
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0:53 - 0:55Wipe it up, throw it away.
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0:55 - 0:58Now, if I compare that to a cotton towel
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0:58 - 1:00that I can use a thousand times,
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1:00 - 1:03I don't have a whole lot of embodied energy
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1:03 - 1:05until I wash that yogurty towel.
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1:05 - 1:08This is now operating energy.
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1:08 - 1:10So if I throw my towel in the washing machine,
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1:10 - 1:12I've now put energy and water
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1:12 - 1:14back into that towel ...
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1:14 - 1:16unless I use a front-loading, high-efficiency washing machine, (Laughter)
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1:16 - 1:19and then it looks a little bit better.
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1:19 - 1:21But what about a recycled paper towel
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1:21 - 1:23that comes in those little half sheets?
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1:23 - 1:25Well, now a paper towel looks better.
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1:25 - 1:27Screw the paper towels. Let's go to a sponge.
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1:27 - 1:30I wipe it up with a sponge, and I put it under the running water,
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1:30 - 1:32and I have a lot less energy and a lot more water.
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1:32 - 1:34Unless you're like me and you leave the handle
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1:34 - 1:36in the position of hot even when you turn it on,
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1:36 - 1:38and then you start to use more energy.
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1:38 - 1:40Or worse, you let it run until it's warm
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1:40 - 1:42to rinse out your towel.
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1:42 - 1:44And now all bets are off.
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1:44 - 1:46(Laughter)
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1:46 - 1:48So what this says is that
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1:48 - 1:51sometimes the things that you least expect --
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1:51 - 1:53the position in which you put the handle --
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1:53 - 1:55have a bigger effect than any of those other things
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1:55 - 1:57that you were trying to optimize.
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1:57 - 1:59Now imagine someone as twisted as me
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1:59 - 2:01trying to build a house.
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2:01 - 2:04(Laughter)
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2:04 - 2:07That's what my husband and I are doing right now.
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2:07 - 2:09And so, we wanted to know, how green could we be?
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2:09 - 2:11And there's a thousand and one articles out there
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2:11 - 2:13telling us how to make all these green trade-offs.
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2:13 - 2:15And they are just as suspect
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2:15 - 2:18in telling us to optimize these little things around the edges
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2:18 - 2:20and missing the elephant in the living room.
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2:20 - 2:22Now, the average house
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2:22 - 2:25has about 300 megawatt hours
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2:25 - 2:27of embodied energy in it;
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2:27 - 2:29this is the energy it takes to make it --
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2:29 - 2:31millions and millions of paper towels.
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2:31 - 2:34We wanted to know how much better we could do.
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2:34 - 2:36And so, like many people,
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2:36 - 2:38we start with a house on a lot,
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2:38 - 2:40and I'm going to show you a typical construction on the top
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2:40 - 2:42and what we're doing on the bottom.
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2:42 - 2:44So first, we demolish it.
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2:44 - 2:47It takes some energy, but if you deconstruct it --
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2:47 - 2:49you take it all apart, you use the bits --
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2:49 - 2:51you can get some of that energy back.
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2:51 - 2:53We then dug a big hole
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2:53 - 2:55to put in a rainwater catchment tank
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2:55 - 2:57to take our yard water independent.
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2:57 - 2:59And then we poured a big foundation
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2:59 - 3:01for passive solar.
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3:01 - 3:03Now, you can reduce the embodied energy
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3:03 - 3:05by about 25 percent
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3:05 - 3:08by using high fly ash concrete.
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3:08 - 3:10We then put in framing.
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3:10 - 3:12And so this is framing -- lumber,
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3:12 - 3:14composite materials --
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3:14 - 3:17and it's kind of hard to get the embodied energy out of that,
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3:17 - 3:19but it can be a sustainable resource
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3:19 - 3:22if you use FSC-certified lumber.
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3:22 - 3:24We then go on to
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3:24 - 3:26the first thing that was very surprising.
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3:26 - 3:29If we put aluminum windows in this house,
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3:29 - 3:32we would double the energy use right there.
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3:32 - 3:34Now, PVC is a little bit better,
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3:34 - 3:37but still not as good as the wood that we chose.
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3:37 - 3:39We then put in plumbing,
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3:39 - 3:41electrical and HVAC,
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3:41 - 3:43and insulate.
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3:43 - 3:46Now, spray foam is an excellent insulator -- it fills in all the cracks --
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3:46 - 3:49but it is pretty high embodied energy,
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3:49 - 3:52and, sprayed-in cellulose or blue jeans
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3:52 - 3:54is a much lower energy alternative to that.
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3:54 - 3:56We also used straw bale
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3:56 - 3:58infill for our library,
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3:58 - 4:00which has zero embodied energy.
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4:00 - 4:02When it comes time to sheetrock,
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4:02 - 4:04if you use EcoRock it's about a quarter
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4:04 - 4:07of the embodied energy of standard sheetrock.
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4:07 - 4:09And then you get to the finishes,
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4:09 - 4:12the subject of all of those "go green" articles,
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4:12 - 4:13and on the scale of a house
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4:13 - 4:16they almost make no difference at all.
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4:16 - 4:18And yet, all the press is focused on that.
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4:18 - 4:20Except for flooring.
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4:20 - 4:22If you put carpeting in your house,
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4:22 - 4:25it's about a tenth of the embodied energy of the entire house,
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4:25 - 4:27unless you use concrete or wood
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4:27 - 4:29for a much lower embodied energy.
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4:29 - 4:32So now we add in the final construction energy, we add it all up,
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4:32 - 4:34and we've built a house for less than half
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4:34 - 4:37of the typical embodied energy for building a house like this.
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4:37 - 4:39But before we pat ourselves
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4:39 - 4:41too much on the back,
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4:41 - 4:44we have poured 151 megawatt hours
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4:44 - 4:46of energy into constructing this house
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4:46 - 4:48when there was a house there before.
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4:48 - 4:50And so the question is:
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4:50 - 4:52How could we make that back?
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4:52 - 4:55And so if I run my new energy-efficient house forward,
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4:55 - 4:58compared with the old, non-energy-efficient house,
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4:58 - 5:01we make it back in about six years.
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5:01 - 5:03Now, I probably would have upgraded the old house
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5:03 - 5:05to be more energy-efficient,
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5:05 - 5:07and in that case,
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5:07 - 5:10it would take me more about 20 years to break even.
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5:11 - 5:13Now, if I hadn't paid attention to embodied energy,
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5:13 - 5:15it would have taken us
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5:15 - 5:17over 50 years to break even
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5:17 - 5:19compared to the upgraded house.
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5:19 - 5:21So what does this mean?
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5:21 - 5:24On the scale of my portion of the house,
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5:24 - 5:26this is equivalent to about
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5:26 - 5:28as much as I drive in a year,
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5:28 - 5:30it's about five times as much
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5:30 - 5:32as if I went entirely vegetarian.
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5:32 - 5:35But my elephant in the living room flies.
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5:35 - 5:38Clearly, I need to walk home from TED.
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5:38 - 5:41But all the calculations
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5:41 - 5:43for embodied energy are on the blog.
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5:43 - 5:46And, remember, it's sometimes the things that you are not expecting
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5:46 - 5:49to be the biggest changes that are.
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5:49 - 5:51Thank you. (Applause)
- Title:
- The tradeoffs of building green
- Speaker:
- Catherine Mohr
- Description:
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In a short, funny, data-packed talk at TED U, Catherine Mohr walks through all the geeky decisions she made when building a green new house -- looking at real energy numbers, not hype. What choices matter most? Not the ones you think.
- Video Language:
- English
- Team:
closed TED
- Project:
- TEDTalks
- Duration:
- 05:52
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