WEBVTT 00:00:00.000 --> 00:00:01.944 align:middle line:90% [SQUEAKING] 00:00:01.944 --> 00:00:02.916 align:middle line:90% [RUSTLING] 00:00:02.916 --> 00:00:04.860 align:middle line:90% [CLICKING] 00:00:04.860 --> 00:00:10.700 align:middle line:90% 00:00:10.700 --> 00:00:13.010 align:middle line:84% DAVID HSU: Welcome to another lecture in my series 00:00:13.010 --> 00:00:15.600 align:middle line:84% on urban energy systems and policy. 00:00:15.600 --> 00:00:16.797 align:middle line:90% My name is David Hsu. 00:00:16.797 --> 00:00:19.130 align:middle line:84% I'm an associate professor of Urban Studies and Planning 00:00:19.130 --> 00:00:20.300 align:middle line:90% at MIT. 00:00:20.300 --> 00:00:25.160 align:middle line:84% And this week, I want to talk about cities, and buildings, 00:00:25.160 --> 00:00:27.470 align:middle line:90% and energy efficiency. 00:00:27.470 --> 00:00:30.590 align:middle line:84% The class materials or the materials for class discussion 00:00:30.590 --> 00:00:32.570 align:middle line:90% on Tuesday are in the syllabus. 00:00:32.570 --> 00:00:35.090 align:middle line:84% We'll talk mostly about the MacKay reading today-- 00:00:35.090 --> 00:00:36.500 align:middle line:90% the first bullet point. 00:00:36.500 --> 00:00:40.218 align:middle line:84% But we'll talk about the other readings in class on Tuesday. 00:00:40.218 --> 00:00:42.010 align:middle line:84% And I really want to start with this quote. 00:00:42.010 --> 00:00:44.230 align:middle line:84% You may have heard this quote before. 00:00:44.230 --> 00:00:46.180 align:middle line:90% It's from Winston Churchill. 00:00:46.180 --> 00:00:48.430 align:middle line:84% It's in a speech he gave after the bombing 00:00:48.430 --> 00:00:52.570 align:middle line:84% of the House of Commons after a raid in the London blitz. 00:00:52.570 --> 00:00:56.350 align:middle line:84% And he says "We shape buildings, and afterwards our buildings 00:00:56.350 --> 00:00:57.520 align:middle line:90% shape us." 00:00:57.520 --> 00:00:59.620 align:middle line:84% At the time, they're discussing how 00:00:59.620 --> 00:01:01.570 align:middle line:84% or whether to rebuild the House of Commons 00:01:01.570 --> 00:01:03.820 align:middle line:84% after it was hit by a bomb, but I 00:01:03.820 --> 00:01:05.500 align:middle line:84% think it's an evocative quote that 00:01:05.500 --> 00:01:08.350 align:middle line:84% gets used quite often to describe 00:01:08.350 --> 00:01:10.720 align:middle line:84% what the influence of buildings on culture is. 00:01:10.720 --> 00:01:13.330 align:middle line:84% And I've had a lifelong fascination with architecture. 00:01:13.330 --> 00:01:16.090 align:middle line:84% And so what I want to focus on today 00:01:16.090 --> 00:01:19.630 align:middle line:84% is how buildings reflect many different things. 00:01:19.630 --> 00:01:21.970 align:middle line:84% Energy efficiency is not usually at the top 00:01:21.970 --> 00:01:23.617 align:middle line:90% of anyone's list of concerns. 00:01:23.617 --> 00:01:25.450 align:middle line:84% And at the same time, I hope to convince you 00:01:25.450 --> 00:01:29.470 align:middle line:84% that buildings are an incredibly important problem that we need 00:01:29.470 --> 00:01:31.420 align:middle line:84% to tackle for the energy transition, 00:01:31.420 --> 00:01:35.260 align:middle line:84% and also argue that there's ways that we can shape buildings 00:01:35.260 --> 00:01:38.972 align:middle line:84% that will shape our later energy-using behaviors. 00:01:38.972 --> 00:01:41.430 align:middle line:84% And so just to give you a few arguments about why buildings 00:01:41.430 --> 00:01:44.850 align:middle line:84% are so important for energy use and climate change, 00:01:44.850 --> 00:01:48.300 align:middle line:84% in terms of operational energy, buildings are about 35% 00:01:48.300 --> 00:01:50.640 align:middle line:84% of the primary energy used in the world. 00:01:50.640 --> 00:01:54.450 align:middle line:84% They are responsible for about 38% of greenhouse gas emissions 00:01:54.450 --> 00:01:56.410 align:middle line:90% worldwide. 00:01:56.410 --> 00:01:59.340 align:middle line:84% And it's also worth noting that for cities in particular, 00:01:59.340 --> 00:02:01.740 align:middle line:84% the subject of this course, buildings 00:02:01.740 --> 00:02:04.560 align:middle line:84% are a much higher percentage of city emissions. 00:02:04.560 --> 00:02:07.650 align:middle line:84% In New York City, buildings represent about 70% 00:02:07.650 --> 00:02:11.340 align:middle line:84% of the greenhouse gas emissions, though we also have to be aware 00:02:11.340 --> 00:02:14.700 align:middle line:84% that this is also reflective of, as I've said before, 00:02:14.700 --> 00:02:16.650 align:middle line:84% New York City being a financial center. 00:02:16.650 --> 00:02:19.200 align:middle line:84% In Singapore, buildings are only 20% 00:02:19.200 --> 00:02:21.390 align:middle line:84% of greenhouse gas emissions because Singapore 00:02:21.390 --> 00:02:25.290 align:middle line:84% has a surprisingly large industrial base, specifically 00:02:25.290 --> 00:02:29.580 align:middle line:84% of liquid natural gas processing. 00:02:29.580 --> 00:02:34.050 align:middle line:84% But in terms of embodied energy, also, their construction 00:02:34.050 --> 00:02:36.390 align:middle line:84% represents a significant additional portion 00:02:36.390 --> 00:02:39.210 align:middle line:84% of their energy use and greenhouse gas emissions. 00:02:39.210 --> 00:02:40.860 align:middle line:84% The building construction industry 00:02:40.860 --> 00:02:43.830 align:middle line:84% is responsible for about 5% of the primary energy used 00:02:43.830 --> 00:02:46.910 align:middle line:90% in the world, 10% of emissions. 00:02:46.910 --> 00:02:49.440 align:middle line:84% And it's also worth noting that in cities like New York, 00:02:49.440 --> 00:02:55.170 align:middle line:84% many of the buildings that are already there here in 2022 00:02:55.170 --> 00:02:58.090 align:middle line:84% are going to be there for mid-century goal in 2050. 00:02:58.090 --> 00:03:01.680 align:middle line:84% So a key part of our challenge for addressing buildings 00:03:01.680 --> 00:03:04.260 align:middle line:84% is retrofitting the existing buildings we have. 00:03:04.260 --> 00:03:05.820 align:middle line:84% New construction may be occurring 00:03:05.820 --> 00:03:07.980 align:middle line:84% in other cities that are faster growing, 00:03:07.980 --> 00:03:09.688 align:middle line:84% but New York City is already quite dense. 00:03:09.688 --> 00:03:11.105 align:middle line:84% We actually need to figure out how 00:03:11.105 --> 00:03:13.110 align:middle line:84% to retrofit the millions of buildings we already 00:03:13.110 --> 00:03:15.180 align:middle line:90% have in New York City. 00:03:15.180 --> 00:03:18.150 align:middle line:84% It's also important to note that buildings shape our health. 00:03:18.150 --> 00:03:19.770 align:middle line:84% And we're quite concerned about how 00:03:19.770 --> 00:03:21.840 align:middle line:90% buildings affect our health. 00:03:21.840 --> 00:03:24.540 align:middle line:84% This famous statistic from Lawrence Berkeley National 00:03:24.540 --> 00:03:27.390 align:middle line:84% Laboratory using the American Time Use Survey 00:03:27.390 --> 00:03:31.020 align:middle line:84% basically asks people how much time do they spend and where. 00:03:31.020 --> 00:03:33.990 align:middle line:84% And they find that people spend about 87% of their lives 00:03:33.990 --> 00:03:37.620 align:middle line:84% indoors and about 6% of their time in enclosed vehicles, 00:03:37.620 --> 00:03:39.840 align:middle line:84% but 93% of their time is essentially 00:03:39.840 --> 00:03:42.510 align:middle line:84% spent in spaces that could be air-conditioned 00:03:42.510 --> 00:03:44.610 align:middle line:90% or affected by air conditioning. 00:03:44.610 --> 00:03:46.560 align:middle line:84% Of course, after three years of COVID 00:03:46.560 --> 00:03:49.200 align:middle line:84% we don't probably need to reinforce this point too much, 00:03:49.200 --> 00:03:51.960 align:middle line:84% but COVID and our concerns about ventilation 00:03:51.960 --> 00:03:55.270 align:middle line:84% have fundamentally affected our desire for real estate. 00:03:55.270 --> 00:03:57.090 align:middle line:84% Recent research from the San Francisco 00:03:57.090 --> 00:03:59.250 align:middle line:84% Fed that Paul Krugman has written about 00:03:59.250 --> 00:04:01.950 align:middle line:84% is essentially looking at inflation and the contribution 00:04:01.950 --> 00:04:03.450 align:middle line:90% of real estate to inflation. 00:04:03.450 --> 00:04:05.310 align:middle line:84% And he argued, I think quite convincingly, 00:04:05.310 --> 00:04:08.340 align:middle line:84% that there's a secular shift in what people want. 00:04:08.340 --> 00:04:10.620 align:middle line:84% People need more space for Zoom calls, 00:04:10.620 --> 00:04:12.360 align:middle line:90% for spending their time at home. 00:04:12.360 --> 00:04:14.610 align:middle line:84% This ties into the remote work trend 00:04:14.610 --> 00:04:16.920 align:middle line:90% that we talked about last week. 00:04:16.920 --> 00:04:20.130 align:middle line:84% And of course, we should not forget that there's always 00:04:20.130 --> 00:04:22.830 align:middle line:84% a crisis, or there is an increasing crisis 00:04:22.830 --> 00:04:25.260 align:middle line:84% in providing affordable and sufficient housing, 00:04:25.260 --> 00:04:28.980 align:middle line:84% not only in this country and in our major cities, 00:04:28.980 --> 00:04:30.570 align:middle line:90% but in many countries also. 00:04:30.570 --> 00:04:32.400 align:middle line:84% So when we talk about buildings, we 00:04:32.400 --> 00:04:35.220 align:middle line:84% need to think about what we're trying to provide, 00:04:35.220 --> 00:04:39.750 align:middle line:84% fundamentally, is a habitat or shelter from the environment. 00:04:39.750 --> 00:04:42.630 align:middle line:84% But how we do that has tremendous implications 00:04:42.630 --> 00:04:46.152 align:middle line:84% for energy use and climate goals. 00:04:46.152 --> 00:04:48.360 align:middle line:84% And so finally, what we'll talk about in this lecture 00:04:48.360 --> 00:04:50.700 align:middle line:90% is mostly the MacKay reading. 00:04:50.700 --> 00:04:53.520 align:middle line:84% He focuses on how much it takes to heat, cool, and use 00:04:53.520 --> 00:04:54.780 align:middle line:90% various appliances. 00:04:54.780 --> 00:04:57.480 align:middle line:84% And we're really trying to get at some underlying questions. 00:04:57.480 --> 00:05:00.060 align:middle line:84% How much energy is used in buildings? 00:05:00.060 --> 00:05:03.060 align:middle line:84% How much more efficient can buildings be? 00:05:03.060 --> 00:05:06.420 align:middle line:84% What specific activities in buildings lead to energy use? 00:05:06.420 --> 00:05:09.990 align:middle line:84% And we will examine whether or not it leads to energy waste. 00:05:09.990 --> 00:05:12.270 align:middle line:84% And finally, how can we motivate individual users 00:05:12.270 --> 00:05:15.180 align:middle line:90% to save energy in buildings? 00:05:15.180 --> 00:05:17.640 align:middle line:84% So just to highlight for a moment 00:05:17.640 --> 00:05:19.990 align:middle line:84% the role of buildings in the economy, 00:05:19.990 --> 00:05:23.850 align:middle line:84% this is our familiar Sankey diagram, the US energy 00:05:23.850 --> 00:05:27.360 align:middle line:84% economy being roughly about 97 quads. 00:05:27.360 --> 00:05:30.300 align:middle line:84% If you look at the final uses here, 00:05:30.300 --> 00:05:32.520 align:middle line:84% the final uses for buildings are generally 00:05:32.520 --> 00:05:36.240 align:middle line:84% categorized as residential and commercial put together. 00:05:36.240 --> 00:05:38.280 align:middle line:84% That's about 20 quads, which means 00:05:38.280 --> 00:05:41.490 align:middle line:84% it's responsible for about 20% of the total energy 00:05:41.490 --> 00:05:45.090 align:middle line:84% going into the economy, and about 30% of our final 00:05:45.090 --> 00:05:48.090 align:middle line:84% uses if you take these two as a proportion of all 00:05:48.090 --> 00:05:53.250 align:middle line:84% the various pink boxes representing final consumption. 00:05:53.250 --> 00:05:56.160 align:middle line:84% Of course, as a proportion of electricity use, 00:05:56.160 --> 00:05:59.130 align:middle line:84% residential and commercial buildings actually tend to use 00:05:59.130 --> 00:06:01.260 align:middle line:84% a much larger proportion of the energy-- 00:06:01.260 --> 00:06:04.140 align:middle line:90% it looks like north of 70%-- 00:06:04.140 --> 00:06:06.810 align:middle line:84% because industrial uses and transportation 00:06:06.810 --> 00:06:10.200 align:middle line:84% tend to use fossil fuels like petroleum and natural gas 00:06:10.200 --> 00:06:11.350 align:middle line:90% or oil. 00:06:11.350 --> 00:06:13.800 align:middle line:84% So most of the electricity that we generate actually 00:06:13.800 --> 00:06:16.900 align:middle line:90% goes into buildings. 00:06:16.900 --> 00:06:20.890 align:middle line:84% And just to highlight what the users' uses of energy 00:06:20.890 --> 00:06:23.620 align:middle line:84% are in our buildings, this is a Sankey diagram 00:06:23.620 --> 00:06:25.780 align:middle line:84% specifically for buildings, specifically 00:06:25.780 --> 00:06:27.727 align:middle line:90% for commercial buildings. 00:06:27.727 --> 00:06:29.560 align:middle line:84% And this is actually a relatively old report 00:06:29.560 --> 00:06:31.690 align:middle line:84% from Pacific Northwest National Labs. 00:06:31.690 --> 00:06:34.820 align:middle line:84% But I'm guessing it hasn't changed too much over time. 00:06:34.820 --> 00:06:38.510 align:middle line:84% And if you look at this, we have input coal, natural gas, 00:06:38.510 --> 00:06:40.790 align:middle line:90% petroleum, natural gas. 00:06:40.790 --> 00:06:42.880 align:middle line:84% And this is all going through electric utilities. 00:06:42.880 --> 00:06:44.338 align:middle line:84% And these arrows here on the bottom 00:06:44.338 --> 00:06:47.220 align:middle line:84% are natural gas, petroleum, and biomass going directly 00:06:47.220 --> 00:06:49.100 align:middle line:84% into the commercial building sector. 00:06:49.100 --> 00:06:51.610 align:middle line:84% And you can see all the uses here on the right. 00:06:51.610 --> 00:06:55.180 align:middle line:84% We will focus in on this further. 00:06:55.180 --> 00:06:57.660 align:middle line:84% And if you look at what the total energy that's 00:06:57.660 --> 00:06:59.850 align:middle line:84% delivered to commercial customers is, 00:06:59.850 --> 00:07:02.040 align:middle line:84% you can see that it's really a grab bag 00:07:02.040 --> 00:07:04.260 align:middle line:90% of many different energy uses. 00:07:04.260 --> 00:07:06.690 align:middle line:84% Half of it looks like electricity. 00:07:06.690 --> 00:07:08.880 align:middle line:84% Half of it looks like fossil fuels that 00:07:08.880 --> 00:07:11.590 align:middle line:90% are combusted directly on site. 00:07:11.590 --> 00:07:14.160 align:middle line:84% And you can see that a significant portion of the uses 00:07:14.160 --> 00:07:16.890 align:middle line:84% are for space cooling, ventilation, lighting, 00:07:16.890 --> 00:07:18.840 align:middle line:90% refrigeration, office equipment. 00:07:18.840 --> 00:07:21.450 align:middle line:84% And then most of our natural gas goes 00:07:21.450 --> 00:07:24.390 align:middle line:84% to do space heating, water heating, and other uses-- also 00:07:24.390 --> 00:07:25.740 align:middle line:90% cooking. 00:07:25.740 --> 00:07:29.400 align:middle line:84% The petroleum or coal is still used in many countries, 00:07:29.400 --> 00:07:31.350 align:middle line:84% but less so in the United States. 00:07:31.350 --> 00:07:34.200 align:middle line:84% It's almost all entirely going to be space heating and water 00:07:34.200 --> 00:07:34.800 align:middle line:90% heating. 00:07:34.800 --> 00:07:36.690 align:middle line:84% And then there's a portion of biomass. 00:07:36.690 --> 00:07:38.670 align:middle line:84% That's essentially wood stoves, which 00:07:38.670 --> 00:07:40.320 align:middle line:90% is this little sliver here. 00:07:40.320 --> 00:07:42.540 align:middle line:84% And of course, the smallest sliver 00:07:42.540 --> 00:07:44.820 align:middle line:90% is unfortunately renewables now. 00:07:44.820 --> 00:07:47.670 align:middle line:84% But we hope to perhaps increase that as we 00:07:47.670 --> 00:07:52.320 align:middle line:84% have energy generation in homes occurring at a greater 00:07:52.320 --> 00:07:54.450 align:middle line:90% scale with rooftop solar. 00:07:54.450 --> 00:07:56.220 align:middle line:84% If you look at the residential sector, 00:07:56.220 --> 00:07:59.010 align:middle line:84% again, we have electric utilities here at the top. 00:07:59.010 --> 00:08:02.940 align:middle line:84% And we have the direct delivery of fuels at the bottom. 00:08:02.940 --> 00:08:06.630 align:middle line:84% And you can see if we focus in on residential buildings 00:08:06.630 --> 00:08:09.180 align:middle line:84% from this Pacific Northwest National Lab report, 00:08:09.180 --> 00:08:11.623 align:middle line:84% you can see again that there's many different activities 00:08:11.623 --> 00:08:14.040 align:middle line:84% occurring in buildings-- space heating, cooling, lighting, 00:08:14.040 --> 00:08:15.780 align:middle line:90% refrigeration, and so on. 00:08:15.780 --> 00:08:17.480 align:middle line:90% All of these are the same. 00:08:17.480 --> 00:08:20.400 align:middle line:84% Wood solar is a larger portion of the energy 00:08:20.400 --> 00:08:22.790 align:middle line:84% use for residential buildings than it 00:08:22.790 --> 00:08:24.750 align:middle line:90% is for commercial buildings. 00:08:24.750 --> 00:08:26.990 align:middle line:84% But this is to point out that buildings 00:08:26.990 --> 00:08:31.460 align:middle line:84% are highly integrated objects or tools 00:08:31.460 --> 00:08:33.822 align:middle line:84% that have basically been engineered 00:08:33.822 --> 00:08:35.030 align:middle line:90% for lots of different things. 00:08:35.030 --> 00:08:35.990 align:middle line:90% They provide shelter. 00:08:35.990 --> 00:08:37.039 align:middle line:90% They provide habitat. 00:08:37.039 --> 00:08:37.820 align:middle line:90% They provide home. 00:08:37.820 --> 00:08:41.299 align:middle line:84% This is where we live, work, play, entertainment. 00:08:41.299 --> 00:08:43.370 align:middle line:84% And so we have lots of different uses 00:08:43.370 --> 00:08:44.750 align:middle line:90% we're trying to accomplish. 00:08:44.750 --> 00:08:46.640 align:middle line:84% And what we want to do is also reduce 00:08:46.640 --> 00:08:49.040 align:middle line:84% the energy use or greenhouse gas emission footprint 00:08:49.040 --> 00:08:51.260 align:middle line:90% of this sector. 00:08:51.260 --> 00:08:54.530 align:middle line:84% Just to give you a final sense of the importance of buildings, 00:08:54.530 --> 00:08:56.180 align:middle line:84% if you look back at the Williams et al. 00:08:56.180 --> 00:09:00.260 align:middle line:84% 2020 Deep Decarbonization Pathways or Carbon Neutral 00:09:00.260 --> 00:09:02.720 align:middle line:84% Pathways in the United States, again, we 00:09:02.720 --> 00:09:06.800 align:middle line:84% have this 2020 reference case, this 2050 100% renewable case. 00:09:06.800 --> 00:09:10.280 align:middle line:84% But if we want to achieve decarbonization, 00:09:10.280 --> 00:09:12.230 align:middle line:84% or 100% renewables, we essentially 00:09:12.230 --> 00:09:15.680 align:middle line:84% need to decrease our electricity use by half. 00:09:15.680 --> 00:09:18.980 align:middle line:84% That has to become much more efficient by use of heat pumps 00:09:18.980 --> 00:09:20.900 align:middle line:84% and other more efficient technologies. 00:09:20.900 --> 00:09:23.450 align:middle line:84% We essentially have to eliminate our use of natural gas 00:09:23.450 --> 00:09:25.010 align:middle line:90% pipelined into homes. 00:09:25.010 --> 00:09:30.680 align:middle line:84% We need to actually increase our biomass use through electricity 00:09:30.680 --> 00:09:31.520 align:middle line:90% mostly. 00:09:31.520 --> 00:09:34.023 align:middle line:84% And again, we have to make our homes much, 00:09:34.023 --> 00:09:36.440 align:middle line:84% much more efficient, or make our buildings much, much more 00:09:36.440 --> 00:09:37.460 align:middle line:90% efficient. 00:09:37.460 --> 00:09:39.020 align:middle line:84% So the key message to take home here 00:09:39.020 --> 00:09:41.210 align:middle line:84% is that we actually have to use half as much energy. 00:09:41.210 --> 00:09:45.610 align:middle line:84% And the half that we do use has to become much more efficient. 00:09:45.610 --> 00:09:48.690 align:middle line:84% So just to give you a sense of how we actually lose energy 00:09:48.690 --> 00:09:50.460 align:middle line:84% to the environment, and why are we 00:09:50.460 --> 00:09:53.190 align:middle line:84% continually having to heat and cool our homes, 00:09:53.190 --> 00:09:56.400 align:middle line:84% there's basically three ways that heat transfer occurs. 00:09:56.400 --> 00:09:58.860 align:middle line:84% This is how our heating energy is lost 00:09:58.860 --> 00:10:00.957 align:middle line:84% or what we call our heating load. 00:10:00.957 --> 00:10:02.790 align:middle line:84% There's three ways that we gain or lose heat 00:10:02.790 --> 00:10:04.207 align:middle line:84% from the house in the environment. 00:10:04.207 --> 00:10:07.230 align:middle line:84% It's either ventilation, through conduction, infiltration, which 00:10:07.230 --> 00:10:08.580 align:middle line:90% is air moving in and out-- 00:10:08.580 --> 00:10:11.430 align:middle line:84% essentially, a drafty door or drafty window 00:10:11.430 --> 00:10:14.310 align:middle line:84% loses energy to the environment because our warm energy 00:10:14.310 --> 00:10:16.530 align:middle line:84% is being leaked out to the cool environment. 00:10:16.530 --> 00:10:19.530 align:middle line:84% Or if it's hot outside, we're losing the energy 00:10:19.530 --> 00:10:22.770 align:middle line:84% we use to cool the air outside and equilibrates 00:10:22.770 --> 00:10:24.817 align:middle line:90% to the environment. 00:10:24.817 --> 00:10:27.150 align:middle line:84% Or there is conduction, which is where the heat actually 00:10:27.150 --> 00:10:29.670 align:middle line:84% is conducted out through materials. 00:10:29.670 --> 00:10:32.610 align:middle line:84% Molecules excite, basically, the neighboring molecules. 00:10:32.610 --> 00:10:34.590 align:middle line:84% This is what happens to your external sidewalls 00:10:34.590 --> 00:10:37.060 align:middle line:90% and the ground slab or the roof. 00:10:37.060 --> 00:10:39.550 align:middle line:84% And then radiation-- this is essentially 00:10:39.550 --> 00:10:42.160 align:middle line:84% a process where we do gain some heat, let's say, 00:10:42.160 --> 00:10:44.260 align:middle line:84% from radiation being absorbed by homes. 00:10:44.260 --> 00:10:46.207 align:middle line:84% But also, we know when our houses are warmer 00:10:46.207 --> 00:10:48.040 align:middle line:84% than the environment, they're radiating heat 00:10:48.040 --> 00:10:49.060 align:middle line:90% to the environment. 00:10:49.060 --> 00:10:52.120 align:middle line:84% And there's a good paper that gives a detailed breakdown 00:10:52.120 --> 00:10:55.210 align:middle line:84% for some of these fundamental physical mechanisms 00:10:55.210 --> 00:10:57.880 align:middle line:84% if you're more interested in that. 00:10:57.880 --> 00:11:00.150 align:middle line:84% And the key point that I like that MacKay makes 00:11:00.150 --> 00:11:01.860 align:middle line:84% is that conduction and ventilation 00:11:01.860 --> 00:11:03.750 align:middle line:84% depend on the temperature difference 00:11:03.750 --> 00:11:05.520 align:middle line:84% between inside and outside temperature, 00:11:05.520 --> 00:11:07.440 align:middle line:84% while radiation depends on the area. 00:11:07.440 --> 00:11:09.500 align:middle line:84% So you have this basic breakdown of some 00:11:09.500 --> 00:11:10.500 align:middle line:90% of the factors involved. 00:11:10.500 --> 00:11:13.260 align:middle line:84% Conduction is area times a U value 00:11:13.260 --> 00:11:17.730 align:middle line:84% times the difference in temperature times time. 00:11:17.730 --> 00:11:21.030 align:middle line:84% Ventilation is the volume times the rate, 00:11:21.030 --> 00:11:24.510 align:middle line:84% I think, that the volume is being moved out-- 00:11:24.510 --> 00:11:27.930 align:middle line:84% or sorry, the number of ways the energy could be 00:11:27.930 --> 00:11:31.200 align:middle line:90% lost times delta T times time. 00:11:31.200 --> 00:11:33.933 align:middle line:84% And radiation is area times solar intensity. 00:11:33.933 --> 00:11:35.850 align:middle line:84% Of course, the way it's written here in MacKay 00:11:35.850 --> 00:11:38.183 align:middle line:84% is to highlight the fact that conduction and ventilation 00:11:38.183 --> 00:11:44.260 align:middle line:84% both depend on the delta T, the delta temperature times time. 00:11:44.260 --> 00:11:46.980 align:middle line:84% And so this is how MacKay basically breaks down 00:11:46.980 --> 00:11:50.820 align:middle line:84% how his house lost energy in 2007 00:11:50.820 --> 00:11:54.730 align:middle line:84% and how he tries to tackle this problem of energy efficiency. 00:11:54.730 --> 00:11:56.370 align:middle line:84% It breaks down the horizontal surfaces 00:11:56.370 --> 00:11:59.040 align:middle line:84% to the roofs, the floors, vertical surfaces 00:11:59.040 --> 00:12:01.260 align:middle line:84% to the walls, thin walls, glazed doors, windows, 00:12:01.260 --> 00:12:04.530 align:middle line:84% double glazed windows, and then calculates the leakiness-- 00:12:04.530 --> 00:12:06.940 align:middle line:84% that is, the number of air changes per hour. 00:12:06.940 --> 00:12:09.900 align:middle line:84% So you can calculate the meters squared in terms of area. 00:12:09.900 --> 00:12:15.300 align:middle line:84% The U value is an indication of the power transfer 00:12:15.300 --> 00:12:17.310 align:middle line:84% depending on difference in temperature. 00:12:17.310 --> 00:12:21.060 align:middle line:84% So it's watts per meter squared divided by degrees Celsius. 00:12:21.060 --> 00:12:23.550 align:middle line:84% And that gives us the leakiness if we multiply 00:12:23.550 --> 00:12:26.130 align:middle line:84% area times U value of watts, which 00:12:26.130 --> 00:12:29.340 align:middle line:84% is the power being lost for every degree Celsius 00:12:29.340 --> 00:12:30.420 align:middle line:90% difference. 00:12:30.420 --> 00:12:32.640 align:middle line:84% And with the ventilation, we have the number 00:12:32.640 --> 00:12:34.390 align:middle line:90% of air changes per hour. 00:12:34.390 --> 00:12:38.160 align:middle line:84% So we have a volume of 80 meters cubed in the bedrooms. 00:12:38.160 --> 00:12:41.760 align:middle line:84% We want to change the air in there half every per hour 00:12:41.760 --> 00:12:45.700 align:middle line:84% or change the entire room volume once every two hours. 00:12:45.700 --> 00:12:47.490 align:middle line:84% And that gives us the leakiness in terms 00:12:47.490 --> 00:12:51.190 align:middle line:90% of watts per degrees Celsius. 00:12:51.190 --> 00:12:53.950 align:middle line:84% What MacKay calculates is that the main ways 00:12:53.950 --> 00:12:56.920 align:middle line:84% that he loses heat in his house in Cambridge, 00:12:56.920 --> 00:13:00.355 align:middle line:84% the UK, which is similar to the climate of Boston, 00:13:00.355 --> 00:13:02.920 align:middle line:84% is that he's losing about 78% of its energy 00:13:02.920 --> 00:13:05.710 align:middle line:84% through production and about 22% of its energy 00:13:05.710 --> 00:13:09.090 align:middle line:90% through ventilation changes. 00:13:09.090 --> 00:13:11.090 align:middle line:84% And so what he does to try to reduce 00:13:11.090 --> 00:13:14.690 align:middle line:84% the energy loss of this house is to add cavity wall insulation. 00:13:14.690 --> 00:13:16.880 align:middle line:84% He increases the roof's insulation. 00:13:16.880 --> 00:13:19.040 align:middle line:84% He adds a new storm door and replaces 00:13:19.040 --> 00:13:21.770 align:middle line:84% the back door and window with double glazed windows. 00:13:21.770 --> 00:13:24.680 align:middle line:84% I want to emphasize here that energy efficiency is not 00:13:24.680 --> 00:13:27.110 align:middle line:84% necessarily a high tech endeavor. 00:13:27.110 --> 00:13:29.660 align:middle line:84% It can be a high tech endeavor, but at the same time, 00:13:29.660 --> 00:13:33.350 align:middle line:84% all these things that he does in 2007 are fairly simple things. 00:13:33.350 --> 00:13:35.810 align:middle line:84% This is essentially a technology that you can acquire 00:13:35.810 --> 00:13:37.610 align:middle line:90% from your hardware store. 00:13:37.610 --> 00:13:39.320 align:middle line:84% Having said that, there are startups 00:13:39.320 --> 00:13:41.570 align:middle line:84% that actually drive cars around, like the Google 00:13:41.570 --> 00:13:43.070 align:middle line:90% cars that do street view. 00:13:43.070 --> 00:13:48.470 align:middle line:84% And they actually measure the conductive and radiative losses 00:13:48.470 --> 00:13:51.530 align:middle line:84% of houses using infrared cameras or guns. 00:13:51.530 --> 00:13:53.300 align:middle line:84% And so you can basically drive around 00:13:53.300 --> 00:13:55.405 align:middle line:84% and map out the city from the street, 00:13:55.405 --> 00:13:57.030 align:middle line:84% and see where people are losing energy. 00:13:57.030 --> 00:13:58.250 align:middle line:84% And there's a number of energy startups 00:13:58.250 --> 00:14:00.290 align:middle line:84% I think that are trying to use that technology 00:14:00.290 --> 00:14:03.590 align:middle line:84% to try to identify homes that might be-- 00:14:03.590 --> 00:14:07.178 align:middle line:84% to essentially acquire customers for energy efficiency. 00:14:07.178 --> 00:14:08.720 align:middle line:84% So just to give you a sense of what's 00:14:08.720 --> 00:14:11.090 align:middle line:84% possible with energy efficiency measures now, 00:14:11.090 --> 00:14:12.770 align:middle line:90% this is from an old report. 00:14:12.770 --> 00:14:15.950 align:middle line:84% I think it's from one of the national labs. 00:14:15.950 --> 00:14:18.290 align:middle line:84% And this shows, actually, we have 00:14:18.290 --> 00:14:20.330 align:middle line:84% an R value, which is the resistance value, 00:14:20.330 --> 00:14:23.690 align:middle line:84% or 1 over the U value, 1 over the weakness. 00:14:23.690 --> 00:14:27.470 align:middle line:84% And you can see that the technologies here are basically 00:14:27.470 --> 00:14:31.250 align:middle line:84% net energy losers, but they are increasing 00:14:31.250 --> 00:14:34.640 align:middle line:84% amounts of resistance over time starting in 1970, 00:14:34.640 --> 00:14:35.930 align:middle line:90% going to 1990. 00:14:35.930 --> 00:14:38.540 align:middle line:84% We have very poor single pane windows. 00:14:38.540 --> 00:14:41.090 align:middle line:84% We get a much better improvement from double pane windows. 00:14:41.090 --> 00:14:43.460 align:middle line:84% But we're getting to low E windows, super windows, 00:14:43.460 --> 00:14:46.760 align:middle line:84% and super windows that are essentially net energy losers, 00:14:46.760 --> 00:14:48.710 align:middle line:84% but we're decreasing how much we're losing. 00:14:48.710 --> 00:14:53.180 align:middle line:84% And projected time, I guess, in the last 10 years-- 00:14:53.180 --> 00:14:55.940 align:middle line:84% we're expected to get to a very high resistance super windows. 00:14:55.940 --> 00:14:59.330 align:middle line:84% And so I'm not quite sure of the current state of technology, 00:14:59.330 --> 00:15:02.480 align:middle line:84% but I suspect that we are well above where we 00:15:02.480 --> 00:15:05.650 align:middle line:90% were with double pane windows. 00:15:05.650 --> 00:15:08.350 align:middle line:84% Just to give you a sense of some of the R values included 00:15:08.350 --> 00:15:11.800 align:middle line:84% in a model building code, one area that I've said to you 00:15:11.800 --> 00:15:13.900 align:middle line:84% that local governments and cities can actually 00:15:13.900 --> 00:15:17.650 align:middle line:84% do a lot of work, or implement policies that actually 00:15:17.650 --> 00:15:19.060 align:middle line:90% change the building stock-- 00:15:19.060 --> 00:15:20.530 align:middle line:90% are their building codes. 00:15:20.530 --> 00:15:22.720 align:middle line:84% All of our buildings have to be built 00:15:22.720 --> 00:15:25.180 align:middle line:84% to a fire code, an electrical code, 00:15:25.180 --> 00:15:28.060 align:middle line:84% and in the places that have earthquakes, a seismic code. 00:15:28.060 --> 00:15:30.190 align:middle line:84% These are the fundamental codes that govern 00:15:30.190 --> 00:15:31.720 align:middle line:90% how our buildings are built. 00:15:31.720 --> 00:15:34.833 align:middle line:84% In Florida, after Hurricane Andrew in 1992, 00:15:34.833 --> 00:15:37.000 align:middle line:84% it actually developed some of the strongest building 00:15:37.000 --> 00:15:39.640 align:middle line:84% codes in the country because the hurricane revealed 00:15:39.640 --> 00:15:41.830 align:middle line:84% that relatively simple interventions in the building 00:15:41.830 --> 00:15:45.400 align:middle line:84% code would result in much better and stronger homes. 00:15:45.400 --> 00:15:48.400 align:middle line:84% But this is also a key area where local governments 00:15:48.400 --> 00:15:50.080 align:middle line:90% and cities have jurisdiction. 00:15:50.080 --> 00:15:53.500 align:middle line:84% They're allowed to actually implement building codes 00:15:53.500 --> 00:15:56.260 align:middle line:84% in a way that the state and federal governments cannot. 00:15:56.260 --> 00:15:59.770 align:middle line:84% So just to give you a sense of the R values in model buildings 00:15:59.770 --> 00:16:03.130 align:middle line:84% based on what two International Energy Conservation 00:16:03.130 --> 00:16:07.000 align:middle line:84% Codes require, there's a code from 2000. 00:16:07.000 --> 00:16:09.160 align:middle line:84% There's an upgraded code in 2012. 00:16:09.160 --> 00:16:11.050 align:middle line:84% And there's proposed changes further. 00:16:11.050 --> 00:16:12.760 align:middle line:84% This has been a key area of research 00:16:12.760 --> 00:16:14.460 align:middle line:90% in the last 10 or 12 years. 00:16:14.460 --> 00:16:16.960 align:middle line:84% The federal government, since the ARRA stimulus in the Obama 00:16:16.960 --> 00:16:19.900 align:middle line:84% administration, has pushed building codes very hard 00:16:19.900 --> 00:16:21.830 align:middle line:90% to improve very quickly. 00:16:21.830 --> 00:16:24.400 align:middle line:84% So you can see that the R values of ceilings 00:16:24.400 --> 00:16:27.010 align:middle line:84% have essentially doubled from 2000 to the proposed 00:16:27.010 --> 00:16:30.730 align:middle line:84% code from this Golbazi/Aktas paper 00:16:30.730 --> 00:16:33.160 align:middle line:84% because see that above ground walls have essentially 00:16:33.160 --> 00:16:35.980 align:middle line:84% tripled in their resistance to heat losses. 00:16:35.980 --> 00:16:37.750 align:middle line:84% Basement walls have essentially doubled. 00:16:37.750 --> 00:16:39.010 align:middle line:90% Floors have doubled. 00:16:39.010 --> 00:16:40.270 align:middle line:90% Roofs have doubled. 00:16:40.270 --> 00:16:44.320 align:middle line:84% And mass walls have developed a code value for the first time. 00:16:44.320 --> 00:16:46.930 align:middle line:84% These are all ways that when the local government simply 00:16:46.930 --> 00:16:50.080 align:middle line:84% specifies you have to build to this standard 00:16:50.080 --> 00:16:52.570 align:middle line:84% that the local development industry and contractors have 00:16:52.570 --> 00:16:54.910 align:middle line:90% to respond to that. 00:16:54.910 --> 00:16:57.580 align:middle line:84% So this is why I had you calculate heating degree 00:16:57.580 --> 00:16:59.170 align:middle line:90% days in the problem set. 00:16:59.170 --> 00:17:01.600 align:middle line:84% If you look at MacKay's house, he 00:17:01.600 --> 00:17:03.640 align:middle line:84% shows that in Cambridge, which again 00:17:03.640 --> 00:17:06.849 align:middle line:84% is similar to the climate of Boston, for most of the year, 00:17:06.849 --> 00:17:09.130 align:middle line:84% you can see that he's doing heating in his house. 00:17:09.130 --> 00:17:13.990 align:middle line:84% He has 3,200 degree days of heating and about 91 degree 00:17:13.990 --> 00:17:16.089 align:middle line:90% days of cooling required. 00:17:16.089 --> 00:17:21.040 align:middle line:84% If you look at, I think, what happens after his energy 00:17:21.040 --> 00:17:23.260 align:middle line:84% efficiency installations, he goes 00:17:23.260 --> 00:17:27.160 align:middle line:84% to about 2,200 or 2,300 degrees days of heating 00:17:27.160 --> 00:17:29.710 align:middle line:90% and is unaffected by cooling. 00:17:29.710 --> 00:17:31.570 align:middle line:84% So this is to say that if you simply 00:17:31.570 --> 00:17:34.040 align:middle line:84% change the base temperature, which is what I did, 00:17:34.040 --> 00:17:35.428 align:middle line:84% which you did in the problem set, 00:17:35.428 --> 00:17:37.720 align:middle line:84% you can actually reduce how much time is heating, which 00:17:37.720 --> 00:17:39.670 align:middle line:84% is to say that we measured everything 00:17:39.670 --> 00:17:41.620 align:middle line:84% against the temperature we'd like to keep 00:17:41.620 --> 00:17:43.660 align:middle line:90% our indoor temperature at. 00:17:43.660 --> 00:17:45.910 align:middle line:84% So this looks like around 65 degrees. 00:17:45.910 --> 00:17:49.300 align:middle line:84% And this is about 2 degrees Celsius lower. 00:17:49.300 --> 00:17:51.850 align:middle line:84% And if you simply change the thermostat setting, what you're 00:17:51.850 --> 00:17:54.610 align:middle line:84% trying to target for maintaining indoor temperature, 00:17:54.610 --> 00:17:56.560 align:middle line:84% you can actually significantly decrease 00:17:56.560 --> 00:17:59.980 align:middle line:84% the amount of heating or cooling required 00:17:59.980 --> 00:18:01.700 align:middle line:90% to make up the heat loss. 00:18:01.700 --> 00:18:06.250 align:middle line:84% Remember that we looked at conduction and radiation 00:18:06.250 --> 00:18:09.680 align:middle line:84% dependent on the delta T times time. 00:18:09.680 --> 00:18:12.880 align:middle line:84% If we change simply the delta T that we're 00:18:12.880 --> 00:18:15.070 align:middle line:84% trying to heat or cool to, then we 00:18:15.070 --> 00:18:19.600 align:middle line:84% can reduce a lot of our heating and cooling energy use. 00:18:19.600 --> 00:18:22.970 align:middle line:84% This is also why there's a very large push on heat pumps. 00:18:22.970 --> 00:18:26.645 align:middle line:84% This is a diagram from a book from Randolph and Masters. 00:18:26.645 --> 00:18:28.645 align:middle line:84% And they basically have this very simple diagram 00:18:28.645 --> 00:18:29.590 align:middle line:90% that I like. 00:18:29.590 --> 00:18:31.750 align:middle line:84% It basically shows how a refrigerator 00:18:31.750 --> 00:18:34.720 align:middle line:84% acts as an air conditioner, but it heats the world. 00:18:34.720 --> 00:18:37.600 align:middle line:84% We're air conditioning the space inside a refrigerator. 00:18:37.600 --> 00:18:40.600 align:middle line:84% And the back of your refrigerator is rejecting heat. 00:18:40.600 --> 00:18:42.520 align:middle line:84% Of course, we can flip this thing around. 00:18:42.520 --> 00:18:46.120 align:middle line:84% And we could actually cool the outside world 00:18:46.120 --> 00:18:47.920 align:middle line:84% and heat the inside of our house. 00:18:47.920 --> 00:18:49.820 align:middle line:84% This is essentially how a heat pump works. 00:18:49.820 --> 00:18:51.640 align:middle line:84% It's the same thing as a refrigerator. 00:18:51.640 --> 00:18:53.440 align:middle line:84% It's the same thing as an air conditioner, 00:18:53.440 --> 00:18:55.030 align:middle line:84% but the key difference in a heat pump 00:18:55.030 --> 00:18:57.370 align:middle line:84% is you can operate it in both directions. 00:18:57.370 --> 00:19:00.910 align:middle line:84% I think I told you the story before of research 00:19:00.910 --> 00:19:03.430 align:middle line:84% I did in Brazil that looked at electricity use 00:19:03.430 --> 00:19:04.913 align:middle line:90% in informal settlements. 00:19:04.913 --> 00:19:06.580 align:middle line:84% In informal settlements, a lot of people 00:19:06.580 --> 00:19:08.440 align:middle line:84% don't pay for their electricity use. 00:19:08.440 --> 00:19:12.130 align:middle line:84% 40% of all electricity in Brazil is unpaid for 00:19:12.130 --> 00:19:13.958 align:middle line:90% or stolen from the grid. 00:19:13.958 --> 00:19:16.000 align:middle line:84% And so people actually have very little incentive 00:19:16.000 --> 00:19:16.665 align:middle line:90% to save energy. 00:19:16.665 --> 00:19:18.040 align:middle line:84% So people use their refrigerators 00:19:18.040 --> 00:19:21.550 align:middle line:84% not only to store food or to even cool their home 00:19:21.550 --> 00:19:23.540 align:middle line:84% because they can just leave the doors open, 00:19:23.540 --> 00:19:26.080 align:middle line:84% but people actually use refrigerators to dry clothes. 00:19:26.080 --> 00:19:29.050 align:middle line:84% They put dry clothes on the hot condenser 00:19:29.050 --> 00:19:31.300 align:middle line:84% on the back, or the heating coils, 00:19:31.300 --> 00:19:33.490 align:middle line:90% or the radiating heat fins. 00:19:33.490 --> 00:19:35.350 align:middle line:90% And those actually radiate heat. 00:19:35.350 --> 00:19:38.120 align:middle line:84% And they use them to dry clothes sometimes. 00:19:38.120 --> 00:19:40.370 align:middle line:84% So there's been a very large push 00:19:40.370 --> 00:19:44.360 align:middle line:84% in policy now to use heat pumps because unlike burning fuels 00:19:44.360 --> 00:19:49.910 align:middle line:84% directly, you actually get about four times the heating 00:19:49.910 --> 00:19:53.030 align:middle line:84% or cooling effect for the same unit of energy in a heat pump. 00:19:53.030 --> 00:19:54.920 align:middle line:84% And so the MacKay book explains why 00:19:54.920 --> 00:19:58.130 align:middle line:84% heat pumps are what we're talking about in terms 00:19:58.130 --> 00:20:00.620 align:middle line:84% of why we're generating more heating 00:20:00.620 --> 00:20:02.740 align:middle line:84% and cooling energy has to do with entropy. 00:20:02.740 --> 00:20:04.730 align:middle line:84% The MacKay book goes into more detail 00:20:04.730 --> 00:20:08.030 align:middle line:90% if you're interested in that. 00:20:08.030 --> 00:20:11.420 align:middle line:84% Emphasize why we are trying to treat our climate-- 00:20:11.420 --> 00:20:13.700 align:middle line:84% I think instinctively, we know that the United States 00:20:13.700 --> 00:20:17.940 align:middle line:84% is defined as quite different climate zones. 00:20:17.940 --> 00:20:21.350 align:middle line:84% We have a marine zone, or almost Mediterranean zone 00:20:21.350 --> 00:20:22.490 align:middle line:90% on the West Coast. 00:20:22.490 --> 00:20:26.420 align:middle line:84% We have our very hot, dry, or mixed dry environment. 00:20:26.420 --> 00:20:29.030 align:middle line:84% We have cold or very cold environment 00:20:29.030 --> 00:20:32.280 align:middle line:84% in the upper Midwest, Upper West, and New England. 00:20:32.280 --> 00:20:33.700 align:middle line:90% We have a mixed humid climate. 00:20:33.700 --> 00:20:35.712 align:middle line:84% And we have a hot, humid climate. 00:20:35.712 --> 00:20:38.170 align:middle line:84% The reason why this matters for building design or building 00:20:38.170 --> 00:20:40.000 align:middle line:84% engineering is that engineers actually 00:20:40.000 --> 00:20:42.490 align:middle line:84% use charts that are called psychometric charts. 00:20:42.490 --> 00:20:44.170 align:middle line:84% And those are charts that actually 00:20:44.170 --> 00:20:47.110 align:middle line:84% detail how comfortable people feel in mixes 00:20:47.110 --> 00:20:49.133 align:middle line:90% of humidity and temperature. 00:20:49.133 --> 00:20:51.550 align:middle line:84% So the reason why we look at these different climate zones 00:20:51.550 --> 00:20:53.920 align:middle line:84% is that we know our energy use is closely related 00:20:53.920 --> 00:20:57.527 align:middle line:84% to the humidity and temperature of the outdoor environment. 00:20:57.527 --> 00:20:59.860 align:middle line:84% And that's what our buildings are trying to correct for. 00:20:59.860 --> 00:21:02.200 align:middle line:84% So we know that in hot, humid environments 00:21:02.200 --> 00:21:05.320 align:middle line:84% or hot, dry environments, we use much more air conditioning. 00:21:05.320 --> 00:21:07.930 align:middle line:84% We may use dehumidifiers, or our air conditioners 00:21:07.930 --> 00:21:09.700 align:middle line:84% may have to work differently to account 00:21:09.700 --> 00:21:13.550 align:middle line:90% for this humid environment. 00:21:13.550 --> 00:21:17.720 align:middle line:84% The US EIA also defines these climate zones 00:21:17.720 --> 00:21:20.660 align:middle line:84% in slightly different ways, but you can see here on the bottom, 00:21:20.660 --> 00:21:24.220 align:middle line:84% they define their zones in terms of how many cooling degree days 00:21:24.220 --> 00:21:27.680 align:middle line:84% and how many heating degree days our buildings use. 00:21:27.680 --> 00:21:31.340 align:middle line:84% These numbers actually factor into how we measure Energy Star 00:21:31.340 --> 00:21:33.870 align:middle line:84% ratings on buildings because we rate buildings 00:21:33.870 --> 00:21:36.800 align:middle line:84% according to how effectively they're heating or cooling 00:21:36.800 --> 00:21:38.617 align:middle line:84% relative to the environment, but we also 00:21:38.617 --> 00:21:40.700 align:middle line:84% know that our commercial buildings for Energy Star 00:21:40.700 --> 00:21:42.810 align:middle line:84% are located in many different environments. 00:21:42.810 --> 00:21:45.510 align:middle line:84% So we try to score them differently. 00:21:45.510 --> 00:21:47.210 align:middle line:84% So just to show you, the reason why 00:21:47.210 --> 00:21:48.620 align:middle line:84% I had you look at your appliances 00:21:48.620 --> 00:21:51.110 align:middle line:84% briefly is that MacKay estimates the loads 00:21:51.110 --> 00:21:52.862 align:middle line:84% from various electrical appliances. 00:21:52.862 --> 00:21:55.070 align:middle line:84% And you can see it's a pretty simple calculation, OK? 00:21:55.070 --> 00:21:57.362 align:middle line:84% We have these different categories-- cooking, cleaning, 00:21:57.362 --> 00:21:58.190 align:middle line:90% and cooling. 00:21:58.190 --> 00:22:03.290 align:middle line:84% They have a power use, which is kilowatts or joules per second. 00:22:03.290 --> 00:22:06.240 align:middle line:84% We simply multiply times a unit of time-- 00:22:06.240 --> 00:22:07.040 align:middle line:90% here hours. 00:22:07.040 --> 00:22:08.930 align:middle line:84% And then we get kilowatt hours, which 00:22:08.930 --> 00:22:12.990 align:middle line:84% are a measure of energy per person per day. 00:22:12.990 --> 00:22:15.080 align:middle line:84% And so we just multiply it in a spreadsheet. 00:22:15.080 --> 00:22:17.780 align:middle line:84% You can see that the largest users of energy 00:22:17.780 --> 00:22:21.710 align:middle line:84% are the tumble dryer, the freezer, the electric oven, 00:22:21.710 --> 00:22:23.480 align:middle line:90% and the electric cooker. 00:22:23.480 --> 00:22:26.540 align:middle line:84% You can see, on an annual basis for two people, 00:22:26.540 --> 00:22:29.928 align:middle line:84% you get about 4,500 kilowatt hours per person per year. 00:22:29.928 --> 00:22:31.220 align:middle line:90% That's actually relatively low. 00:22:31.220 --> 00:22:32.887 align:middle line:84% I think in the US, the average household 00:22:32.887 --> 00:22:37.597 align:middle line:84% uses about 14,000 kilowatt hours per person per year. 00:22:37.597 --> 00:22:39.680 align:middle line:84% So you can see the average electricity consumption 00:22:39.680 --> 00:22:40.597 align:middle line:90% in the United Kingdom. 00:22:40.597 --> 00:22:42.380 align:middle line:90% It tends-- are relatively lower. 00:22:42.380 --> 00:22:45.470 align:middle line:84% One reason for that might be that MacKay's house has a party 00:22:45.470 --> 00:22:47.240 align:middle line:90% wall, it's built quite densely. 00:22:47.240 --> 00:22:51.810 align:middle line:84% It's a relatively small home by American standards. 00:22:51.810 --> 00:22:54.510 align:middle line:84% So just to show you what some of the technologies 00:22:54.510 --> 00:22:57.120 align:middle line:84% are that might help us understand how we use energy 00:22:57.120 --> 00:23:02.160 align:middle line:84% in buildings, I'm going to show you some of the devices 00:23:02.160 --> 00:23:05.460 align:middle line:84% I use to manage my own home, mostly out of interest 00:23:05.460 --> 00:23:07.050 align:middle line:84% and because I like to show students 00:23:07.050 --> 00:23:09.900 align:middle line:84% every year what some of these different technologies 00:23:09.900 --> 00:23:12.510 align:middle line:90% look like. 00:23:12.510 --> 00:23:13.020 align:middle line:90% OK. 00:23:13.020 --> 00:23:15.570 align:middle line:84% So just to show you what some of these technologies I 00:23:15.570 --> 00:23:20.100 align:middle line:84% use to manage my home look like, I'm going to show you-- 00:23:20.100 --> 00:23:21.388 align:middle line:90% this is a Sense monitor. 00:23:21.388 --> 00:23:23.430 align:middle line:84% This is actually a small monitor that I installed 00:23:23.430 --> 00:23:25.080 align:middle line:90% in my electrical panel box. 00:23:25.080 --> 00:23:27.570 align:middle line:84% And it basically measures the entire energy use 00:23:27.570 --> 00:23:30.450 align:middle line:84% going from the electrical grid into my house. 00:23:30.450 --> 00:23:32.820 align:middle line:84% You can see this is a typical day from 6:00 AM 00:23:32.820 --> 00:23:34.860 align:middle line:90% to about midnight. 00:23:34.860 --> 00:23:37.530 align:middle line:84% And you can see several different things happening. 00:23:37.530 --> 00:23:40.020 align:middle line:84% First, energy use is pretty low in the morning 00:23:40.020 --> 00:23:40.925 align:middle line:90% before we wake up. 00:23:40.925 --> 00:23:43.050 align:middle line:84% What it measures-- you can see what I'm moving here 00:23:43.050 --> 00:23:45.570 align:middle line:90% is the current meter. 00:23:45.570 --> 00:23:48.120 align:middle line:84% This measures 500 watts going into the house. 00:23:48.120 --> 00:23:49.860 align:middle line:84% You see these occasional small cycles. 00:23:49.860 --> 00:23:53.612 align:middle line:84% That's probably a refrigerator cycling to keep the food cool. 00:23:53.612 --> 00:23:55.320 align:middle line:84% And then we wake up, and we start running 00:23:55.320 --> 00:23:56.410 align:middle line:90% a lot of our appliances. 00:23:56.410 --> 00:23:57.510 align:middle line:90% Things go very high. 00:23:57.510 --> 00:23:59.910 align:middle line:84% That could be the tumble dryer coming on in the morning. 00:23:59.910 --> 00:24:02.460 align:middle line:84% It could be a hair dryer coming on. 00:24:02.460 --> 00:24:04.920 align:middle line:84% And then this is probably a dishwasher load 00:24:04.920 --> 00:24:06.930 align:middle line:84% that we set when I leave for work. 00:24:06.930 --> 00:24:08.610 align:middle line:84% You can see throughout the day when 00:24:08.610 --> 00:24:11.730 align:middle line:84% we're away at work or at school, our energy is quite low. 00:24:11.730 --> 00:24:14.610 align:middle line:84% Again, these are refrigerator, cycling, going through. 00:24:14.610 --> 00:24:17.130 align:middle line:84% And then you can see we get home around 6:00 PM. 00:24:17.130 --> 00:24:18.630 align:middle line:84% And then we start turning on lights, 00:24:18.630 --> 00:24:19.890 align:middle line:90% turning on cooking devices. 00:24:19.890 --> 00:24:22.625 align:middle line:84% And our energy load goes up quite high again. 00:24:22.625 --> 00:24:26.610 align:middle line:84% And we probably run the dishwasher or the tumble dryer 00:24:26.610 --> 00:24:28.270 align:middle line:90% at the end of the day again. 00:24:28.270 --> 00:24:31.640 align:middle line:84% This is a small box that goes into the electrical panel. 00:24:31.640 --> 00:24:33.810 align:middle line:90% It gives me a handy dashboard. 00:24:33.810 --> 00:24:37.860 align:middle line:84% It tells me how much energy I'm consuming relative to my bill. 00:24:37.860 --> 00:24:39.960 align:middle line:84% Much to my frustration, it shows I'm 00:24:39.960 --> 00:24:42.240 align:middle line:84% totally average in how much energy I use compared 00:24:42.240 --> 00:24:44.490 align:middle line:90% to other similar homes. 00:24:44.490 --> 00:24:47.370 align:middle line:84% I use less than other Sense homes in Massachusetts. 00:24:47.370 --> 00:24:50.980 align:middle line:84% And I use less than most Sense homes all over the country, 00:24:50.980 --> 00:24:54.440 align:middle line:84% but it gives me some useful ways to manage my energy use. 00:24:54.440 --> 00:24:58.440 align:middle line:84% It shows me when pumps or heat goes on off in my house. 00:24:58.440 --> 00:25:02.490 align:middle line:84% And it also shows me when certain appliances are on 00:25:02.490 --> 00:25:03.990 align:middle line:90% or how much they use. 00:25:03.990 --> 00:25:06.987 align:middle line:84% For example, "always on" represents the vampire load. 00:25:06.987 --> 00:25:09.570 align:middle line:84% These are all the chargers that are plugged into all the walls 00:25:09.570 --> 00:25:10.470 align:middle line:90% all the time. 00:25:10.470 --> 00:25:12.540 align:middle line:84% This is a point that MacKay makes. 00:25:12.540 --> 00:25:15.615 align:middle line:84% But it also shows me how much each of the AC units use. 00:25:15.615 --> 00:25:18.570 align:middle line:84% It shows me how much that applies on a bill basis. 00:25:18.570 --> 00:25:21.750 align:middle line:84% It shows me which appliances use the most. 00:25:21.750 --> 00:25:23.760 align:middle line:84% And it shows me ways that I could possibly 00:25:23.760 --> 00:25:25.260 align:middle line:90% reduce my energy consumption. 00:25:25.260 --> 00:25:28.620 align:middle line:84% Here you can see that my clothes dryer cost about $41 00:25:28.620 --> 00:25:31.240 align:middle line:84% per year, 6% of my electricity use. 00:25:31.240 --> 00:25:35.250 align:middle line:84% And you can see how many times or how often I put it on. 00:25:35.250 --> 00:25:39.750 align:middle line:84% Another device that I use to manage our home electricity use 00:25:39.750 --> 00:25:41.208 align:middle line:90% is a Nest thermostat. 00:25:41.208 --> 00:25:42.750 align:middle line:84% You can see right now, the downstairs 00:25:42.750 --> 00:25:44.190 align:middle line:90% is set for 65 degrees. 00:25:44.190 --> 00:25:47.220 align:middle line:84% Upstairs is set for 63 degrees because we're not upstairs 00:25:47.220 --> 00:25:49.002 align:middle line:90% during the day very much. 00:25:49.002 --> 00:25:50.460 align:middle line:84% If I click on one of these, you can 00:25:50.460 --> 00:25:54.540 align:middle line:84% see that I have a schedule that changes throughout the day. 00:25:54.540 --> 00:25:56.670 align:middle line:84% Obviously, I want it to heat it while we're awake. 00:25:56.670 --> 00:25:59.340 align:middle line:84% And I like to have the house cold when we're asleep. 00:25:59.340 --> 00:26:02.222 align:middle line:84% But also crucially, it's useful that when you go, 00:26:02.222 --> 00:26:04.680 align:middle line:84% let's say, to the airport and you're on your way to a trip, 00:26:04.680 --> 00:26:06.540 align:middle line:84% you realize, oh, I left the thermostat on. 00:26:06.540 --> 00:26:08.490 align:middle line:84% I can actually turn the energy down 00:26:08.490 --> 00:26:10.740 align:middle line:90% in my entire house remotely. 00:26:10.740 --> 00:26:12.520 align:middle line:84% Finally, I have rooftop solar panels. 00:26:12.520 --> 00:26:14.790 align:middle line:84% You can see here in the middle of the day one 00:26:14.790 --> 00:26:17.610 align:middle line:84% set of panels that are facing the east are still 00:26:17.610 --> 00:26:18.900 align:middle line:90% getting a lot of power. 00:26:18.900 --> 00:26:23.430 align:middle line:84% But slowly, as the sun moves over the top of the house 00:26:23.430 --> 00:26:25.650 align:middle line:84% or the roof line of the house, all these panels 00:26:25.650 --> 00:26:28.030 align:middle line:84% here on the right are going to get more energy. 00:26:28.030 --> 00:26:28.860 align:middle line:90% And it's cool. 00:26:28.860 --> 00:26:33.450 align:middle line:84% You can actually see on a weekly basis how much energy, 00:26:33.450 --> 00:26:36.580 align:middle line:90% how much energy is being used. 00:26:36.580 --> 00:26:40.370 align:middle line:84% And you can actually see throughout the week, 00:26:40.370 --> 00:26:43.100 align:middle line:84% I got a nice sunny day with lots of solar energy, 00:26:43.100 --> 00:26:45.350 align:middle line:84% maybe a cloudier day with less solar energy, 00:26:45.350 --> 00:26:47.390 align:middle line:84% and more solar energy throughout the day 00:26:47.390 --> 00:26:49.440 align:middle line:90% the last few days of the week. 00:26:49.440 --> 00:26:51.890 align:middle line:84% There are fancier setups for people. 00:26:51.890 --> 00:26:55.130 align:middle line:84% A lot of electrical energy engineers 00:26:55.130 --> 00:26:57.680 align:middle line:84% like to calculate how much solar is coming into the house, 00:26:57.680 --> 00:26:58.880 align:middle line:90% and how much they're using. 00:26:58.880 --> 00:27:01.130 align:middle line:84% I clearly don't have all these systems integrated. 00:27:01.130 --> 00:27:03.560 align:middle line:84% But this is to point out that all the data we 00:27:03.560 --> 00:27:06.770 align:middle line:84% need to manage our energy efficiency uses 00:27:06.770 --> 00:27:08.450 align:middle line:90% is much easier to get. 00:27:08.450 --> 00:27:12.920 align:middle line:84% It involves installing one device on my electrical panel, 00:27:12.920 --> 00:27:15.440 align:middle line:84% and involves managing my thermostats, 00:27:15.440 --> 00:27:17.090 align:middle line:90% communicating through Wi-Fi. 00:27:17.090 --> 00:27:19.820 align:middle line:84% This is my solar panels communicating to the internet 00:27:19.820 --> 00:27:23.950 align:middle line:84% and sending information to my computer or web app. 00:27:23.950 --> 00:27:24.450 align:middle line:90% OK. 00:27:24.450 --> 00:27:26.100 align:middle line:84% And the last point I want to point out, 00:27:26.100 --> 00:27:29.490 align:middle line:84% the last point I want to make is that a lot of this information 00:27:29.490 --> 00:27:31.380 align:middle line:84% that you need to measure your energy use 00:27:31.380 --> 00:27:34.170 align:middle line:84% is actually on your electricity or natural gas bills. 00:27:34.170 --> 00:27:36.390 align:middle line:84% I know we talked in class about only 1/3 of you 00:27:36.390 --> 00:27:39.030 align:middle line:84% get your bills because the 2/3 of you live in dorms, 00:27:39.030 --> 00:27:41.010 align:middle line:90% or let's say shared apartments. 00:27:41.010 --> 00:27:43.153 align:middle line:84% But if you look at your electricity bill, 00:27:43.153 --> 00:27:45.070 align:middle line:84% for those of you who get them, very carefully, 00:27:45.070 --> 00:27:48.810 align:middle line:84% you can see a number of policy implications on your bill. 00:27:48.810 --> 00:27:51.240 align:middle line:84% There's various charges for energy efficiency, 00:27:51.240 --> 00:27:53.850 align:middle line:84% whether or not you access energy efficiency services. 00:27:53.850 --> 00:27:55.200 align:middle line:90% There's a delivery charge. 00:27:55.200 --> 00:27:57.312 align:middle line:90% There's a fuel charge. 00:27:57.312 --> 00:27:58.770 align:middle line:84% We know all these different charges 00:27:58.770 --> 00:28:02.230 align:middle line:84% are changing over time because of our changing energy markets. 00:28:02.230 --> 00:28:05.790 align:middle line:84% And so I'll probably show you some bills in class. 00:28:05.790 --> 00:28:08.230 align:middle line:84% If only because there's privacy implications, 00:28:08.230 --> 00:28:10.780 align:middle line:84% I don't want to show them on this video. 00:28:10.780 --> 00:28:13.650 align:middle line:84% But let's just think about why buildings, again, are 00:28:13.650 --> 00:28:15.690 align:middle line:90% important in a global sense. 00:28:15.690 --> 00:28:18.990 align:middle line:84% The International Energy Agency did a report in 2020 00:28:18.990 --> 00:28:20.790 align:middle line:90% called "Tracking Buildings." 00:28:20.790 --> 00:28:24.600 align:middle line:84% And they point out that building energy use is not on track 00:28:24.600 --> 00:28:26.640 align:middle line:84% to meet our Paris Climate Agreement goals. 00:28:26.640 --> 00:28:29.880 align:middle line:84% So we focus on different aspects of the report. 00:28:29.880 --> 00:28:32.670 align:middle line:84% We can see that lighting has actually 00:28:32.670 --> 00:28:34.380 align:middle line:90% been a relative success story. 00:28:34.380 --> 00:28:37.020 align:middle line:84% We had other forms of lighting and fluorescent lighting, 00:28:37.020 --> 00:28:39.660 align:middle line:84% but light emitting diodes, LED bulbs, 00:28:39.660 --> 00:28:41.820 align:middle line:90% have shot up remarkably-- 00:28:41.820 --> 00:28:49.710 align:middle line:84% almost to about 50% of lighting sales from 2010 to 2018, 00:28:49.710 --> 00:28:51.510 align:middle line:90% and about 50% of lighting sales. 00:28:51.510 --> 00:28:53.820 align:middle line:84% And they're headed for about 80%. 00:28:53.820 --> 00:28:56.820 align:middle line:84% That is on track for us to meet our sustainable development 00:28:56.820 --> 00:29:00.330 align:middle line:84% scenarios or our Paris Climate agreements. 00:29:00.330 --> 00:29:04.020 align:middle line:84% LEDs are a success story because they're essentially 00:29:04.020 --> 00:29:06.870 align:middle line:84% developed with government research funding, 00:29:06.870 --> 00:29:09.180 align:middle line:84% but they required subsidies in the beginning. 00:29:09.180 --> 00:29:11.820 align:middle line:84% And then as they are produced in scale, 00:29:11.820 --> 00:29:13.620 align:middle line:90% they became much, much cheaper. 00:29:13.620 --> 00:29:17.340 align:middle line:84% I actually bought LED light bulbs in graduate school 00:29:17.340 --> 00:29:19.320 align:middle line:90% for, I think, about $50 a bulb. 00:29:19.320 --> 00:29:22.140 align:middle line:84% And now, these bulbs have the exact same light quality 00:29:22.140 --> 00:29:24.810 align:middle line:84% as incandescent bulbs or fluorescent bulbs. 00:29:24.810 --> 00:29:27.270 align:middle line:90% But now, they cost $1 or less. 00:29:27.270 --> 00:29:31.810 align:middle line:84% So LED bulbs are an energy efficiency success story. 00:29:31.810 --> 00:29:33.870 align:middle line:84% If you look at building envelopes, all the things 00:29:33.870 --> 00:29:37.350 align:middle line:84% that Dave MacKay did in his home to try to reduce induction, 00:29:37.350 --> 00:29:39.390 align:middle line:84% ventilation, and radiative losses, 00:29:39.390 --> 00:29:43.470 align:middle line:84% you can see that the IEA says we are not on track. 00:29:43.470 --> 00:29:46.740 align:middle line:84% Almost 2/3 of countries lack any mandatory building energy 00:29:46.740 --> 00:29:49.770 align:middle line:84% codes, meaning that many buildings are not 00:29:49.770 --> 00:29:52.710 align:middle line:84% built with any kind of code or any kind of energy efficiency 00:29:52.710 --> 00:29:53.210 align:middle line:90% at all. 00:29:53.210 --> 00:29:54.960 align:middle line:84% This is similar to the number of buildings 00:29:54.960 --> 00:29:56.670 align:middle line:84% that are built with architects, which 00:29:56.670 --> 00:29:59.538 align:middle line:84% is only a small fraction of buildings built in the world. 00:29:59.538 --> 00:30:01.080 align:middle line:84% We know we have a lot of construction 00:30:01.080 --> 00:30:05.520 align:middle line:84% that people do themselves, either do it yourself, 00:30:05.520 --> 00:30:07.180 align:middle line:90% or in informal settlements. 00:30:07.180 --> 00:30:10.058 align:middle line:84% But those places are often not governed by energy codes. 00:30:10.058 --> 00:30:11.850 align:middle line:84% So therefore, they're not energy efficient. 00:30:11.850 --> 00:30:14.610 align:middle line:84% And therefore, they're not using energy very efficiently 00:30:14.610 --> 00:30:17.340 align:middle line:84% in a way that is going to help us reach our Paris Climate 00:30:17.340 --> 00:30:19.250 align:middle line:90% Agreement goals. 00:30:19.250 --> 00:30:22.760 align:middle line:84% In terms of heating, you can see that we have fossil fuel based 00:30:22.760 --> 00:30:25.910 align:middle line:84% equipment, conventional electrical equipment, heat 00:30:25.910 --> 00:30:29.780 align:middle line:84% pumps, district heat, and other renewable sources of energy. 00:30:29.780 --> 00:30:32.300 align:middle line:84% In order to meet our sustainable development scenarios, 00:30:32.300 --> 00:30:36.110 align:middle line:84% we need heat pumps to expand by a factor of probably four 00:30:36.110 --> 00:30:36.710 align:middle line:90% or five. 00:30:36.710 --> 00:30:39.080 align:middle line:84% And we need our use of fossil fuel based equipment, 00:30:39.080 --> 00:30:41.810 align:middle line:84% like the natural gas coming into our homes and spaces 00:30:41.810 --> 00:30:43.155 align:middle line:90% now, to decrease. 00:30:43.155 --> 00:30:44.780 align:middle line:84% We need conventional electric equipment 00:30:44.780 --> 00:30:47.270 align:middle line:84% to decrease because it's relatively much less 00:30:47.270 --> 00:30:48.950 align:middle line:90% efficient than heat pumps. 00:30:48.950 --> 00:30:52.940 align:middle line:84% District heat is not actually predicted to expand very much. 00:30:52.940 --> 00:30:55.460 align:middle line:84% And the use of other renewables and perhaps hydrogen 00:30:55.460 --> 00:30:56.780 align:middle line:90% is expected to expand. 00:30:56.780 --> 00:31:00.860 align:middle line:84% But the problem is to meet our 2050 goals, or 2030 goals, 00:31:00.860 --> 00:31:04.760 align:middle line:84% sorry, we are not on track according to the IEA. 00:31:04.760 --> 00:31:07.550 align:middle line:84% In terms of heat pumps, we need more efforts. 00:31:07.550 --> 00:31:10.940 align:middle line:84% Many households purchased heat pumps in 2019. 00:31:10.940 --> 00:31:13.490 align:middle line:84% If anything, that's probably expanded rapidly 00:31:13.490 --> 00:31:16.680 align:middle line:84% with the explosion in natural gas prices because 00:31:16.680 --> 00:31:18.080 align:middle line:90% of the war in Ukraine. 00:31:18.080 --> 00:31:20.825 align:middle line:84% We know heat pump sales are going up very quickly. 00:31:20.825 --> 00:31:22.700 align:middle line:84% Some people have said that one of the biggest 00:31:22.700 --> 00:31:24.230 align:middle line:84% things we can do to try to reduce 00:31:24.230 --> 00:31:29.090 align:middle line:84% Europe's dependence on Russian gas is to send in heat pumps. 00:31:29.090 --> 00:31:32.135 align:middle line:84% We need to manufacture heat pumps as quickly as possible, 00:31:32.135 --> 00:31:34.010 align:middle line:84% but I can tell you from personal experience-- 00:31:34.010 --> 00:31:35.810 align:middle line:90% my home uses natural gas-- 00:31:35.810 --> 00:31:38.790 align:middle line:84% it is difficult to retrofit a relatively old home with a heat 00:31:38.790 --> 00:31:39.290 align:middle line:90% pump. 00:31:39.290 --> 00:31:42.890 align:middle line:84% Or rather, it is not inherently difficult, 00:31:42.890 --> 00:31:45.020 align:middle line:84% but right now, even as somebody who's 00:31:45.020 --> 00:31:46.538 align:middle line:84% very interested in this problem, I 00:31:46.538 --> 00:31:48.080 align:middle line:84% have a hard time trying to figure out 00:31:48.080 --> 00:31:52.590 align:middle line:84% how to retrofit my 1925 home with a heat pump. 00:31:52.590 --> 00:31:55.740 align:middle line:84% So this is an area where contractors, architects, 00:31:55.740 --> 00:31:59.720 align:middle line:84% engineers, small businesses have a tremendous opportunity 00:31:59.720 --> 00:32:01.638 align:middle line:84% to increase the adoption of heat pumps. 00:32:01.638 --> 00:32:03.680 align:middle line:84% And this is an area where the Inflation Reduction 00:32:03.680 --> 00:32:05.810 align:middle line:84% Act gives a lot of tax incentives 00:32:05.810 --> 00:32:08.660 align:middle line:84% for homeowners to increase their use of heat pumps, which 00:32:08.660 --> 00:32:12.960 align:middle line:84% is why I included that ACEEE report for you to read. 00:32:12.960 --> 00:32:16.470 align:middle line:84% If you look at cooling efforts, cooling 00:32:16.470 --> 00:32:18.210 align:middle line:84% is actually a big area of concern 00:32:18.210 --> 00:32:21.227 align:middle line:84% because we know that not only is the world getting hotter, 00:32:21.227 --> 00:32:23.560 align:middle line:84% but lots of places in the world that are getting richer, 00:32:23.560 --> 00:32:27.060 align:middle line:84% like sub-Saharan Africa or Southeast Asia, India, 00:32:27.060 --> 00:32:30.720 align:middle line:84% essentially, are relatively hot and humid climates. 00:32:30.720 --> 00:32:33.060 align:middle line:84% As those places get richer and more urbanized, 00:32:33.060 --> 00:32:35.260 align:middle line:84% there will be greater demand for cooling. 00:32:35.260 --> 00:32:37.080 align:middle line:84% So the energy demand for space cooling 00:32:37.080 --> 00:32:39.300 align:middle line:84% is actually going up quite a bit. 00:32:39.300 --> 00:32:41.820 align:middle line:84% There's a space cooling intensity index 00:32:41.820 --> 00:32:43.830 align:middle line:84% in a sustainable development scenario. 00:32:43.830 --> 00:32:46.020 align:middle line:84% And we'd like our space cooling intensity index 00:32:46.020 --> 00:32:49.290 align:middle line:84% to go down, which is the amount of energy we use for cooling. 00:32:49.290 --> 00:32:52.050 align:middle line:84% The good news is if we're going to install air conditioning, 00:32:52.050 --> 00:32:53.550 align:middle line:84% we can simply install a heat pump 00:32:53.550 --> 00:32:55.762 align:middle line:84% and get both heating and cooling benefits. 00:32:55.762 --> 00:32:57.345 align:middle line:84% And they're relatively more efficient. 00:32:57.345 --> 00:33:00.990 align:middle line:84% But the problem is in order to increase the use of heat pumps, 00:33:00.990 --> 00:33:03.960 align:middle line:84% again, for cooling, we need to make more policy efforts 00:33:03.960 --> 00:33:09.020 align:middle line:84% or more efforts need to be made across industry and government. 00:33:09.020 --> 00:33:12.110 align:middle line:84% And if you look at appliances and equipment, Energy Star, 00:33:12.110 --> 00:33:15.770 align:middle line:84% Energy Guide-- those yellow tags on appliances you might buy 00:33:15.770 --> 00:33:18.110 align:middle line:90% in the store-- 00:33:18.110 --> 00:33:20.000 align:middle line:84% equipment has become much more efficient 00:33:20.000 --> 00:33:23.120 align:middle line:84% than before, partly because of changes in technology 00:33:23.120 --> 00:33:25.100 align:middle line:84% and partly because energy efficiency codes 00:33:25.100 --> 00:33:28.287 align:middle line:84% have pushed the technology to become more efficient. 00:33:28.287 --> 00:33:30.620 align:middle line:84% But in order for us to reach our sustainable development 00:33:30.620 --> 00:33:34.250 align:middle line:84% scenario in 2030, we still need to make more effort. 00:33:34.250 --> 00:33:37.370 align:middle line:84% Demand is being driven by rising ownership of connected plug 00:33:37.370 --> 00:33:38.180 align:middle line:90% load devices-- 00:33:38.180 --> 00:33:40.213 align:middle line:84% those are devices you plug into the wall-- 00:33:40.213 --> 00:33:41.630 align:middle line:84% especially in developing countries 00:33:41.630 --> 00:33:42.860 align:middle line:90% that are becoming wealthier. 00:33:42.860 --> 00:33:46.370 align:middle line:84% So we need to try to pass performance standards that 00:33:46.370 --> 00:33:50.610 align:middle line:84% govern how much energy all of our devices use. 00:33:50.610 --> 00:33:53.100 align:middle line:84% And finally, there's also behavioral interventions 00:33:53.100 --> 00:33:53.600 align:middle line:90% we can make. 00:33:53.600 --> 00:33:54.975 align:middle line:84% This is an important thing I want 00:33:54.975 --> 00:33:58.310 align:middle line:84% to touch on today leading into next week's discussion. 00:33:58.310 --> 00:34:01.550 align:middle line:84% This is a paper by Tyler Marghetis, Shahzeen Attari, 00:34:01.550 --> 00:34:05.150 align:middle line:84% and David Landy that was published in Nature in 2019 00:34:05.150 --> 00:34:07.070 align:middle line:90% or Nature Energy in 2019. 00:34:07.070 --> 00:34:09.350 align:middle line:84% And the headline is simply that simple interventions 00:34:09.350 --> 00:34:11.757 align:middle line:84% can correct misperceptions of home energy use. 00:34:11.757 --> 00:34:14.090 align:middle line:84% And the reason why I had you look around your apartments 00:34:14.090 --> 00:34:16.299 align:middle line:84% and homes at how much energy things use and try 00:34:16.299 --> 00:34:17.674 align:middle line:84% to calculate it, and the reason I 00:34:17.674 --> 00:34:19.918 align:middle line:84% wanted you to look through Dave MacKay's home 00:34:19.918 --> 00:34:22.460 align:middle line:84% is that people don't have a very good sense, actually, of how 00:34:22.460 --> 00:34:25.260 align:middle line:90% much various appliances use. 00:34:25.260 --> 00:34:27.350 align:middle line:84% And if you look at this graph, this 00:34:27.350 --> 00:34:29.870 align:middle line:84% is the estimate that people give on a survey, 00:34:29.870 --> 00:34:32.030 align:middle line:84% a logarithmic scale on the vertical axis, 00:34:32.030 --> 00:34:35.000 align:middle line:84% and the actual energy use of these appliances 00:34:35.000 --> 00:34:38.449 align:middle line:84% on the horizontal scale, also a logarithmic scale, which 00:34:38.449 --> 00:34:41.120 align:middle line:84% means if people perfectly predicted the amount of energy 00:34:41.120 --> 00:34:42.949 align:middle line:84% use all of these different devices used, 00:34:42.949 --> 00:34:45.080 align:middle line:84% they'd be right on this dotted line. 00:34:45.080 --> 00:34:48.620 align:middle line:84% But you can see for small devices like LEDs, 00:34:48.620 --> 00:34:51.710 align:middle line:84% they actually estimate they use more than they actually do. 00:34:51.710 --> 00:34:54.290 align:middle line:84% And for large devices like a central air conditioner, 00:34:54.290 --> 00:34:56.540 align:middle line:84% they actually estimate it using less energy 00:34:56.540 --> 00:34:57.620 align:middle line:90% than they actually do. 00:34:57.620 --> 00:35:00.480 align:middle line:84% Or else, they would be on this dotted line. 00:35:00.480 --> 00:35:03.390 align:middle line:84% And so the key point here is that they actually 00:35:03.390 --> 00:35:06.780 align:middle line:84% do an experiment where they target the use of energy use. 00:35:06.780 --> 00:35:09.180 align:middle line:84% And they try to develop two interventions. 00:35:09.180 --> 00:35:12.330 align:middle line:84% First, they try to target how people respond 00:35:12.330 --> 00:35:14.340 align:middle line:84% by just giving people quantitative information 00:35:14.340 --> 00:35:16.340 align:middle line:84% about the extremes of electricity. 00:35:16.340 --> 00:35:19.110 align:middle line:84% They tell people how much a phone charger uses, 00:35:19.110 --> 00:35:21.000 align:middle line:90% how much a clothes dryer uses. 00:35:21.000 --> 00:35:22.470 align:middle line:84% And they predict that this is going 00:35:22.470 --> 00:35:24.570 align:middle line:84% to help people understand or translate 00:35:24.570 --> 00:35:27.720 align:middle line:84% their beliefs into energy use into explicit estimates 00:35:27.720 --> 00:35:29.760 align:middle line:84% without necessarily changing their underlying 00:35:29.760 --> 00:35:31.050 align:middle line:90% beliefs about energy use. 00:35:31.050 --> 00:35:33.067 align:middle line:84% And that's relevant because we know 00:35:33.067 --> 00:35:36.243 align:middle line:84% we have very different beliefs about energy use and climate. 00:35:36.243 --> 00:35:38.910 align:middle line:84% The second thing they do is they target systematic understanding 00:35:38.910 --> 00:35:42.240 align:middle line:84% by supplying a simple, explicit, heuristic rule. 00:35:42.240 --> 00:35:44.850 align:middle line:84% They say people underestimate the energy used by appliances 00:35:44.850 --> 00:35:46.710 align:middle line:84% that change the temperature perhaps 00:35:46.710 --> 00:35:48.510 align:middle line:84% because heat generation and heat removal 00:35:48.510 --> 00:35:51.430 align:middle line:84% may not be as noticeable as movement or lighting. 00:35:51.430 --> 00:35:54.510 align:middle line:84% So therefore, they give this explicit heuristic, this rule 00:35:54.510 --> 00:35:55.870 align:middle line:90% for people to judge energy use. 00:35:55.870 --> 00:35:59.260 align:middle line:84% They say large appliances that primarily heat or cool 00:35:59.260 --> 00:36:01.570 align:middle line:84% use a lot more energy than people think they use. 00:36:01.570 --> 00:36:02.640 align:middle line:90% That's all they say. 00:36:02.640 --> 00:36:04.560 align:middle line:84% And they give people these two interventions 00:36:04.560 --> 00:36:07.133 align:middle line:84% and see how well they can estimate energy use. 00:36:07.133 --> 00:36:08.550 align:middle line:84% The reason why that's important is 00:36:08.550 --> 00:36:11.340 align:middle line:84% because our underlying beliefs about energy and climate 00:36:11.340 --> 00:36:13.800 align:middle line:84% may actually shape how well we can actually 00:36:13.800 --> 00:36:15.390 align:middle line:90% perceive energy use. 00:36:15.390 --> 00:36:18.360 align:middle line:84% These are all graphs that show the understanding 00:36:18.360 --> 00:36:22.680 align:middle line:84% of appliances' relative energy use on the horizontal axis, 00:36:22.680 --> 00:36:24.180 align:middle line:84% and to see how they're correlated 00:36:24.180 --> 00:36:26.880 align:middle line:84% with behavioral choice accuracy-- 00:36:26.880 --> 00:36:31.080 align:middle line:84% behavioral choices people make to change their energy use. 00:36:31.080 --> 00:36:34.050 align:middle line:84% They see if it correlates with pro-environmental attitudes. 00:36:34.050 --> 00:36:36.480 align:middle line:84% They see if it correlates with climate change beliefs. 00:36:36.480 --> 00:36:39.940 align:middle line:84% And they see if it correlates with climate policy support. 00:36:39.940 --> 00:36:43.320 align:middle line:84% And you can see that behavioral choice accuracy is actually 00:36:43.320 --> 00:36:46.710 align:middle line:84% relatively the same among liberals, moderates, 00:36:46.710 --> 00:36:47.700 align:middle line:90% and conservatives. 00:36:47.700 --> 00:36:50.030 align:middle line:84% But you can see that pro-environmental attitudes, 00:36:50.030 --> 00:36:51.780 align:middle line:84% climate change beliefs, and climate policy 00:36:51.780 --> 00:36:53.340 align:middle line:90% support all diverge. 00:36:53.340 --> 00:36:56.370 align:middle line:84% And so their point in this paper is that if you actually supply 00:36:56.370 --> 00:36:59.310 align:middle line:84% people with both this scale use intervention-- 00:36:59.310 --> 00:37:02.130 align:middle line:84% telling people how much energy appliances use-- 00:37:02.130 --> 00:37:04.560 align:middle line:84% or giving them an increased understanding 00:37:04.560 --> 00:37:07.830 align:middle line:84% of appliance energy use, they have different implications 00:37:07.830 --> 00:37:10.620 align:middle line:84% for who may be listening to this message 00:37:10.620 --> 00:37:12.430 align:middle line:84% and how they might act on these beliefs. 00:37:12.430 --> 00:37:14.598 align:middle line:84% So they argue in this paper that if you increase 00:37:14.598 --> 00:37:16.890 align:middle line:84% people's understanding of appliance and relative energy 00:37:16.890 --> 00:37:19.115 align:middle line:84% use, you may be able to not necessarily affect 00:37:19.115 --> 00:37:21.240 align:middle line:84% their pro-environmental attitudes, or their climate 00:37:21.240 --> 00:37:23.490 align:middle line:84% change beliefs, or their support for climate policies, 00:37:23.490 --> 00:37:26.220 align:middle line:84% but at least you can correct their misperceptions of home 00:37:26.220 --> 00:37:28.960 align:middle line:90% energy use. 00:37:28.960 --> 00:37:30.630 align:middle line:84% Finally, just to touch on the health 00:37:30.630 --> 00:37:32.970 align:middle line:84% aspect of decarbonization, this is 00:37:32.970 --> 00:37:35.670 align:middle line:84% a project I'm working on in indoor air quality in New York 00:37:35.670 --> 00:37:36.302 align:middle line:90% City. 00:37:36.302 --> 00:37:38.010 align:middle line:84% It's an interesting project because we're 00:37:38.010 --> 00:37:40.320 align:middle line:84% working on a low income or affordable housing 00:37:40.320 --> 00:37:42.150 align:middle line:84% building-- a subsidized housing building. 00:37:42.150 --> 00:37:44.550 align:middle line:84% And what the developer or the owner is doing 00:37:44.550 --> 00:37:47.430 align:middle line:84% is essentially retrofitting this building to be decarbonized. 00:37:47.430 --> 00:37:49.460 align:middle line:84% They're upgrading it to passive house standards, 00:37:49.460 --> 00:37:51.960 align:middle line:84% meaning that they're wrapping the whole building in a highly 00:37:51.960 --> 00:37:53.400 align:middle line:90% efficient envelope. 00:37:53.400 --> 00:37:55.260 align:middle line:84% And they're decarbonizing the building 00:37:55.260 --> 00:37:57.660 align:middle line:84% by taking the water heating and the space 00:37:57.660 --> 00:37:59.670 align:middle line:84% heating out and installing basically 00:37:59.670 --> 00:38:02.250 align:middle line:84% heat pumps to the roof that will push air down 00:38:02.250 --> 00:38:05.260 align:middle line:84% to each of the apartment lines through these blue ventilation 00:38:05.260 --> 00:38:05.760 align:middle line:90% shafts. 00:38:05.760 --> 00:38:09.870 align:middle line:84% And of course, when the ventilation or the exhaust air 00:38:09.870 --> 00:38:11.573 align:middle line:84% comes out of the apartments, it'll 00:38:11.573 --> 00:38:13.740 align:middle line:84% come up back to this blue line and go through a heat 00:38:13.740 --> 00:38:16.525 align:middle line:84% exchanger, meaning that all the heat will be captured 00:38:16.525 --> 00:38:18.150 align:middle line:84% in the building even if we need to push 00:38:18.150 --> 00:38:20.500 align:middle line:84% in new fresh air for ventilation. 00:38:20.500 --> 00:38:22.830 align:middle line:84% But we also have to think of the implications this has 00:38:22.830 --> 00:38:24.990 align:middle line:90% for ventilation and for health. 00:38:24.990 --> 00:38:31.530 align:middle line:84% We know that gas appliances produce combusted methane, 00:38:31.530 --> 00:38:36.090 align:middle line:84% but also particulate matter, and have a gas or chemical-- 00:38:36.090 --> 00:38:38.920 align:middle line:84% they release chemicals into living spaces. 00:38:38.920 --> 00:38:40.860 align:middle line:84% So what we're hoping to see in this project is 00:38:40.860 --> 00:38:43.680 align:middle line:84% by decarbonizing and removing the gas of the building, 00:38:43.680 --> 00:38:47.350 align:middle line:84% we improve air quality inside this building. 00:38:47.350 --> 00:38:49.650 align:middle line:84% And so we put these air quality sensors 00:38:49.650 --> 00:38:51.970 align:middle line:84% in all these points in the building. 00:38:51.970 --> 00:38:55.510 align:middle line:84% What we are hoping to show is that not only can we 00:38:55.510 --> 00:38:59.470 align:middle line:84% decarbonize a relatively inexpensive or low income 00:38:59.470 --> 00:39:01.550 align:middle line:84% building, if we can decarbonize it, 00:39:01.550 --> 00:39:04.580 align:middle line:84% we also improve people's air quality inside their homes. 00:39:04.580 --> 00:39:06.850 align:middle line:84% So we're hoping for a triple win. 00:39:06.850 --> 00:39:10.030 align:middle line:84% And that is applicable to any building. 00:39:10.030 --> 00:39:12.100 align:middle line:90% It is relatively cheap. 00:39:12.100 --> 00:39:15.010 align:middle line:84% It eliminates the greenhouse gas use in these buildings, 00:39:15.010 --> 00:39:17.095 align:middle line:84% and also improves people's health. 00:39:17.095 --> 00:39:18.970 align:middle line:84% We've been doing a two-year field experiment, 00:39:18.970 --> 00:39:20.220 align:middle line:90% and we're almost done with it. 00:39:20.220 --> 00:39:22.720 align:middle line:84% So I'm looking forward to sharing the results with you 00:39:22.720 --> 00:39:23.420 align:middle line:90% soon. 00:39:23.420 --> 00:39:26.100 align:middle line:84% And that concludes our lecture for today. 00:39:26.100 --> 00:39:43.000 align:middle line:90%