1 00:00:01,800 --> 00:00:03,900 - Welcome to Wednesday Nite at the Lab. 2 00:00:04,000 --> 00:00:05,866 I'm Liz Jesse, the media specialist 3 00:00:05,966 --> 00:00:07,500 for UW Science Outreach. 4 00:00:07,600 --> 00:00:10,033 On behalf of Wisconsin Alumni Association, 5 00:00:10,133 --> 00:00:14,133 Wisconsin Public Television, UW Madison Science Alliance, 6 00:00:14,233 --> 00:00:15,800 UW Madison Biotech Center, 7 00:00:15,900 --> 00:00:18,933 and UW Extension and Cooperative Extension, 8 00:00:19,033 --> 00:00:21,300 thanks for coming out to Wednesday Nite at the Lab. 9 00:00:21,400 --> 00:00:25,000 We do this every Wednesday, 50 times a year. 10 00:00:25,100 --> 00:00:29,166 Tonight, it is my pleasure to introduce Andrea Hicks. 11 00:00:29,266 --> 00:00:31,133 Andrea grew up in Dearborn, Michigan, 12 00:00:31,233 --> 00:00:33,600 which I just found out tonight is right outside of Detroit. 13 00:00:33,700 --> 00:00:36,266 I don't know Michigan very well, apparently. 14 00:00:36,366 --> 00:00:39,766 She completed her PhD in civil engineering 15 00:00:39,866 --> 00:00:41,833 at the University of Illinois at Chicago 16 00:00:41,933 --> 00:00:43,466 and then completed a postdoc 17 00:00:43,566 --> 00:00:46,433 at the Institute of Environmental Science and Policy. 18 00:00:46,533 --> 00:00:49,066 Her research at the UW, and maybe beyond, 19 00:00:49,166 --> 00:00:51,233 focuses on the environmental, economic, 20 00:00:51,333 --> 00:00:53,166 and social impacts of new technologies 21 00:00:53,266 --> 00:00:55,033 compared to conventional counterparts. 22 00:00:55,133 --> 00:00:56,466 So I kind of thought of this like, 23 00:00:56,566 --> 00:00:57,800 we don't use Keurig at home 24 00:00:57,900 --> 00:00:59,900 because I know that conventional brewing is better. 25 00:01:00,000 --> 00:01:02,533 So maybe that's kind of what she talks about. 26 00:01:02,633 --> 00:01:04,100 Tonight, she's going to be focusing, 27 00:01:04,200 --> 00:01:07,866 and we're going to be talking a little bit about 28 00:01:07,966 --> 00:01:09,766 the history of artificial light 29 00:01:09,866 --> 00:01:12,000 and how it relates to sustainability 30 00:01:12,100 --> 00:01:13,900 of today's emerging lighting technologies. 31 00:01:14,000 --> 00:01:16,900 So, here we go with the LED paradox. 32 00:01:17,000 --> 00:01:19,533 Please join me in welcoming Andrea Hicks. 33 00:01:19,633 --> 00:01:21,633 [audience applauding] 34 00:01:24,366 --> 00:01:25,800 - Thank you for that warm welcome. 35 00:01:25,900 --> 00:01:27,800 Can everyone hear me? 36 00:01:27,900 --> 00:01:29,333 Nods? Okay. 37 00:01:29,433 --> 00:01:31,633 So, first, I'd like to thank the organizers 38 00:01:31,733 --> 00:01:34,500 of Wednesday Night at the Lab for allowing me 39 00:01:34,600 --> 00:01:36,466 this platform to present some work, 40 00:01:36,566 --> 00:01:38,700 and to thank all of you for being here 41 00:01:38,800 --> 00:01:41,966 to learn about the LED paradox. 42 00:01:42,066 --> 00:01:45,466 So, a little bit about what we'll go over tonight. 43 00:01:45,566 --> 00:01:48,466 We'll look at what is artificial light? 44 00:01:48,566 --> 00:01:50,566 What's the history of lighting in Chicago? 45 00:01:50,666 --> 00:01:52,433 It's a major city not so far from here. 46 00:01:52,533 --> 00:01:54,033 It's a nice place to start. 47 00:01:54,133 --> 00:01:55,433 Our consumption of light, 48 00:01:55,533 --> 00:01:57,933 what technologies changes mean, 49 00:01:58,033 --> 00:02:01,266 Jevons paradox, and novel consumption. 50 00:02:02,266 --> 00:02:04,766 So, what is artificial light? 51 00:02:04,866 --> 00:02:06,200 This is the point where everyone's like, 52 00:02:06,300 --> 00:02:07,500 artificial light, it's in this room. 53 00:02:07,600 --> 00:02:08,700 We have it. 54 00:02:08,800 --> 00:02:10,266 I'll point to it. 55 00:02:10,366 --> 00:02:13,433 So, to take it a more philosophical way, 56 00:02:13,533 --> 00:02:16,300 it renders the invisible visible. 57 00:02:17,300 --> 00:02:18,533 It's safety. 58 00:02:18,633 --> 00:02:20,433 It's traffic control signals. 59 00:02:20,533 --> 00:02:21,666 I'm from civil engineering, 60 00:02:21,766 --> 00:02:24,200 so I have to throw in some examples like that. 61 00:02:24,300 --> 00:02:28,066 It's street lights at night that encourage people to walk. 62 00:02:28,166 --> 00:02:29,866 It's productivity. 63 00:02:29,966 --> 00:02:31,100 Without artificial light, 64 00:02:31,200 --> 00:02:33,133 there would be no night shift at hospitals. 65 00:02:33,233 --> 00:02:36,466 There would be no third shift at plants. 66 00:02:36,566 --> 00:02:39,300 And it decouples us from the patterns of the sun. 67 00:02:39,400 --> 00:02:41,433 We're no longer dependent on the sun 68 00:02:41,533 --> 00:02:43,266 as our sole source of light. 69 00:02:43,366 --> 00:02:45,433 And here's a quote from Harold Platt, 70 00:02:45,533 --> 00:02:47,566 who wrote The Electric City in 1991, 71 00:02:47,666 --> 00:02:50,633 and that centers on Chicago and it's history of light. 72 00:02:50,733 --> 00:02:53,066 We'll talk a little bit about his book 73 00:02:53,166 --> 00:02:55,100 to give some background context. 74 00:02:55,200 --> 00:02:56,633 "But the bright lights of the city 75 00:02:56,733 --> 00:02:58,800 quickly became both a status symbol 76 00:02:58,900 --> 00:03:00,800 and a physical manifestation of progress, 77 00:03:00,900 --> 00:03:03,100 wealth, and amenities." 78 00:03:03,200 --> 00:03:05,166 So, light isn't just light. 79 00:03:05,266 --> 00:03:07,200 It's a symbol of progress. 80 00:03:07,300 --> 00:03:09,233 If you think about a cartoon, 81 00:03:09,333 --> 00:03:12,466 what happens when someone has an idea? 82 00:03:12,566 --> 00:03:14,400 They get the light bulb. 83 00:03:14,500 --> 00:03:17,500 So it's more than just illumination. 84 00:03:18,666 --> 00:03:22,400 So, this is a timeline of lighting in Chicago. 85 00:03:22,500 --> 00:03:26,433 In 1878, Barrett demonstrated Brush's arc lamp. 86 00:03:28,200 --> 00:03:31,533 And within a decade, there are almost 7,000 arc lamps 87 00:03:31,633 --> 00:03:33,733 built and operated in the city of Chicago 88 00:03:33,833 --> 00:03:36,833 at an annual cost of a million dollars, 89 00:03:36,933 --> 00:03:38,166 which is a lot. 90 00:03:40,133 --> 00:03:41,966 "And so the electric suppliers..." 91 00:03:42,066 --> 00:03:44,500 This is also from Platt's book. 92 00:03:44,600 --> 00:03:48,033 "...faced a consumer market with no bounds." 93 00:03:48,133 --> 00:03:50,300 And this is a question that will permeate our talk tonight. 94 00:03:50,400 --> 00:03:52,433 What is saturation of light? 95 00:03:52,533 --> 00:03:54,233 When do we have enough light? 96 00:03:54,333 --> 00:03:57,800 How much light is too much light? 97 00:03:57,900 --> 00:04:00,133 But there were some problems with this arc lamp. 98 00:04:00,233 --> 00:04:02,233 It was a fire hazard. 99 00:04:02,333 --> 00:04:03,500 It was big. 100 00:04:03,600 --> 00:04:05,966 You couldn't use it in a residential setting. 101 00:04:06,066 --> 00:04:07,066 So, in 1880, 102 00:04:08,300 --> 00:04:09,800 or 1879 depending, 103 00:04:11,033 --> 00:04:12,466 Thomas Edison invented the first 104 00:04:12,566 --> 00:04:14,966 marketable incandescent bulb. 105 00:04:16,133 --> 00:04:18,566 And Chicagoans suddenly had this choice, 106 00:04:18,666 --> 00:04:20,900 what kind of light do I want? 107 00:04:21,000 --> 00:04:22,300 Do I want electric light? 108 00:04:22,400 --> 00:04:23,766 Do I want a kerosene lamp? 109 00:04:23,866 --> 00:04:27,266 Do I want to go by the old gas lighting standby? 110 00:04:27,366 --> 00:04:29,200 And so these incandescent bulbs 111 00:04:29,300 --> 00:04:30,766 were much safer than arc lamps, 112 00:04:30,866 --> 00:04:34,033 and could be easily scaled to residential use. 113 00:04:34,133 --> 00:04:35,266 But really, electric lighting 114 00:04:35,366 --> 00:04:38,100 was only for the wealthy at first. 115 00:04:38,200 --> 00:04:40,966 It wasn't for the everyday person. 116 00:04:43,533 --> 00:04:46,533 But, at the same point, there was this radical shift 117 00:04:46,633 --> 00:04:50,166 in psychological perception of interior lighting levels. 118 00:04:50,266 --> 00:04:51,400 And this goes back to our question 119 00:04:51,500 --> 00:04:53,466 of how much light is enough light? 120 00:04:53,566 --> 00:04:55,833 How much light is too much light? 121 00:04:55,933 --> 00:04:57,166 So what had seemed all right before 122 00:04:57,266 --> 00:05:00,000 was dark, gloomy, and depressing. 123 00:05:00,100 --> 00:05:02,966 So already we're craving more light, 124 00:05:03,066 --> 00:05:05,366 because we have more light. 125 00:05:05,466 --> 00:05:08,800 Now, in 1893, Chicago's World Fair, 126 00:05:08,900 --> 00:05:11,700 Chicago was dubbed the city of light. 127 00:05:11,800 --> 00:05:15,266 And, by 1912, about half of Chicago's middle class families 128 00:05:15,366 --> 00:05:19,533 had electricity in their homes and electric light. 129 00:05:22,033 --> 00:05:24,566 So, look at that quote again. 130 00:05:24,666 --> 00:05:25,833 It's a status symbol. 131 00:05:25,933 --> 00:05:28,400 It's progress, it's wealth, it's amenities. 132 00:05:28,500 --> 00:05:30,566 Light is more than just illumination. 133 00:05:30,666 --> 00:05:33,233 It means we're moving forward. 134 00:05:33,333 --> 00:05:36,866 And some photos from the World's Fair. 135 00:05:36,966 --> 00:05:40,766 They're not great, but, you know, early 1900s. 136 00:05:41,900 --> 00:05:43,133 And it was amazing. 137 00:05:43,233 --> 00:05:45,300 We had all of this light. 138 00:05:47,700 --> 00:05:50,433 So, before we start to talk about the actual consumption 139 00:05:50,533 --> 00:05:53,466 of light, some little background. 140 00:05:53,566 --> 00:05:56,900 One unit I'll talk a lot about today is a lumen, 141 00:05:57,000 --> 00:06:00,100 and a lumen is an international standards unit 142 00:06:00,200 --> 00:06:02,600 for the measurement of brightness. 143 00:06:02,700 --> 00:06:04,666 And another way to think about it, 144 00:06:04,766 --> 00:06:08,366 it's the light of one candle one foot away. 145 00:06:09,500 --> 00:06:10,966 Although, I suspect most people don't compare 146 00:06:11,066 --> 00:06:13,666 their light bulbs to candles at feet. 147 00:06:13,766 --> 00:06:17,066 Maybe people do, and that's okay. 148 00:06:17,166 --> 00:06:19,333 And so it's a measure of light output, 149 00:06:19,433 --> 00:06:21,233 and it's a nice way when we talk about 150 00:06:21,333 --> 00:06:24,100 different efficiencies of lighting to compare them. 151 00:06:24,200 --> 00:06:28,166 About 800 lumens is about a 60-watt incandescent, 152 00:06:28,266 --> 00:06:31,266 which translates into CFLs and LEDs. 153 00:06:35,333 --> 00:06:38,600 So, this we're already using our lumen. 154 00:06:40,000 --> 00:06:42,866 This is teralumen hours per year 155 00:06:42,966 --> 00:06:45,233 of light consumed in the United Kingdom. 156 00:06:45,333 --> 00:06:48,566 It's a study by Tsao et al in 2010 157 00:06:48,666 --> 00:06:52,400 that looks at the consumption of light 158 00:06:52,500 --> 00:06:55,566 over time and changes in technology. 159 00:06:55,666 --> 00:06:57,966 So here we are transitioning from candles 160 00:06:58,066 --> 00:07:02,300 to gas, to kerosene, and eventually to electricity. 161 00:07:03,466 --> 00:07:07,166 And the whole time we're consuming more light. 162 00:07:08,366 --> 00:07:11,800 Yes, the lines go up, consuming more light. 163 00:07:13,733 --> 00:07:16,066 And it's largely, this work by Tsao et al, 164 00:07:16,166 --> 00:07:18,533 was largely based on some earlier work 165 00:07:18,633 --> 00:07:21,133 by Fouquet and Pearson, 166 00:07:21,233 --> 00:07:24,600 that looked at the price of lighting. 167 00:07:24,700 --> 00:07:28,166 So, how much per million lumen hours? 168 00:07:28,266 --> 00:07:30,500 We're using those lumens again. 169 00:07:30,600 --> 00:07:32,466 So what's the cost of light, 170 00:07:32,566 --> 00:07:35,066 as we transition over time from gas light 171 00:07:35,166 --> 00:07:37,866 to kerosene light to electric light? 172 00:07:37,966 --> 00:07:40,233 And the point is, it's been going down, 173 00:07:40,333 --> 00:07:43,600 over time in the UK during this study, 174 00:07:43,700 --> 00:07:45,800 which ends at about 2000. 175 00:07:49,233 --> 00:07:52,800 I see people talking, this is a good sign. 176 00:07:54,700 --> 00:07:56,600 So okay, so we've been using more light 177 00:07:56,700 --> 00:07:58,533 and the cost of light has been going down, 178 00:07:58,633 --> 00:08:00,433 at least in the UK. 179 00:08:00,533 --> 00:08:04,300 So, the Energy Information Administration very recently 180 00:08:04,400 --> 00:08:06,800 put together a chart of energy consumption 181 00:08:06,900 --> 00:08:10,233 in the United States starting from 1776, 182 00:08:11,766 --> 00:08:13,266 which is nice. 183 00:08:13,366 --> 00:08:15,633 Usually you can't find data, at least in engineering 184 00:08:15,733 --> 00:08:18,833 when I'm looking for something from the 1700s. 185 00:08:18,933 --> 00:08:22,366 And, okay, so we consume more energy. 186 00:08:22,466 --> 00:08:26,000 This is in quadrillion British thermal units. 187 00:08:26,100 --> 00:08:29,400 And our energy consumption broken down by 188 00:08:29,500 --> 00:08:30,866 what we're consuming. 189 00:08:30,966 --> 00:08:32,833 And over time, we've transitioned from coal 190 00:08:32,933 --> 00:08:36,766 to more toward natural gas and petroleum products. 191 00:08:36,866 --> 00:08:38,866 So, okay, the question is, 192 00:08:38,966 --> 00:08:42,833 how much energy do we use for artificial light? 193 00:08:44,100 --> 00:08:45,100 Is it a lot? 194 00:08:45,200 --> 00:08:46,366 Is it a little? 195 00:08:46,466 --> 00:08:48,866 Would we even see it on this graph? 196 00:08:48,966 --> 00:08:51,733 So, when I started studying this, 197 00:08:53,666 --> 00:08:56,633 and the first data is from maybe around 2001, 198 00:08:56,733 --> 00:09:01,233 we were using 8.2 quadrillion British thermal units 199 00:09:01,333 --> 00:09:04,466 of electricity for lighting in the United States. 200 00:09:04,566 --> 00:09:05,966 So, if you take a look, 201 00:09:06,066 --> 00:09:08,433 that is a little bit higher 202 00:09:08,533 --> 00:09:11,866 than nuclear energy consumption in 2015. 203 00:09:13,333 --> 00:09:14,933 So, based on the premise of this talk, 204 00:09:15,033 --> 00:09:17,866 do you think it's gone up or down? 205 00:09:19,033 --> 00:09:20,600 Some up? 206 00:09:20,700 --> 00:09:21,766 Shall we raise hands? 207 00:09:21,866 --> 00:09:24,133 Who thinks it's gone up? 208 00:09:24,233 --> 00:09:25,666 Okay. 209 00:09:25,766 --> 00:09:28,600 Who thinks it's gone down? 210 00:09:28,700 --> 00:09:31,300 - [Audience Member] Are you asking input or output? 211 00:09:31,400 --> 00:09:33,633 - Total energy consumption. 212 00:09:35,033 --> 00:09:37,033 - [Audience Member] So the energy input into it. 213 00:09:37,133 --> 00:09:38,833 - Right. 214 00:09:38,933 --> 00:09:40,500 And who doesn't know? 215 00:09:40,600 --> 00:09:41,733 [audience chuckling] 216 00:09:41,833 --> 00:09:43,833 That's okay. 217 00:09:45,066 --> 00:09:48,000 So it's actually gone down, 218 00:09:48,100 --> 00:09:50,566 which seems a little counterintuitive with a talk called, 219 00:09:50,666 --> 00:09:53,766 The LED Paradox and the Rebound Effect. 220 00:09:53,866 --> 00:09:54,933 But, in 2010, 221 00:09:56,866 --> 00:09:59,900 about 7.5 quadrillion British thermal units 222 00:10:00,000 --> 00:10:02,800 were devoted to electricity for lighting, 223 00:10:02,900 --> 00:10:04,833 and in 2013, 6.9 quads, 224 00:10:06,800 --> 00:10:10,966 which comprised about 18% of total US electricity usage. 225 00:10:13,133 --> 00:10:14,466 So it's gone down. 226 00:10:14,566 --> 00:10:18,566 Why are we talking about energy rebound and the paradox? 227 00:10:18,666 --> 00:10:20,000 We'll get there. 228 00:10:21,666 --> 00:10:25,800 So, let's think a little bit about efficiency. 229 00:10:25,900 --> 00:10:29,900 And, here, we've got a compact fluorescent lamp, 230 00:10:31,633 --> 00:10:34,800 which was invented or inspired in 1973 231 00:10:36,133 --> 00:10:37,800 during the oil crisis, 232 00:10:37,900 --> 00:10:42,000 and in 1974, made by an engineer at General Electric. 233 00:10:43,566 --> 00:10:47,100 And in the 1980s, CFLs were introduced to the public. 234 00:10:47,200 --> 00:10:49,100 So, who remembers that? 235 00:10:50,266 --> 00:10:51,600 Okay. 236 00:10:51,700 --> 00:10:54,800 Maybe half a dozen people, that's a good start. 237 00:10:54,900 --> 00:10:57,633 And, but there were some problems. 238 00:10:57,733 --> 00:10:58,966 They were expensive. 239 00:10:59,066 --> 00:11:02,766 They were about $25-$35 per light bulb, 240 00:11:02,866 --> 00:11:04,966 and that number is a little fuzzy, 241 00:11:05,066 --> 00:11:06,200 because they were often subsidized 242 00:11:06,300 --> 00:11:08,733 by the electrical utilities. 243 00:11:08,833 --> 00:11:10,366 They're blue. 244 00:11:10,466 --> 00:11:11,800 They failed early, 245 00:11:11,900 --> 00:11:15,366 and they had inconsistent light input, output. 246 00:11:15,466 --> 00:11:16,966 Not well received. 247 00:11:18,333 --> 00:11:21,900 So, as we talk about lighting technologies, 248 00:11:23,200 --> 00:11:27,366 let's talk a little bit about how they work. 249 00:11:27,466 --> 00:11:28,933 So in an incandescent, 250 00:11:29,033 --> 00:11:30,633 which is sort of what we think of 251 00:11:30,733 --> 00:11:32,300 as the conventional technology, 252 00:11:32,400 --> 00:11:35,533 an electric current runs through the filament, heating it, 253 00:11:35,633 --> 00:11:39,733 and then it starts to glow and light is produced. 254 00:11:39,833 --> 00:11:41,533 But what about a CFL? 255 00:11:42,933 --> 00:11:46,733 So, in a CFL, it has this curlicue shape, right? 256 00:11:48,533 --> 00:11:51,433 And an electric current goes through the argon 257 00:11:51,533 --> 00:11:53,200 and a small amount of mercury vapor, 258 00:11:53,300 --> 00:11:56,300 which is stored in the curlicue. 259 00:11:56,400 --> 00:11:58,800 That generates invisible ultraviolet light 260 00:11:58,900 --> 00:12:01,700 that excites a fluorescent coating, 261 00:12:01,800 --> 00:12:05,466 which is on the outside, and produces light. 262 00:12:07,533 --> 00:12:11,700 This is from the friendly folks at Energy Star. 263 00:12:11,800 --> 00:12:13,466 So, what about LEDs? 264 00:12:16,833 --> 00:12:19,033 So, LEDs, or light emitting diodes, 265 00:12:19,133 --> 00:12:20,833 and we'll talk about how they work in a second, 266 00:12:20,933 --> 00:12:23,600 are considered an enabling technology, 267 00:12:23,700 --> 00:12:26,233 because they enable other products and other technologies 268 00:12:26,333 --> 00:12:29,233 that would not be possible without them. 269 00:12:29,333 --> 00:12:30,900 And this is a graph 270 00:12:32,366 --> 00:12:35,966 from data mined from the US patent database 271 00:12:36,066 --> 00:12:40,066 on the percentage of light emitting diode patents per year, 272 00:12:40,166 --> 00:12:41,766 applications per year, 273 00:12:41,866 --> 00:12:45,600 broken down by the application's application. 274 00:12:47,400 --> 00:12:49,833 So, what is the goal of this? 275 00:12:51,200 --> 00:12:54,266 And you can see LEDs for illumination are near the top. 276 00:12:54,366 --> 00:12:55,866 And illumination is what we primarily thought of 277 00:12:55,966 --> 00:12:57,700 for what we do with light. 278 00:12:57,800 --> 00:13:00,700 You light a candle to have light. 279 00:13:00,800 --> 00:13:04,066 You turn on an incandescent light bulb to have light. 280 00:13:04,166 --> 00:13:07,166 But with LEDs, we start to have other options. 281 00:13:07,266 --> 00:13:10,400 We have liquid crystal displays. 282 00:13:10,500 --> 00:13:14,733 We have manufacturing, communication, military, medicine. 283 00:13:14,833 --> 00:13:17,700 There's all, and novelties, which we'll talk about later. 284 00:13:17,800 --> 00:13:20,466 There's some exciting novelties. 285 00:13:21,666 --> 00:13:25,233 And so they have all of these properties. 286 00:13:25,333 --> 00:13:28,033 They don't get really hot, they're small. 287 00:13:28,133 --> 00:13:30,833 You can enclose them, and they can get wet. 288 00:13:30,933 --> 00:13:35,000 And the first red LED came about in 1961. 289 00:13:35,100 --> 00:13:36,266 So they've been around, 290 00:13:36,366 --> 00:13:37,933 but we're now just starting to use them 291 00:13:38,033 --> 00:13:40,533 for residential lighting applications. 292 00:13:42,866 --> 00:13:44,633 So, how do LEDs work? 293 00:13:46,266 --> 00:13:47,600 And I enjoyed this. 294 00:13:47,700 --> 00:13:50,300 This is from howstuffworks.com. 295 00:13:51,833 --> 00:13:54,500 And forgive me if you've spent time 296 00:13:54,600 --> 00:13:55,800 studying quantum mechanics. 297 00:13:55,900 --> 00:13:59,466 This is just a very brief overview. 298 00:13:59,566 --> 00:14:02,466 So, LEDs are semiconductors, 299 00:14:02,566 --> 00:14:06,733 and current flows through the diode, and the electrons move. 300 00:14:11,633 --> 00:14:14,366 There's holes that exist at a lower energy 301 00:14:14,466 --> 00:14:16,433 and there's free electrons, 302 00:14:16,533 --> 00:14:20,933 and when the electron moves to a lower energy level, 303 00:14:21,033 --> 00:14:23,833 it emits a photon, which is light. 304 00:14:25,000 --> 00:14:26,666 Very brief overview. 305 00:14:27,900 --> 00:14:29,033 And that is, 306 00:14:29,133 --> 00:14:30,400 this a red LED, 307 00:14:31,533 --> 00:14:33,800 but it doesn't have to be a red LED. 308 00:14:33,900 --> 00:14:37,900 You have your semiconducting material embedded in the lamp. 309 00:14:38,900 --> 00:14:40,966 Okay, so we have LEDs. 310 00:14:41,066 --> 00:14:43,066 They work a little bit differently. 311 00:14:43,166 --> 00:14:45,366 Does anyone have an LED? 312 00:14:45,466 --> 00:14:46,866 At home? 313 00:14:46,966 --> 00:14:48,366 [audience murmurs responses] 314 00:14:48,466 --> 00:14:49,733 Okay. 315 00:14:49,833 --> 00:14:51,866 There's a few folks. 316 00:14:51,966 --> 00:14:54,966 How about an LED with you right now? 317 00:14:58,600 --> 00:15:01,033 Okay, so there's people with LEDs. 318 00:15:01,133 --> 00:15:05,166 Are there people with smartphones right now? 319 00:15:05,266 --> 00:15:06,966 Okay. 320 00:15:07,066 --> 00:15:09,733 So, these exist, we have them. 321 00:15:09,833 --> 00:15:13,433 There are many in this room at this moment. 322 00:15:14,900 --> 00:15:18,966 So when we start to look at the lighting market, 323 00:15:19,066 --> 00:15:21,400 and this is from the US Department of Energy in 2012 324 00:15:21,500 --> 00:15:23,300 based on their 2010 data. 325 00:15:23,400 --> 00:15:25,366 This is annual electricity consumption 326 00:15:25,466 --> 00:15:28,433 in terawatt hours per year, 327 00:15:28,533 --> 00:15:30,800 broken down by sector. 328 00:15:30,900 --> 00:15:34,466 And the focus today will be residential. 329 00:15:34,566 --> 00:15:35,733 And residential, 330 00:15:35,833 --> 00:15:39,600 okay, so it's primarily, in 2010, incandescents. 331 00:15:40,700 --> 00:15:43,000 Do you think that's changed? 332 00:15:43,833 --> 00:15:45,500 Maybe? 333 00:15:46,633 --> 00:15:48,133 [audience responds] 334 00:15:48,233 --> 00:15:50,633 So it has at some people's houses for sure. 335 00:15:50,733 --> 00:15:55,233 And other people's houses, we'll talk about too. 336 00:15:55,333 --> 00:15:57,166 But, overall, in 2010, 337 00:15:58,766 --> 00:16:02,233 we used about 700 terawatt hours of electricity 338 00:16:02,333 --> 00:16:04,733 annually for lighting. 339 00:16:04,833 --> 00:16:08,300 And although residential isn't the biggest sector, 340 00:16:08,400 --> 00:16:09,800 it's interesting because you're starting 341 00:16:09,900 --> 00:16:14,066 to deal with consumers and their individual behaviors. 342 00:16:14,166 --> 00:16:18,166 Do you think people demand more light over time? 343 00:16:20,166 --> 00:16:21,333 Maybe? 344 00:16:22,333 --> 00:16:24,600 So, in 2001, the average number 345 00:16:24,700 --> 00:16:27,366 of sockets per household was 43. 346 00:16:29,200 --> 00:16:30,366 Do you think that's gone up? 347 00:16:30,466 --> 00:16:33,100 - [Audience Member] Yeah. 348 00:16:33,200 --> 00:16:36,566 So, as of 2010, the average is 51. 349 00:16:36,666 --> 00:16:39,633 And that's one way of consuming more light, 350 00:16:39,733 --> 00:16:43,166 that you have more light bulbs in your house. 351 00:16:43,266 --> 00:16:48,066 Now, there's been some evolutions in technology too. 352 00:16:48,166 --> 00:16:51,933 And this starts at 2011 and goes through 2016. 353 00:16:52,033 --> 00:16:53,400 And we've got pictures of an incandescent 354 00:16:53,500 --> 00:16:55,533 and a CFL and an LED. 355 00:16:55,633 --> 00:16:58,900 And these are residential screw-in type replacements 356 00:16:59,000 --> 00:17:01,466 with a lumen output of about 800. 357 00:17:01,566 --> 00:17:04,233 So, 60-watt bulb equivalents. 358 00:17:04,333 --> 00:17:07,933 So we're comparing apples to apples mostly. 359 00:17:10,133 --> 00:17:11,133 So, in 2011, 360 00:17:12,266 --> 00:17:13,766 an LED was $33.90, 361 00:17:17,133 --> 00:17:20,366 which seems like a lot for a light bulb. 362 00:17:20,466 --> 00:17:24,166 And if we go to 2013, okay, we're at about $13, 363 00:17:24,266 --> 00:17:27,200 and today we're at about $4.50. 364 00:17:27,300 --> 00:17:29,100 And incandescents have dropped a little bit. 365 00:17:29,200 --> 00:17:32,500 There's some other factors at play that we'll talk about. 366 00:17:32,600 --> 00:17:35,700 And CFLs have dropped a little bit too. 367 00:17:35,800 --> 00:17:37,633 The energy consumption 368 00:17:39,266 --> 00:17:43,433 has steadied for the conventional incandescent, 369 00:17:43,533 --> 00:17:45,566 and it's gone down a bit for an LED, 370 00:17:45,666 --> 00:17:48,600 going from 12 watts to about eight. 371 00:17:48,700 --> 00:17:49,900 There's also a huge difference 372 00:17:50,000 --> 00:17:52,500 in the lifetimes of these bulbs. 373 00:17:52,600 --> 00:17:54,033 So the lifetime of an incandescent 374 00:17:54,133 --> 00:17:56,633 is about 1,000 to 2,000 hours. 375 00:17:57,466 --> 00:17:58,633 And a CFL? 376 00:17:59,633 --> 00:18:01,533 About 8,000 to 12,000. 377 00:18:02,400 --> 00:18:05,333 But an LED is about 25,000. 378 00:18:05,433 --> 00:18:07,333 So, in theory, you could have a light bulb 379 00:18:07,433 --> 00:18:09,733 that lasts a really long time, 380 00:18:09,833 --> 00:18:12,066 even if it costs a little more. 381 00:18:12,166 --> 00:18:14,300 And it should be more efficient to run 382 00:18:14,400 --> 00:18:17,566 because it consumes less energy. 383 00:18:17,666 --> 00:18:20,600 So then everyone should buy them, right? 384 00:18:20,700 --> 00:18:22,700 No? Maybe? 385 00:18:24,700 --> 00:18:28,200 So, we talked a little bit about the cost, 386 00:18:28,300 --> 00:18:31,366 and this is a chart looking at ownership cost. 387 00:18:31,466 --> 00:18:33,566 So the ownership cost is the purchase price 388 00:18:33,666 --> 00:18:37,633 plus the use price normalized over the lifetime. 389 00:18:37,733 --> 00:18:41,366 And, in this case, this is all in 2010 dollars. 390 00:18:41,466 --> 00:18:43,900 And it looks at the ownership cost of light 391 00:18:44,000 --> 00:18:46,000 from 1800 to about 2011, 392 00:18:48,133 --> 00:18:49,733 where we're transitioning from fire, 393 00:18:49,833 --> 00:18:53,000 which are things like candles, kerosene lamps, 394 00:18:53,100 --> 00:18:55,266 to incandescents, fluorescents, 395 00:18:55,366 --> 00:18:58,766 high intensity discharge, LEDs, and CFLs. 396 00:19:00,933 --> 00:19:03,966 So the ownership cost has been going down, 397 00:19:04,066 --> 00:19:06,266 much like we saw in that one chart 398 00:19:06,366 --> 00:19:08,500 looking at the United Kingdom, 399 00:19:08,600 --> 00:19:12,633 where they were transitioning from gas and kerosene 400 00:19:12,733 --> 00:19:13,966 to electricity. 401 00:19:18,100 --> 00:19:21,566 And there's some other factors at play also. 402 00:19:21,666 --> 00:19:26,400 So, the Energy Independence and Security Act of 2007, 403 00:19:26,500 --> 00:19:28,166 who has heard of it? 404 00:19:29,166 --> 00:19:30,600 Four people. 405 00:19:30,700 --> 00:19:31,700 All right, we're doing well. 406 00:19:31,800 --> 00:19:33,833 [audience laughing] 407 00:19:33,933 --> 00:19:37,933 Who has heard somewhere on television or the internet 408 00:19:38,033 --> 00:19:41,733 about someone trying to ban incandescent bulbs? 409 00:19:41,833 --> 00:19:44,600 All right, we're talking about the same thing. 410 00:19:44,700 --> 00:19:48,466 So, the Energy Independence and Security Act of 2007 411 00:19:48,566 --> 00:19:51,833 took effect between 2012 and 2014. 412 00:19:51,933 --> 00:19:55,733 And it's not a ban, per se, on bulbs, 413 00:19:55,833 --> 00:19:58,966 but it requires increasing of the efficiency 414 00:19:59,066 --> 00:20:00,466 of incandescents. 415 00:20:01,833 --> 00:20:05,066 So, if you look, we've got this EcoSmart box, 416 00:20:05,166 --> 00:20:08,433 and it says it's a better incandescent. 417 00:20:08,533 --> 00:20:11,766 So it's formerly a 60-watt incandescent, 418 00:20:11,866 --> 00:20:15,833 and what they mean is it produces about 800 lumens. 419 00:20:15,933 --> 00:20:18,366 But now it requires 43 watts, 420 00:20:19,933 --> 00:20:22,533 so we've made an efficiency gain. 421 00:20:22,633 --> 00:20:24,966 You also start to see things 422 00:20:26,166 --> 00:20:28,466 like the lighting facts per bulb, 423 00:20:28,566 --> 00:20:32,300 which, does this remind anybody else of food labels? 424 00:20:32,400 --> 00:20:33,533 [audience laughing] 425 00:20:33,633 --> 00:20:36,966 That's why I'm like, calories of brightness. 426 00:20:37,066 --> 00:20:38,700 So I can tell by looking at this, 427 00:20:38,800 --> 00:20:41,033 the brightness is about 800 lumens, 428 00:20:41,133 --> 00:20:44,566 so it's a 60-watt equivalent bulb. 429 00:20:44,666 --> 00:20:46,933 And the energy used is about 13 watts, 430 00:20:47,033 --> 00:20:48,966 so it's probably a CFL. 431 00:20:51,666 --> 00:20:54,466 Or it could be a really early LED. 432 00:20:54,566 --> 00:20:56,566 And they rate the lifetime, and they say, okay, 433 00:20:56,666 --> 00:20:59,066 I'll use this for three hours a day, 434 00:20:59,166 --> 00:21:02,166 and it will last for nine years. 435 00:21:02,266 --> 00:21:05,600 So it's a way of distilling information. 436 00:21:07,133 --> 00:21:08,366 But here's the question, 437 00:21:08,466 --> 00:21:10,433 when you heard about the ban on bulbs, 438 00:21:10,533 --> 00:21:13,600 did anyone start ordering incandescents? 439 00:21:13,700 --> 00:21:15,566 [audience laughing] 440 00:21:15,666 --> 00:21:17,666 It's okay, two honest people. 441 00:21:17,766 --> 00:21:19,766 All right. 442 00:21:21,200 --> 00:21:26,066 So, this is David Brooks of Just Bulbs in Manhattan. 443 00:21:26,166 --> 00:21:28,533 And I got this from the New York Times, 444 00:21:28,633 --> 00:21:31,333 where he's commenting that he has one customer 445 00:21:31,433 --> 00:21:34,500 who's ordering thousands and thousands of incandescents, 446 00:21:34,600 --> 00:21:37,200 because she never wants to be without them, 447 00:21:37,300 --> 00:21:39,500 and to please not tell her husband. 448 00:21:39,600 --> 00:21:40,766 [audience laughing] 449 00:21:40,866 --> 00:21:42,766 So, he'll be surprised one day when he finds 450 00:21:42,866 --> 00:21:44,833 their storage unit of incandescent bulbs. 451 00:21:44,933 --> 00:21:47,233 [audience laughing] 452 00:21:47,333 --> 00:21:49,533 But, So we have interesting behaviors 453 00:21:49,633 --> 00:21:51,566 that come about too that, 454 00:21:51,666 --> 00:21:53,800 I do not want a more energy efficient bulb, 455 00:21:53,900 --> 00:21:55,900 I'm going to use this incandescent forever. 456 00:21:56,000 --> 00:21:57,333 Okay. 457 00:21:57,433 --> 00:22:00,766 That's part of evolutions of technology. 458 00:22:00,866 --> 00:22:03,200 So whenever I talk about CFLs, 459 00:22:03,300 --> 00:22:06,100 the question of mercury comes up. 460 00:22:06,200 --> 00:22:09,366 Who here knows that a CFL has mercury? 461 00:22:10,200 --> 00:22:12,200 All right. 462 00:22:14,066 --> 00:22:17,066 How much mercury do you think? 463 00:22:18,066 --> 00:22:20,766 So, I see some people saying a little bit. 464 00:22:20,866 --> 00:22:22,466 So, it's about, 465 00:22:22,566 --> 00:22:24,166 currently they have about five milligrams 466 00:22:24,266 --> 00:22:26,200 of mercury per bulb. 467 00:22:26,300 --> 00:22:28,900 And, okay, is that a lot? 468 00:22:29,000 --> 00:22:30,066 Is that a little? 469 00:22:30,166 --> 00:22:31,333 Should we care? 470 00:22:31,433 --> 00:22:34,666 There was one study that came out several years ago, 471 00:22:34,766 --> 00:22:36,166 where they said, okay, 472 00:22:36,266 --> 00:22:38,666 so there's five milligrams of mercury in the CFL, 473 00:22:38,766 --> 00:22:41,300 but it's more efficient than an incandescent. 474 00:22:41,400 --> 00:22:44,766 So what if I look at the life cycle 475 00:22:44,866 --> 00:22:47,833 and I burn coal to make my incandescent, 476 00:22:47,933 --> 00:22:50,100 power my incandescent throughout the lifetime? 477 00:22:50,200 --> 00:22:53,566 Is that, how does the mercury balance work out? 478 00:22:53,666 --> 00:22:59,100 And if you move to the CFL even though it has mercury in it, 479 00:22:59,200 --> 00:23:02,233 you're saving mercury through the gains in efficiency. 480 00:23:02,333 --> 00:23:04,100 So you're coming out ahead. 481 00:23:04,200 --> 00:23:05,366 Now, 482 00:23:06,533 --> 00:23:09,533 I've given talks similar to this enough times, 483 00:23:09,633 --> 00:23:13,100 that there are some good anecdotes that come up. 484 00:23:14,733 --> 00:23:16,433 Who here has heard of Mercurochrome? 485 00:23:16,533 --> 00:23:17,600 [audience laughing] 486 00:23:17,700 --> 00:23:19,533 All right. 487 00:23:19,633 --> 00:23:22,833 So, I was giving this talk once 488 00:23:22,933 --> 00:23:26,766 and I always, almost always, got attacked by someone 489 00:23:26,866 --> 00:23:29,066 for the mercury content in CFLs and they're terrible 490 00:23:29,166 --> 00:23:33,300 and they're going to kill us all and [muffled]. 491 00:23:33,400 --> 00:23:34,433 I was like, okay. 492 00:23:34,533 --> 00:23:36,066 So that's what I was expecting. 493 00:23:36,166 --> 00:23:37,466 And he comes up 494 00:23:37,566 --> 00:23:40,266 and he starts telling me that he doesn't think 495 00:23:40,366 --> 00:23:42,100 the mercury is a big deal. 496 00:23:42,200 --> 00:23:43,366 Okay. 497 00:23:43,466 --> 00:23:45,733 Good, someone's finally not attacking me over this. 498 00:23:45,833 --> 00:23:47,600 And so then he tells me 499 00:23:47,700 --> 00:23:48,800 about something called Mercurochrome, 500 00:23:48,900 --> 00:23:50,633 which, help me if I'm wrong, 501 00:23:50,733 --> 00:23:54,066 is something at one point we used to dab on cuts 502 00:23:54,166 --> 00:23:56,566 to sort of clean them and heal them? 503 00:23:56,666 --> 00:23:58,066 I was like, oh, okay. 504 00:23:58,166 --> 00:24:00,233 So then he proceeds to tell me 505 00:24:00,333 --> 00:24:02,800 that similar to our friend in New York 506 00:24:02,900 --> 00:24:04,000 hoarding the light bulbs, 507 00:24:04,100 --> 00:24:05,233 that he's hoarded Mercurochrome. 508 00:24:05,333 --> 00:24:06,500 [audience laughing] 509 00:24:06,600 --> 00:24:09,033 And he has boxes and boxes full of this, 510 00:24:09,133 --> 00:24:11,400 that he still uses it today, 511 00:24:11,500 --> 00:24:15,033 mercury is not a big deal, and then he pulls out a bottle. 512 00:24:15,133 --> 00:24:16,266 I was like, okay, 513 00:24:16,366 --> 00:24:19,600 I guess mercury isn't a big deal to everyone. 514 00:24:19,700 --> 00:24:22,433 And that's a really great anecdote 515 00:24:22,533 --> 00:24:25,300 to keep next time I talk about this. 516 00:24:25,400 --> 00:24:27,166 So, just a side note. 517 00:24:29,033 --> 00:24:31,166 So one way to think about this, 518 00:24:31,266 --> 00:24:33,100 and I alluded to this a little bit 519 00:24:33,200 --> 00:24:36,333 when I was talking about the mercury in a CFL 520 00:24:36,433 --> 00:24:40,366 versus if you burned coal for the lifetime of incandescent. 521 00:24:40,466 --> 00:24:43,600 So, something called life cycle assessment. 522 00:24:43,700 --> 00:24:45,600 Has anyone heard of it? 523 00:24:46,800 --> 00:24:48,600 Okay, three or four people in the back. 524 00:24:48,700 --> 00:24:50,100 That's a good start. 525 00:24:50,200 --> 00:24:52,900 So life cycle assessment is a systematic tool 526 00:24:53,000 --> 00:24:55,466 for looking at the environmental impact 527 00:24:55,566 --> 00:24:58,700 of a product or process throughout its lifetime. 528 00:24:58,800 --> 00:24:59,900 So you're breaking it down 529 00:25:00,000 --> 00:25:01,833 into components like raw materials. 530 00:25:01,933 --> 00:25:04,433 What's the environmental impact of my raw materials? 531 00:25:04,533 --> 00:25:07,500 What is the environmental impact of my manufacturing? 532 00:25:07,600 --> 00:25:09,000 What about the use phase? 533 00:25:09,100 --> 00:25:11,166 So in this case, when I take the light bulb home, 534 00:25:11,266 --> 00:25:13,900 I put it in the socket, I turn it on. 535 00:25:14,000 --> 00:25:15,233 And what about end of life? 536 00:25:15,333 --> 00:25:17,333 What happens when it's done? 537 00:25:17,433 --> 00:25:20,966 So there's some Coca-Cola bottles on this slide, 538 00:25:21,066 --> 00:25:23,900 and that's because the first documented life cycle 539 00:25:24,000 --> 00:25:27,300 assessment was actually done by the Coca-Cola Company, 540 00:25:27,400 --> 00:25:29,300 I believe in the 1960s. 541 00:25:30,666 --> 00:25:32,533 And they were curious about the energy consumption 542 00:25:32,633 --> 00:25:34,333 for their packaging, 543 00:25:34,433 --> 00:25:37,066 because energy means money. 544 00:25:37,166 --> 00:25:40,200 And they wanted to know what kind of packaging should I use? 545 00:25:40,300 --> 00:25:42,566 What should I put my soda in? 546 00:25:42,666 --> 00:25:46,400 Or I could say pop because I'm from Michigan. 547 00:25:47,766 --> 00:25:50,033 And so the study results were never released, 548 00:25:50,133 --> 00:25:51,300 but that's sort of what we herald 549 00:25:51,400 --> 00:25:54,300 as the first life cycle assessment. 550 00:25:58,666 --> 00:26:00,666 So, to put that in perspective, 551 00:26:00,766 --> 00:26:01,933 we can look at one. 552 00:26:02,033 --> 00:26:03,866 This is from the US Department of Energy 553 00:26:03,966 --> 00:26:06,400 for an incandescent light bulb. 554 00:26:06,500 --> 00:26:10,900 And I've got the electricity generation mix on the side, 555 00:26:11,000 --> 00:26:13,533 because that's a valid point in this. 556 00:26:13,633 --> 00:26:16,333 And, okay, so you have your materials and manufacturing, 557 00:26:16,433 --> 00:26:17,966 it's a very small part of the life cycle 558 00:26:18,066 --> 00:26:19,566 environmental impact. 559 00:26:19,666 --> 00:26:21,700 And the really big part is the use phase. 560 00:26:21,800 --> 00:26:24,533 So when you take your light bulb home and you use it. 561 00:26:24,633 --> 00:26:26,633 And on the bottom we've got all of these categories. 562 00:26:26,733 --> 00:26:29,100 So you see things like global warming. 563 00:26:29,200 --> 00:26:30,700 And global warming, 564 00:26:30,800 --> 00:26:35,366 has anyone heard of an environmental footprint? 565 00:26:35,466 --> 00:26:38,266 Right, so these are different units to do. 566 00:26:38,366 --> 00:26:39,733 So global warming, 567 00:26:39,833 --> 00:26:42,033 you're thinking about carbon dioxide emissions. 568 00:26:42,133 --> 00:26:44,700 Nitrification you're worried about nitrogen. 569 00:26:44,800 --> 00:26:46,700 And we like to look at a suite, 570 00:26:46,800 --> 00:26:48,366 because you might find that while something 571 00:26:48,466 --> 00:26:51,600 is very good in one category, it is very bad in another. 572 00:26:51,700 --> 00:26:54,433 And you need to think about the environmental trade-offs. 573 00:26:54,533 --> 00:26:56,100 So, it's long been established 574 00:26:56,200 --> 00:26:58,366 that the environmental impact for incandescent lighting 575 00:26:58,466 --> 00:27:00,366 is during the use phase. 576 00:27:00,466 --> 00:27:02,700 So the question was, what about these new, 577 00:27:02,800 --> 00:27:04,966 more energy-efficient lights? 578 00:27:05,066 --> 00:27:06,200 They're more energy efficient, 579 00:27:06,300 --> 00:27:08,300 so they should have less use phase impact, 580 00:27:08,400 --> 00:27:10,900 but they require more raw materials. 581 00:27:11,000 --> 00:27:13,666 So how does this balance out? 582 00:27:13,766 --> 00:27:17,333 So, we can look at a compact fluorescent, 583 00:27:17,433 --> 00:27:19,500 and the use phase is still dominant. 584 00:27:19,600 --> 00:27:22,800 Although, some phases like non-carcinogenics, 585 00:27:22,900 --> 00:27:26,200 we start to see more in materials and manufacturing. 586 00:27:26,300 --> 00:27:28,300 And the same is true when we start to think about 587 00:27:28,400 --> 00:27:30,600 light emitting diodes. 588 00:27:30,700 --> 00:27:33,833 And in categories like non-carcinogenics, 589 00:27:33,933 --> 00:27:36,466 the bigger manufacturing and materials cost 590 00:27:36,566 --> 00:27:38,233 has to do with the heat syncs 591 00:27:38,333 --> 00:27:41,966 that go into making light emitting diodes. 592 00:27:42,066 --> 00:27:43,933 But we're going to go back. 593 00:27:44,033 --> 00:27:45,766 So we know the use phase is dominant, 594 00:27:45,866 --> 00:27:49,100 and we know the ownership cost has been going down, 595 00:27:49,200 --> 00:27:51,700 so it costs less to use these. 596 00:27:52,900 --> 00:27:57,266 So, who's ever heard of William Stanley Jevons? 597 00:27:57,366 --> 00:28:00,366 All right, I got like three or four people again. 598 00:28:00,466 --> 00:28:03,700 So, he is an economist from the 1800s, 599 00:28:05,000 --> 00:28:06,833 and he was looking at coal. 600 00:28:06,933 --> 00:28:10,700 And he said when the efficiency of coal usage increases, 601 00:28:10,800 --> 00:28:13,333 we're actually using more coal, 602 00:28:13,433 --> 00:28:16,166 which was this big revolutionary idea at the time. 603 00:28:16,266 --> 00:28:19,333 And some people would say it's revolutionary today. 604 00:28:19,433 --> 00:28:22,700 If it's more efficient, how are we consuming more? 605 00:28:22,800 --> 00:28:24,466 So who thinks we do? 606 00:28:25,600 --> 00:28:28,200 Discounting the title of this talk, 607 00:28:28,300 --> 00:28:31,966 of energy efficiency and the rebound effect. 608 00:28:33,700 --> 00:28:36,666 So, there was a study out of MIT, 609 00:28:36,766 --> 00:28:39,600 that looked at multiple industries 610 00:28:41,000 --> 00:28:44,866 over multiple time periods and geographic scales. 611 00:28:44,966 --> 00:28:47,900 And they said, okay, we can look at 612 00:28:49,200 --> 00:28:52,533 the annual average change in efficiency. 613 00:28:54,166 --> 00:28:56,066 So that's your delta E over E. 614 00:28:56,166 --> 00:28:58,866 And we can look at the change in consumption. 615 00:28:58,966 --> 00:29:01,366 And if the change in consumption 616 00:29:01,466 --> 00:29:03,533 is more than the change in efficiency, 617 00:29:03,633 --> 00:29:06,833 we're going to out-consume our benefits of efficiency. 618 00:29:06,933 --> 00:29:09,500 So, if you look at the last column, 619 00:29:09,600 --> 00:29:12,833 with delta Q over Q and delta E over E, 620 00:29:14,000 --> 00:29:16,466 all of the numbers are bigger than one, 621 00:29:16,566 --> 00:29:18,933 which means that over the time scales they looked at, 622 00:29:19,033 --> 00:29:21,766 we out-consumed all the benefits of efficiency 623 00:29:21,866 --> 00:29:24,366 from a consumption standpoint. 624 00:29:25,400 --> 00:29:27,966 And they qualified this though. 625 00:29:28,066 --> 00:29:30,400 They said in the short-term, 626 00:29:30,500 --> 00:29:33,166 you might see savings because increased consumption 627 00:29:33,266 --> 00:29:37,600 hasn't caught up with your increases in efficiency. 628 00:29:37,700 --> 00:29:38,900 But on the long-term, 629 00:29:39,000 --> 00:29:41,766 we haven't seen this in any of these industries. 630 00:29:41,866 --> 00:29:43,633 And they took a large spread of things 631 00:29:43,733 --> 00:29:47,900 like passenger air travel, motor vehicles, refrigeration. 632 00:29:50,000 --> 00:29:54,466 So, one question would be, how do you consume more light? 633 00:29:54,566 --> 00:29:56,400 Do we buy more lights? 634 00:29:57,833 --> 00:30:00,333 So, suddenly the cost of lighting has gone down, 635 00:30:00,433 --> 00:30:02,300 I'll buy more? 636 00:30:02,400 --> 00:30:04,300 I buy brighter lights. 637 00:30:04,400 --> 00:30:07,166 This goes back to when we were talking about 638 00:30:07,266 --> 00:30:09,333 electric lighting in Chicago, 639 00:30:09,433 --> 00:30:12,033 where they were saying what had once seemed adequate 640 00:30:12,133 --> 00:30:13,566 for indoor lighting, 641 00:30:13,666 --> 00:30:17,400 suddenly seemed dim and dark and hopeless and depressing. 642 00:30:17,500 --> 00:30:20,066 So let's have more light because we can have more light, 643 00:30:20,166 --> 00:30:23,233 and we think we need more light. 644 00:30:23,333 --> 00:30:26,166 You could leave the lights on longer. 645 00:30:26,266 --> 00:30:29,000 Maybe you never turn off your lights then, 646 00:30:29,100 --> 00:30:31,033 because they're efficient. 647 00:30:31,133 --> 00:30:33,500 It's an extreme example, 648 00:30:33,600 --> 00:30:34,800 but it's possible. 649 00:30:34,900 --> 00:30:37,733 And the more times I've given a talk like this, 650 00:30:37,833 --> 00:30:42,133 someone will say, no, I would never ever ever 651 00:30:42,233 --> 00:30:45,700 leave my lights on longer, never. 652 00:30:45,800 --> 00:30:47,000 And then they'll start telling me that, 653 00:30:47,100 --> 00:30:48,400 you know, I bought this LED. 654 00:30:48,500 --> 00:30:50,400 I'm like, great, you bought an LED. 655 00:30:50,500 --> 00:30:54,300 And I decided to put in on my garage, 656 00:30:54,400 --> 00:30:55,933 and now I leave it on all night, 657 00:30:56,033 --> 00:30:58,566 because it's so cheap to run. 658 00:30:58,666 --> 00:31:00,066 Okay. 659 00:31:00,166 --> 00:31:04,800 Well, that goes back to our safety, to what is light. 660 00:31:04,900 --> 00:31:06,366 And there's some utility of light 661 00:31:06,466 --> 00:31:09,133 that you can't really measure for lumens per watt. 662 00:31:09,233 --> 00:31:12,433 It's what is safety, what is security? 663 00:31:16,366 --> 00:31:19,066 So, there, this is results from a study 664 00:31:19,166 --> 00:31:23,333 that looked at how long do people leave their lights on. 665 00:31:24,233 --> 00:31:26,600 And this is a national survey 666 00:31:26,700 --> 00:31:30,800 that looked at five or six major metropolitan areas. 667 00:31:30,900 --> 00:31:33,066 So there's a spread. 668 00:31:33,166 --> 00:31:37,333 The average is 8.9 hours per day plus or minus 5.1. 669 00:31:38,166 --> 00:31:39,233 Okay. 670 00:31:40,966 --> 00:31:44,966 And the most commonly occurring value was six. 671 00:31:45,066 --> 00:31:46,333 However, if you look, there are people 672 00:31:46,433 --> 00:31:48,766 who leave their lights on one hour per day, 673 00:31:48,866 --> 00:31:52,833 and people who leave their lights on 24 hours per day. 674 00:31:52,933 --> 00:31:54,666 So, looking at this, I would say 675 00:31:54,766 --> 00:31:57,433 the population is heterogeneous. 676 00:31:58,266 --> 00:31:59,833 And I get nods. 677 00:31:59,933 --> 00:32:01,833 So, they're different. 678 00:32:03,066 --> 00:32:05,466 And we can look at questions. 679 00:32:06,666 --> 00:32:08,833 This is a slightly older study. 680 00:32:08,933 --> 00:32:12,766 So, what's the highest price you would pay for an LED? 681 00:32:12,866 --> 00:32:16,866 And at the time of the study, an LED was $33.99. 682 00:32:18,433 --> 00:32:22,266 And most people said they would pay about $17. 683 00:32:24,000 --> 00:32:27,766 Does anyone remember what we're at now? 684 00:32:27,866 --> 00:32:29,500 Right, about $4.50. 685 00:32:29,600 --> 00:32:30,966 So, in theory, based on this, 686 00:32:31,066 --> 00:32:33,866 we should see people buying a lot more LEDs. 687 00:32:33,966 --> 00:32:36,566 But populations are heterogeneous, 688 00:32:36,666 --> 00:32:39,666 people interpret things differently. 689 00:32:39,766 --> 00:32:43,166 And this was a really interesting question from the survey, 690 00:32:43,266 --> 00:32:46,266 where we asked, we framed the same question 691 00:32:46,366 --> 00:32:48,833 three different ways, essentially. 692 00:32:48,933 --> 00:32:51,833 And we called it light bulb A, 693 00:32:51,933 --> 00:32:54,200 light bulb B, and light bulb C. 694 00:32:54,300 --> 00:32:58,466 So A is an incandescent, B is a CFL, and C is an LED. 695 00:32:59,566 --> 00:33:02,066 So, we framed asking people, 696 00:33:02,166 --> 00:33:04,433 so it costs so many dollars 697 00:33:04,533 --> 00:33:05,733 and it lasts for so many hours, 698 00:33:05,833 --> 00:33:07,500 what would you pick? 699 00:33:07,600 --> 00:33:09,733 And then we asked the same question, 700 00:33:09,833 --> 00:33:11,200 it costs so much 701 00:33:11,300 --> 00:33:14,666 and it would cost you this much to run per year, 702 00:33:14,766 --> 00:33:16,766 which would you pick? 703 00:33:16,866 --> 00:33:18,700 And then we also said, okay, 704 00:33:18,800 --> 00:33:20,233 it costs this much to purchase, 705 00:33:20,333 --> 00:33:21,600 and for the same amount of money 706 00:33:21,700 --> 00:33:25,366 you could drive so many miles per year, 707 00:33:25,466 --> 00:33:27,633 which would you pick? 708 00:33:27,733 --> 00:33:30,866 So across all three, about half the respondents 709 00:33:30,966 --> 00:33:33,233 said they would pick option B, the CFL, 710 00:33:33,333 --> 00:33:35,766 and they didn't know it was a CFL. 711 00:33:35,866 --> 00:33:37,666 I'm sure if they Googled it, 712 00:33:37,766 --> 00:33:40,200 they would have known it was the CFL. 713 00:33:40,300 --> 00:33:42,733 But you see this movement between question 18, 714 00:33:42,833 --> 00:33:46,233 and then when you look at question 19 and 20 of, 715 00:33:46,333 --> 00:33:47,466 LED versus incandescent. 716 00:33:47,566 --> 00:33:49,633 So there's some interesting issues of perception 717 00:33:49,733 --> 00:33:52,200 of what is efficient, what should I buy, 718 00:33:52,300 --> 00:33:53,900 how should we word things. 719 00:33:55,766 --> 00:33:58,200 So, how should we model this? 720 00:34:00,566 --> 00:34:03,966 Has anyone heard of an agent-based model? 721 00:34:04,066 --> 00:34:07,000 Maybe a social scientist out there? 722 00:34:08,000 --> 00:34:10,000 So, agent-based modeling 723 00:34:11,766 --> 00:34:13,566 has roots in the social sciences. 724 00:34:13,666 --> 00:34:17,833 And it's a method commonly used to model individuals. 725 00:34:19,900 --> 00:34:21,033 And it's really good at that, 726 00:34:21,133 --> 00:34:23,800 and it's been used to model things like fish, 727 00:34:23,900 --> 00:34:27,633 geese flying in a V, sheep, and people. 728 00:34:27,733 --> 00:34:30,666 But there's more, those are just a few examples. 729 00:34:30,766 --> 00:34:32,900 And the idea is you have all these individuals 730 00:34:33,000 --> 00:34:34,400 following some set of rules, 731 00:34:34,500 --> 00:34:39,200 seeking to maximize some utility, and what do they do. 732 00:34:39,300 --> 00:34:40,533 So there's this question of, 733 00:34:40,633 --> 00:34:42,666 could we apply this to lighting? 734 00:34:42,766 --> 00:34:43,866 What do people do 735 00:34:43,966 --> 00:34:46,400 if they can pick energy efficient lighting? 736 00:34:46,500 --> 00:34:50,666 So the result is this nice chart for an agent-based model, 737 00:34:51,900 --> 00:34:53,866 where you've got some population 738 00:34:53,966 --> 00:34:57,300 that we informed with our survey data, 739 00:34:57,400 --> 00:34:59,166 and if their bulb is burned out, 740 00:34:59,266 --> 00:35:01,466 they go and buy a new light bulb. 741 00:35:01,566 --> 00:35:03,500 Okay, that's a good assumption. 742 00:35:03,600 --> 00:35:05,333 If it burns out, I'll buy a new one. 743 00:35:05,433 --> 00:35:08,300 They use some probabilistic utility to decide 744 00:35:08,400 --> 00:35:09,933 which light bulb based on the fact 745 00:35:10,033 --> 00:35:12,533 they're a heterogeneous population. 746 00:35:12,633 --> 00:35:16,900 So, different people value things differently. 747 00:35:17,000 --> 00:35:19,400 And then, if their bulb is more efficient, 748 00:35:19,500 --> 00:35:21,466 they have this question of, do they consumer more light? 749 00:35:21,566 --> 00:35:24,166 And I was informed with the survey data 750 00:35:24,266 --> 00:35:26,533 that some people will consume more light. 751 00:35:26,633 --> 00:35:28,533 And the question of how much, 752 00:35:28,633 --> 00:35:31,933 is sort of this interesting tipping point we looked at. 753 00:35:32,033 --> 00:35:34,666 So okay, we've got some sort of model. 754 00:35:34,766 --> 00:35:38,766 What do we know about the data we put in the model? 755 00:35:38,866 --> 00:35:42,533 So, one question on the survey that went to this model, 756 00:35:42,633 --> 00:35:43,900 was your environmental mindfulness, 757 00:35:44,000 --> 00:35:45,266 or your environmental attitude. 758 00:35:45,366 --> 00:35:48,000 How environmentally friendly do you think you are? 759 00:35:48,100 --> 00:35:49,266 Do you care? 760 00:35:51,200 --> 00:35:52,900 And this is looking at 761 00:35:53,000 --> 00:35:55,466 statistically significant correlations, 762 00:35:55,566 --> 00:35:58,233 for people who thought they were extremely mindful. 763 00:35:58,333 --> 00:36:00,866 And, okay, so they want to save energy. 764 00:36:00,966 --> 00:36:02,633 They're concerned about environmental friendliness 765 00:36:02,733 --> 00:36:04,866 of what they buy. 766 00:36:04,966 --> 00:36:06,233 They apparently were not that interested 767 00:36:06,333 --> 00:36:08,066 in the quality of light, 768 00:36:08,166 --> 00:36:10,900 or how long their light bulbs lasted, 769 00:36:11,000 --> 00:36:12,366 which I thought was interesting 770 00:36:12,466 --> 00:36:15,900 because you would worry about, well I'm throwing it out. 771 00:36:16,000 --> 00:36:18,833 In the survey, more than 50% of the people 772 00:36:18,933 --> 00:36:21,833 threw them out and did not recycle. 773 00:36:23,866 --> 00:36:26,066 Then we have our average mindfulness. 774 00:36:26,166 --> 00:36:27,833 They're actually worried about the lifetime of the bulb. 775 00:36:27,933 --> 00:36:29,666 So it's just interesting to think about 776 00:36:29,766 --> 00:36:32,766 the heterogeneity of the population. 777 00:36:34,400 --> 00:36:37,800 And, okay, so one way you can think about 778 00:36:37,900 --> 00:36:40,333 making these agents in a model, 779 00:36:40,433 --> 00:36:41,966 is they were trying, 780 00:36:42,066 --> 00:36:44,700 how would they pick a light bulb? 781 00:36:44,800 --> 00:36:47,533 So, in order to use a probabilistic utility, 782 00:36:47,633 --> 00:36:51,300 the question was, what do you think is most important, 783 00:36:51,400 --> 00:36:52,900 when you pick a light bulb? 784 00:36:53,000 --> 00:36:54,700 Because we all go and buy a light bulb 785 00:36:54,800 --> 00:36:58,600 and we think about this internally, maybe not formally. 786 00:36:58,700 --> 00:37:01,033 But there's trade-offs. 787 00:37:01,133 --> 00:37:04,500 And so 36% of the respondents 788 00:37:04,600 --> 00:37:06,433 thought saving money as a result 789 00:37:06,533 --> 00:37:09,300 of increased efficiency was most important. 790 00:37:09,400 --> 00:37:13,500 Only 12% ranked environmental friendliness as the first. 791 00:37:13,600 --> 00:37:16,600 So yet again we have a spread of data. 792 00:37:16,700 --> 00:37:19,566 We also said, would you use more if you adopted 793 00:37:19,666 --> 00:37:22,666 a more energy efficient light bulb? 794 00:37:22,766 --> 00:37:26,233 Which is crude and surveys are never perfect. 795 00:37:26,333 --> 00:37:27,933 Every time I talk about something like this, 796 00:37:28,033 --> 00:37:30,133 people tell me surveys are never perfect. 797 00:37:30,233 --> 00:37:33,166 And I say yes, they're not, I know. 798 00:37:34,500 --> 00:37:37,566 So about 50% said they would use more light. 799 00:37:37,666 --> 00:37:40,566 And we said, okay, well, how would we use more light? 800 00:37:40,666 --> 00:37:45,133 So, of that, 33% would leave current lights on longer, 801 00:37:45,233 --> 00:37:46,933 31% would purchase more lights. 802 00:37:47,033 --> 00:37:48,866 And you could do both. 803 00:37:50,233 --> 00:37:51,500 So, we have this model. 804 00:37:51,600 --> 00:37:53,400 We have some scenarios, 805 00:37:53,500 --> 00:37:56,100 predicated on the rebound effect or Jevons' paradox. 806 00:37:56,200 --> 00:37:58,366 The idea that people will consume more. 807 00:37:58,466 --> 00:38:01,466 So there's scenarios with varying degrees of, 808 00:38:01,566 --> 00:38:05,000 if you consume more, how much more light would you consume? 809 00:38:05,100 --> 00:38:06,466 Because the question is, when are you 810 00:38:06,566 --> 00:38:10,833 going to erode the savings gained by efficiency? 811 00:38:10,933 --> 00:38:12,900 So it varies from no rebound, 812 00:38:13,000 --> 00:38:14,500 and we have some spontaneous adoption 813 00:38:14,600 --> 00:38:16,233 where people say I don't care 814 00:38:16,333 --> 00:38:17,733 that my light bulb's not burned out. 815 00:38:17,833 --> 00:38:21,466 This LED is so cool, I must go buy one right now, 816 00:38:21,566 --> 00:38:22,933 which happens. 817 00:38:23,033 --> 00:38:26,600 We're all guilty of that sometimes with some things. 818 00:38:26,700 --> 00:38:29,966 To scenario eight, which is extreme rebound. 819 00:38:30,066 --> 00:38:32,466 If you buy a more energy efficient bulb 820 00:38:32,566 --> 00:38:34,033 and you're that 50% of the population, 821 00:38:34,133 --> 00:38:38,300 you will leave your lights on 75% longer and buy 75% more. 822 00:38:41,933 --> 00:38:45,500 So, the results aren't that surprising. 823 00:38:45,600 --> 00:38:47,733 We have our average annual household light consumption 824 00:38:47,833 --> 00:38:49,900 in mega lumen hours. 825 00:38:50,000 --> 00:38:52,800 So, in the extreme scenarios, 826 00:38:52,900 --> 00:38:55,633 the respondent, you consume a lot more light. 827 00:38:55,733 --> 00:38:57,833 You'd expect this. 828 00:38:57,933 --> 00:38:59,666 So the question was really, 829 00:38:59,766 --> 00:39:02,666 what does energy consumption look like? 830 00:39:02,766 --> 00:39:07,533 And in the extreme scenarios, you consume a lot more energy, 831 00:39:07,633 --> 00:39:11,533 more energy than you were consuming initially. 832 00:39:11,633 --> 00:39:13,933 So, what does this mean? 833 00:39:14,033 --> 00:39:16,266 So, this is comparing with some data 834 00:39:16,366 --> 00:39:18,733 from the US Department of Energy. 835 00:39:18,833 --> 00:39:20,233 In their earlier studies, 836 00:39:20,333 --> 00:39:23,200 they didn't consider the rebound effect, 837 00:39:23,300 --> 00:39:27,466 but they did consider a 1.75% annual growth in lit spaces, 838 00:39:28,666 --> 00:39:32,366 due to bigger houses and expansion of lit spaces. 839 00:39:32,466 --> 00:39:36,233 So, this is comparing their data, the US DOE, 840 00:39:38,600 --> 00:39:42,033 with the non-extreme rebound scenarios. 841 00:39:42,133 --> 00:39:44,600 So, in the study we found that, okay, 842 00:39:44,700 --> 00:39:47,166 we can predict that energy consumption for light 843 00:39:47,266 --> 00:39:48,766 will drop a lot. 844 00:39:48,866 --> 00:39:51,833 And then eventually it'll inch back up, 845 00:39:51,933 --> 00:39:54,233 which is what the paper by [muffled] out of MIT, 846 00:39:54,333 --> 00:39:56,033 that looked at all the sectors, said. 847 00:39:56,133 --> 00:39:57,666 Unless we come up with something new, 848 00:39:57,766 --> 00:40:00,300 or we come up with a policy, 849 00:40:00,400 --> 00:40:03,633 we're eventually going to out-consume. 850 00:40:03,733 --> 00:40:07,166 So this brings up an interesting question 851 00:40:08,100 --> 00:40:11,200 called the saturation of light. 852 00:40:11,300 --> 00:40:14,566 So what is the limit for light? 853 00:40:14,666 --> 00:40:17,066 Is it constant daylight? 854 00:40:17,166 --> 00:40:20,066 Everywhere, all the time, outside even? 855 00:40:20,166 --> 00:40:23,166 Is it light of a certain brightness? 856 00:40:24,400 --> 00:40:26,400 Does the saturation for light in a room 857 00:40:26,500 --> 00:40:29,666 change depending on who's designing it? 858 00:40:29,766 --> 00:40:31,366 So we don't know. 859 00:40:31,466 --> 00:40:34,966 And there was a paper a few years ago 860 00:40:35,066 --> 00:40:37,366 by Tsao et al, that said, 861 00:40:38,533 --> 00:40:40,300 it was a controversial paper. 862 00:40:40,400 --> 00:40:42,266 They got lots of comments. 863 00:40:43,433 --> 00:40:45,766 That said using a Cobb-Douglas framework, 864 00:40:46,766 --> 00:40:49,466 we don't think we've reached saturation of light 865 00:40:49,566 --> 00:40:50,633 anywhere in the world. 866 00:40:50,733 --> 00:40:51,900 Okay. 867 00:40:53,233 --> 00:40:54,733 So, going on that, there's this question of, 868 00:40:54,833 --> 00:40:57,266 what is saturation of light? 869 00:40:57,366 --> 00:40:58,433 What does it look like? 870 00:40:58,533 --> 00:41:01,633 But there's this question because LEDs 871 00:41:01,733 --> 00:41:04,433 are an enabling technology. 872 00:41:04,533 --> 00:41:08,500 So what if we start using light and lighting, 873 00:41:08,600 --> 00:41:10,966 for things we never have before? 874 00:41:11,066 --> 00:41:14,766 Or what if we start using bigger things 875 00:41:14,866 --> 00:41:16,533 we haven't thought of? 876 00:41:16,633 --> 00:41:19,900 So this is looking at television screens. 877 00:41:21,066 --> 00:41:26,333 So the new flat screens commonly have LEDs or all LEDs. 878 00:41:27,500 --> 00:41:29,800 TV screens are getting bigger. 879 00:41:30,966 --> 00:41:32,133 In 2015, 880 00:41:33,300 --> 00:41:34,966 52% of television sales 881 00:41:35,066 --> 00:41:37,766 were between 40 and 49 inches, 882 00:41:37,866 --> 00:41:41,033 and 20% was greater than 49 inches. 883 00:41:41,133 --> 00:41:43,333 So, it's an enabling technology, 884 00:41:43,433 --> 00:41:45,600 we can make bigger televisions. 885 00:41:45,700 --> 00:41:48,900 We're consuming in ways we hadn't thought. 886 00:41:49,000 --> 00:41:50,266 What about this? 887 00:41:53,266 --> 00:41:55,600 Does anyone recognize this? 888 00:41:57,466 --> 00:41:58,966 So, County Stadium 889 00:42:00,666 --> 00:42:02,966 and circa 1950s, I believe. 890 00:42:05,566 --> 00:42:07,566 So this is a scoreboard. 891 00:42:09,100 --> 00:42:12,300 And County Stadium no longer exists. 892 00:42:12,400 --> 00:42:16,500 But does the scoreboard in Miller Park look like this? 893 00:42:16,600 --> 00:42:18,100 No. 894 00:42:18,200 --> 00:42:20,933 So, okay, this might have had some light, 895 00:42:21,033 --> 00:42:24,700 but it's not some brightly lit television display. 896 00:42:24,800 --> 00:42:25,900 And here we go. 897 00:42:26,000 --> 00:42:28,233 This is a scoreboard at Miller Park. 898 00:42:28,333 --> 00:42:32,100 And we've got this black and orange lighting. 899 00:42:33,066 --> 00:42:35,000 And what about today? 900 00:42:35,100 --> 00:42:38,700 We seem to have caught Clay Matthews. 901 00:42:38,800 --> 00:42:40,133 So we're using light in ways 902 00:42:40,233 --> 00:42:42,366 we wouldn't have thought to in the past. 903 00:42:42,466 --> 00:42:44,866 If you would ask someone in the 1950s, 904 00:42:44,966 --> 00:42:47,000 is this the scoreboard of the future, 905 00:42:47,100 --> 00:42:49,533 I don't know that they would have known. 906 00:42:49,633 --> 00:42:51,733 So it's hard to come up with a saturation for light 907 00:42:51,833 --> 00:42:55,300 and a limit, if we have all these new ways to use it. 908 00:42:55,400 --> 00:42:57,900 And another example is a book. 909 00:42:59,533 --> 00:43:01,800 So, Silent Spring by Rachel Carson, 910 00:43:01,900 --> 00:43:06,666 a very famous book credited with the environmental movement, 911 00:43:06,766 --> 00:43:09,000 talking about the dangers of chemicals, 912 00:43:09,100 --> 00:43:10,466 which isn't really a topic of this. 913 00:43:10,566 --> 00:43:14,633 But, okay, is this the only way to read books today? 914 00:43:16,666 --> 00:43:17,800 No. 915 00:43:18,633 --> 00:43:19,800 All right. 916 00:43:19,900 --> 00:43:22,166 So this is the first Kindle 917 00:43:23,733 --> 00:43:25,400 in, I believe, 2007. 918 00:43:26,700 --> 00:43:28,433 So only 11 years ago. 919 00:43:29,866 --> 00:43:34,000 And both of these are not backlit, you need light, 920 00:43:34,100 --> 00:43:36,433 but light comes from external sources, 921 00:43:36,533 --> 00:43:39,766 like for illumination in the room. 922 00:43:39,866 --> 00:43:42,533 But then we go to something like the Kindle Fire, 923 00:43:42,633 --> 00:43:43,966 which you can buy today, 924 00:43:44,066 --> 00:43:48,433 or many people probably bought on Prime Day yesterday. 925 00:43:48,533 --> 00:43:49,633 And you still need light, 926 00:43:49,733 --> 00:43:52,133 but you've got this backlit screen. 927 00:43:52,233 --> 00:43:53,533 So we're using light in new ways 928 00:43:53,633 --> 00:43:56,533 that we haven't thought of before. 929 00:43:56,633 --> 00:43:58,566 And I mentioned 930 00:43:58,666 --> 00:44:03,000 that LED is an enabling technology and novelties. 931 00:44:03,100 --> 00:44:04,666 So we're using ways, 932 00:44:04,766 --> 00:44:07,366 we're lighting things that we wouldn't have lit before also. 933 00:44:07,466 --> 00:44:09,666 So we've got LED screens, 934 00:44:09,766 --> 00:44:13,366 but how about some pretend candles that change color? 935 00:44:13,466 --> 00:44:15,166 Or light-up glasses? 936 00:44:15,266 --> 00:44:16,733 Or rope lighting, which, on the way in, 937 00:44:16,833 --> 00:44:19,366 someone told me they bought for their garage. 938 00:44:19,466 --> 00:44:21,966 Or what about a light-up shower? 939 00:44:22,066 --> 00:44:24,533 You can buy it with an LED. 940 00:44:24,633 --> 00:44:25,900 And light-up balloons 941 00:44:26,000 --> 00:44:30,166 and snuggly children's nightlights that don't get hot. 942 00:44:31,533 --> 00:44:33,366 So, it's hard to come up with this saturation of light 943 00:44:33,466 --> 00:44:35,000 if we have all of these new 944 00:44:35,100 --> 00:44:37,933 enabled technologies coming about. 945 00:44:39,333 --> 00:44:42,100 So just to think about conclusions a little bit. 946 00:44:42,200 --> 00:44:43,966 Historically, artificial light has been about 947 00:44:44,066 --> 00:44:45,033 more than just illumination. 948 00:44:45,133 --> 00:44:46,200 It's progress. 949 00:44:46,300 --> 00:44:47,666 It's wealth. 950 00:44:47,766 --> 00:44:49,500 It's a status symbol. 951 00:44:50,633 --> 00:44:53,400 And there's a potential to save energy, 952 00:44:53,500 --> 00:44:57,200 if we adopt energy efficient technology for a while. 953 00:44:57,300 --> 00:44:59,766 But eventually they either need to come up with a policy, 954 00:44:59,866 --> 00:45:02,666 or we need to come up with a more efficient technology, 955 00:45:02,766 --> 00:45:05,533 if we're considering the rebound effect. 956 00:45:05,633 --> 00:45:07,333 What is the saturation of light? 957 00:45:07,433 --> 00:45:09,233 That's a good question. 958 00:45:09,333 --> 00:45:12,733 It depends what we're coming up with next. 959 00:45:12,833 --> 00:45:15,133 And there are many novel uses of light, 960 00:45:15,233 --> 00:45:18,233 from children's toys to light-up showers, 961 00:45:18,333 --> 00:45:20,100 which I don't have. 962 00:45:20,200 --> 00:45:24,466 But, maybe someone does and that'd be very exciting. 963 00:45:24,566 --> 00:45:25,900 So, with that, I need to thank 964 00:45:26,000 --> 00:45:27,366 the University of Illinois Institute 965 00:45:27,466 --> 00:45:29,466 for Environmental Science and Policy, 966 00:45:29,566 --> 00:45:31,733 and the Civil and Environmental Engineering Department, 967 00:45:31,833 --> 00:45:35,900 here at the University of Wisconsin, Madison. 968 00:45:36,000 --> 00:45:38,566 And I enjoy this for questions. 969 00:45:39,533 --> 00:45:42,700 [audience applauding]