0:00:12.494,0:00:17.392 Every individual needs energy to live[br]and to make his body work. 0:00:17.611,0:00:24.006 You, I, that refugee in Syria,[br]each of us needs energy. 0:00:24.136,0:00:26.646 The amount of energy that we need, 0:00:26.646,0:00:32.141 I can express it as a definite[br]quantity: 25 cl of petrol. 0:00:32.708,0:00:36.925 This is the energy equivalent[br]that we consume and need daily. 0:00:37.295,0:00:42.894 Our society, our civilisation[br]has developed a set of technologies 0:00:42.894,0:00:48.957 that enables us to guarantee our comfort[br]but actually consumes much more energy. 0:00:49.410,0:00:52.354 So, first, we produce waste: 0:00:52.354,0:00:59.021 each of us produces 2 kg of waste daily,[br]30% of which is organic waste, 0:00:59.032,0:01:04.156 that is, the residue of the food we eat, 0:01:04.156,0:01:06.667 the food that Nature gives us. 0:01:08.121,0:01:14.240 We consume energy: 5 litres of petrol[br]is the daily average in Switzerland. 0:01:14.500,0:01:17.264 The problem is that we burn it 0:01:17.264,0:01:20.434 and, as a result, it releases CO2: 0:01:20.434,0:01:22.274 14 kg every day. 0:01:22.684,0:01:26.744 Fourteen kilos per day,[br]imagine if it were solid, 0:01:26.744,0:01:32.047 you'd have to leave home each morning[br]with two packs of six bottles of water[br] 0:01:32.067,0:01:34.445 and put them on the pavement. 0:01:34.665,0:01:39.776 Fourteen kilos per day ...[br]Luckily, it is a gas.[br] 0:01:39.776,0:01:42.606 So it dissipates into the atmosphere,[br]we don't see it. 0:01:42.606,0:01:45.387 Too often we tend to forget 0:01:45.403,0:01:47.696 that it keeps on accumulating[br]in the atmosphere. 0:01:47.873,0:01:50.368 We ourselves don't feel it, 0:01:50.368,0:01:55.328 but Teddy-x here[br]is already seeing its effect. 0:01:55.659,0:01:59.054 We thought it was important[br]to save Teddy-x 0:01:59.054,0:02:03.056 and come up with a solution[br]to limit our CO2 emissions. 0:02:03.276,0:02:05.799 To do so, we need to study[br]the energy system. 0:02:05.799,0:02:09.731 So we took Switzerland and looked[br]where energy was consumed. 0:02:09.954,0:02:13.018 Forty-seven per cent[br]of Switzerland's energy consumption 0:02:13.018,0:02:16.775 is for keeping ourselves warm[br]and illuminating our buildings. 0:02:17.753,0:02:20.523 This energy consumption[br]occurs mainly in winter 0:02:20.523,0:02:24.443 when it's cold and we need to heat,[br]mainly in the form of heat. 0:02:24.749,0:02:28.395 Only 25% of our energy[br]consumption is electricity, 0:02:28.395,0:02:30.443 the rest is heat. 0:02:31.498,0:02:37.947 To this 47%, I'll add transport[br]which uses 36%, 0:02:38.191,0:02:44.248 and our society's driving force, industry,[br]which needs about 20%. 0:02:44.546,0:02:48.908 Each square here represents[br]100 litres of petrol per inhabitant, 0:02:48.908,0:02:56.381 and every red square[br]represents one CO2 emission. 0:02:56.661,0:03:00.261 When we observe cities, we see that[br]they tend to concentrate the population. 0:03:00.261,0:03:02.627 It is said that, in the future, 0:03:02.627,0:03:06.803 75% of the population will live in cities. 0:03:06.954,0:03:10.930 When it concentrates the population,[br]it takes up space. 0:03:11.431,0:03:17.015 In Geneva, each square metre of floor area 0:03:17.015,0:03:21.015 equals a square metre of heated area. 0:03:21.248,0:03:23.434 This means that energy is consumed. 0:03:23.434,0:03:27.792 The Swiss average[br]is 260 million litres per year 0:03:27.792,0:03:30.462 for the population[br]in Geneva's city centre. 0:03:30.462,0:03:34.295 It means that one million tons [br]of CO2 is emitted. 0:03:34.569,0:03:38.402 Cities also produce waste, 0:03:38.697,0:03:43.176 100,000 tons of solid waste[br]plus 40,000 tons of organic waste, 0:03:43.196,0:03:45.432 and they have opportunities. 0:03:45.734,0:03:47.938 In Geneva there's the lake[br]on the one hand, 0:03:47.938,0:03:54.762 and on the other hand, we have[br]the sun that shines on all our roofs. 0:03:55.078,0:03:58.246 If we convert the amount[br]of energy that we receive daily 0:03:58.246,0:04:00.022 into litres of petrol, 0:04:00.022,0:04:02.912 we can see that there are[br]620 million litres of petrol 0:04:02.912,0:04:08.245 that come to our roof each year. 0:04:08.515,0:04:12.137 We can see that there is[br]more energy available 0:04:12.137,0:04:14.388 than the energy that is consumed today. 0:04:14.388,0:04:17.999 So, together with some of my colleagues[br]and industrial partners, 0:04:17.999,0:04:20.309 we have asked ourselves[br]if we could make cities 0:04:20.309,0:04:22.889 really energy-autonomous. 0:04:22.909,0:04:26.972 'Energy-autonomous' means[br]ideally that we would no longer emit CO2, 0:04:26.972,0:04:30.160 we would not need to import energy, 0:04:30.173,0:04:34.337 that we would not have[br]to knock down all the buildings 0:04:34.337,0:04:37.890 to rebuild them later[br]but would use the city as it is, 0:04:37.890,0:04:40.572 and we would not bankrupt[br]ourselves, of course. 0:04:41.382,0:04:42.993 So, how did we do this? 0:04:42.993,0:04:46.754 As engineers, the first thing we do[br]is to look at the needs. 0:04:46.754,0:04:50.720 We don't need energy, and the best[br]would be precisely not to need it. 0:04:50.720,0:04:54.209 So we look at the minimum we need. 0:04:54.209,0:04:57.740 We call on science and thermodynamics. 0:04:57.993,0:05:01.639 Carnot, a French scientist[br]specialised in thermodynamics, 0:05:01.639,0:05:04.295 showed that in order to heat[br]a building up to 21°C 0:05:04.295,0:05:07.315 when the environment is at 0°C, 0:05:07.315,0:05:11.405 we need to buy one unit of energy[br]to deliver 10 of it. 0:05:12.048,0:05:16.920 This is an important element[br]because it can guide and motivate us. 0:05:17.120,0:05:18.879 Where is the motivation? 0:05:18.879,0:05:22.442 If I look at the amount of energy[br]I spend using a very good boiler 0:05:22.442,0:05:26.838 that has 90% efficiency, uses gas[br]and so burns and produces CO2, 0:05:26.868,0:05:30.555 I realise that for the same amount[br]of heat, that is 10 units, 0:05:30.555,0:05:32.636 I must buy 11 units. 0:05:33.005,0:05:34.882 Here emerges a new question: 0:05:34.882,0:05:36.807 why do we consume 10 times more 0:05:36.807,0:05:39.165 than the minimum[br]indicated by thermodynamics, 0:05:39.165,0:05:41.936 while producing CO2 on top of it? 0:05:42.186,0:05:44.811 The answer is to be found[br]in the heat pump. 0:05:44.811,0:05:46.292 What is a heat pump? 0:05:46.292,0:05:47.915 You all have a fridge at home. 0:05:47.915,0:05:51.521 This fridge works on the following principle: 0:05:51.524,0:05:53.039 you take electricity,[br] 0:05:53.039,0:05:56.882 you extract heat to cool[br]the inside of the fridge, 0:05:56.882,0:05:58.988 and in doing that you heat your room. 0:05:58.988,0:06:03.208 The heat pump does exactly the same:[br]it takes the outside heat 0:06:03.217,0:06:06.125 and with the help of electricity[br]it increases the temperature[br] 0:06:06.125,0:06:08.845 in order to provide you with heat. 0:06:09.125,0:06:10.935 Thermodynamics tells us two things. 0:06:10.935,0:06:12.751 The first is that 0:06:12.751,0:06:19.119 the lower the temperature[br]at which you have to heat, 0:06:19.129,0:06:21.780 the less energy you have to spend. 0:06:21.960,0:06:23.715 That's why the recommendation 0:06:23.715,0:06:26.201 is to install low temperature[br]heating systems 0:06:26.201,0:06:28.176 and not high temperature ones. 0:06:28.326,0:06:29.844 Thermodynamics also tells us[br] 0:06:29.844,0:06:35.224 that the higher the source temperature,[br]in other words the environment, the better. 0:06:35.613,0:06:38.111 The problem is finding that source. 0:06:38.161,0:06:40.776 Cities are dense ;[br]there are buildings everywhere, 0:06:40.777,0:06:43.358 so it is very difficult to make[br]only one heat pump. 0:06:43.358,0:06:47.385 So we thought of splitting[br]the heat pump into two: 0:06:47.649,0:06:49.606 On one side, we will use a heat pump 0:06:49.606,0:06:52.810 that will find the good heat sources[br]in the environment. 0:06:52.810,0:06:58.686 For example, if I have water in the lake,[br]a river or underground, 0:06:58.695,0:07:03.284 I can extract this heat[br]and carry it where I need it. 0:07:03.747,0:07:06.730 Then I can use a second heat pump 0:07:06.730,0:07:10.040 which gives me exactly[br]the temperature that I need. 0:07:10.225,0:07:13.793 You have a heating system[br]at low temperature, 0:07:13.793,0:07:17.694 so you will pay less than someone[br]who has a high temperature heating system. 0:07:17.694,0:07:21.333 In order to carry the heat,[br]the idea is to use the CO2.[br] 0:07:21.533,0:07:24.139 What we can do is use two tubes: 0:07:24.139,0:07:28.625 one tube with CO2 in the liquid state, [br]one tube with CO2 in the vapour state. 0:07:29.035,0:07:32.022 We can take the steam, condense it, 0:07:32.092,0:07:35.502 and in this way we can deliver heat, 0:07:35.502,0:07:40.041 and we can use a heat pump[br]to reach the temperature we need. 0:07:40.704,0:07:45.153 Now, if someone wants to be cooled,[br]I can take the liquid and boil it off. 0:07:45.615,0:07:49.443 I can then cool my buildings[br]down directly. 0:07:50.176,0:07:52.059 Because they are connected with a pipe, 0:07:52.059,0:07:55.070 I can also cool the building[br]that needs to be cooled 0:07:55.070,0:07:58.315 with the building that needs to be heated. 0:07:58.697,0:08:01.802 This ultimately allows me[br]to save a good amount of energy. 0:08:02.124,0:08:06.913 Then, on the way, we can identify[br]all the good heat sources that we have. 0:08:06.913,0:08:10.805 For example, the waste water[br]that leaves your house at around 20°C 0:08:10.805,0:08:14.213 can be used to heat the buildings. 0:08:14.213,0:08:16.163 as well as the water in the lake, 0:08:16.163,0:08:19.623 or the water that leaves the water[br]treatment plant, or geothermal energy. 0:08:19.623,0:08:22.835 So now, I have a system[br]that enables me 0:08:22.835,0:08:26.926 to exchange energy[br]between the different users. 0:08:27.237,0:08:30.070 Another important element[br]is that I use CO2. 0:08:30.070,0:08:33.797 CO2 has a high energy density[br]which means we don't need large pipes. 0:08:33.797,0:08:35.969 We can insert pipes in the pavement 0:08:35.969,0:08:41.189 and don't have to bury them[br]because CO2 doesn't freeze. 0:08:41.189,0:08:43.011 We don't have to go very deep. 0:08:43.011,0:08:45.377 Therefore we can manufacture[br]precast pavement 0:08:45.377,0:08:49.033 that enable us to transport[br]the energy that you need. 0:08:49.284,0:08:53.140 So, here is a complex system[br]that, thanks to a heat pump, 0:08:53.140,0:08:57.767 allows us to warm up,[br]to be directly cooled, 0:08:57.767,0:09:01.280 that also enables refrigeration[br]in shopping centres, for example, 0:09:01.280,0:09:03.794 where fridges or freezers are needed, 0:09:03.794,0:09:08.635 that also enables us to recycle[br]the heat of our waste when we burn it, 0:09:08.635,0:09:12.491 and that uses all the opportunities[br]that the environment has to offer. 0:09:13.044,0:09:14.581 Now the question is: 0:09:14.581,0:09:18.413 is it more efficient[br]than the traditional system? 0:09:18.937,0:09:20.946 To get the answer, we did a case study: 0:09:20.946,0:09:24.086 an area in Geneva[br]where there are offices, 0:09:24.086,0:09:28.720 appartments, banks, shops - 0:09:28.720,0:09:31.366 for those who know it,[br]it is the "Rues Basses" area. 0:09:31.366,0:09:33.166 We calculated the amount of energy 0:09:33.166,0:09:36.735 that is needed and used today[br]to provide heating and cooling 0:09:36.735,0:09:40.795 and we saw that we need 12 energy units, 0:09:40.795,0:09:46.129 10 in the form of heat and natural gas[br]and two in the form of electricity. 0:09:46.834,0:09:50.635 We also saw that the natural gas[br]is mainly used in winter, 0:09:50.635,0:09:54.122 while electricity is used[br]in summer for cooling. 0:09:55.044,0:09:59.217 The same system with the CO2 network[br]only needs two units. 0:09:59.217,0:10:05.380 We made a factor of six[br]in our energy consumption. 0:10:05.790,0:10:09.982 We only need 16% of the energy[br]that we consume today 0:10:09.982,0:10:11.619 without changing the buildings. 0:10:11.619,0:10:17.792 Obviously, if we insulate the buildings[br]we will save even more. 0:10:17.956,0:10:21.224 Of course, everybody said,[br]'Yes, but it's going to be too expensive'. 0:10:21.224,0:10:24.970 And the answer is: 'Yes,[br]it's very expensive at present. 0:10:24.970,0:10:29.654 But in fact, the system we propose[br]will cost less and will be profitable, 0:10:29.654,0:10:32.813 while today's system is not profitable'. 0:10:32.975,0:10:36.046 Now. I've almost achieved my goal, 0:10:36.046,0:10:38.944 but I still need to provide[br]electricity to the system 0:10:38.944,0:10:40.908 so I am not quite self-sufficient yet. 0:10:40.908,0:10:44.106 I have to provide electricity in winter,[br]so now the question is: 0:10:44.106,0:10:46.690 how do we make electricity in winter? 0:10:47.454,0:10:51.298 We can import electricity from outside 0:10:51.298,0:10:55.547 but then, we will emit a lot of CO2[br]and so lose many benefits. 0:10:55.957,0:10:59.620 I can also use new technologies[br]such as the gas combined cycle 0:10:59.620,0:11:01.618 which has a better efficiency 0:11:01.618,0:11:05.519 and emits far less CO2[br]because it uses natural gas. 0:11:05.894,0:11:07.429 But I can also say, 0:11:07.429,0:11:11.441 'Why not use renewable energies[br]to make my heat pumps work?' 0:11:11.803,0:11:15.287 The problem is that renewable energies[br]are mainly available in summer. 0:11:15.287,0:11:18.654 The sun shines a lot in the summer,[br]far less in the winter. 0:11:18.960,0:11:21.470 We can also use[br]a different kind of technology. 0:11:21.486,0:11:24.257 The EPFL has patented a new concept 0:11:24.257,0:11:28.287 that combines a fuel cell[br]and a gas turbine, 0:11:28.287,0:11:32.131 that has 80% electrical efficiency, 0:11:32.131,0:11:34.420 much higher than the best[br]gas power plant, 0:11:34.420,0:11:36.870 and that separates CO2 for free. 0:11:36.870,0:11:40.673 So now, I have some CO2 in a tube, 0:11:40.673,0:11:43.779 and that's perfect[br]since I already have a tube. 0:11:43.921,0:11:46.585 I have residual heat because I'm at 80%. 0:11:46.585,0:11:48.915 I still have 20% left which is great 0:11:48.915,0:11:51.363 since I have the means[br]to carry it towards my users. 0:11:51.363,0:11:54.121 So now, my system enables me[br]to produce electricity, 0:11:54.121,0:11:57.664 to catch CO2 and to meet my heat needs. 0:11:57.674,0:12:02.197 But I’m still using fossil fuel[br]because I’m using natural gas. 0:12:02.548,0:12:05.478 So here, we must go back[br]to look into History 0:12:05.478,0:12:09.868 and see what gifts[br]Mother Nature has given us. 0:12:09.876,0:12:12.208 In fact, Nature has given us two things. 0:12:12.208,0:12:13.968 On the one hand, we have a treasure. 0:12:13.969,0:12:19.259 The treasure is something[br]that never gets refilled. 0:12:19.263,0:12:23.153 It is there and we can only use it,[br]and this is what we do: 0:12:23.153,0:12:27.938 we take a part of the treasure[br]and burn it to produce CO2. 0:12:28.755,0:12:31.998 And Teddy-x is not very happy actually. 0:12:32.505,0:12:36.024 What you can observe[br]is that the reservoir has run out 0:12:36.024,0:12:37.455 and nobody is refilling it. 0:12:37.455,0:12:41.804 That means our children will have less[br]than what we've received from our parents. 0:12:42.612,0:12:46.921 We can also look at Nature’s[br]current and savings accounts 0:12:46.921,0:12:50.284 which are renewable energies[br]that come in different forms. 0:12:50.284,0:12:56.299 We have the sun, the wind,[br]the water and the biomass. 0:12:56.299,0:13:02.435 The biomass is much like the savings[br]account because it is stored. 0:13:03.511,0:13:07.207 I can therefore take the biomass[br]and convert it into gas. 0:13:07.217,0:13:10.536 Organic and chemical processes exist 0:13:10.536,0:13:13.484 that enable us to convert[br]the biomass into gas. 0:13:13.484,0:13:17.233 When the process is not efficient,[br]it generates heat 0:13:17.233,0:13:22.616 and I have a tube to use that heat[br]so it's great when I need heat. 0:13:22.800,0:13:26.168 As for the gas, I can use it[br]in fuel cells. 0:13:27.323,0:13:29.627 I’m also trying to learn from Nature. 0:13:29.627,0:13:33.085 If I think carefully, I need energy,[br]where do I find it? 0:13:33.085,0:13:36.005 I find it in food which is stored energy. 0:13:36.005,0:13:38.192 I don’t feel variations[br]like I do with the sun 0:13:38.192,0:13:42.017 that changes from hour to hour[br]and from season to season. 0:13:42.335,0:13:45.100 How did Nature do that?[br]By photosynthesis. 0:13:45.100,0:13:46.860 It took CO2 from the atmosphere, 0:13:46.860,0:13:50.360 used the photons coming[br]from the sun, used water, 0:13:50.360,0:13:53.961 and created carbohydrates[br]that make up my food 0:13:53.961,0:13:56.453 and the trees as well. 0:13:56.764,0:13:59.859 We can do the same[br]with a technical system. 0:13:59.859,0:14:01.429 I can take the sun, 0:14:01.429,0:14:04.833 transform it into electricity[br]with photovoltaic cells, 0:14:04.833,0:14:09.846 then I can take these, CO2[br]and water, and create methane. 0:14:10.036,0:14:13.707 And what I'm going to do[br]is to take the CO2 I stored 0:14:13.707,0:14:16.614 and create methane in the[br]liquid state to store as well. 0:14:16.614,0:14:18.916 It's going to become[br]quite a complex system 0:14:18.916,0:14:22.058 because, in the summer,[br]I'll take liquid CO2 0:14:22.058,0:14:27.394 to make liquid methane[br]by means of the shining sun, 0:14:27.394,0:14:29.682 and in the winter, I'll take[br]the liquid methane 0:14:29.682,0:14:31.686 and feed it into the fuel cell 0:14:31.686,0:14:35.746 to produce the electricity that I need[br]for heating and lighting, 0:14:35.746,0:14:37.642 then, I'll capture the CO2, 0:14:37.642,0:14:42.297 bring it back into my tube[br]and convert it into liquid CO2. 0:14:43.254,0:14:47.801 By doing so, I’ll have a system[br]that seems very complicated, 0:14:47.801,0:14:52.672 but don’t forget that you have many tubes[br]coming into your houses every day. 0:14:52.672,0:14:56.452 You have the electrical cable,[br]the Internet cable, 0:14:56.452,0:15:00.502 and also the drinking water[br]and the waste water leaving your home. 0:15:00.502,0:15:04.182 So adding a new tube is not necessarily[br]as difficult as it seems. 0:15:04.196,0:15:08.768 It's a system that enables us[br]to warm up, to cool down, to refrigerate, 0:15:08.768,0:15:10.504 to add value to all of our waste, 0:15:10.504,0:15:15.600 and to store the solar energy produced[br]during the summer on our roofs 0:15:15.600,0:15:19.013 to make it available during the winter. 0:15:19.747,0:15:25.368 If I can do that, I'll have a system[br]entirely autonomous in energy. 0:15:25.941,0:15:27.292 The system I had before 0:15:27.292,0:15:31.782 burnt a large quantity of energy[br]to meet my needs, 0:15:31.782,0:15:35.417 emitted a lot of CO2,[br]and emptied my treasure. 0:15:35.545,0:15:40.780 Today, with an investment -[br]the installation of new infrastructure 0:15:40.780,0:15:46.822 with heat pumps, fuel cells and storage - 0:15:46.822,0:15:51.047 I will be able to fulfil the same needs. 0:15:51.357,0:15:54.630 I don't need to change the buildings[br]or to change your comfort, 0:15:54.630,0:15:57.460 you will still have the same[br]temperature in all your rooms. 0:15:57.630,0:16:00.715 You will simply have[br]solar panels on your roof, 0:16:00.985,0:16:03.296 You will have fuel cells 0:16:03.296,0:16:09.965 that generate electricity from the methane[br]produced during the summer. 0:16:10.480,0:16:14.852 You will recycle the heat from the hot[br]water poured in the sewer 0:16:14.852,0:16:17.572 because you will be able to use it[br]in your heat pumps. 0:16:17.572,0:16:19.967 You will recycle energy from your waste, 0:16:19.967,0:16:25.001 and in the end, in fact,[br]you're going to export electricity, 0:16:25.001,0:16:28.331 an electricity available on request. 0:16:28.341,0:16:31.200 That means that you'll be able[br]to decide when to export it 0:16:31.200,0:16:34.500 when you have too much,[br]and it'll be stored as methane. 0:16:34.783,0:16:35.979 As a point of interest, 0:16:35.979,0:16:39.429 the storage space required for this[br]is 10 times smaller 0:16:39.429,0:16:45.510 than the amount of tanks [br]we would need in all the buildings 0:16:45.510,0:16:49.511 if we heated everything with fuel oil. 0:16:51.000,0:16:52.924 And that's my conclusion. 0:16:53.070,0:16:54.960 Anyway, Teddy-x can thank us, 0:16:54.960,0:17:00.413 because if you are able[br]to transform cities 0:17:00.413,0:17:04.423 into independent electricity producers[br]without CO2 emissions, 0:17:04.423,0:17:09.371 he may have the opportunity[br]to find a more secure block of ice. 0:17:09.746,0:17:11.069 Thank you very much. 0:17:11.069,0:17:13.350 (Applause)