1 00:00:04,400 --> 00:00:12,239 Speaker 1: Welcome to tech Stuff, a production from iHeartRadio. Hey there, 2 00:00:12,280 --> 00:00:15,560 Speaker 1: and welcome to tech Stuff. I'm your host, John Vin Strickland. 3 00:00:15,640 --> 00:00:19,000 Speaker 1: I'm an executive producer with iHeartRadio and how the tech 4 00:00:19,120 --> 00:00:22,799 Speaker 1: are you. It is time for a classic episode of 5 00:00:22,840 --> 00:00:25,680 Speaker 1: tech stuff, and that means we're gonna be taking a 6 00:00:25,680 --> 00:00:30,360 Speaker 1: look at how solar towers work. This episode originally published 7 00:00:30,360 --> 00:00:34,840 Speaker 1: on March ninth, twenty sixteen. It's an interesting way of 8 00:00:35,000 --> 00:00:38,640 Speaker 1: harnessing energy from the Sun that does not involve directly 9 00:00:38,760 --> 00:00:43,920 Speaker 1: transmitting or translating photons to electricity the way a solar 10 00:00:43,920 --> 00:00:47,760 Speaker 1: panel would. So sit back and enjoy this classic episode 11 00:00:47,800 --> 00:00:50,600 Speaker 1: of tech stuff. Today, I want to talk a little 12 00:00:50,600 --> 00:00:53,559 Speaker 1: bit about solar towers, which is a different way of 13 00:00:53,600 --> 00:00:56,840 Speaker 1: harnessing the Sun's energy, and I think it's a really 14 00:00:56,880 --> 00:01:01,600 Speaker 1: clever way as well, because it doesn't rely on sunlight 15 00:01:01,720 --> 00:01:06,720 Speaker 1: hitting a panel. Obviously, the big big drawback to that 16 00:01:06,800 --> 00:01:10,400 Speaker 1: approach is when the sun isn't hitting a panel, you're 17 00:01:10,440 --> 00:01:14,280 Speaker 1: not generating any electricity. Right, So if it's super cloudy 18 00:01:14,760 --> 00:01:17,640 Speaker 1: or if it's nighttime, if the sun is not able 19 00:01:17,680 --> 00:01:20,640 Speaker 1: to hit the panel, the sunlight's not getting there, you 20 00:01:20,720 --> 00:01:23,960 Speaker 1: have nothing to convert into electricity and your solar panels 21 00:01:24,040 --> 00:01:28,120 Speaker 1: go on to be unused for that duration. So that 22 00:01:28,160 --> 00:01:30,720 Speaker 1: can be really rough if you have a long stretch 23 00:01:30,800 --> 00:01:33,800 Speaker 1: of overcast days, or you live in a place where 24 00:01:34,640 --> 00:01:38,560 Speaker 1: you don't get solar exposure at your house because of 25 00:01:38,760 --> 00:01:42,160 Speaker 1: maybe they're taller buildings around you, or trees or whatever 26 00:01:42,200 --> 00:01:44,240 Speaker 1: it may be. Maybe you have a north facing house 27 00:01:45,160 --> 00:01:47,760 Speaker 1: rather than a south facing house here in the Northern Hemisphere. 28 00:01:48,320 --> 00:01:50,560 Speaker 1: If you have a south facing house in the Northern Hemisphere, 29 00:01:50,560 --> 00:01:52,680 Speaker 1: you're going to get more solar exposure than a north 30 00:01:52,720 --> 00:01:57,040 Speaker 1: facing house, So solar panels have that drawback. They're also 31 00:01:57,200 --> 00:02:01,240 Speaker 1: there's efficiency issues with solar panels. When we talk about efficiency, 32 00:02:02,240 --> 00:02:05,240 Speaker 1: what we mean is how much of the sun's energy 33 00:02:05,280 --> 00:02:08,760 Speaker 1: can we actually convert into electricity and how much of 34 00:02:08,800 --> 00:02:11,040 Speaker 1: it do we lose? How much of that energy bounces 35 00:02:11,080 --> 00:02:14,320 Speaker 1: off the panel and we do not capture it. Most 36 00:02:14,639 --> 00:02:17,160 Speaker 1: commercial solar panels, the kind that you would put on 37 00:02:17,240 --> 00:02:20,560 Speaker 1: your house, the efficiency is around eleven to fifteen percent, 38 00:02:21,200 --> 00:02:25,520 Speaker 1: meaning that you're losing a lot, like eighty five percent 39 00:02:25,600 --> 00:02:30,520 Speaker 1: of that energy is not converting into electricity. What that 40 00:02:30,560 --> 00:02:33,720 Speaker 1: means is that you have to buy more solar panels 41 00:02:34,120 --> 00:02:37,880 Speaker 1: to cover more space to collect more solar energy to 42 00:02:37,960 --> 00:02:41,640 Speaker 1: generate enough electricity to meet your needs. Obviously, if solar 43 00:02:41,639 --> 00:02:44,360 Speaker 1: panels were one hundred percent efficient, which is impossible by 44 00:02:44,360 --> 00:02:47,800 Speaker 1: the way, physically impossible. People have proved it with masth, 45 00:02:48,720 --> 00:02:52,600 Speaker 1: then if it were one hundred percent efficient, you wouldn't 46 00:02:52,600 --> 00:02:55,400 Speaker 1: need as many solar panels in order to do what 47 00:02:55,520 --> 00:03:00,400 Speaker 1: you need to do. That's just not the case in reality. Instead, 48 00:03:01,040 --> 00:03:03,400 Speaker 1: we often have to buy more than what we would 49 00:03:03,680 --> 00:03:07,640 Speaker 1: like cover a larger area. And even then again you're 50 00:03:08,200 --> 00:03:11,720 Speaker 1: limited to collecting electricity or generating electricity i should say, 51 00:03:12,400 --> 00:03:15,320 Speaker 1: during the daylight hours. An electricity also is a use 52 00:03:15,360 --> 00:03:18,040 Speaker 1: it or lose it kind of thing, meaning that if 53 00:03:18,080 --> 00:03:20,960 Speaker 1: you don't have an immediate use for that electricity and 54 00:03:21,000 --> 00:03:23,160 Speaker 1: you don't have a way to store it, you lose 55 00:03:23,200 --> 00:03:25,679 Speaker 1: that electricity. You have to use it when it's generated, 56 00:03:26,720 --> 00:03:29,040 Speaker 1: so you need to have some sort of battery system 57 00:03:29,040 --> 00:03:31,760 Speaker 1: as well, so that in the times when you're not 58 00:03:32,240 --> 00:03:34,720 Speaker 1: using the electricity you're generating, you can still save it 59 00:03:34,800 --> 00:03:38,320 Speaker 1: for later use. And until recently, batteries have been really 60 00:03:38,360 --> 00:03:41,360 Speaker 1: expensive for the home, but Tesla's powerwall has kind of 61 00:03:41,440 --> 00:03:44,680 Speaker 1: led a revolution in that space and we're starting to 62 00:03:44,720 --> 00:03:49,240 Speaker 1: see more affordable versions of batteries hit the home market. Okay, 63 00:03:49,280 --> 00:03:51,360 Speaker 1: all that's out of the way to just say that 64 00:03:51,400 --> 00:03:56,280 Speaker 1: the traditional solar panel approach has its drawbacks. Now, let's 65 00:03:56,280 --> 00:03:59,600 Speaker 1: talk about solar towers, because they take a totally different 66 00:03:59,640 --> 00:04:04,240 Speaker 1: approach to harnessing electricity from the sun, and it's really 67 00:04:04,280 --> 00:04:07,640 Speaker 1: pretty clever. And they can harness electricity or they can 68 00:04:07,680 --> 00:04:10,960 Speaker 1: generate electricity day or night. So you might wonder, well, 69 00:04:10,960 --> 00:04:13,520 Speaker 1: how is that possible? And when the Earth rotates so 70 00:04:13,600 --> 00:04:16,400 Speaker 1: that the sun is no longer shining on a solar tower, 71 00:04:17,080 --> 00:04:20,920 Speaker 1: where's that electricity coming from. So here's the way it works. Now, 72 00:04:20,920 --> 00:04:25,800 Speaker 1: I'm largely going to refer to a company called Solar Reserve, 73 00:04:25,880 --> 00:04:29,120 Speaker 1: which is here in the United States. Solar Reserve is 74 00:04:29,160 --> 00:04:33,719 Speaker 1: just one company that is building structures like these around 75 00:04:33,720 --> 00:04:36,560 Speaker 1: the world, So I don't mean to suggest they're the 76 00:04:36,640 --> 00:04:39,240 Speaker 1: only one. I'm using them as the example because that 77 00:04:39,320 --> 00:04:43,160 Speaker 1: so much of their information is available to actually read 78 00:04:43,200 --> 00:04:49,080 Speaker 1: about and understand. So it's a really helpful approach. Solar towers. Well, 79 00:04:49,080 --> 00:04:52,160 Speaker 1: first of all, the name kind of gives away the 80 00:04:52,200 --> 00:04:55,160 Speaker 1: main feature. There's a tower at the center of this 81 00:04:56,120 --> 00:04:59,800 Speaker 1: structure or really multiple structures. So how tall are these 82 00:05:00,000 --> 00:05:02,039 Speaker 1: hours Well, according to Solar Reserve, the height of the 83 00:05:02,120 --> 00:05:05,080 Speaker 1: tower and its thermal receiver. More on that in just 84 00:05:05,120 --> 00:05:08,800 Speaker 1: a second tends to be six hundred forty feet combined, 85 00:05:08,960 --> 00:05:12,160 Speaker 1: or about one hundred and ninety five meters. So you've 86 00:05:12,200 --> 00:05:17,039 Speaker 1: got this tower in a large area. You want to 87 00:05:17,080 --> 00:05:19,880 Speaker 1: have an area that gets a lot of solar exposure, 88 00:05:19,960 --> 00:05:23,600 Speaker 1: otherwise this is not a practical way of generating electricity. 89 00:05:23,640 --> 00:05:27,240 Speaker 1: So imagine like a desert, nice flat desert, lots of 90 00:05:27,360 --> 00:05:31,240 Speaker 1: sunlight hitting that dessert every typical day, and you have 91 00:05:31,360 --> 00:05:33,960 Speaker 1: a tall tower with a receiver on the top of it. 92 00:05:34,040 --> 00:05:39,160 Speaker 1: Now that receiver is actually a series of dark panels. 93 00:05:39,520 --> 00:05:42,080 Speaker 1: And these aren't solar panels, not in the way that 94 00:05:42,160 --> 00:05:44,200 Speaker 1: you would put on top of your house. They are 95 00:05:44,240 --> 00:05:49,440 Speaker 1: not converting sunlight into electricity directly. Rather, they are panels 96 00:05:49,480 --> 00:05:54,440 Speaker 1: that transfer thermal energy. In other words, they're all about 97 00:05:54,520 --> 00:06:00,479 Speaker 1: transmitting heat. So these panels have sixty six thin wall 98 00:06:00,680 --> 00:06:04,320 Speaker 1: straight tubes in them. Those tubes are designed to conduct 99 00:06:04,400 --> 00:06:07,000 Speaker 1: heat from the outside to the inside of that tower, 100 00:06:07,839 --> 00:06:10,480 Speaker 1: and the tubes are made out of a steel alloy 101 00:06:10,600 --> 00:06:14,600 Speaker 1: that's covered in a high absorptivity black coating to maximize 102 00:06:14,640 --> 00:06:18,039 Speaker 1: the amount of energy the panel can absorb. So you've 103 00:06:18,080 --> 00:06:21,040 Speaker 1: got sunlight shining on this tower, Well, how is that 104 00:06:21,160 --> 00:06:24,800 Speaker 1: enough to generate electricity on its own. It's not. In fact, 105 00:06:24,839 --> 00:06:28,400 Speaker 1: what you end up doing is surrounding the tower with mirrors. Now, 106 00:06:28,440 --> 00:06:32,800 Speaker 1: Solar Reserve uses mirrors that they call heliostats. These heliostats 107 00:06:32,839 --> 00:06:38,560 Speaker 1: are mounted on arms essentially that allow them to track 108 00:06:38,720 --> 00:06:42,680 Speaker 1: the motion of the sun. That way, the mirrors maintain 109 00:06:42,800 --> 00:06:47,920 Speaker 1: the ideal angle to reflect the sun's light directly toward 110 00:06:48,120 --> 00:06:51,359 Speaker 1: the top of that tower at that receiving point of 111 00:06:51,400 --> 00:06:55,320 Speaker 1: the tower on those panels. And we're talking about a 112 00:06:55,400 --> 00:07:00,440 Speaker 1: lot of mirrors. Solar Reserve has one area called the 113 00:07:00,480 --> 00:07:04,920 Speaker 1: Crescent Dunes. That's their tower that they have in the US, 114 00:07:05,680 --> 00:07:08,599 Speaker 1: and the Crescent Dunes towers surrounded by more than ten 115 00:07:08,760 --> 00:07:13,360 Speaker 1: thousand mirrors, covering a fifteen hundred acre field. So this 116 00:07:13,440 --> 00:07:16,040 Speaker 1: is a big operation. You've got to have a lot 117 00:07:16,080 --> 00:07:19,520 Speaker 1: of open land for this to work. That's obviously one 118 00:07:19,560 --> 00:07:23,559 Speaker 1: of the potential drawbacks, right that you need a place 119 00:07:23,560 --> 00:07:25,920 Speaker 1: that's going to have a lot of solar exposure, and 120 00:07:26,000 --> 00:07:28,800 Speaker 1: you need to have enough space to make it make sense. 121 00:07:29,240 --> 00:07:31,080 Speaker 1: But assuming you have both of those things, you can 122 00:07:31,080 --> 00:07:34,920 Speaker 1: do something pretty incredible. We'll be back with more about 123 00:07:34,960 --> 00:07:48,040 Speaker 1: how solar towers work after these messages. So what these 124 00:07:48,280 --> 00:07:51,160 Speaker 1: mirrors do is direct that sunlight up at those dark 125 00:07:51,160 --> 00:07:54,040 Speaker 1: panels I was talking about. Remember I mentioned there were fourteen. 126 00:07:54,400 --> 00:07:57,440 Speaker 1: These fourteen panels are divided up into two groups of seven. 127 00:07:58,320 --> 00:08:01,800 Speaker 1: Each group of seven represent kind of a circuit, and 128 00:08:01,880 --> 00:08:05,200 Speaker 1: that circuit is not for electricity. It's rather for a 129 00:08:05,240 --> 00:08:11,440 Speaker 1: circuit of pipes that are circulating liquid salts. So liquid 130 00:08:11,440 --> 00:08:14,920 Speaker 1: salts are pretty cool, which is a weird way of 131 00:08:14,920 --> 00:08:17,920 Speaker 1: putting it when you're talking about thermal energy, But liquid 132 00:08:17,920 --> 00:08:22,480 Speaker 1: salts can hold on to more heat than water can 133 00:08:23,200 --> 00:08:26,880 Speaker 1: and can remain in liquid form, so in other words, 134 00:08:26,880 --> 00:08:31,000 Speaker 1: they don't vaporize into steam. And what solar reserve does 135 00:08:31,280 --> 00:08:35,920 Speaker 1: is it pumps around five eight hundred gallons of liquid 136 00:08:35,920 --> 00:08:40,360 Speaker 1: salts per minute through the receiver circuits that run back 137 00:08:40,400 --> 00:08:44,240 Speaker 1: and forth across the inside of these black panels. So 138 00:08:44,559 --> 00:08:47,120 Speaker 1: imagine you've got this really tall tower. At the top 139 00:08:47,160 --> 00:08:50,800 Speaker 1: of the tower, you have these fourteen dark panels, and 140 00:08:50,840 --> 00:08:53,040 Speaker 1: then let's just take seven on one side. You've got 141 00:08:53,040 --> 00:08:54,920 Speaker 1: seven of those dark pounds on one side. On the 142 00:08:55,040 --> 00:08:58,240 Speaker 1: inside of those panels, you would see this criss crossing 143 00:08:58,559 --> 00:09:03,920 Speaker 1: of a pipe that is circulating liquid salts through the pipe. 144 00:09:04,840 --> 00:09:08,440 Speaker 1: Heat from the outside comes into the tower and it 145 00:09:08,440 --> 00:09:12,000 Speaker 1: begins to heat those liquid salts running through that circuit. 146 00:09:12,640 --> 00:09:15,600 Speaker 1: It's a simple heat transfer. And if you've listened to 147 00:09:15,640 --> 00:09:19,280 Speaker 1: our podcasts about things like refrigerators and air conditioners, you 148 00:09:19,360 --> 00:09:21,920 Speaker 1: know about you know how this, what the principles are, 149 00:09:22,120 --> 00:09:25,200 Speaker 1: how how this is based same basic thing. You want 150 00:09:25,200 --> 00:09:27,800 Speaker 1: to give as much surface area you know you want 151 00:09:27,800 --> 00:09:29,400 Speaker 1: to you want to dedicate as much surface area as 152 00:09:29,400 --> 00:09:31,480 Speaker 1: you can to heat and have the liquid salts cross 153 00:09:31,559 --> 00:09:33,720 Speaker 1: over as much of that surface area as as possible 154 00:09:33,760 --> 00:09:38,319 Speaker 1: to heat up the liquid salts. As the liquid salts 155 00:09:38,400 --> 00:09:43,360 Speaker 1: move through the circuit, they become molten, so incredibly high temperatures. 156 00:09:44,200 --> 00:09:48,040 Speaker 1: So the low side of the temperatures for these liquid 157 00:09:48,040 --> 00:09:50,679 Speaker 1: salts is five hundred and fifty degrees fahrenheit or two 158 00:09:50,800 --> 00:09:54,520 Speaker 1: hundred eighty eight degrees celsius. That's the low end. That's 159 00:09:54,600 --> 00:09:57,280 Speaker 1: that's the chili side. If you want to talk about 160 00:09:57,280 --> 00:09:59,240 Speaker 1: how hot they get, they can get up to a 161 00:09:59,320 --> 00:10:03,320 Speaker 1: thousand ifty degrees fahrenheit or five hundred and sixty six 162 00:10:03,400 --> 00:10:08,120 Speaker 1: degrees celsius. That's really impressive. And so you've got this 163 00:10:08,320 --> 00:10:12,280 Speaker 1: massive amount of stored thermal energy. It's all inside the 164 00:10:12,320 --> 00:10:15,480 Speaker 1: molten salts. So you've got a lot of heat stored up. 165 00:10:16,120 --> 00:10:19,320 Speaker 1: What good is heat, Well, you can use heat to 166 00:10:19,440 --> 00:10:22,360 Speaker 1: do the same thing that is done in power plants 167 00:10:22,480 --> 00:10:26,439 Speaker 1: all over the world. You use heat to turn water 168 00:10:26,480 --> 00:10:30,160 Speaker 1: into steam and use the steam to turn a turbine, 169 00:10:30,400 --> 00:10:35,200 Speaker 1: which generates electricity. It's an incredibly simple idea. It's the 170 00:10:35,240 --> 00:10:39,680 Speaker 1: basis of almost every other type of power plant, with 171 00:10:39,800 --> 00:10:43,680 Speaker 1: the exception of things like solar panels that are used 172 00:10:43,679 --> 00:10:47,960 Speaker 1: in solar farms. Like that's generating electricity straight from sunlight, 173 00:10:48,000 --> 00:10:52,000 Speaker 1: as opposed to using that electricity to somehow turn water 174 00:10:52,080 --> 00:10:54,000 Speaker 1: into steam. That would be ridiculous. You would lose way 175 00:10:54,040 --> 00:10:56,480 Speaker 1: too much energy in that approach. But things like coal 176 00:10:56,559 --> 00:11:00,680 Speaker 1: fired plants, even nuclear power plants, you're talking about generating 177 00:11:00,720 --> 00:11:04,960 Speaker 1: electricity by heating up water into steam and using that 178 00:11:05,000 --> 00:11:07,480 Speaker 1: steam to turn a turbine to do work, and that 179 00:11:07,600 --> 00:11:10,559 Speaker 1: turbine ends up being an electric generator and you get 180 00:11:10,559 --> 00:11:16,240 Speaker 1: electricity from that. So the purpose of the solar tower 181 00:11:16,400 --> 00:11:19,600 Speaker 1: is really just to collect heat that's it. It's not 182 00:11:19,679 --> 00:11:23,319 Speaker 1: doing anything magical. It's just generating tons and tons of heat. 183 00:11:23,720 --> 00:11:26,600 Speaker 1: I know that tons is not really a unit when 184 00:11:26,640 --> 00:11:28,800 Speaker 1: it comes to heat or temperature, but you understand what 185 00:11:28,840 --> 00:11:31,800 Speaker 1: I mean. It creates an enormous amount of heat, and 186 00:11:31,880 --> 00:11:34,679 Speaker 1: the molten salts then go into a big storage tank. 187 00:11:35,400 --> 00:11:38,800 Speaker 1: And it's pretty cool because that storage tank ends up 188 00:11:38,880 --> 00:11:42,240 Speaker 1: being a way of holding onto the heat for a 189 00:11:42,280 --> 00:11:46,520 Speaker 1: long time. According to Solar Reserve, the company says that 190 00:11:46,559 --> 00:11:49,800 Speaker 1: the molten salt only loses one degree of fahrenheit or 191 00:11:49,840 --> 00:11:54,240 Speaker 1: about point five, five, five, etc. Etc. Degrees celsius in 192 00:11:54,400 --> 00:11:58,440 Speaker 1: heat per day. So, in other words, if you have 193 00:11:58,679 --> 00:12:01,840 Speaker 1: a long stretch of over days, you still have this 194 00:12:02,040 --> 00:12:06,200 Speaker 1: massive vat. Really tank, it's not a vat, it's a 195 00:12:06,240 --> 00:12:10,240 Speaker 1: tank because it's completely enclosed of molten salts and they 196 00:12:10,280 --> 00:12:13,120 Speaker 1: hold onto that heat, which means you can continuously pump 197 00:12:13,200 --> 00:12:17,320 Speaker 1: that through your water tank in order to heat water 198 00:12:17,440 --> 00:12:19,840 Speaker 1: up to steam. And when I say pump it through, 199 00:12:20,000 --> 00:12:23,000 Speaker 1: it's a very similar circuit that you would find at 200 00:12:23,040 --> 00:12:27,800 Speaker 1: the top of the receiver. The molten salts don't mix 201 00:12:27,880 --> 00:12:30,920 Speaker 1: with the water. Instead, you have a pipe that runs 202 00:12:30,960 --> 00:12:34,440 Speaker 1: through the water tank. The molten salts run through the 203 00:12:34,440 --> 00:12:37,480 Speaker 1: pipe and transfer some of their heat to the water 204 00:12:38,040 --> 00:12:41,920 Speaker 1: through the material of the pipe itself. So you're not 205 00:12:42,000 --> 00:12:44,560 Speaker 1: laying the molten salts in the water mixed together. That 206 00:12:44,600 --> 00:12:48,120 Speaker 1: would be ridiculous. Instead, you're having the molten salts move 207 00:12:48,200 --> 00:12:50,920 Speaker 1: through a pathway, and as they move through that pathway, 208 00:12:50,960 --> 00:12:53,520 Speaker 1: they heat up the water. The water turns, the steam 209 00:12:53,559 --> 00:12:56,840 Speaker 1: turns the turbine. Then the steam goes through a condenser 210 00:12:57,360 --> 00:13:00,480 Speaker 1: to condense the steam back into water and goes back 211 00:13:00,480 --> 00:13:03,839 Speaker 1: into the water tank. So once you use the molten 212 00:13:03,880 --> 00:13:07,200 Speaker 1: salts to transfer some of this heat, they've lost that 213 00:13:07,360 --> 00:13:11,920 Speaker 1: thermal energy. They're now moving into a different tank. It's 214 00:13:11,920 --> 00:13:14,800 Speaker 1: a tank to pump the liquid salts back up into 215 00:13:14,840 --> 00:13:18,600 Speaker 1: the top of the tower. So the neat thing with 216 00:13:18,679 --> 00:13:22,440 Speaker 1: this system is that you can use it to deliver 217 00:13:22,480 --> 00:13:25,480 Speaker 1: electricity day or night. You've got so much stored heat. 218 00:13:25,559 --> 00:13:27,920 Speaker 1: After you get the system up and running and it's 219 00:13:27,960 --> 00:13:30,760 Speaker 1: generated enough molten salt, like it's created enough molten salt 220 00:13:30,800 --> 00:13:34,440 Speaker 1: through this process to allow this to happen, you can 221 00:13:34,640 --> 00:13:37,920 Speaker 1: deliver electricity on demand twenty four hours a day, and 222 00:13:37,960 --> 00:13:41,400 Speaker 1: that's how all power plants work. They deliver electricity on demand. 223 00:13:41,400 --> 00:13:44,800 Speaker 1: They're not set to a certain level, and then if 224 00:13:44,800 --> 00:13:47,520 Speaker 1: you don't meet that level, they you know, just that 225 00:13:47,559 --> 00:13:51,200 Speaker 1: electricity goes to waste. They base it upon what the 226 00:13:51,360 --> 00:13:53,520 Speaker 1: current demand. And I don't mean that as a pun, 227 00:13:53,640 --> 00:13:55,480 Speaker 1: but it came out of that way. Chris would be 228 00:13:55,520 --> 00:14:00,000 Speaker 1: so proud. They don't. They respond to whatever the demand 229 00:14:00,000 --> 00:14:02,400 Speaker 1: and is at that time to produce the amount of 230 00:14:02,400 --> 00:14:07,760 Speaker 1: electricity needed. So super interesting way of doing this by 231 00:14:08,360 --> 00:14:11,640 Speaker 1: using the sun as an energy source to create the 232 00:14:11,760 --> 00:14:14,960 Speaker 1: heat needed to turn water into steam and turn a turbine, 233 00:14:15,400 --> 00:14:18,200 Speaker 1: as opposed to a fossil fuel like coal or oil, 234 00:14:18,640 --> 00:14:21,880 Speaker 1: or a nuclear fuel in the case of nuclear fusion. Now, 235 00:14:21,880 --> 00:14:25,040 Speaker 1: if we ever are a fission, I should say nuclear fission. 236 00:14:25,440 --> 00:14:27,000 Speaker 1: I know all of you were ready to write in, 237 00:14:27,200 --> 00:14:29,400 Speaker 1: and you should be because that was a silly mistake 238 00:14:29,440 --> 00:14:32,440 Speaker 1: I made nuclear fusion. If we ever crack that nut, 239 00:14:33,240 --> 00:14:37,240 Speaker 1: solar towers may seem quaint in comparison, but that's a 240 00:14:37,360 --> 00:14:41,040 Speaker 1: very difficult problem in physics to solve. So we're still 241 00:14:41,080 --> 00:14:44,960 Speaker 1: waiting on that. We'll conclude our episode on how solar 242 00:14:45,000 --> 00:14:58,840 Speaker 1: towers work after these brief messages. So the neat thing 243 00:14:58,880 --> 00:15:01,520 Speaker 1: about this obviously is that if you do have that 244 00:15:01,600 --> 00:15:04,360 Speaker 1: amount of space, you can really offset a lot of 245 00:15:04,520 --> 00:15:09,560 Speaker 1: a community's electricity needs with a solar tower. And the 246 00:15:09,600 --> 00:15:13,320 Speaker 1: company thinks that the lifespan of these solar towers is 247 00:15:13,440 --> 00:15:17,520 Speaker 1: somewhere in the area of about thirty years, meaning that 248 00:15:17,680 --> 00:15:19,760 Speaker 1: after thirty years you would have to start to replace 249 00:15:19,840 --> 00:15:23,120 Speaker 1: parts because just of wear and tear, or they would 250 00:15:23,120 --> 00:15:27,560 Speaker 1: not be as efficient as they had previously been. So, 251 00:15:27,840 --> 00:15:31,440 Speaker 1: for example, those panels, if the panels become less efficient 252 00:15:31,480 --> 00:15:34,920 Speaker 1: at transferring heat over time, you would definitely want to 253 00:15:34,960 --> 00:15:37,800 Speaker 1: replace them because you would be transferring less heat to 254 00:15:37,880 --> 00:15:41,040 Speaker 1: generate your molten salts will be at a lower temperature. 255 00:15:41,040 --> 00:15:44,840 Speaker 1: It would require more of them to turn water into steam, 256 00:15:45,600 --> 00:15:48,320 Speaker 1: who become less efficient overall. So you have to make 257 00:15:48,360 --> 00:15:53,440 Speaker 1: sure that all the parts are working. They're very few 258 00:15:53,520 --> 00:15:55,920 Speaker 1: moving parts, which is awesome, but you have to make 259 00:15:55,960 --> 00:15:59,480 Speaker 1: sure they're working throughout the lifetime of the facility and 260 00:15:59,520 --> 00:16:03,000 Speaker 1: then obviously replace parts as needed. So the question then 261 00:16:03,040 --> 00:16:07,920 Speaker 1: becomes doesn't make financial sense to switch over to using 262 00:16:07,920 --> 00:16:12,000 Speaker 1: solar towers at least to offset electricity generation in a 263 00:16:12,040 --> 00:16:15,240 Speaker 1: particular area. To answer that question, you have to look 264 00:16:15,280 --> 00:16:18,040 Speaker 1: at a lot of different factors, and it is way 265 00:16:18,120 --> 00:16:21,160 Speaker 1: more complicated than just a simple yes or no. For 266 00:16:21,240 --> 00:16:26,440 Speaker 1: one thing, how much solar exposure is the area getting. Obviously, 267 00:16:26,480 --> 00:16:28,360 Speaker 1: if you're not getting a lot, then that's not going 268 00:16:28,400 --> 00:16:31,360 Speaker 1: to be a good choice for solar towers or a 269 00:16:31,400 --> 00:16:33,480 Speaker 1: good place to put a solar tower. I should say 270 00:16:34,560 --> 00:16:38,800 Speaker 1: also not just where, and you know what time of 271 00:16:38,880 --> 00:16:41,320 Speaker 1: year do you get solar exposure? Those would be two 272 00:16:41,320 --> 00:16:45,320 Speaker 1: big things. But how much does electricity cost in that 273 00:16:45,360 --> 00:16:47,760 Speaker 1: region already? And the reason why you have to ask 274 00:16:47,840 --> 00:16:51,000 Speaker 1: that question is if you were to provide electricity through 275 00:16:51,320 --> 00:16:55,880 Speaker 1: the solar reserve system, would it make financial sense to 276 00:16:55,920 --> 00:16:59,680 Speaker 1: make that switch? If coal is incredibly cheap in the area, 277 00:17:00,000 --> 00:17:03,360 Speaker 1: and financially it might make more sense to stick with coal, 278 00:17:03,480 --> 00:17:07,199 Speaker 1: even though we all know there are big environmental drawbacks 279 00:17:07,240 --> 00:17:09,480 Speaker 1: to using coal. You create a lot of fossil fuels, 280 00:17:09,480 --> 00:17:13,359 Speaker 1: you have a big carbon footprint that way, But it's 281 00:17:13,400 --> 00:17:19,040 Speaker 1: hard to argue with the dollar cost of energy. If 282 00:17:19,080 --> 00:17:23,800 Speaker 1: that dollar cost is higher with solar reserve, that's a 283 00:17:23,800 --> 00:17:27,320 Speaker 1: tough sell because not everyone's willing to spend more money 284 00:17:27,680 --> 00:17:34,000 Speaker 1: to keep their homes supplied with electricity just so that 285 00:17:34,040 --> 00:17:37,879 Speaker 1: they have a lower carbon footprint with the electricity generation. 286 00:17:38,680 --> 00:17:40,760 Speaker 1: It's just the truth of the matter, and some people 287 00:17:40,800 --> 00:17:44,879 Speaker 1: don't have the money to afford the luxury. Obviously, now, 288 00:17:44,920 --> 00:17:48,440 Speaker 1: if solar reserve is able to be significantly less expensive 289 00:17:48,480 --> 00:17:52,119 Speaker 1: than whatever the alternatives are, that's a huge win for 290 00:17:52,240 --> 00:17:56,000 Speaker 1: solar towers. So it's a lot of different questions along 291 00:17:56,000 --> 00:17:59,920 Speaker 1: those lines. Obviously, there are other questions to ask why 292 00:18:00,119 --> 00:18:02,960 Speaker 1: is the carbon footprint of actually building the solar tower? 293 00:18:03,520 --> 00:18:06,560 Speaker 1: But I would argue that whatever it is, it probably 294 00:18:06,760 --> 00:18:11,959 Speaker 1: is significantly less than the carbon footprint produced over the 295 00:18:12,000 --> 00:18:15,199 Speaker 1: lifetime of a coal plant or a gas plant or 296 00:18:15,200 --> 00:18:21,199 Speaker 1: oil plant. I think that's a pretty fair assumption, but 297 00:18:21,240 --> 00:18:25,000 Speaker 1: it still could be a very large upfront carbon footprint 298 00:18:25,280 --> 00:18:28,760 Speaker 1: creation there. So that's kind of the approach that I 299 00:18:28,840 --> 00:18:30,800 Speaker 1: wanted to talk about, this idea of being able to 300 00:18:30,800 --> 00:18:33,959 Speaker 1: generate electricity twenty four hours a day using sun power 301 00:18:34,119 --> 00:18:37,840 Speaker 1: without it being a solar panel, and I thought it 302 00:18:37,880 --> 00:18:42,360 Speaker 1: was a really cool approach to that, something that could 303 00:18:42,400 --> 00:18:47,600 Speaker 1: really get around a tricky problem with solar power, because 304 00:18:47,720 --> 00:18:50,320 Speaker 1: I know a lot of critics point out, hey, if 305 00:18:50,320 --> 00:18:53,760 Speaker 1: the sun's not shining, then you're not making electricity. Well, 306 00:18:54,400 --> 00:18:57,119 Speaker 1: that's true with your traditional solar panels, but not with 307 00:18:57,200 --> 00:19:02,720 Speaker 1: solar towers, assuming that you don't enter into cataclysmic event 308 00:19:02,800 --> 00:19:06,600 Speaker 1: where you've got crazy overcast skies for a really long time, 309 00:19:06,720 --> 00:19:08,399 Speaker 1: in which case, if we do have that, we're going 310 00:19:08,440 --> 00:19:10,919 Speaker 1: to have other problems besides where we get our electricity. 311 00:19:11,920 --> 00:19:13,840 Speaker 1: Oh and you might want to know how much electricity 312 00:19:13,880 --> 00:19:16,440 Speaker 1: can one of these facilities generate. It would be good 313 00:19:16,440 --> 00:19:19,040 Speaker 1: for me to tell you that. So Solar Reserve says 314 00:19:19,119 --> 00:19:22,240 Speaker 1: that depending on the plant design, it can generate between 315 00:19:22,240 --> 00:19:26,160 Speaker 1: fifty and two hundred megawatts over electricity, and one megawatt 316 00:19:26,240 --> 00:19:30,040 Speaker 1: is enough power to supply around a thousand homes. So 317 00:19:30,160 --> 00:19:33,879 Speaker 1: you're talking about with one solar tower facility between fifty 318 00:19:33,880 --> 00:19:37,399 Speaker 1: thousand and two hundred thousand homes. Obviously, there are a 319 00:19:37,440 --> 00:19:39,399 Speaker 1: lot of cities that are bigger than that, and in 320 00:19:39,520 --> 00:19:42,480 Speaker 1: order to supply the electricity for those cities, you would 321 00:19:42,560 --> 00:19:47,960 Speaker 1: need multiple solar tower facilities to do that. And again 322 00:19:48,080 --> 00:19:51,480 Speaker 1: that's another question is where would this be most appropriate. 323 00:19:51,560 --> 00:19:55,000 Speaker 1: Obviously a lot of desert towns that have medium to 324 00:19:55,160 --> 00:19:59,600 Speaker 1: small populations, this would be an amazing approach to generating 325 00:19:59,600 --> 00:20:03,760 Speaker 1: electric but it might not work for someplace like New 326 00:20:03,840 --> 00:20:08,280 Speaker 1: York city for multiple reasons, the population size, the lack 327 00:20:08,400 --> 00:20:12,119 Speaker 1: of land to dedicate to solar power. Obviously, that's another issue, 328 00:20:12,240 --> 00:20:15,200 Speaker 1: is that if you are going to dedicate a land 329 00:20:15,240 --> 00:20:17,800 Speaker 1: to a solar tower facility, you're not able to use 330 00:20:17,840 --> 00:20:21,639 Speaker 1: that land for other stuff, at least not easily, So 331 00:20:22,000 --> 00:20:25,080 Speaker 1: that's another consideration. Obviously, you don't want to end up 332 00:20:25,119 --> 00:20:27,640 Speaker 1: going to a place where you're dedicating land that could 333 00:20:27,680 --> 00:20:32,760 Speaker 1: be otherwise used for a more productive purpose, possibly not 334 00:20:33,000 --> 00:20:35,760 Speaker 1: energy related. It might be food related, or water or 335 00:20:35,800 --> 00:20:38,399 Speaker 1: something along those lines. So a lot of things to 336 00:20:38,400 --> 00:20:41,120 Speaker 1: take into consideration, but I think it's a very elegant 337 00:20:41,119 --> 00:20:45,159 Speaker 1: approach to generating electricity in using a renewable resource the 338 00:20:45,240 --> 00:20:50,399 Speaker 1: Sun's energy, and very low impact to the environment. The 339 00:20:50,440 --> 00:20:55,000 Speaker 1: mountain salts are inert, they're not dangerous. They're obviously dangerous 340 00:20:55,000 --> 00:20:56,920 Speaker 1: in their temperature. You would not want to touch them 341 00:20:56,920 --> 00:21:00,480 Speaker 1: while they're at one thousand and fifty degrees fahrenheit, but 342 00:21:01,440 --> 00:21:05,280 Speaker 1: they're not dangerous to the environment. And these, again the 343 00:21:06,000 --> 00:21:08,879 Speaker 1: systems are separate. The water system and the salt system 344 00:21:08,920 --> 00:21:11,719 Speaker 1: are separate from each other. So I think it's a 345 00:21:11,760 --> 00:21:14,760 Speaker 1: really interesting approach. Now I'm curious to hear what you 346 00:21:14,760 --> 00:21:19,800 Speaker 1: guys think about the most promising energy sources for the future. 347 00:21:19,920 --> 00:21:22,359 Speaker 1: Do you really think that solar power is going to 348 00:21:22,400 --> 00:21:27,200 Speaker 1: become a major way to offset our electricity generation. I'm 349 00:21:27,240 --> 00:21:30,879 Speaker 1: pretty sure. I feel fairly confident it's never going to 350 00:21:30,920 --> 00:21:35,320 Speaker 1: be the primary way we generate electricity. I don't think 351 00:21:35,320 --> 00:21:39,200 Speaker 1: it's practical enough to be our primary, but I certainly 352 00:21:39,200 --> 00:21:44,520 Speaker 1: see it as a very strong contender for a support system, 353 00:21:44,760 --> 00:21:48,560 Speaker 1: something that can offset some of our electricity needs. But 354 00:21:48,640 --> 00:21:49,920 Speaker 1: what do you think? Do you think there are other 355 00:21:49,960 --> 00:21:53,119 Speaker 1: ones that are better? Do you think wind power is 356 00:21:53,200 --> 00:21:58,320 Speaker 1: better than solar? Or maybe maybe you think hydropower is better, 357 00:21:59,000 --> 00:22:03,480 Speaker 1: Maybe think geothermal. Maybe you're looking for that nuclear fusion 358 00:22:03,800 --> 00:22:06,920 Speaker 1: approach if that break If there is a breakthrough nuclear fusion, 359 00:22:06,920 --> 00:22:09,520 Speaker 1: that would be an enormous benefit to all of humanity 360 00:22:10,359 --> 00:22:14,320 Speaker 1: because we would suddenly be capable of going into an 361 00:22:14,359 --> 00:22:18,959 Speaker 1: era of energy surplus, which would be phenomenal. And I 362 00:22:19,000 --> 00:22:22,879 Speaker 1: hope it happens. Hope you enjoyed that classic episode of 363 00:22:22,920 --> 00:22:26,119 Speaker 1: tech Stuff how solar towers work. I might need to 364 00:22:26,119 --> 00:22:29,960 Speaker 1: do an update on the various ways that we can 365 00:22:30,040 --> 00:22:34,280 Speaker 1: use solar power to generate electricity. If you have suggestions 366 00:22:34,320 --> 00:22:36,680 Speaker 1: for topics I should cover in future episodes of tech Stuff. 367 00:22:36,800 --> 00:22:39,840 Speaker 1: Let me know by using the iHeartRadio app, which is 368 00:22:39,920 --> 00:22:43,040 Speaker 1: free to use, free to download. Navigate over to tech Stuff. 369 00:22:43,040 --> 00:22:45,919 Speaker 1: You'll see there's a little microphone icon you click on 370 00:22:45,960 --> 00:22:47,879 Speaker 1: that you can leave me a voice message up to 371 00:22:47,920 --> 00:22:50,160 Speaker 1: thirty seconds in length, or you can let me know 372 00:22:50,640 --> 00:22:52,320 Speaker 1: what you would like me to cover in the future 373 00:22:52,480 --> 00:22:56,240 Speaker 1: by going to Twitter and tweeting me. The show handle 374 00:22:57,040 --> 00:23:01,080 Speaker 1: is tech Stuff HSW and I'll talk to you again 375 00:23:01,760 --> 00:23:11,399 Speaker 1: really soon. Y. Text Stuff is an iHeartRadio production. For 376 00:23:11,560 --> 00:23:16,400 Speaker 1: more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, 377 00:23:16,520 --> 00:23:18,520 Speaker 1: or wherever you listen to your favorite shows.