WEBVTT - RERUN: How Solar Towers Work

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<v Speaker 1>Get in touch with technology with tech Stuff from how

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<v Speaker 1>stuff Works dot com. Hey, everybody, welcome to tech Stuff.

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<v Speaker 1>I'm Jonathan Strickland. I am your host. I'm an executive

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<v Speaker 1>producer with How Stuff Works in my Heart Radio, and

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<v Speaker 1>I love all things tech and uh. I'm currently on vacation, y'all.

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<v Speaker 1>And because I'm on vacation for a couple of weeks

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<v Speaker 1>out in sunny London and Paris, I thought I would

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<v Speaker 1>bring some classic episodes to you guys. I didn't want

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<v Speaker 1>to skip any episode dates, but at the same time,

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<v Speaker 1>I didn't quite have the time to record a whole

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<v Speaker 1>bunch of extra episodes. So we're gonna look at some

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<v Speaker 1>classic episodes in the next few shows, with the exception

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<v Speaker 1>of the April first show, that will be a brand

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<v Speaker 1>new episode, so make sure you tune in for that

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<v Speaker 1>because I recorded something special for April Fool's Day. But

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<v Speaker 1>today we're gonna take a look back on a classic

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<v Speaker 1>episode of how solar towers work. This is a method

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<v Speaker 1>of harnessing energy from the sun, but it's not the

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<v Speaker 1>same thing as solar panels, which convert solar power directly

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<v Speaker 1>to electricity. I think it's a pretty fascinating technology, and

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<v Speaker 1>I talk about how it works and some of the

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<v Speaker 1>challenges in this episode I hope you enjoy. Today. I

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<v Speaker 1>want to talk a little bit about solar towers, which

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<v Speaker 1>is a different way of harnessing the sun's energy, and

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<v Speaker 1>I think it's a really clever way as well because

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<v Speaker 1>it doesn't rely on sunlight hitting a panel. Obviously, the

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<v Speaker 1>big big drawback to that approach is when the sun

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<v Speaker 1>isn't hitting a panel, you're not generating any electricity, right,

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<v Speaker 1>So if it's super cloudy or if it's nighttime, if

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<v Speaker 1>the sun is not able to hit the panel, the

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<v Speaker 1>sunlight's not getting there, you have nothing to convert into electricity,

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<v Speaker 1>and your solar panels go on to be unused for

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<v Speaker 1>that duration. So that can be really rough if you

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<v Speaker 1>have a long stretch of overcast days, or you live

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<v Speaker 1>in a place where you don't get solar exposure at

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<v Speaker 1>your house because of maybe they're taller buildings around you,

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<v Speaker 1>or trees or whatever. It maybe maybe you have a

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<v Speaker 1>north facing house rather than a south facing house here

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<v Speaker 1>in the Northern Hemisphere. If you have a south facing

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<v Speaker 1>house in the Northern Hemisphere, you're going to get more

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<v Speaker 1>solar exposure than a north facing house, so solar panels

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<v Speaker 1>have that drawback. There also, there's efficiency issues with solar panels.

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<v Speaker 1>When we talk about efficiency, what we mean is how

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<v Speaker 1>much of the sun's energy can we actually convert into

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<v Speaker 1>electricity and how much of it do we lose? How

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<v Speaker 1>much of that energy bounces off the panel and we

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<v Speaker 1>do not capture it. Most commercial solar panels, the kind

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<v Speaker 1>that you would put on your house, the efficiencies around eleven,

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<v Speaker 1>meaning that you're losing a lot of that energy not

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<v Speaker 1>is not converting into electricity. What that means is that

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<v Speaker 1>you have to buy more solar panels to cover more space,

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<v Speaker 1>to collect more solar energy, to generate enough electricity to

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<v Speaker 1>meet your needs. Obviously, if solar panels were efficient, which

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<v Speaker 1>is impossible, by the way, physically impossible. People have proved

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<v Speaker 1>it with mass, then if you if it were a

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<v Speaker 1>hundred percent efficient, you wouldn't need as many solar panels

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<v Speaker 1>in order to do what you need to do. That's

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<v Speaker 1>just not the case in reality. So instead we often

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<v Speaker 1>have to buy more than what we would like cover

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<v Speaker 1>a larger area, and even then again you're limited to

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<v Speaker 1>collecting electricity or generating electricity. I should say during the

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<v Speaker 1>daylight hours, and electricity also is a use it or

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<v Speaker 1>lose it kind of thing, meaning that if you don't

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<v Speaker 1>have an immediate use for that electricity and you don't

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<v Speaker 1>have a way to store it, you lose that electricity.

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<v Speaker 1>You have to use it when it's generated, so you

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<v Speaker 1>need to have some sort of battery system as well,

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<v Speaker 1>so that in the times when you're not using the

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<v Speaker 1>electricity you're generating, you can still save it for later use.

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<v Speaker 1>And until recently, batteries have been really expensive for the home,

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<v Speaker 1>but Tesla's power wall has kind of led a revolution

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<v Speaker 1>in that space, and we're starting to see more affordable

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<v Speaker 1>versions of batteries hit the home market. Okay, all of

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<v Speaker 1>that's out of the way to just say that the

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<v Speaker 1>traditional solar panel approach has its drawbacks. Now let's talk

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<v Speaker 1>about solar towers, because they take a totally different approach

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<v Speaker 1>to harnessing electricity from the sun and it's really pretty clever,

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<v Speaker 1>and they can harness electricity or they can generate electricity

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<v Speaker 1>day or night. So you might wonder, how is that

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<v Speaker 1>possible when when the Earth rotates so that the sun

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<v Speaker 1>is no longer shining on a solar tower, where's that

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<v Speaker 1>electricity coming from. So here's the way it works. Now,

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<v Speaker 1>I'm largely going to refer to a company called Solar Reserve,

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<v Speaker 1>which is here in the United States. Solar Reserve is

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<v Speaker 1>just one company that is building struct is like these

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<v Speaker 1>around the world, So I don't mean to suggest they're

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<v Speaker 1>the only one. I'm using them as the example because

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<v Speaker 1>that so much of their information is available to actually

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<v Speaker 1>read about and understand. So it's a really helpful approach.

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<v Speaker 1>Solar towers, Well, first of all, the name kind of

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<v Speaker 1>gives away the main feature. There's a tower in the

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<v Speaker 1>center of this uh structure or really multiple structures. So

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<v Speaker 1>how tall are these towers will according to Solar Reserve,

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<v Speaker 1>the height of the tower and its thermal receiver. More

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<v Speaker 1>on that in just a second, tends to be six

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<v Speaker 1>d forty feet combined or about one. So you've got

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<v Speaker 1>this tower in a a large area. You want to

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<v Speaker 1>have an area that gets a lot of solar exposure,

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<v Speaker 1>otherwise this is not a practical way of generating electricity.

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<v Speaker 1>So imagine like a desert, nice flat desert, lots of

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<v Speaker 1>sunlight hitting that desert every typical day, and you have

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<v Speaker 1>a tower with a receiver on the top of it. Now,

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<v Speaker 1>that receiver is actually a series of dark panels. And

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<v Speaker 1>these aren't solar panels, not in the way that you

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<v Speaker 1>would put on top of your house. They are not

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<v Speaker 1>converting sunlight into electricity directly. Rather, they are panels that

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<v Speaker 1>transfer thermal energy. In other words, they're all about transmitting heat.

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<v Speaker 1>So these panels have sixty six thin wall straight tubes

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<v Speaker 1>in them. Those tubes are designed to conduct heat from

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<v Speaker 1>the outside to the inside of that tower. And the

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<v Speaker 1>tubes are made out of a steel alloy that's covered

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<v Speaker 1>in a high absorptivity black coating to maximize the amount

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<v Speaker 1>of energy the panel can absorb. So you've got sunlight

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<v Speaker 1>shining on this tower, Well, how is that enough to

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<v Speaker 1>generate electricity on its own. It's not. In fact, what

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<v Speaker 1>you end up doing is surrounding the tower with mirrors. Now,

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<v Speaker 1>Solar Reserve uses mirrors that they call heliostats. These helio

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<v Speaker 1>stats are mounted on arms essentially that allow them to

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<v Speaker 1>track the motion of the sun. That way, the mirrors

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<v Speaker 1>maintain the ideal angle to uh to reflect the sun's

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<v Speaker 1>light directly towards the top of that tower. At that

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<v Speaker 1>receiving point of the tower. On those panels, and we're

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<v Speaker 1>talking about a lot of mirrors. Solar Reserve has one

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<v Speaker 1>area it's called the Crescent Dunes. That's there. There um

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<v Speaker 1>tower that they have in the US, and the Crescent

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<v Speaker 1>Dunes towers surrounded by more than ten thousand mirrors covering

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<v Speaker 1>a fifteen hundred acre field. So this is a big operation.

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<v Speaker 1>You've got to have a lot of open land for

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<v Speaker 1>this to work. That's obviously one of the potential drawbacks,

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<v Speaker 1>right that you need a place that's going to have

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<v Speaker 1>a lot of solar exposure and you need to have

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<v Speaker 1>enough space to make it make sense. But assuming you

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<v Speaker 1>have both of those things, you can do something pretty incredible.

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<v Speaker 1>I'll have more to say about solar towers in just

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<v Speaker 1>a second, but first let's take a quick break to

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<v Speaker 1>thank our sponsor. So what these mirrors do is direct

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<v Speaker 1>that sunlight up at those dark panels I was talking about.

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<v Speaker 1>Remember I mentioned there were fourteen. These fourteen panels are

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<v Speaker 1>divided up into two groups of seven. Each group of

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<v Speaker 1>seven represents kind of a circuit, and that circuit is

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<v Speaker 1>not for electricity. It's rather for a circuit of pipes

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<v Speaker 1>that are circulating liquid salts. So liquid salts are pretty cool, uh,

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<v Speaker 1>which is a weird way of putting it when you're

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<v Speaker 1>talking about thermal energy. But liquid salts can hold on

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<v Speaker 1>to more heat than water can and can remain in

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<v Speaker 1>liquid form, so in other words, they don't vaporize into steam.

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<v Speaker 1>And what solar reserve does is it pumps around five thousand,

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<v Speaker 1>eight hundred gallons of liquid salts per minute through the

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<v Speaker 1>receiver circuits that run back and forth across the inside

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<v Speaker 1>of these black panels. So imagine you've got this really

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<v Speaker 1>tall tower. At the top of the tower, you have

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<v Speaker 1>these fourteen dark panels, and then let's just take seven

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<v Speaker 1>on one side. You've got seven of those dark pounds

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<v Speaker 1>on one side. On the inside of those panels, you

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<v Speaker 1>would see this criss crossing of a pipe that is

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<v Speaker 1>circulating liquid salts through the pipe. Heat from the outside

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<v Speaker 1>comes into the tower and it begins to heat those

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<v Speaker 1>liquid salts running through that circuit. It's a simple heat transfer.

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<v Speaker 1>And if you've listened to our podcasts about things like

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<v Speaker 1>refrigerators and air conditioners, you know about you know how

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<v Speaker 1>this what the principles are, how how this is based

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<v Speaker 1>same basic thing. You want to give as much surface area,

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<v Speaker 1>you know, you want to. You want to dedicate as

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<v Speaker 1>much surface area as you can to heat and have

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<v Speaker 1>the liquid salts cross over as much of that surface

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<v Speaker 1>area as is possible to heat up the liquid salts.

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<v Speaker 1>As the liquid salts move through the circuit, they become molten,

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<v Speaker 1>so incredibly high temperatures. So the low side of the

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<v Speaker 1>temperatures for these liquid salts is five fifty degrees fahrenheit

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<v Speaker 1>or two degrees celsius. That's the low end. That's that's

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<v Speaker 1>the chili site. If you want to talk about how

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<v Speaker 1>hot they get, they can get up to a thousand

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<v Speaker 1>fifty degrees fahrenheit or five hundred sixty six degrees celsius.

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<v Speaker 1>That's really impressive. And so you've got this massive amount

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<v Speaker 1>of stored thermal energy. It's all inside the molten salts.

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<v Speaker 1>So you've got a lot of heat stored up. What

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<v Speaker 1>good is heat, Well, you can use heat to do

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<v Speaker 1>the same thing that is done in power plants all

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<v Speaker 1>over the world. You use heat to turn water into

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<v Speaker 1>steam and use the steam to turn a turbine which

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<v Speaker 1>generates electricity. It's an incredibly simple idea. It's the basis

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<v Speaker 1>of almost every other type of power plant. With the

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<v Speaker 1>exception of things like solar panels that are used in

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<v Speaker 1>solar farms like that, that's generating electricity straight from sunlight,

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<v Speaker 1>as opposed to using that electricity to somehow turn water

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<v Speaker 1>into steam. That would be ridiculous. You would lose way

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<v Speaker 1>too much energy in that approach. But things like coal

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<v Speaker 1>fired plants, even nuclear power plants, you're talking about generating

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<v Speaker 1>electricity by heating up water into steam and using that

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<v Speaker 1>steam to turn a turbine to do work, and that

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<v Speaker 1>turbine ends up being an electric generator and you get

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<v Speaker 1>electricity from that. So the the purpose of the solar

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<v Speaker 1>tower is really just to collect heat. That's it. It's

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<v Speaker 1>not doing anything magical. It's just generating tons and tons

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<v Speaker 1>of heat. I know that tons is not really a

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<v Speaker 1>unit when it comes to heat or temperature, but you

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<v Speaker 1>understand what I mean. It creates an enormous amount of

0:11:58.280 --> 0:12:01.079
<v Speaker 1>heat and the molten salts and go into a big

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<v Speaker 1>storage tank. And it's pretty cool because that storage tank

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<v Speaker 1>ends up being a a way of holding onto the

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<v Speaker 1>heat for a long time. According to Solar Reserve, the

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<v Speaker 1>company says that the molten salt only loses one degree

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<v Speaker 1>of fahrenheit, or about point five, five, five, etcetera, etcetera

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<v Speaker 1>degrees celsius in heat per day. So, in other words,

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<v Speaker 1>if you have a long stretch of overcast days, you

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<v Speaker 1>still have this massive that really tank. It's not a vat,

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<v Speaker 1>it's a tank because it's completely enclosed of molten salts

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<v Speaker 1>and they hold onto that heat, which means you can

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<v Speaker 1>continuously pump that through your water tank in order to

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<v Speaker 1>heat water up to steam. And when I say pump,

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<v Speaker 1>you pump it through. It's a very similar circuit that

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<v Speaker 1>you would find at the top of the receiver. The

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<v Speaker 1>molten salts don't mix with the water. Instead, you have

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<v Speaker 1>a pipe that runs through the water tank. The molten

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<v Speaker 1>salts run through the pipe and transfer some of their

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<v Speaker 1>heat to the water through the material of the pipe itself.

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<v Speaker 1>So you're not laying the molten salts in the water

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<v Speaker 1>mixed together. That would be ridiculous. Instead, you're having the

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<v Speaker 1>molten salts move through a pathway, and as they move

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<v Speaker 1>through that pathway, they heat up the water. The water turns,

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<v Speaker 1>the steam turns the turbine. Then the steam goes through

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<v Speaker 1>a condenser to condense the steam back into water, and

0:13:27.040 --> 0:13:30.360
<v Speaker 1>it goes back into the water tank. So once you

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<v Speaker 1>use the molten salts to transfer some of this heat,

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<v Speaker 1>they they've lost that thermal energy. They're now moving into

0:13:37.160 --> 0:13:40.920
<v Speaker 1>a different tank. It's a tank to pump the liquid

0:13:40.960 --> 0:13:44.160
<v Speaker 1>salts back up into the top of the tower. So

0:13:45.120 --> 0:13:48.600
<v Speaker 1>the neat thing with this system is that you can

0:13:48.800 --> 0:13:51.560
<v Speaker 1>use it to deliver electricity day or night. You've got

0:13:51.600 --> 0:13:54.040
<v Speaker 1>so much stored heat. After you get the system up

0:13:54.040 --> 0:13:56.880
<v Speaker 1>and running and it's generated enough molten salt, like it's

0:13:56.920 --> 0:13:59.720
<v Speaker 1>created enough molten salt through this process to allow this

0:13:59.840 --> 0:14:04.199
<v Speaker 1>to happen, you can deliver electricity on demand twenty four

0:14:04.240 --> 0:14:06.680
<v Speaker 1>hours a day. And that's how all power plants work.

0:14:06.720 --> 0:14:10.600
<v Speaker 1>They deliver electricity on demand. They're not uh set to

0:14:10.640 --> 0:14:13.000
<v Speaker 1>a certain level, and then if you don't meet that level,

0:14:13.280 --> 0:14:17.120
<v Speaker 1>they you know, just that electricity goes to waste. They

0:14:17.160 --> 0:14:19.920
<v Speaker 1>base it upon what the current demand. And I don't

0:14:19.960 --> 0:14:21.520
<v Speaker 1>mean that as a pun, but it came out of

0:14:21.640 --> 0:14:24.560
<v Speaker 1>that way. Chris would be so proud. They don't. They

0:14:24.600 --> 0:14:28.640
<v Speaker 1>respond to whatever the demand is at that time to

0:14:28.760 --> 0:14:33.720
<v Speaker 1>produce the amount of electricity needed. So super interesting way

0:14:33.720 --> 0:14:37.200
<v Speaker 1>of doing this by using the sun as an energy

0:14:37.240 --> 0:14:40.960
<v Speaker 1>source to create the heat needed to turn water into

0:14:40.960 --> 0:14:43.840
<v Speaker 1>steam and turn a turbine as opposed to a fossil

0:14:43.880 --> 0:14:47.280
<v Speaker 1>fuel like coal or oil, or a nuclear fuel in

0:14:47.280 --> 0:14:50.680
<v Speaker 1>the case of nuclear fusion. Now, if we ever are fission,

0:14:50.760 --> 0:14:53.360
<v Speaker 1>I should say nuclear fission. I know all of you

0:14:53.400 --> 0:14:55.480
<v Speaker 1>were ready to write in, and you should be because

0:14:55.480 --> 0:14:58.440
<v Speaker 1>that was a silly mistake I made nuclear fusion. If

0:14:58.440 --> 0:15:02.120
<v Speaker 1>we ever crack that nut, solar towers may seem quaint

0:15:02.200 --> 0:15:06.560
<v Speaker 1>in comparison. But that's a very difficult problem in physics

0:15:06.600 --> 0:15:09.480
<v Speaker 1>to to solve. So we're still waiting on that. I

0:15:09.520 --> 0:15:11.920
<v Speaker 1>have a little bit more about solar towers to talk about,

0:15:12.120 --> 0:15:14.560
<v Speaker 1>but before we get there, let's take another quick break.

0:15:22.400 --> 0:15:25.560
<v Speaker 1>So the neat thing about this, obviously is that if

0:15:25.600 --> 0:15:27.920
<v Speaker 1>you do have that amount of space, you can really

0:15:27.960 --> 0:15:31.760
<v Speaker 1>offset a lot of the community's electricity needs with a

0:15:31.800 --> 0:15:36.280
<v Speaker 1>solar tower. And uh, the company thinks that the lifespan

0:15:36.360 --> 0:15:39.600
<v Speaker 1>of these solar towers is somewhere in the area of

0:15:39.640 --> 0:15:43.520
<v Speaker 1>about thirty years, meaning that after thirty years we would

0:15:43.520 --> 0:15:46.320
<v Speaker 1>have to start to replace parts because just of wear

0:15:46.320 --> 0:15:50.479
<v Speaker 1>and tear, or they would not be as uh efficient

0:15:50.720 --> 0:15:53.800
<v Speaker 1>as they had previously been. So, for example, those panels,

0:15:54.360 --> 0:15:57.960
<v Speaker 1>if the panels become less efficient at transferring heat over time,

0:15:58.480 --> 0:16:01.080
<v Speaker 1>you would definitely want to reply them because you would

0:16:01.280 --> 0:16:04.760
<v Speaker 1>be transferring less heat to generate your Your molden salts

0:16:04.760 --> 0:16:06.600
<v Speaker 1>will be at a lower temperature. It would require more

0:16:06.640 --> 0:16:11.000
<v Speaker 1>of them to turn water into steam, who become less

0:16:11.040 --> 0:16:15.240
<v Speaker 1>efficient overall. So you have to make sure that, uh,

0:16:15.320 --> 0:16:18.200
<v Speaker 1>you're all the parts are working very they're very few

0:16:18.240 --> 0:16:20.680
<v Speaker 1>moving parts, which is awesome, but you have to make

0:16:20.720 --> 0:16:24.240
<v Speaker 1>sure they're working throughout the lifetime of the facility and

0:16:24.280 --> 0:16:27.720
<v Speaker 1>then obviously replaced parts as needed. So the question then

0:16:27.800 --> 0:16:32.640
<v Speaker 1>becomes doesn't make financial sense to switch over to using

0:16:32.680 --> 0:16:36.760
<v Speaker 1>solar towers at least to offset electricity generation in a

0:16:36.760 --> 0:16:40.000
<v Speaker 1>particular area. To answer that question, you have to look

0:16:40.000 --> 0:16:42.800
<v Speaker 1>at a lot of different factors and it is way

0:16:42.840 --> 0:16:45.920
<v Speaker 1>more complicated than just a simple yes or no. For

0:16:46.000 --> 0:16:51.200
<v Speaker 1>one thing, how much solar exposure is the area getting. Obviously,

0:16:51.240 --> 0:16:53.080
<v Speaker 1>if you're not getting a lot, then that's not going

0:16:53.120 --> 0:16:56.120
<v Speaker 1>to be a good choice for solar towers or a

0:16:56.160 --> 0:16:58.400
<v Speaker 1>good place to about a solar tower. I should say

0:16:59.280 --> 0:17:03.440
<v Speaker 1>also not just where and and you know what time

0:17:03.440 --> 0:17:05.919
<v Speaker 1>of year do you get solar exposure? Those would be

0:17:05.920 --> 0:17:09.879
<v Speaker 1>two big things. But how much does electricity cost in

0:17:09.920 --> 0:17:12.320
<v Speaker 1>that region already. And the reason why you have to

0:17:12.359 --> 0:17:15.520
<v Speaker 1>ask that question is if you were to provide electricity

0:17:15.520 --> 0:17:20.520
<v Speaker 1>through the solar reserve system, would it make financial sense

0:17:20.560 --> 0:17:23.480
<v Speaker 1>to make that switch. If coal is incredibly cheap in

0:17:23.520 --> 0:17:27.439
<v Speaker 1>the area, then financially it might make more sense to

0:17:27.440 --> 0:17:30.200
<v Speaker 1>stick with coal, even though we all know there are

0:17:30.280 --> 0:17:33.479
<v Speaker 1>big environmental drawbacks to using coal. You create a lot

0:17:33.480 --> 0:17:36.960
<v Speaker 1>of fossil fuels, you have a big carbon footprint that way,

0:17:37.000 --> 0:17:43.480
<v Speaker 1>but it's hard to argue with the dollar cost of energy.

0:17:43.640 --> 0:17:48.440
<v Speaker 1>If that dollar cost is higher with solar reserve, that's

0:17:48.440 --> 0:17:51.240
<v Speaker 1>a tough sell because not everyone is willing to spend

0:17:51.359 --> 0:17:56.480
<v Speaker 1>more money to keep their homes, uh, you know, supplied

0:17:56.480 --> 0:17:59.959
<v Speaker 1>with electricity, just so that they have a lower car

0:18:00.040 --> 0:18:04.560
<v Speaker 1>been footprint with the electricity generation. It's just the truth

0:18:04.560 --> 0:18:06.560
<v Speaker 1>of the matter, and some people don't have the money

0:18:06.600 --> 0:18:10.800
<v Speaker 1>to afford the luxury. Obviously, Now, if solar reserve is

0:18:10.840 --> 0:18:14.879
<v Speaker 1>able to be significantly less expensive than whatever the alternatives are,

0:18:15.359 --> 0:18:19.479
<v Speaker 1>that's a huge win for solar towers. So it's a

0:18:19.480 --> 0:18:23.199
<v Speaker 1>lot of different questions along those lines. Obviously, there are

0:18:23.200 --> 0:18:25.960
<v Speaker 1>other questions to ask, like what is the carbon footprint

0:18:25.960 --> 0:18:29.439
<v Speaker 1>of actually building the solar tower, but I would argue

0:18:29.480 --> 0:18:33.640
<v Speaker 1>that whatever it is, it probably has significantly less than

0:18:33.680 --> 0:18:37.840
<v Speaker 1>the carbon footprint produced over the lifetime of a coal

0:18:37.920 --> 0:18:42.879
<v Speaker 1>plant or a gas plant or oil plant. Um I

0:18:42.920 --> 0:18:46.280
<v Speaker 1>think that's pretty a pretty fair assumption, but it still

0:18:46.320 --> 0:18:50.800
<v Speaker 1>could be a very large upfront uh carbon footprint creation there.

0:18:51.400 --> 0:18:53.879
<v Speaker 1>So that's kind of the approach that I wanted to

0:18:53.880 --> 0:18:56.440
<v Speaker 1>talk about, this idea of being able to generate electricity

0:18:56.440 --> 0:19:00.200
<v Speaker 1>twenty four hours a day using sun power without being

0:19:00.240 --> 0:19:03.080
<v Speaker 1>a solar panel, and I thought it was a really

0:19:03.080 --> 0:19:08.240
<v Speaker 1>cool approach to that, something that could really get around

0:19:08.280 --> 0:19:12.840
<v Speaker 1>a tricky problem with solar power because I know a

0:19:12.880 --> 0:19:15.520
<v Speaker 1>lot of critics point out, hey, if the sun is

0:19:15.560 --> 0:19:19.680
<v Speaker 1>not shining, then you're not making electricity. Well that's true

0:19:19.760 --> 0:19:22.760
<v Speaker 1>with your traditional solar panels, but not with solar towers,

0:19:22.800 --> 0:19:27.760
<v Speaker 1>assuming that you don't enter into some cataclysmic event where

0:19:27.760 --> 0:19:31.360
<v Speaker 1>you've got crazy overcast skies for a really long time,

0:19:31.480 --> 0:19:33.280
<v Speaker 1>in which case, if we do have that, we're gonna

0:19:33.320 --> 0:19:36.840
<v Speaker 1>have other problems besides where we get our electricity. Um Oh,

0:19:36.960 --> 0:19:38.760
<v Speaker 1>and you might want to know how much electricity can

0:19:38.800 --> 0:19:41.280
<v Speaker 1>one of these facilities generate. It would be good for

0:19:41.320 --> 0:19:44.080
<v Speaker 1>me to tell you that. So Solar Reserves says that

0:19:44.160 --> 0:19:47.320
<v Speaker 1>depending on the plant design, it can generate between fifty

0:19:47.359 --> 0:19:51.000
<v Speaker 1>and two hundred megawatts on electricity, and one megawatt is

0:19:51.119 --> 0:19:55.040
<v Speaker 1>enough power to supply around a thousand homes. So you're

0:19:55.040 --> 0:19:59.080
<v Speaker 1>talking about with one solar tower facility between fifty thousand

0:19:59.080 --> 0:20:02.159
<v Speaker 1>and two hundred tho and homes. Obviously, there are a

0:20:02.160 --> 0:20:04.159
<v Speaker 1>lot of cities that are bigger than that, and in

0:20:04.280 --> 0:20:07.240
<v Speaker 1>order to supply the electricity for those cities, you would

0:20:07.320 --> 0:20:12.040
<v Speaker 1>need multiple solar tower facilities to to do that. Uh.

0:20:12.080 --> 0:20:15.320
<v Speaker 1>And again that's another question is where would this be

0:20:15.440 --> 0:20:18.280
<v Speaker 1>most appropriate. Obviously a lot of desert towns that have

0:20:19.119 --> 0:20:23.720
<v Speaker 1>medium to small populations, this would be an amazing approach

0:20:23.800 --> 0:20:27.280
<v Speaker 1>to generating electricity, but it might not work for someplace

0:20:27.320 --> 0:20:31.840
<v Speaker 1>like New York City for multiple reasons, the population size,

0:20:32.320 --> 0:20:36.000
<v Speaker 1>the lack of land to dedicate to solar power. Obviously,

0:20:36.000 --> 0:20:38.040
<v Speaker 1>that's another issue is that if you are going to

0:20:38.080 --> 0:20:41.959
<v Speaker 1>dedicate a land to a solar tower facility, you're not

0:20:42.040 --> 0:20:45.040
<v Speaker 1>able to use that land for other stuff, at least

0:20:45.040 --> 0:20:49.160
<v Speaker 1>not easily, So that's another consideration. Obviously, you don't want

0:20:49.200 --> 0:20:51.760
<v Speaker 1>to end up going to a place where you're dedicating

0:20:51.840 --> 0:20:56.040
<v Speaker 1>land that could be otherwise used for a more productive purpose,

0:20:56.840 --> 0:21:00.000
<v Speaker 1>possibly not energy related. It might be food related, or

0:21:00.040 --> 0:21:02.840
<v Speaker 1>water or something along those lines. So a lot of

0:21:02.840 --> 0:21:05.040
<v Speaker 1>things to take into consideration. But I think it's a

0:21:05.160 --> 0:21:08.800
<v Speaker 1>very elegant approach to generating electricity in a using a

0:21:08.840 --> 0:21:14.119
<v Speaker 1>renewable resource the Sun's energy, and very low impact to

0:21:14.160 --> 0:21:18.399
<v Speaker 1>the environment. The modern salts are inert they're not dangerous. Uh.

0:21:18.760 --> 0:21:20.960
<v Speaker 1>They're obviously dangerous in their temperature. You would not want

0:21:21.000 --> 0:21:24.320
<v Speaker 1>to touch them while they're at a thousand fifty degrees fahrenheit,

0:21:25.200 --> 0:21:29.919
<v Speaker 1>but they're not dangerous to the environment. Uh. And these again,

0:21:30.000 --> 0:21:33.280
<v Speaker 1>the systems are separate. The water system and the salt

0:21:33.320 --> 0:21:36.360
<v Speaker 1>system are separate from each other. So I think it's

0:21:36.359 --> 0:21:39.240
<v Speaker 1>a really interesting approach. Now I'm curious to hear what

0:21:39.320 --> 0:21:44.040
<v Speaker 1>you guys think about the most promising energy sources for

0:21:44.080 --> 0:21:46.800
<v Speaker 1>the future. Do you really think that solar power is

0:21:46.840 --> 0:21:51.680
<v Speaker 1>going to become a major way to offset our electricity generation.

0:21:51.800 --> 0:21:55.480
<v Speaker 1>I'm pretty sure. I feel fairly confident it's never going

0:21:55.520 --> 0:21:59.800
<v Speaker 1>to be the primary way we generate electricity. I don't

0:21:59.800 --> 0:22:03.399
<v Speaker 1>think gets practical enough to be our primary but I

0:22:03.480 --> 0:22:07.119
<v Speaker 1>certainly see it as a very strong contender for a

0:22:07.280 --> 0:22:12.439
<v Speaker 1>support system, something that can offset some of our electricity needs.

0:22:13.280 --> 0:22:14.479
<v Speaker 1>But what do you think? Do you think there are

0:22:14.520 --> 0:22:17.600
<v Speaker 1>other ones that are better? Do you think wind power

0:22:17.800 --> 0:22:21.120
<v Speaker 1>is better than solar? Or maybe uh, maybe you think

0:22:21.680 --> 0:22:26.480
<v Speaker 1>hydro power is better. Maybe you think geothermal. Maybe you're

0:22:26.520 --> 0:22:30.239
<v Speaker 1>looking for that nuclear fusion approach. If that break, If

0:22:30.240 --> 0:22:32.119
<v Speaker 1>there is a breakthrough nuclear fusion, that would be an

0:22:32.240 --> 0:22:36.160
<v Speaker 1>enormous benefit to all of humanity because we would suddenly

0:22:36.640 --> 0:22:40.800
<v Speaker 1>be capable of going into an era of energy surplus,

0:22:41.480 --> 0:22:45.320
<v Speaker 1>which would be phenomenal. And I hope it happens, but

0:22:45.400 --> 0:22:47.919
<v Speaker 1>there are a lot of challenges to get out of

0:22:47.960 --> 0:22:49.760
<v Speaker 1>the way first. So maybe I'll do a full episode

0:22:49.760 --> 0:22:52.280
<v Speaker 1>about nuclear fusion in the in the future and talk

0:22:52.320 --> 0:22:55.560
<v Speaker 1>about why it's such a tricky issue. Guys, I hope

0:22:55.600 --> 0:22:58.280
<v Speaker 1>you enjoyed that classic episode of tech Stuff. I'll be

0:22:58.359 --> 0:23:02.000
<v Speaker 1>back soon recording on episodes. I can't wait to hear

0:23:02.040 --> 0:23:04.120
<v Speaker 1>from you. If you have anything you want to send

0:23:04.119 --> 0:23:07.320
<v Speaker 1>to me, maybe it's a suggestion for a future episode,

0:23:07.840 --> 0:23:11.200
<v Speaker 1>send me that via email. The addresses tech Stuff at

0:23:11.240 --> 0:23:14.520
<v Speaker 1>how stuff works dot com, drop on by our website

0:23:14.560 --> 0:23:17.800
<v Speaker 1>that's tech stuff podcast dot com, and I'll talk to

0:23:17.800 --> 0:23:26.800
<v Speaker 1>you again really soon. For more on this and thousands

0:23:26.800 --> 0:23:38.960
<v Speaker 1>of other topics, because it how stuff works. Dot com