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Geothermal Energy - The Basics · PlanetGeo: The Geology Podcast

• 0:08
  SPEAKER_00: Welcome to Planet Geo, the podcast where we talk about our amazing planet, how it works, and why it matters to you.
• 0:31
  SPEAKER_01: Jesse Rymanck.
• 0:32
  SPEAKER_01: How are you doing today, man?
• 0:34
  SPEAKER_01: Christopher.
• 0:34
  SPEAKER_01: What's going on, man?
• 0:36
  SPEAKER_01: Not a whole lot.
• 0:37
  SPEAKER_01: You busted out to Christopher again.
• 0:38
  SPEAKER_01: I like it.
• 0:40
  SPEAKER_00: Respect in that tone.
• 0:41
  SPEAKER_00: You're kind of looking like a Christopher right now.
• 0:43
  SPEAKER_01: Oh, really?
• 0:44
  SPEAKER_01: Okay.
• 0:44
  SPEAKER_01: I don't know what that means.
• 0:46
  SPEAKER_00: You're looking to steam.
• 0:46
  SPEAKER_00: You got the gray goatee going on.
• 0:48
  SPEAKER_00: You're looking very esteemed.
• 0:50
  SPEAKER_01: I decided I'm growing a beard.
• 0:52
  SPEAKER_00: Oh no.
• 0:53
  SPEAKER_00: I am growing a grade.
• 0:54
  SPEAKER_00: We gotta start to be all gray.
• 0:56
  SPEAKER_00: Hit pause.
• 0:56
  SPEAKER_00: Hit pause.
• 0:57
  SPEAKER_00: We're done with the podcast.
• 0:58
  SPEAKER_00: We can't do this anymore.
• 0:59
  SPEAKER_01: No, I am.
• 1:00
  SPEAKER_01: I am.
• 1:00
  SPEAKER_01: I'm growing up, I'm growing a beard.
• 1:02
  SPEAKER_01: Jenny really wants it, and uh, I'm gonna hit it.
• 1:05
  SPEAKER_00: I don't know what you mean by I'm gonna hit it, but I don't think that uh Jenny wants you to have a beard.
• 1:13
  SPEAKER_00: So she does.
• 1:14
  SPEAKER_01: She has been uh actually she's been after this for a long time.
• 1:18
  SPEAKER_00: That sounds so exciting for me and all of our listeners.
• 1:21
  SPEAKER_00: Wow, we are just so excited here.
• 1:23
  SPEAKER_01: Unfortunately, they cannot see me.
• 1:25
  SPEAKER_01: So that's right.
• 1:26
  SPEAKER_01: All right.
• 1:26
  SPEAKER_01: Hey, what do we have going today, Jesse?
• 1:28
  SPEAKER_01: Let's go.
• 1:29
  SPEAKER_00: We are talking about geothermal energy.
• 1:31
  SPEAKER_00: Love it.
• 1:32
  SPEAKER_00: Yeah, me too.
• 1:33
  SPEAKER_00: This is exciting.
• 1:34
  SPEAKER_01: So, where did this topic come from?
• 1:35
  SPEAKER_00: Why are we doing this?
• 1:36
  SPEAKER_00: Well, first of all, we like to do things here on Planet Geo that matter or topics that matter, and geothermal is very much in the conversation with the energy transition and sort of alternative energy resources.
• 1:47
  SPEAKER_00: So it's an important thing to understand the basics of.
• 1:50
  SPEAKER_00: But really, it came from a conversation I was having, well, really a suggestion from my father-in-law, who was like, Yeah, you guys should do something on geothermal energy.
• 1:59
  SPEAKER_00: That's pretty interesting.
• 2:00
  SPEAKER_00: We're talking about Grant here, yeah, yeah.
• 2:01
  SPEAKER_00: But you know, he added a little twist to it, which kind of caught me off guard.
• 2:04
  SPEAKER_00: He's like, but really, like, like, why is the earth hot?
• 2:08
  SPEAKER_00: And I'm doing my best impression there.
• 2:10
  SPEAKER_00: Like, you know, like, but really, like, why is the earth hot?
• 2:14
  SPEAKER_00: You know?
• 2:15
  SPEAKER_00: That's good.
• 2:16
  SPEAKER_00: And I was like, oh, that you know, that's actually a really fundamental question that probably not many people think about or know the answer to, right?
• 2:27
  SPEAKER_01: And it's right in our wheelhouse.
• 2:28
  SPEAKER_01: Totally in our wheelhouse.
• 2:29
  SPEAKER_01: It's a really important thing.
• 2:30
  SPEAKER_00: So, so we're gonna go through geothermal energy and why the earth is hot.
• 2:36
  SPEAKER_01: Hey, before we begin, we should do some introductions, Jesse.
• 2:39
  SPEAKER_01: So you are Dr.
• 2:40
  SPEAKER_01: Jesse Remick.
• 2:41
  SPEAKER_01: You are one of my former high school students, and you went on to get your PhD in geoscience and now work as a professor of geoscience at Penn State University.
• 2:51
  SPEAKER_00: That's right.
• 2:51
  SPEAKER_00: You're Chris Bullhois, my former high school teacher, as you said.
• 2:54
  SPEAKER_00: And uh, this is the only compliment I'm gonna give you for the whole day, probably, but you are a very inspiring geoscience teacher.
• 3:01
  SPEAKER_00: You've trained a lot of people who go on to become geoscientists, you've won national awards, and uh you still teach in Michigan and you coach in Michigan um and Huttsville High School.
• 3:10
  SPEAKER_00: So, Chris, where are we going here?
• 3:12
  SPEAKER_01: So, just like you said, we're gonna talk about geothermal energy.
• 3:15
  SPEAKER_01: But before we do this, before we dive into this, we need to distinguish the two major types of geothermal energy and what it's used for.
• 3:26
  SPEAKER_01: So one of them is used to generate electricity, and it does this by using superheated water.
• 3:35
  SPEAKER_01: This is water that's above the boiling point, and it's used to generate steam, steam creates pressure, and pressure turns turbines.
• 3:44
  SPEAKER_01: And that's one.
• 3:46
  SPEAKER_00: And the second one, the other type, which is a very dramatically different type, this is a little bit more of a passive process.
• 3:52
  SPEAKER_00: It's lower heat.
• 3:54
  SPEAKER_00: Some people call them geothermal heat pumps, but basically, it's just a moderator for the temperature in our homes.
• 3:59
  SPEAKER_00: It's using the moderate temperatures beneath the ground, relatively shallow beneath the ground, to sort of reduce the energy that's required to heat and cool our homes with traditional methods.
• 4:10
  SPEAKER_00: And this is the type that I have in my house.
• 4:13
  SPEAKER_01: Yeah, that's important.
• 4:14
  SPEAKER_01: That's an important thing to make note of is that you know, the one that's used to generate electricity is done by like commercial power plants where they use processes that are going on inside the earth because the conditions are right, and they use that superheated water to generate electricity.
• 4:33
  SPEAKER_01: The geothermal that most people think of is accessible to pretty much anyone.
• 4:39
  SPEAKER_00: Yeah, that right there is key because the electricity generation one is actually a resource and is in some ways a limited resource, whereas the background passive heat pump method is basically universally accessible.
• 4:53
  SPEAKER_00: I mean, for most people, for most of the population, you can tap into this moderating source.
• 4:58
  SPEAKER_00: So those are the two types, and we're gonna get into those in some detail, but we kind of have to back up and answer the the basic question first, right, Chris?
• 5:06
  SPEAKER_01: We do, which is the question that came from Grant, which is why is the earth hot?
• 5:12
  SPEAKER_01: Why does the earth get predictably hotter the deeper in toward the core uh you go?
• 5:20
  SPEAKER_01: So I think that's where we have to start with this.
• 5:23
  SPEAKER_01: So let's go.
• 5:24
  SPEAKER_01: Why does the earth get hot?
• 5:25
  SPEAKER_01: So I think we have to start with heat, basically.
• 5:27
  SPEAKER_00: I mean, a little bit of a very basic understanding of what heat is, and heat is just energy.
• 5:33
  SPEAKER_00: Think of it as, for our purposes, molecules moving faster.
• 5:38
  SPEAKER_00: These are molecules or atoms that are basically vibrating really fast.
• 5:42
  SPEAKER_00: Picture your favorite molecule, H2O or whatever.
• 5:44
  SPEAKER_00: You see those diagrams, a big red ball and little white balls.
• 5:47
  SPEAKER_00: Just think of that thing vibrating back and forth a lot faster.
• 5:51
  SPEAKER_00: And that's heat that has more heat in it.
• 5:53
  SPEAKER_01: Okay, so the mantle is hot.
• 5:56
  SPEAKER_01: You know, like what are we talking about in terms of energy, Jesse?
• 5:58
  SPEAKER_01: How hot is the mantle?
• 5:59
  SPEAKER_01: How hot is the earth?
• 6:00
  SPEAKER_00: Yeah, so the the heat lost by Earth, so this is heat moving from Earth to outer space, is 47 terawatts.
• 6:09
  SPEAKER_00: And that is gonna require breaking down a little bit, that term terawatt.
• 6:14
  SPEAKER_00: So, first of all, a watt is a unit of power, which is energy per second, basically, it's a rate transfer.
• 6:22
  SPEAKER_00: So, when we think of when you get your electricity bill, you get something that says kilowatt hours.
• 6:27
  SPEAKER_00: That's actually a packet of energy, that's the amount of energy, for instance, that's a there's a battery analogy here that a battery can store a certain number of kilowatt hours.
• 6:37
  SPEAKER_00: If you release all that energy very quickly, think your computer, when it's running a whole bunch of different programs and apps, it's draining the battery really quickly.
• 6:45
  SPEAKER_00: That rate of loss of energy is would be in watts.
• 6:49
  SPEAKER_00: So it's really a rate of energy transfer.
• 6:52
  SPEAKER_00: So that's what a watt is.
• 6:53
  SPEAKER_00: It's just a rate of energy movement, and the Terra is stands for trillion, basically.
• 6:59
  SPEAKER_00: So Earth is losing 47 terawatts or 47 trillion watts of energy per second.
• 7:07
  SPEAKER_01: In other words, to make a short story long, which you just did here, I'm gonna make a long story short.
• 7:13
  SPEAKER_01: So the earth is losing an unbelievable amount of energy every single second.
• 7:19
  SPEAKER_00: That is exactly right.
• 7:21
  SPEAKER_01: It's impossible to wrap your mind around how much energy the earth is losing every single second.
• 7:26
  SPEAKER_01: So let's get into that then.
• 7:27
  SPEAKER_01: Let's answer Grant's question, right?
• 7:29
  SPEAKER_01: Where's this heat coming from?
• 7:31
  SPEAKER_01: Okay, well, really, it comes down to three basic things that are going on.
• 7:36
  SPEAKER_01: Basically, the internal heat engine of the earth, which is the way I like to refer to it, what is the internal heat engine of the earth?
• 7:45
  SPEAKER_01: Over half of that heat is from radioactive decay.
• 7:50
  SPEAKER_01: We're talking about elements like uranium, thorium, and potassium.
• 7:55
  SPEAKER_00: Yes, and we talked about radioactive decay in some previous episodes.
• 7:58
  SPEAKER_00: There's a couple of them if you go back to about geochronology or ancient nuclear reactors.
• 8:03
  SPEAKER_00: So, yes, we've talked about radioactive decay a little bit, so we won't go into too much detail about that.
• 8:08
  SPEAKER_01: Right.
• 8:08
  SPEAKER_01: But basically, you know, when uranium 235 decays all the way down to lead two oh seven, heat is a product of this decay process.
• 8:20
  SPEAKER_01: Okay, and same goes with every other radioactive element that decays.
• 8:24
  SPEAKER_01: Heat is a byproduct of this.
• 8:25
  SPEAKER_01: So in the mantle of the earth, which is beneath the crust, there's a lot of rock, and this rock has uh radioactive elements in it.
• 8:34
  SPEAKER_01: Elements like uranium and thorium and potassium, and when they decay, part of the byproduct of that decay is heat, and that heat then has to radiate outward toward the surface, and that takes time, but that is the heat engine of the earth, is that, or at least over half of the heat engine of the earth is radioactive decay.
• 8:53
  SPEAKER_00: That's right.
• 8:53
  SPEAKER_00: And the other half, the other half of the heat produced in Earth, is actually kind of left over in some ways.
• 9:01
  SPEAKER_00: So there's two other components here.
• 9:03
  SPEAKER_00: First of all, is the way that Earth formed is that little dust particles got aggregated together and formed little pebbles.
• 9:12
  SPEAKER_00: Those pebbles then got added together and became boulders.
• 9:15
  SPEAKER_00: The boulders smashed together and eventually became bigger boulders and bigger meteorites, and then those kind of smashed together and became a planet.
• 9:23
  SPEAKER_00: So you kind of have this process that is a lot of smashing together.
• 9:28
  SPEAKER_00: There's boulders colliding, there's planets colliding or planetesimals, small planets colliding.
• 9:34
  SPEAKER_00: That energy of that collision gets trapped in the earth.
• 9:37
  SPEAKER_00: So there is a significant amount of heat that is left over from Earth formation that is constantly trying to escape Earth, and we'll come back to this, but it takes a long time for that process to occur.
• 9:48
  SPEAKER_00: So we have this latent heat of accretion, which is the term for the heat from collisions that formed the earth.
• 9:55
  SPEAKER_01: What about the growth of the solid core at the expense of the liquid outer core as it cools off?
• 10:01
  SPEAKER_01: What happened you get heat produced from that?
• 10:03
  SPEAKER_00: That's right.
• 10:04
  SPEAKER_00: And this, so this is a uh, you know, we don't get into the details here, but basically, whenever a liquid crystallizes, like the liquid outer core, the iron nickel outer core, when that becomes solid, so that kind of crystallizes, there is heat released during that process.
• 10:19
  SPEAKER_00: And so the fact that the outer liquid core is crystallizing slowly to become the solid inner core, that releases heat as well, and that heat is trying to escape Earth as well.
• 10:29
  SPEAKER_00: So those are the three components to heat within the earth is radioactive decay, latent heat of accretion or leftover from earth formation, and the crystallization of the core that is going on.
• 10:42
  SPEAKER_00: Three ways to produce heat, but heat takes a long time to leave Earth.
• 10:46
  SPEAKER_00: It's a hard road for heat to get out of the earth.
• 10:50
  SPEAKER_01: Yeah, right.
• 10:51
  SPEAKER_01: Because it either has to move through the material, like it, you know, we were talking, you used an analogy of like food color and drop food color in and watch the food color move through the liquid.
• 11:01
  SPEAKER_01: That's what kind of has to happen.
• 11:02
  SPEAKER_01: Is this heat then has to move through the mantle, through the crust to escape onto the surface of the earth?
• 11:09
  SPEAKER_01: And Earth is a big planet, and it takes then time for that to happen.
• 11:14
  SPEAKER_01: The the other way is if it doesn't diffuse through the earth like this, then it has to move material closer to the surface.
• 11:22
  SPEAKER_01: It has to move hot rock to the surface.
• 11:25
  SPEAKER_00: That's right.
• 11:26
  SPEAKER_00: And this is what we call convection.
• 11:28
  SPEAKER_00: And this is you can think of hot air rises.
• 11:30
  SPEAKER_00: A lot of our weather is because hot air rises up, cold air sinks.
• 11:34
  SPEAKER_00: That's something most people know.
• 11:35
  SPEAKER_00: The same is happening in the interior of the earth, and that is another great way to get hot stuff closer to the surface where it eventually loses heat to the atmosphere and then eventually to outer space.
• 11:45
  SPEAKER_00: So convection or think of your lava lamp, you know, the classic lava lamp analogy, things heat up down by that light bulb, and then it kind of rises up, and then it hits the surface and it cools off, and then it sinks back down.
• 11:58
  SPEAKER_00: Well, when it hits the surface, that cooling off that is heat being lost from the lava lamp and the earth is behaving the same way.
• 12:05
  SPEAKER_00: So those are the two ways the earth is trying to cool itself off, but really those are the reasons that earth is hot.
• 12:10
  SPEAKER_00: It's because those processes, advection and convection, diffusion of heat and movement of hot material, those take a long time.
• 12:19
  SPEAKER_00: We still have 4.5 billion year old heat in the earth that's trying to get out.
• 12:24
  SPEAKER_01: And people might have a hard time like conceptualizing, wrapping their minds around the age of the earth, the size of the earth, and why it hasn't lost its heat yet.
• 12:34
  SPEAKER_01: Well, because Earth is bigger, it takes longer to lose its heat.
• 12:39
  SPEAKER_01: Like you take, for instance, Mars.
• 12:41
  SPEAKER_01: Mars is about half the size of Earth, and Mars is has basically, we believe it is cooled off at this point.
• 12:50
  SPEAKER_00: At least a lot more than Earth has, for sure.
• 12:53
  SPEAKER_01: Yeah, it it doesn't have to move through as much material to lose heat to the surface.
• 12:58
  SPEAKER_01: So the smaller the planets are, the faster they cool off.
• 13:02
  SPEAKER_01: Mercury's the same thing, it's already cooled off in terms of its internal heat, right?
• 13:07
  SPEAKER_01: Now Mercury is much closer to the sun, and that's a whole other discussion.
• 13:10
  SPEAKER_01: But think about this, right?
• 13:12
  SPEAKER_01: A huge, massive pile of bark.
• 13:15
  SPEAKER_01: We've all seen this before, where this you know, this massive pile of bark is steaming.
• 13:20
  SPEAKER_00: We're talking about landscaping bark here.
• 13:22
  SPEAKER_00: You put bark in your lawn or something like that.
• 13:24
  SPEAKER_01: That's a good point.
• 13:25
  SPEAKER_01: That's a good point.
• 13:26
  SPEAKER_01: Um, you know, and it's steaming, and that very question makes me think of that.
• 13:31
  SPEAKER_01: Because why is bark hot?
• 13:32
  SPEAKER_01: If you stuck your hand and fist and you stuffed it into a big heaping pile of bark, it would get really hot really fast, right?
• 13:40
  SPEAKER_01: Well, the heat that's generated in the center of the bark is from organic material that's breaking down the bark, it's decaying, right?
• 13:48
  SPEAKER_01: And bar bypart of that decay is heat.
• 13:50
  SPEAKER_01: Well, the heat still has to move outward and it takes time.
• 13:54
  SPEAKER_01: It's the same thing, it has to diffuse outward to the surface of the bark.
• 13:58
  SPEAKER_00: You know, Chris, that is that's a great analogy.
• 14:01
  SPEAKER_00: All right, you you you get a point in the analogy column here because you know, I landscaped as a job in the summers for a lot of college and some of high school, and you know, I would be back in the loading dock, you know, with the front end loader, like, you know, driving the front end loader and scooping up this big pile of bark and dumping it off.
• 14:19
  SPEAKER_00: Yeah, and dumping it off in people's pickup trucks, you know, who are coming in customers.
• 14:23
  SPEAKER_00: And every time I'd go in there, I mean it smelled bad.
• 14:26
  SPEAKER_00: And on a hot day, that was a hot job because you're near this like steaming pile of bark, and you can see the steam coming off this stuff when you dump it in.
• 14:34
  SPEAKER_00: I mean, it is hot in there, and that is a great analogy for how long it takes for heat to either diffuse or can you know convect out of a big pile of heat-producing stuff.
• 14:44
  SPEAKER_00: Okay, so let's come back.
• 14:46
  SPEAKER_00: Humans, how much heat do we use as humans?
• 14:49
  SPEAKER_00: And humans use on average about 18 terawatts of energy.
• 14:54
  SPEAKER_00: And again, to recalibrate, a terawatt is one trillion watts, and one terawatt is enough to power about 10 billion light bulbs.
• 15:04
  SPEAKER_00: So just to kind of calibrate, that is a shitload of power.
• 15:08
  SPEAKER_01: Well, yeah, we got to qualify that though.
• 15:10
  SPEAKER_01: It's you said 10 billion light bulbs, but that is hopefully none of our listeners are using these light bulbs in their homes.
• 15:18
  SPEAKER_01: We're talking about the incandescent height light bulbs, right?
• 15:22
  SPEAKER_01: So, you know, one of those hundred watt light bulbs that are they're incandescent with the filaments that we talked about in one of the earlier episodes.
• 15:30
  SPEAKER_01: 90% of the electricity in those light bulbs generates heat.
• 15:34
  SPEAKER_01: LED light bulbs flip that, they're 10 times more efficient.
• 15:37
  SPEAKER_01: Uh, one terawatt will power 100 billion LED light bulbs as opposed to only 10 billion.
• 15:43
  SPEAKER_00: Yes, so as human.
• 15:45
  SPEAKER_00: Which is crazy.
• 15:45
  SPEAKER_00: I mean, it's crazy.
• 15:46
  SPEAKER_00: We're using a lot of power as humanity.
• 15:48
  SPEAKER_00: So, Chris, let's get into how we use the heat from the earth.
• 15:53
  SPEAKER_00: Okay, right.
• 15:54
  SPEAKER_00: So the first one, we're gonna kind of flip the order.
• 15:57
  SPEAKER_00: We're gonna start with the passive geothermal heat pumps, the one that I actually have in my house right now in Pennsylvania.
• 16:04
  SPEAKER_01: I think it makes sense to start with this because this is what anybody can have.
• 16:07
  SPEAKER_01: You can either build a home with this or you can have you can live in a home and have this done to your home.
• 16:13
  SPEAKER_01: It's common like in remodel projects and things like that.
• 16:16
  SPEAKER_00: Yes, and we bought just bought a house, you know, a little while ago.
• 16:19
  SPEAKER_00: And oh my goodness, we have a geothermal system in this house.
• 16:23
  SPEAKER_00: The previous owners installed it, so we didn't absorb necessarily all of the upfront cost of that, and we're very happy with it because we're saving a lot on our energy bills right now.
• 16:32
  SPEAKER_00: Um, so the way that this works is really actually quite simple.
• 16:36
  SPEAKER_00: And we're gonna kind of go into a little bit of the details here.
• 16:38
  SPEAKER_00: So about 10 feet down, beneath the surface of the earth, the ground has a constant temperature of around about 54 degrees Fahrenheit, or you know, it's around 13 degrees centigrade.
• 16:50
  SPEAKER_01: I think that's a crazy stat.
• 16:52
  SPEAKER_01: That's amazing, and you know, but I gotta believe, right, that this is not universally true.
• 16:59
  SPEAKER_01: Like 54 degrees at 10 feet isn't everywhere on the planet, is it?
• 17:05
  SPEAKER_00: Yeah, that's right.
• 17:06
  SPEAKER_00: That's right.
• 17:06
  SPEAKER_00: So things like permafrost, you know, you hear the term permafrost, that's permanently frozen ground in northern latitudes.
• 17:12
  SPEAKER_00: You know, the ground 10 feet below is always frozen.
• 17:15
  SPEAKER_00: You got to go further below to actually get to that moderate heat level that's not permanently frozen in the tropics, it's higher.
• 17:23
  SPEAKER_00: That 10 feet number is variable depending on where you are.
• 17:26
  SPEAKER_01: Yeah, that permafrost thing was the first thing that popped into my head when I saw that stat.
• 17:29
  SPEAKER_01: I'm like, wait a minute, no, up at 12,000 feet in Colorado, that's not true.
• 17:34
  SPEAKER_01: Oh, or up in Alaska, that's not true.
• 17:36
  SPEAKER_01: Anyway, um, it's interesting.
• 17:38
  SPEAKER_01: I just filled my hot tub two days ago, and my well is like 184 feet deep, and the water came out and it always does, doesn't matter the season, came out 54 degrees.
• 17:50
  SPEAKER_01: Boom.
• 17:50
  SPEAKER_01: Every single time.
• 17:51
  SPEAKER_01: Boom.
• 17:52
  SPEAKER_00: That right there is the key.
• 17:54
  SPEAKER_00: It does not matter the season, that temperature is always 54 degrees, and that's exactly what we tap into.
• 18:00
  SPEAKER_00: How deep was your well, Chris?
• 18:01
  SPEAKER_00: Did you say 184 feet?
• 18:03
  SPEAKER_00: 184 feet.
• 18:04
  SPEAKER_00: So that's kind of typical for these geothermal energy systems, the one we have in our house.
• 18:08
  SPEAKER_00: So, what happens is we're basically using this constant temperature ground to moderate the temperature in our homes.
• 18:17
  SPEAKER_00: So, what happens and what we have in our house is basically two or three vertical pipes that are drilled down to fairly deep and then they come back up.
• 18:28
  SPEAKER_01: Okay, that's interesting.
• 18:29
  SPEAKER_01: So yours is vertical because most of the ones out where I live are going to be horizontal that are like 10 to 15 feet down, and they're bit, but that makes sense because I'm live in a more spread out area.
• 18:41
  SPEAKER_00: Exactly.
• 18:42
  SPEAKER_00: Our property is not large enough to actually do an efficient thing.
• 18:45
  SPEAKER_00: If you laid it grid-wise, you know, like you'd imagine a grid throughout your backyard, you need to have a large property to have that.
• 18:52
  SPEAKER_00: So you need like a lot of businesses will put that under a parking lot or something.
• 18:55
  SPEAKER_00: Ours goes straight down.
• 18:57
  SPEAKER_01: Let's paint a picture a second.
• 18:59
  SPEAKER_01: What's in these pipes then that are either vertical or horizontal?
• 19:02
  SPEAKER_00: What's in them?
• 19:02
  SPEAKER_00: It's a fluid of some kind.
• 19:04
  SPEAKER_00: Sometimes it's water, sometimes it's treated water, sometimes it's other uh, you know, highly antifreeze kind of thing, right?
• 19:09
  SPEAKER_01: It's a mixture of thing.
• 19:11
  SPEAKER_00: Exactly.
• 19:12
  SPEAKER_00: But what we're doing here is we're taking that fluid in our house.
• 19:15
  SPEAKER_00: If it just sat in our house, it would reach our house temperature, whatever that temperature is.
• 19:19
  SPEAKER_00: What we're doing instead is pumping it down into the ground and it is getting cooled, just like your groundwater that's coming out of your well, it's getting cooled down to that 54 degrees.
• 19:28
  SPEAKER_00: It gets pumped back up and it comes into our house and it is 54 degrees or 13 degrees centigrade.
• 19:34
  SPEAKER_01: All right, how is that beneficial, Jesse?
• 19:36
  SPEAKER_01: Because nobody wants their house to be at 54 degrees at any season of the year.
• 19:40
  SPEAKER_01: Nobody wants that.
• 19:41
  SPEAKER_01: So what's going on?
• 19:42
  SPEAKER_00: So, how do we use that?
• 19:44
  SPEAKER_00: The obvious way to use that is during the summer when it's 80, 90 degrees, or 100 degrees outside, and we want our house to be 68 or 70 or 72 or 74, whatever you want.
• 19:54
  SPEAKER_00: You take your a 90 degree air and you pass it over a manifold or heat exchanger that has that 54 degree fluid in it, and you can make whatever temperature you want between 90 degrees and 54 degrees.
• 20:06
  SPEAKER_00: And so that's what happens in the summer.
• 20:08
  SPEAKER_00: We do not have a traditional air conditioning unit, we don't have an air conditioning compressor outside of our house at all.
• 20:14
  SPEAKER_00: In the summertime, our air conditioning is only taking hot air from outside, mixing it with that cold water, and making whatever temperature we want in the summertime.
• 20:25
  SPEAKER_01: Basically, then you're saying you can cool your house down to let's say it's super hot outside, you can cool it down to 65 degrees guilt-free.
• 20:34
  SPEAKER_01: Because I could not do that.
• 20:36
  SPEAKER_01: I couldn't do that.
• 20:37
  SPEAKER_01: Basically, if it's super hot outside, everybody else is trying to do the same thing, right?
• 20:42
  SPEAKER_01: And my I'm using tons of electricity then to turn my house down to 72 degrees.
• 20:49
  SPEAKER_01: You don't have to worry about that.
• 20:51
  SPEAKER_01: You're not using any more electricity, you're just using that 54 degree temperature from the earth.
• 20:57
  SPEAKER_00: That's right.
• 20:58
  SPEAKER_00: We're using maybe a little bit more electricity, but it's minuscule on the grand scheme of things.
• 21:02
  SPEAKER_00: Like air conditioning in the summer, geothermal energy is really efficient, saves you a lot on your energy bill and in your guilty consciousness.
• 21:09
  SPEAKER_00: So that's how it works in the summer.
• 21:10
  SPEAKER_00: In the winter, we're taking air outside, that's let's call it freezing, 32 degrees Fahrenheit, zero degrees centigrade.
• 21:17
  SPEAKER_01: Or if you live in Michigan, much colder than that.
• 21:20
  SPEAKER_00: Much colder than that.
• 21:21
  SPEAKER_00: That's right.
• 21:21
  SPEAKER_00: But you're taking that outside air, and instead, we're not bringing it up to 72 degrees or whatever, or you know, 15, 16 degrees centigrade, whatever we want our house to be, because we can't get it there.
• 21:31
  SPEAKER_00: We only have 54 degrees to work with.
• 21:33
  SPEAKER_00: Instead, in the winter, what we're doing is we're heating that outside air up to 54 degrees, and then we're using a traditional, we have a natural gas in our house, uh uh heating unit, but it's just using a traditional HVAC system to heat it up from 54 to whatever we set it at.
• 21:50
  SPEAKER_01: The bottom line is it's much more efficient to raise the temperature from 54 degrees as opposed to raising the temperature from 15 degrees, which is what I have to do.
• 22:00
  SPEAKER_01: Any anything lower than fifty four degrees outside, which is always in the like late fall, winter, and early spring in Michigan, it's much more efficient to go from fifty-four degrees than it is from whatever it is outside.
• 22:14
  SPEAKER_01: And that's how that's beneficial then.
• 22:16
  SPEAKER_00: Yes.
• 22:17
  SPEAKER_00: So let me paint you a picture of what it looks like in the basement of my house real quick, Chris.
• 22:21
  SPEAKER_00: It's a really simple system.
• 22:22
  SPEAKER_00: All I have is in the basement there are an extra set of pipes running along the roof of the basement.
• 22:29
  SPEAKER_00: They go out in my foundations, one in one out and one in.
• 22:34
  SPEAKER_00: They go, these little pipes, they're insulated.
• 22:37
  SPEAKER_00: They go out, they go out into my yard and they go down 100, 150 feet.
• 22:42
  SPEAKER_00: They come back up.
• 22:43
  SPEAKER_00: It goes down another 100, 150 feet, comes back up, and it does that two or three times, depending on your system.
• 22:49
  SPEAKER_00: And then it comes back inside my house.
• 22:50
  SPEAKER_00: And now that inlet pipe is 54 degrees, it still has insulation on it.
• 22:55
  SPEAKER_00: It's running back to my traditional heating unit.
• 22:58
  SPEAKER_00: And it's like any heating unit you see in a basement of anybody's houses, a natural gas heating unit, and it runs into there, and that's where the air exchanger is.
• 23:08
  SPEAKER_00: So it looks on the surface.
• 23:09
  SPEAKER_00: It's it's actually a really simple add-on.
• 23:12
  SPEAKER_00: And it's actually really cheap to run because all you're doing is running a pump that's circulating this fluid.
• 23:16
  SPEAKER_00: That fluid never actually sees the air.
• 23:19
  SPEAKER_00: It just a closed loop, it just runs through those pipes at a given rate all the time.
• 23:24
  SPEAKER_00: And if you turn it on, it starts to pump it through and you start to cool.
• 23:28
  SPEAKER_00: You blow your air across this cool pipe, and then you cool down your house that way.
• 23:32
  SPEAKER_01: Basically, you either use the heat from the earth to bring it into your house, or you use the heat from your house and dump it into the ground.
• 23:41
  SPEAKER_00: That is exactly it, Chris.
• 23:43
  SPEAKER_00: Could not be phrased better.
• 23:44
  SPEAKER_00: It's using the earth as a moderator for the temperatures in our house.
• 23:48
  SPEAKER_01: I love that because it is so clever, and we're using something that is just naturally produced in the earth.
• 23:55
  SPEAKER_01: And this is called the geothermal gradient.
• 23:57
  SPEAKER_01: The geothermal, geo means earth, thermal means heat.
• 24:01
  SPEAKER_01: The bottom line is the deeper you go into the earth, it gets predictably warmer and warmer and warmer the deeper in you go.
• 24:09
  SPEAKER_00: And so these units, these sort of passive units that exist in residential homes or uh commercial properties, these are they're kind of expensive to install, but the main cost is up front.
• 24:19
  SPEAKER_00: It's just drilling the well that's really or drilling the holes for the pipes.
• 24:23
  SPEAKER_00: That's really the expense.
• 24:24
  SPEAKER_00: And you know, they can be expensive.
• 24:25
  SPEAKER_00: I'm glad that we did not pay for them, but the previous owners paid for them.
• 24:29
  SPEAKER_00: So we're just reaping the rewards.
• 24:30
  SPEAKER_00: But you know, it costs, I mean, the it varies depending on where you are, but these are$10,000 to$30,000 uh, you know, to install.
• 24:38
  SPEAKER_00: And the payback is it takes a little while, you know, it can take five to twenty years, depending on how you're doing the heating, size of your house, all that stuff.
• 24:47
  SPEAKER_00: But they can be very worth it.
• 24:48
  SPEAKER_00: And we walked in, I mean, Tess and I are overjoyed because we walked into this amazing situation.
• 24:52
  SPEAKER_00: We didn't really pay for it.
• 24:53
  SPEAKER_00: Maybe we paid up for a house with geothermal, but not a lot, and now we're reaping the benefits.
• 24:58
  SPEAKER_00: So we can crank the AC without feeling too bad.
• 25:00
  SPEAKER_00: That's a real thing, by the way.
• 25:02
  SPEAKER_01: But uh, yeah, I know several people, friends, even some of the schools within Hudsonville district are geothermal now.
• 25:09
  SPEAKER_01: Um, it's very, very cool technology and very efficient.
• 25:13
  SPEAKER_01: It's just it's you know better for the planet, and so everybody wins.
• 25:17
  SPEAKER_01: Hey, we need a transition into the other geothermal.
• 25:23
  SPEAKER_01: So this is something that is not like you can't decide, oh, I want to generate my electricity, um, I want to use geothermal.
• 25:31
  SPEAKER_01: This is like this is more geographic in nature, so let's go.
• 25:36
  SPEAKER_00: This is the more active or aggressive type of geothermal energy, and it is a resource.
• 25:42
  SPEAKER_00: You're exactly right, Chris.
• 25:43
  SPEAKER_00: We can't take 54 degree water and generate electricity with it, we need something hotter.
• 25:49
  SPEAKER_00: So this is considered a resource in geologic terminology that it's like mining something.
• 25:55
  SPEAKER_00: We are actually mining energy out of the earth with this type of process.
• 25:59
  SPEAKER_00: And basically, we're taking really hot water or really hot parts of the earth and using it to generate steam.
• 26:06
  SPEAKER_00: So we need to get to 212 degrees Fahrenheit or 100 degrees centigrade.
• 26:10
  SPEAKER_00: We need to be somewhere where there's a lot of heat close to the surface that we can access as humans.
• 26:16
  SPEAKER_01: And the reason why we need to do this to generate steam, so it's got to be above the boiling point at whatever pressures we're talking about, because steam creates pressure, pressure turns turbines in the same way that wind turns turbines, and the same way that running water behind a dam turns turbines, steam can be used to do the same thing and generate electricity.
• 26:37
  SPEAKER_00: So instead of using like a coal-fired power plant where you're burning coal, heating up water, generating steam, we're just getting hot water from the interior of the earth.
• 26:46
  SPEAKER_00: And the US currently produces about 3.5 gigawatts of electricity, and that's round about 3.5 million homes worth of electricity that is being produced via geothermal energy, and we could produce a lot more.
• 27:01
  SPEAKER_00: This is a resource that is around in places, and we can do this efficiently.
• 27:06
  SPEAKER_01: So, how could we do more of this?
• 27:10
  SPEAKER_00: Well, let's back up quick and talk about the ways that this happens.
• 27:13
  SPEAKER_00: I mean, one there's a couple different ways, and the engineering here is actually quite complicated.
• 27:18
  SPEAKER_00: There's three different ways to produce steam.
• 27:21
  SPEAKER_00: One is to just take steam out of the earth, to tap into a place where there is steam.
• 27:25
  SPEAKER_00: Think of Yellowstone, picture a Yellowstone geyser.
• 27:28
  SPEAKER_00: There is steam being emitted there.
• 27:30
  SPEAKER_00: You could tap into that, pull that steam into a pipe, and use it to drive a turbine that would generate electricity.
• 27:36
  SPEAKER_00: So that's what's called dry steam.
• 27:38
  SPEAKER_00: Another way is flash steam, where you take what would be boiling water, water that is above the boiling point from at depth, and bring it up.
• 27:47
  SPEAKER_01: But it's at a lot of pressure then, right?
• 27:49
  SPEAKER_01: So it's not boiling.
• 27:50
  SPEAKER_01: Yeah.
• 27:51
  SPEAKER_00: So you bring it up under pressure, and then it flash boils in your steam turbine generator, and it's a little bit more efficient.
• 27:58
  SPEAKER_00: This is called flash steam generating plant, and that's another way.
• 28:01
  SPEAKER_01: So basically, you're t you're saying that they use water that's superheated, but it's under high pressure, bring it up to the surface, lower the pressure quickly, and it flashes into steam.
• 28:12
  SPEAKER_00: Exactly.
• 28:12
  SPEAKER_00: And then that's driving your turbine in the same way.
• 28:15
  SPEAKER_00: Another way is a binary plant, which basically brings that hot, pressurized water, brings it up, uses a heat exchanger to exchange with some water that doesn't ever go into the ground, and use your heat exchanger to heat up that water, flash that to steam, generate your turbine.
• 28:28
  SPEAKER_00: And it all depends on the water chemistry.
• 28:30
  SPEAKER_00: Basically, we don't want to some of the water in the earth is actually really quite aggressive chemically and reactive.
• 28:36
  SPEAKER_00: And we Yeah, it's acidic or basic.
• 28:38
  SPEAKER_00: Yeah.
• 28:38
  SPEAKER_00: Exactly.
• 28:39
  SPEAKER_00: We don't want to bring it up all the time and be flashing it into steam.
• 28:42
  SPEAKER_01: So Okay.
• 28:43
  SPEAKER_01: You know, very different from the geothermal that is used to operate buildings and homes, individual homes.
• 28:50
  SPEAKER_01: This is, you know, a whole a different mechanism and very geographic in terms of what the geology is around that makes like this kind of electricity generation possible.
• 29:03
  SPEAKER_00: That's right.
• 29:04
  SPEAKER_00: And a lot of these places where we currently have geothermal energy plants have hot rocks at the surface or near the surface.
• 29:12
  SPEAKER_00: California, Nevada, Hawaii, Iceland, Germany has a big geothermal plant.
• 29:16
  SPEAKER_00: You know, Yellowstone would make a hell of a geothermal energy plant, but it's never going to happen, and it's a good thing because it's a beautiful national park.
• 29:23
  SPEAKER_00: You know, we're not going to put a geothermal energy plant there.
• 29:26
  SPEAKER_00: Because geothermal energy is a resource.
• 29:28
  SPEAKER_00: There is not an infinite amount of heat in these shallow, really hot reservoirs.
• 29:34
  SPEAKER_00: Think of it like a small body of magma that's really close to the surface.
• 29:39
  SPEAKER_00: We could actually drain the heat out of that pretty quickly, or it's like a bunch of really hot water that's circulating around.
• 29:46
  SPEAKER_00: If we remove all that hot water, we've kind of lost all of the energy that we needed to generate the electricity.
• 29:53
  SPEAKER_01: If you go back to our episode on geysers, we talked a little bit about this in terms of how some hot springs in geyser areas have gone inactive because of geothermal plants that have siphoned off that heat energy.
• 30:06
  SPEAKER_00: That's exactly right.
• 30:08
  SPEAKER_00: And there are ways to make this resource more uh tractable for a long term, like enhanced geothermal, which is basically fracking for geothermal instead of fracking to get more oil out.
• 30:22
  SPEAKER_01: There's a hot button right there.
• 30:23
  SPEAKER_00: Yeah, we're fracking to get more hot water out.
• 30:26
  SPEAKER_00: Um, and so it is a resource.
• 30:29
  SPEAKER_00: So geothermal energy, there's a lot more um sort of geoscience that goes into that type of geothermal energy, meaning you gotta have geologists who are on the ground who kind of know what the rocks are, measure temperature, predict you generate models for how much heat is actually in there that can be used.
• 30:48
  SPEAKER_01: And we have like two fairly large geothermal plants that that do this kind of thing, right?
• 30:55
  SPEAKER_01: I think they're both in California, is that correct?
• 30:58
  SPEAKER_00: Yes, I believe so.
• 30:59
  SPEAKER_01: Okay, like the geysers in Northern California, and then one in Southern California.
• 31:04
  SPEAKER_01: I forget what it's called, but it's uh in the Salton Basin.
• 31:07
  SPEAKER_00: Yeah, that's right.
• 31:08
  SPEAKER_00: It's I mean, there's a couple of them.
• 31:09
  SPEAKER_00: I think it's Imperial Valley is down there uh around the Salton Sea.
• 31:14
  SPEAKER_00: And yeah, these are geothermal energy projects that are actually producing a decent amount of electricity.
• 31:19
  SPEAKER_00: This 3.5 million homes worth of power is being produced by geothermal energy.
• 31:25
  SPEAKER_01: That's cool.
• 31:25
  SPEAKER_01: All right.
• 31:26
  SPEAKER_01: So in summary, two really broad categories of geothermal energy, right?
• 31:32
  SPEAKER_01: One is geologically very specific.
• 31:35
  SPEAKER_01: It uses superheated water to generate electricity, we're using steam.
• 31:39
  SPEAKER_01: And the other one, though, is just geothermal that uses the buffering effect to moderate our house.
• 31:46
  SPEAKER_01: We can use it to make our house warmer, we can use it to make our house cooler, and we can do that relatively guilt-free.
• 31:52
  SPEAKER_01: And this is also something that anyone can do.
• 31:55
  SPEAKER_01: You can, you know, revamp your house, you can remodel your house, you can build a new house and choose to integrate this kind of you know geologic energy.
• 32:04
  SPEAKER_00: Yeah, super cool.
• 32:05
  SPEAKER_00: And it, you know, I think there's an important distinction between exactly the residential one that anybody can tap into.
• 32:11
  SPEAKER_00: That's basically an unlimited resource and the geothermal electricity generation, which is in some areas kind of unlimited, but in some areas a little bit more of a limited resource, a consumable resource.
• 32:22
  SPEAKER_00: All right, Chris, I just want to add one thing here too.
• 32:24
  SPEAKER_00: All this geothermal energy that we're talking about, when I'm using that 54 degree heat coming out of the ground and using it to heat up air in the wintertime, I'm actually tapping into 4.5 billion year old heat because it takes so long for heat to come out of the earth, or at least some fraction of the heat I'm using is 4.5 billion years old.
• 32:43
  SPEAKER_00: That's pretty cool.
• 32:44
  SPEAKER_00: All right, Chris, this was a fun one.
• 32:46
  SPEAKER_00: As usual, yeah, you bet.
• 32:47
  SPEAKER_00: Reach out to us if you have any questions, if you have any feedback for us, please follow us on all the social medias.
• 32:55
  SPEAKER_00: We are at Planet Geocast and Instagram, Facebook, Twitter, and send us an email at planetgeocast at gmail.com.
• 33:02
  SPEAKER_00: Yeah, we appreciate any feedback.
• 33:05
  SPEAKER_00: That's right.
• 33:05
  SPEAKER_01: Yeah, awesome.
• 33:06
  SPEAKER_01: That's all right.
• 33:07
  SPEAKER_01: Thanks.
• 33:08
  SPEAKER_01: Take care.
• 33:09
  SPEAKER_01: See you next week.