Wisconsin Public Television University Place Wednesday Nite at the Lab  Dave Hart UP690   cc >> Cassie Immel: Good evening. Thank you for watching tonight's Wednesday Nite at the Lab. I'm Cassie Immel from here at the Biotech Center. For tonight's presentation, Dr. Dave Hart presents "Tapping Geothermal Resources in Wisconsin: Energy from the Earth for Heating and Cooling our Homes." Dr. Dave Hart is a professor in the Department of Environmental Sciences in the University of Wisconsin Extension in hydrogeologists and geophysicists for the Wisconsin Geological and Natural History Survey. His current research and interests include measurement of the hydraulic properties of midcontinental rift sediments to determine their suitability for carbon sequestration, the hydrogeology of the Cedarburg bog in eastern Wisconsin, and the connectedness of sand bodies within the lakes of the Glacial Lake Oshkosh. He is also interested in developing web applications to allow citizen input of Wisconsin features and provide information on sites of geologic interest in Wisconsin. He received his BA from Luther College in Iowa and his PhD from here at the UW. Please help me in welcoming Dr. Dave Hart. [APPLAUSE] >> Dave Hart: Thank you, Cassie. Thanks for your applause here. 

I hope to, tonight, give you a tour of geothermal resources in Wisconsin, and I changed the title a little bit from the less colorful one that I sent Tom. And so geothermal, is it hot as Hades? Does that mean is it a resource that's viable for Wisconsin or is it the frozen tundra and maybe we should put our energy into different energy resources. So that's kind of the question I'm asking. That's kind of framework for tonight's talk. I'm Dave Hart with the Wisconsin Geological and Natural History Survey. I want to acknowledge two collaborators/co-workers. One is James Tinjum, and the other Dante Fratta. They're both kind of kitty-corner here in the Department of Engineering in the Geological Engineering Department there. I'd also like to acknowledge the Department of Energy. They kind of got me funded and interested in geothermal in Wisconsin. 

They provided a grant to the American Association of State Geologists. Wisconsin's state geologist came to me and said, Dave, I strongly urge you to look at geothermal in Wisconsin, and when the director, the state geologist asks me to do things and strongly urges me to do them, I generally follow his lead. But I think there's a lot of good things that are going to come out of this research here. Also, the Wisconsin Water and Well Systems, we're going to collaborate with this driller on some research hopefully. And then two engineers from Affiliated Engineers Inc., they provided some of the slides that I'll be showing you tonight and some of the information. So geothermal energy is not new. We've been using this for centuries, in fact. Here's one of those places I'd like to get to eventually: the Roman baths at Bath in England. Here's the great bath. This is the Roman part and then they added this later on. 

This is, I think, from second century AD or so. And then here's the original spring that kind of bubbled up. It was a sacred spring, then the king took over and made it his bath. So we had rainwater fall on these nearby hills. It percolates downward almost two miles or so, or so they estimate. Picks up heat and comes to the surface. Now, it's not exactly hot. It's only 115 degrees, Fahrenheit, not Celsius, but I imagine if you're in England, 115 degrees may feel kind of  nice on some of those foggy, cold day. Just another example of geothermal, if you found an archeologist that could do a whole presentation on this. The hot springs at Thermopylae which translates as hot gates where you could, I suppose, go see Hades and his dog there. 

This is very close to where the Persians met their demise by the Spartans too. But I guess it was a swamp at that time and smelled like sulfur, and they kind of ditched it and turned it into a tourist area now. Another slide, this is, you've probably seen this, this troop of monkeys discovered in the late '60s that these hot springs in Japan were kind of nice places to go hang out. So it's not just humans that like to go hang out in a hot springs; some other species have figured this out as well. All right, I'm going to take you now through kind of the research, our understanding of, it's really kind of a history of the Earth and it kind of tracks the way we think about science. And I know you guys see a lot of science talks so we'll kind of go with that. Some of the early research, Robert Boyle, Boyle's Gas Law, you may have heard of that from high school. And he, in 1738, states in one of his books: "Provided a man descends low enough into the bowels of the Earth, he will find it very hot." And he wasn't just speaking from a religious perspective, he knew this, which it's not just the Christian tradition that thinks it gets hot. There are other traditions but there are others that believe it gets cold, so that may or may not be founded on geothermal energy, those traditions. But this was an observation here too. 

Then we have an Englishman, Robert Were Fox the Younger, in 1820, in a report to the Royal Geological Society of Cornwall, and here's that. We have it on the temperature of mines. So he noticed that these mines were getting hot and in 1820 makes his report to the Royal Society, Geological Society, that there is a progressive increase of temperature in descending from the surface to the greatest depths hitherto examined. And he now begs to submit the result of further inquiries to this society. And his results, and so here I think is really the first example where someone has calculated, put a number on, people have noticed it gets warm when you go down. Here we've got somebody who's calculated how warm it gets with depth. And so he looks at Professor Meyer's tables, finds the surface temperature is 53 degrees Fahrenheit, and finds out as he goes down in the mine it gets 6 degrees warmer for every 300 feet. And if we look at the temperature increase with depth, I'll just divide it, that means two degrees per hundred feet of depth you get a warm up two degrees. And that's a pretty decent number. We see numbers like that around Wisconsin, as I'll show later. 

And if you want to do a little math, you start at 50 degrees and you go 5,000 feet, about a mile down, you can do 5,000 times 2, divided by 100. So we have 10,000 divided by 100 gets us to 100 degrees. So at a mile, we'd be at 150 degrees. Two miles, 250 degrees. And so right there that's kind of a powerful thing. We'd know if we brought that water up to the surface, if we could get it from two miles down, it would boil at the surface. It would be that hot. And so maybe we could use that to run turbines or something. Some more early research kind of just tracking along. In 1867, the British Association for the Advancement of Science formed a committee. 

And the purpose of this committee was to investigate the rate of increase of underground temperatures downward in various localities of dry land and underwater. And I've captured the capitalization that they used at that time. I'm not sure of the rules they used, but it must be for emphasis. And what they're looking for there is they're trying to understand, they're looking at working conditions in mines. They're finally making the mines deep enough that it's getting a little bit hot for the workers to work down there. We have this impression you go in a cave and it's 50 degrees. Well, that's because we're not going down very deep. If we keep going down, it's going to start to become uncomfortable. We could use that number that Robert Fox calculated earlier, and we could go, yeah, we go down a thousand feet, it's going to get pretty uncomfortable. We're not going to want to be there. 

And so this committee wanted to understand how things were changing. And so they started to do temperature measurements in wells. And so you can imagine, if you have a deep well and you have a thermometer, just a regular mercury thermometer, and it takes you five minutes to lower it to the bottom of your well, you have to pull it back up, you're not going to get the right temperature. So this committee also drove some science. It drove the maximum temperature thermometer, and that's a kind of, for those of us who are a little bit older, you'd get the thermometer in your mouth and you'd have to shake it? That was a maximum temperature thermometer. And that was actually, it seems to me, invented by a German, I can't recall his name, to make these measurements. He would lower it down in the well, and then he could pull it up. He didn't have to pull it up really quickly to try to get the measurement. So this actually drove some technology. And so the idea here is you have a well and you just take a series of measurements of depth and then we can look at how the temperature here increases with depth, and we can just see it going up and up and up and up. 

And that would be the two degrees per hundred foot or so that we saw earlier. And then we have Alexander Stewart Herschel still moving forward in time. He was the grandson of the astronomer, the Herschel who made all of the telescopes and discovered all of the galaxies. And what he did, this grandson of the astronomer, was he measured how well the rocks conduct heat. He develop an apparatus to measure, some rocks are going to conduct heat better than others, and let's put a number on how well it conducts heat. And so we can actually get heat flow, if we know the temperature change with depth and we get this thermal conductivity, we can now calculate heat. Any large temperature change, more heat flow. That makes sense. Larger conductivity, more heat flow. That makes sense. 

This law just kind of makes sense. And then also, I think this GA Labour was his laboratory helper, and apparently if he had patented one-hundredth of the inventions or improvements he was constantly making or contriving for others, he would have been a rich man indeed. So he just cared about his science. He just wanted to do his science. And here's his apparatus. You have a sample here. He had steam come in one end. He had water come in around the other. And so you have hot and cold, and then you've got heat flow. And then, as this water went around the sampler bar, it picked up the heat and because he knew how much heat it took to raise water one-degree Celsius, he could figure out how much heat is coming out the other side because he could measure the temperature being picked up by this coil here and then he could measure the conductivity of his rock. 

And now we're ready for Lord Kelvin. And I'm a geologist not a physicist, and geologists love to remind physicists that Lord Kelvin was wrong about the age of the Earth. And he was telling all the geologists, you guys don't know math, you guys are challenged, and the geologists were like, no, no, the ocean's too salty, we have too much erosion, how did these rocks get here in the time we want, but Lord Kelvin did some calculations using those gradients that were measured by the committee, using the conductivities measured by Herschel, we can calculate the average heat flow. And if we do that, we get about, or they did that and they got a pretty good number. 68 milliwatts per meter squared. So like this by that by that. You're going to get 68 milliwatts. So if we have a thousand square meters, we're going to get 68 watts. And so he's going to use this to calculate the age of the Earth. And so the idea is the Earth starts off molten, super hot, at some hot temperature you have a really high heat flow, and at later times the heat flow is going to decrease. 

And so if we plug in that number, 68.4, on this curve, so here's heat flow as a function of time, we plug in this and then he says, ah-ha, the Earth is around 100 million years old. And he has a nice estimate for the age of the Earth. And RJ Lilly has a nice book out where he says basically what was done was they assumed the Earth was a hot potato. So you take your potato out of the oven. In about five minutes it's too hot to touch. You let it cool. After about 15 minutes and it's a nice temperature. Here's the Earth just out of the oven. It's cooling and then you can calculate the temperature after a hundred million years. And so that's what was done to calculate the Earth. 

However, we know now that the Earth is about 4.5 billion years old, and what was missing was the heat of radioactive decay. And there are three radioactive elements that are in the crust. You'll find them in most every rock in low quantities. Some rocks more than others. Potassium, uranium, and thorium. And they've been around since the Earth formed. They're still around today. And you can see some rocks have more potassium, uranium, and thorium than others. For instance, granite and rhyolites, granite's a pretty common rock, have about 2.95 microwatts per cubic meter. So this by this by this is going to produce three microwatts. 

That's not much. You need a huge, huge volume if you want to even get a watt. A football field by a hundred meters is going to maybe get you several watts, maybe 10 watts of this being produced. And so that's in the upper continental crust. Basalt and gabbro, which is a rock that we find in the oceanic crust, this would be the rock that you see erupting in Hawaii. That only would give you half a microwatt per cubic meter. And in peridotite, which is all this rock is going to make up most of the mantel here, has hardly any but there's a lot of it. And so here's the numbers that you come up with. And so Lilly says you're actually more like a hot potato in the microwave. It's getting heat heated from the inside by that radioactive decay, and there's heat conducting outward. 

And so then in that way we have our heat flow working with what we know about the age of the Earth. So the heat that we see, the geothermal increase with depth is a function of the radioactivity in the crust from potassium, uranium, and thorium and the heat flow from heat of formation when the Earth first formed. Both of those things are working together to give us that heat flow. And here's just a present day measurement of what we see in the continental US. Blue is 25 milliwatts per square meter, and red is 100 milliwatts per square meter. And you can see we've got lots more red out in this part. The reddest part, or just about the reddest part, is Yellowstone. That's sitting over a hotspot, a lot like Hawaii where things are really coming up there. And then you can see over here in Wisconsin, we're kind of cold and green here. So maybe we are the frozen tundra. 

We'll get back to this map later. I have a few quibbles with this map, and we'll get back to it. But you can see, moving to the east, it's cooler; the west is warmer. All right, now I'm going to switch into more talking about the technology. More talking about our energy use, talking about our technology. And this, Jim Tinjum put this in a talk, I couldn't resist it, and it's what if it's a big hoax and we create a better world for nothing. You can also take the other side of that and say maybe we want to make sure what we're doing is actually a step forward and not a step backward. But anyway, I like that cartoon. Here's our energy consumption by sector in 2009, and the two things that geothermal can probably speak to, the two sectors are the commercial, heating and cooling commercial buildings, and heating and cooling our homes, our residential. So that's about 45% to half of our energy needs are those two sectors. 

Maybe geothermal can be part of that heating and cooling. I should also point out that here in Wisconsin we import all of our energy except that which we make through the power plants. The uranium is maybe not the biggest part of the nuclear power plants. But we import almost all of our energy, and so anything we can do to be more energy efficient means more dollars that stay in Wisconsin. So I think there's a good economic reason to take some of this energy discussion to heart. Here's our electrical energy sources in 2009. You can see a large part of how we generate electricity is through coal. Some natural gas, that would be, I'm drawing a blank. They just put in the new, thank you, that would be the Co-Gen plant here on campus. But the coal would be probably doing most of the work here in Madison. 

Nuclear accounts for 20%. Hydroelectric a little bit, and then renewables also just a little bit. And that would include the geothermal. Here's energy use closer to home. In fact, it is my home. And we can see last year I spent $1,600 on electricity and gas. And when I went and looked on MG&E for a house my size, this is typical, maybe a little bit low. But we spend a fair amount of our dollars on heating and cooling our homes, running our appliances. It's not an inconsequential cost. Here's US energy consumption by energy source. 

Fossil fuels are 83% of our current energy sources. Renewable energy is 7%. A lot of that is biomass. So that's things like ethanol, wood burning, maybe the corn burning. Geothermal is a tiny little piece of that right now. Hydroelectric is larger. Solar and wind. Where's nuclear? There's nuclear and that's about 8% as well too. One thing that, there's no free lunch in nature. Nature always, we like to say in geology that Mother Nature always gets to bat last. 

And kind of a corollary of that is all energy sources have impacts. Whether or not it's oil spills, whether or not it's people not wanting to have their horizon cluttered with windmills, whether or not it's the manufacturing process of photovoltaics, all energy sources have impacts, and we need to take that into account. We need to understand those impacts and really be careful about, think about them and take them into account when we're developing them. And some are going to have worse impacts than others. Some are going to have impacts that are farther away, not in my backyard, or in my backyard. So those are all things to consider. US renewable energy technologies, you can see biomass has grown quite a bit. That's probably a lot of that's ethanol. Wind has really taken off. Geothermal has held pretty constant in the last decade and a half. 

Solar as well. So when we look at sustainable energy, we can look at energy conservation with heat pumps or we can look at creating an energy with the geothermal. Now we're going to go to the, I've kind of split geothermal into five different types. The heat pump; the ground source or geoexchange; enhanced geothermal systems, also known as hot, dry rocks; direct use, you just take the hot water out of the ground and then you use it to heat your buildings, you don't do anything to it, you just pump it around; hydrothermal used to generate electricity; and then co-produced fluids, hot water produced during petroleum extraction to generate electricity. So co-produced fluids, if you remember on the map of heat flow in the US, if you look down in Texas and Louisiana, Arkansas, they had a little bit of red and orange to it. A lot of that corresponds to the oil fields. And when they produce oil, I think it's like one barrel of oil you get 10 gallons of water. That water is warm, and perhaps you can use, it's a byproduct. They don't want it. What are they going to do with it? They re-inject it lots of times, but it might be hot enough to generate electricity. 

It's maybe not going to drive a turbine, but you can maybe use it with a binary cycle generator where you pump it up, you heat exchange it with some fluid that has a lower boiling point than water, and rather than just injecting this hot, briny, not very useful water back into the ground, we can create electricity with it. And the DOE has some pileup projects going with that. Hydrothermal, this has been in use for a long time. First used in Italy 1904. Geysers in California, the plant, here's some of the cooling towers in geysers. Generates 725 megawatts. And just so comparison, MG&E down on Blount Street generates 190 megawatts, those big coal-fired plants down there. And so this you just take the hot water out of the steam out of the ground, runs a turbine and then you reinject it. So a really nice, simple way to go. You have to be careful because you don't want to pull out too much water and inject too much cold water. 

You can kind of kill off your fuel by sucking the heat up too fast. So they need to be managed. And then also direct use. This is hot water. You just pump it into your buildings. If you live in one of those parts of the US where things are red, you can probably heat a building. The Idaho state capitol is heated this way. A lot of the buildings in downtown Boise are heated this way. There's a great photo, I thought about bringing it, of snow everywhere but the sidewalk's completely melted. They just use this geothermal direct use to keep their sidewalks melt-free, ice-free. 

It would be kind of a nice way to go. I don't think we're going to be able to do that here in Wisconsin. The enhance geothermal has kind of made the news in the last couple years or so. This one intrigues me because we can provide base load power with a small footprint. Just a regular power plant sized thing. And it can operate any time. We can locate it anywhere as long as the wells are drilled deep enough. I want you to note what I say when I mean drill deep enough. Two to six miles deep. That's a problem. 

We don't know how to drill that deep economically. It's prohibitively expensive to drill. You can imagine, currently you need to replace you bits if you drilled down a mile and you have to pull all of that drill rod, it usually comes, you could maybe do it in 40-foot sections, maybe 80-foot if you have one of those big derricks. It's going to take you all day, a couple days to pull all the drill rod, put a new bit back on, go back down, drill for a day, and so the deeper you go, the more bits you're going to have to replace. You're going to be drilling in granite or some hard, hard rock like that, and the drilling costs are prohibitive at this time. Here's the other one that made the news. In Switzerland they actually closed a pilot plant down because, and this is the geophysicist in me coming out, some pilot plants caused disquieting earthquakes. So they made people uncomfortable. They were magnitude three and four, which would hurt this building if it happened, but we would all be quite disturbed if it happened beneath us. So three and four generally don't cause damage, but they make everybody uncomfortable. 

So those are some issues with enhanced geothermal. And then the last is ground sourced heat pumps. These just exchange heat between the ground and a building, and it's just like a refrigerator in reverse or a refrigerator when you want to cool your house. You can either pull heat out of the ground, put it in your house, or vice versa. It doesn't generate energy, it just moves it from one place to another. And it can function anywhere. All right, so let's run down our options for Wisconsin. What can we viably do here? Heat pump, definitely. We're doing this now, and I think nationwide it's a 10% growth for geothermal systems. I know lots of well drillers in Wisconsin, they used to be called somebody's son well drilling, now they're called Ground Source Well Drilling. 

So a lot of these well drillers are switching over from drilling water wells to drilling geothermal wells. It's a growth industry. So heat pump, it's viable. It works in Wisconsin. Enhanced geothermal systems, maybe but we've got to reduce the drilling costs. And in Wisconsin we don't have very many earthquakes, so maybe we could do the enhanced geothermal here and not make people uncomfortable. Direct use, I doubt we do that. Temperatures are unlikely to be hot enough and we'd put in a heat pump. Hydrothermal, no. We don't have any hot springs in Wisconsin. 

We have a database at the survey of 10,000 springs, not one of them is warm. They're all nice, cool, clean places trout would like to live not other things. And co-produced fluids, no. There's no petroleum in Wisconsin. Our survey would be three times as big as it is if we had petroleum. Not that people haven't looked. In kind of working on this project, I've run across, I've looked for really deeps wells in Wisconsin because I wanted to measure the temperatures, and there's still one if you go west to Arena down in the Wisconsin River Valley there's a test well that someone drilled to look for oil near Arena, and it's like 2500 feet deep, and the bottom, I think it's like 1,800 feet of that or 2,000 feet of that is through granite. So please, if someone offers you the chance to get into a drilling company and you hit granite, tell them it's time to stop the rig. These people kept going through several thousand feet of granite. Similar story over in Sheboygan where there's a 4,500-foot well, and it's at least a couple thousand feet of granite. 

That well, we'll be able to test the well in Arena. The one in Sheboygan has been filled up and it may be lost and no one knows where it is anymore, but I would love to test that well. I think it would have use as a geothermal well. The several thousand feet of granite has no use for petroleum. When you hit the granite, that's when you stop looking. We know that now. Geothermal heat pumps. So let's talk about the geothermal heat pumps, how they might work in Wisconsin. So you have your building, you have stable ground where water temperatures, you can put your condenser, your coils, in the dirt. You can put them in rock. 

You can put them in a pond. You can do all sorts of different things with them. You just need a stable water where water temperature is used to control the building temperatures. That's actually what we have just across the way at the Wisconsin Center there. So a horizontal loop, you dig a trench two to three meters deep. It zig-zags back and forth. I'm not going to be able to do this in Madison. My neighbors would not be pleased with the backhoe in there. And then you put high density pipe in the trench. You fill it back with soil. 

This is what people do out in the country. You can do a vertical loop where you drill several wells, and actually I have a neighbor several blocks away who installed on of these systems in his home and is using geothermal energy in Madison. And you just drill a bore hole, you put your pipe down and you circulate there. You can use the Earth to store and remove the energy. So the heating cycle is you have your heat pump here, and if you're going to heat you put cold water in, it picks up some heat out of the ground, you increase the temperature with your heat pump, and then you run that to a blower or a heat exchanger, and you can heat your house with that. You can also use it to help heat your hot water a little bit as well too. Cooling cycles, just the opposite. So rather than take the heat out as we'd be doing this time of year, in the summer you put the heat in. So it really balances out nicely for places farther south. Here in Wisconsin we do way more heating than we do cooling. 

So if you're in southern Illinois, this works really, really well because then you have more balance. All the heat you take out in the winter out of the Earth when you heat your home, you can put all that back in in the summer as you're cooling your home. So you can get things to balance, and so in Wisconsin we need to be a little bit careful when we're installing systems because we keep taking heat out and putting it into our house, and we can end up cooling off our field, and what that means, when we cool off our field is that efficiency of our heat pump goes down and we have to put more energy in to move the heat. So that's one of the things that we need to be a little bit careful with. I have a question. >> What's the price tag on one of these babies? >> Price tag? It depends. Let me give you a range, though. It depends if you want to heat, so let's say we're going to heat my house kind of 1500 square feet. So if I just wanted to do kind of an auxiliary heating and maybe a quarter and I had room for a trench, maybe $8,000. If I wanted to do everything 100% and I'm going to have to drill wells, you might be looking at $32,000. 

So there's a range. We'll get to that in a little bit. That's a great question, though. That includes everything here as well too. So here's the unit, the heat pump, an exchanger. It's about the size of a furnace is really all it is. Here's just some photos of some people putting in the ground source heat pumps with bore holes. Here's some well drillers looking like well drillers. There's a trench excavated. Here you can see some of the tubes that come out the top. 

If you have a lot of wells, it can get pretty complicated all these tubes going back and forth. Here's kind of the process. You drill, you put in your pipe loop going down, comes back up, you fuse it, you make sure it doesn't leak, you make sure the loops are ready for the unit, and then you install your heat pump. Very often these loops don't use water to circulate and transmit the heat, carry the heat. They use antifreeze so it doesn't freeze and crack your system. And there are some environmental concerns. If the system leaks is that antifreeze going to cause problems, is it going to cause trouble? And that's something we need to be thinking about. So just some facts about geothermal heat pumps. We could save 2.15 million barrels per year if 100,000 homes did this. In my 25% to 50% savings on my utility bill, if I put in that super expensive system, I can maybe save $800 a year. 

And let's do the math, it may or may not work out for me if I'm going to own that home for a long time. It's going to be really close for me, and that 25% to 50% also depends where I get my fuel. Is it more expensive heating oil or is it less expensive natural gas? The energy consumption emissions 40% less than air source heat pumps. That's central air if I use it to cool. Because I'm not exchanging that heat, I'm not blasting that heat into the hot air, I'm blasting that heat into the cool Earth. And 70% less in electric. Resistance heating efficiency more efficient than air source heat pumps, more efficient than gas furnaces. And that's even the 95% efficient gas furnace, 75% more efficient than oil furnaces. Penn, in 2000, did a study of emissions and economic analysis of ground source heat pumps in Wisconsin. And he looked at, he did this for, I think, Green Bay, Madison, and then some place farther north than Green Bay, but I'm just showing for Madison. 

For a large school, 390,000 square feet, energy in costs savings. So what's the negative of a savings? That's an increase. So a negative number means in increase here. Sorry about that, but that's the way he decided to do his table. So negative means we're going to use more electricity for the large school, but we're going to save all of this natural gas. We're not going to burn that natural gas. And our yearly annual energy savings are going to be $33,000 if we decide to heat with geothermal. And our payback time is 10 and a half years. So for a large system, something big like a school, it really kind of makes sense. And one of the other points he made is these systems have a smaller footprint than the boilers that you can use, and that has value as well too. 

So you can think about that. If we look at an office, we're going to be a little bit more efficient on the electrical side. And that number's not negative, that's not a typo. We're actually going to be more efficient because offices generally have more air conditioning than homes or schools. I know my office temperature is cranked way lower than it is at my home in the summertime for the air conditioning. Natural gas will save about 10,000 therms and annual energy savings $6,000, It's going to take a long time, 21 years to pay back this. Home, this is similar to my home, I'm going to save on electricity or I'm going to use more electricity, I'm going to spend more on natural gas, I'm only going to save about $70, according to their analysis, per year, and it's going to take 26 years in Madison. Yeah? >> So this is in terms of dollars. >> Yeah. >> When you're talking about natural gas you're not factoring in what electricity might be used to produce natural gas. 

>> Yeah, I know. How big are we going to draw the circle. That's a good point. >> I mean, if you think of it globally. [INAUDIBLE] Yeah, right, and there's a lot of things associated with natural gas production as well, too. Yeah, that's right. Let's expand on that. So if you look at energy use, right now the energy that produces our electricity is from coal. So if we can eliminate that coal use, we're going to end up better off, and that's why, actually, sometimes switching in Madison to more electricity results in higher emissions because of our electrical source in Madison is coal. So if we could switch to Co-Gen plant produced electricity or the wind generated produced electricity, this number, our emissions would go way down, we'd be a lot better off, and that would be something I hope we eventually look at doing. 

The whole life cycle of energy is a tough topic. One other thing to point out, though, is if you live out in the country and you use propane to heat rather than natural gas, that higher cost you may recoup in eight years rather than in 26 that you would have in Madison. So it may make more sense if you live out in the country. >> What prices were used for electricity and gas? >> I would have to reference you to this study by Penn. It would have been like the 2000 or '99 cost in Madison. They used those. Natural gas has come down or has held steady because of the fracking technology. It's a lot more abundant now. All these things are, the interplay is, I think I probably pulled this payback times are highly variable and dependent on electric and gas costs. It's really tough to say. 

So, again, eight to 26 years. Take your pick. But you're probably going to come out ahead in 26 years. Now just look at some examples around the Madison area. The Wisconsin Institute of Discovery, just across the way, those red dots are the geothermal well locations, the proposed ones. Here's another plot of it. Here's the Wisconsin Institute of Discovery, and here there's 75 wells, 50 some here, and then the remainder here. They're all 300 feet deep, and they're at 20-foot spacing. 300 tons of heat pump capacity. What is a ton? If you talk to a refrigeration person they'll start talking in tons rather than kilowatts, and a ton is the amount of energy needed to turn a ton of water that's at 32 degrees Fahrenheit into ice. 

It comes from the old refrigeration days. So when they talk about a ton, they're talking about, so four or five tons, that's a lot of energy to turn four or five tons of water into ice when it's at near freezing. And here it's kilowatts, 14 to 18 kilowatts per well. So when the engineers went out and tested the wells, they were doing due diligence here. They went out and tested a well and said we can get four to five tons, 14 to 18 kilowatts of energy per well in one location. So they tested it. Unfortunately, the system is coming back at about only two tons or seven to nine kilowatts per well. So that heat pump that's circulating, that's taking the heat out of the ground, is having to work way harder than they had anticipated. So its efficiency is way down below what the design was because there's not as much heat coming out of the ground that the design had hinted at. And so they think it might be underground water flow. 

The First Unitarian meeting house in Madison has 16 geothermal wells they use. Epic Systems in Verona, this is a huge system. They have 500 borings. Each one is 300 feet below ground, and they've seen a 40% energy reduction. So for these really large facilities, it's making a ton of sense for them to use geothermal. I do know the drilling out there has been difficult. I know that dolomite, it's a carbonate, it's a limestone so it's got big holes, fractures, maybe caves even, so when they're drilling they'll be drilling and all the sudden they'll be in air or water. So it's kind of hard and painful. It's not easy for them to drill there as well either. But it's been working for them. 

Here's an example, there's the pipe that goes down, carries the warm fluid back out. And I should say they don't just put these in the ground, they also put a grout in so that there's a seal between the Earth and the pipe so things aren't going to run into the ground. And you can see here they are sticking up out of the ground. And here's some more of the field that's looking off. That's probably 151 right there, Highway 151. And here's the collector system. All those wells have to come into a manifold. They all get connected and they run to really big pumps, and then they run to really big heat pumps that then heat the facility out there at Epic in Verona. So industry challenges. Heat pump stuff has high first costs. 

It's expensive with no guarantees of performance. It's more expensive than your boilers and chillers. I think if we pay more attention to geology, as a geologist I'm going to say this, we can probably get better guarantees at performance. If we start looking at what the geology is, we can start to say better this is how many tons of energy you can get out of the rock. And that's one thing that I'm very interested in doing. Uncertainties, variable fuel composition. Again, geology. And seasonal underground water flow. Hydrogeology. And grouting materials. 

That's some engineering. So I think there's room in this. I think the above ground engineering has worked out. I think we need to be smarter about what we're doing underground with the geology, and we can come up with better, more efficient systems. And so now I'm going to kind of segue into the last piece is the current geothermal research that we're doing here. And just some basic information. We want to find basic information for these systems. I want to get temperatures with depth. What is the actual geothermal gradient in Wisconsin? Can we improve heat pump efficiency? The hotter water coming in, the more efficient the system. So is one 1,000-foot well, does that make more sense than five 200-foot wells? We're going deeper and we should have hotter water going into our heat pump. 

Maybe that will pay off to do it that way. And then, also, this is my enhanced geothermal pie in the sky. Wisconsin produces its own electricity. How deep do we need to drill before we get to temperatures where we could use to generate electricity? And then heat flow. Will the well fuel cool off because we're pulling out all the heat? And is there enough energy to be able to generate electricity? So here we're back at this map, and my quibble with this map is they use three points to draw those contours around Wisconsin. That's not really enough points for me. I wish we had more. So that's where we're headed. The geothermal gradients in Wisconsin, we're the coldest. Come on, I just don't hardly believe that. 

We can do better. So here, if we're looking, remember, I forget his name right now, where Fox got two degrees per hundred feet, they're saying we only have .7 degrees per hundred feet. And the hotspots out here have almost four degrees per hundred feet. So I was just wondering about that. Are we really that cold? This map's just based on two points in Wisconsin and one in Illinois. So there we really have to be suspect. And we have rocks with high heat production, we have all these granites that we know have high radioactive heat production. They should produce more heat. So I was expecting higher temperatures. So let's look at the data we have. 

And here's the existing data. The people who made the map didn't have access to this. We just pulled it together in this project. And you can see we go from .6 is the blue to 2.5 is the red. It's kind of scattered and I need to figure out what the scatter is, but I'm thinking we're more in the 1.5. We're out of the .7 range. We're doing a little bit better than that national map. We probably have 1.5 or 1.4 degrees per hundred feet. We may even have two or three. And that may mean that we can get a lot more heat out of the ground as we drill down deep. 

So I would say that map's a little low. And then if we look at how geology impacts temperatures with depth, there's a couple things. The type of lithology insulates the underlying rock. Sandstone is a good insulator. Heat doesn't travel through it as well. Granite is not as good an insulator. Here's some sandstone. Here's some granite. Groundwater, if you have groundwater moving from one aquifer down your well to another one, that makes the heat flow look different when we take those measurements. And then heat produced in the rocks. 

The granites have more heat; sandstones, less heat. Here's is what we might expect. A higher gradient across our insulator then we're going to have gradient down below here too. And so where we're going to collect additional data? We're going to look in granites in central Wisconsin that are going to have higher radioactivity, and then we're going to look in granites underneath the sandstone. So this part of Wisconsin has lots of granites. This part does too but this beige here is sandstone on top of the granite. So we're going to drill through that sandstone that's acting like a blanket and see if we can get higher temperatures. So that sedimentary cover will insulate the underlying granite. And we're going to drill this well and this well in the next month or so, I'm thinking, a thousand-foot well. We drilled a series of three here, and I'm just showing those in Marathon County in the granites. 

And here we're out at the field site. This was actually in the bottom of a granite quarry just west of Wausau. And every time I wanted to do work in this quarry we would get a half a foot or a foot of snow. And there's my little Dodge Caliber. And so every time I wanted to go down into this quarry, I always wondered if my Dodge Caliber was going to make it back up the hill because usually it was snow-covered, and I wasn't sure it was going to make it out. The driller had a plow in front of his pickup so here he scraped it off for me. But this is one of the pitfalls of working in a low spot, you're never sure if you're going to get out. And so here's the drill rig drilling the thousand-foot well. It took him only three days. He just plowed through it. 

It went fast. Here's some of the cuttings, the ground up rock that comes out the top of the well as they drilled it. And here's some of the results from those three wells. Here we've got the depth. They were all 1,000 feet deep. And then here's the temperature. I put the Fahrenheit equivalent down here just to get a sense of it. And you can see they are all doing something strange. They all are really high, and then they have a low spot here, and then they come back up in terms of temperature. And what I'm interpreting is these things right here, I took these in the fall so I think the rock was still warmed up from the summer. 

So you can imagine hot, cold, hot, cold. The shallow part of this, if I went out and measured this in the spring, this is probably going to be down to zero because it's going to be cold. So this part of the record is going to get cold and hot, cold and hot depending on the time of the year. But as we go deeper, it's going to take longer for that temperature record to go down and in. And so I don't know what's going on in this part, these warm temperatures here. It could be groundwater flow through cracks that are warming things up. It could be global climate change. Our climate could be getting warmer and we're seeing a record of that in this temperature log. People have analyzed this and it's pretty commonly seen. Or it could be clearing of the land surface in a hundred years. 

The foliage kind of kept things cool. You strip it away in a quarry, those rocks heat up as well too. The quarry's been there 40-50 years. So I'm not sure which of these three things it is, but something's going on strange. And then, when I did my deep gradient, oh, gosh, maybe those guys are right. It was only .8 degrees Fahrenheit per hundred feet. But that's in central Wisconsin without the overlying sandstones. And then I looked at the relationship between heat production, how radioactive those rocks were. So here's the heat production, and there's heat flow. This is the kind of rock that we'd expect in Wisconsin, similar to eastern US. 

It's a lot of granites without a lot of cover on it. And I get something down here. I expected more heat flow and hotter temperatures, and we're not getting that and I'm not sure why. It's a nice scientific question but I would have rather had the other question where it's way hotter than I expected and we're getting too hot of temperatures. But, anyway, that's a topic for research. And so the last project we're going to do is we're going to install one of those deep wells, and we're going to see if we can get more heat out of a thousand-foot well than what they typically do now which is a series of shallow several hundred feet wells. And by doing that we can maybe use water rather than antifreeze. Water is easier to pump. Your pumping costs aren't as high, and it can carry as much or more heat with it. So we're going to test this out. 

This is the dish system, invented by Bruce Walker at Wisconsin Well & Water Systems. We're going to instrument it, we'll do all the engineering and check it out. We have applied for a grant to fund a graduate student to look at this system and see if it makes sense. Maybe we can be more efficient. And so here's Dr. Tinjum and myself and a couple of grad students. And so I'll see if you have any questions now. [APPLAUSE]