9UNP1284SD_Greg_Kleinheinz_WordPress

- Welcome, everyone, to Wednesday Nite @ The Lab. I'm Tom Zinnen. I work here at the UW-Madison Biotechnology Center. I also work for UW-Extension Cooperative Extension, and on behalf of those folks, and our other co-organizers, Wisconsin Public Television, the Wisconsin Alumni Association, and the UW-Madison Science Alliance, thanks again for coming to Wednesday Nite @ The Lab. We do this every Wednesday night, 50 times a year. Tonight, it's my pleasure to introduce to you, Greg Kleinheinz. He grew up here in Madison, went to school at Edgewood High School, got his undergraduate degree at Northern Michigan University, and his PhD at Michigan Tech. Both of those are up in the UP. Then he worked at Tech for a while, and then he joined the faculty at the University of Wisconsin-Oshkosh. Greg gave a talk for us back a few months ago when the Northern Lights Tour, and he agreed to come, and give a talk on another topic. 

Tonight, he's gonna be talking about Biogas Production in Wisconsin: Dry, Wet, and High-Solids Solutions. Please join me in welcoming Greg Kleinheinz to Wednesday Nite @ The Lab. 
(applause)
- Thank you. It's a pleasure to be here. The jokes on biogas already started, but we call that the smell, or we say it's the smell of money. So, we like it. And in the spirit of full disclosures, Tom said I am a native Madisonian. He warned me that the questions get pretty brutal at the end of this, so I actually brought my parents. So, be gentle. 

I want to talk to you a little bit about different types of anaerobic digestion, and a lot of people ask, "I'm at a university. "We're standing in a building "of our sister campus in Madison. "Why is a university in the biogas business?" And I just want to tell you a little bit about our campus. UW-Oshkosh just came out in August. It was ranked number three in the Sierra Magazine's Cool Schools rating. So, by far the highest ranking of any Midwestern school. We barely, it was a half a point, and we missed number two. And we're ranked number five in the nation in the green schools ranking. And so what does all that mean? 

There's a lot of text on this slide that you can read, but one of the core principles, and values at UW-Oshkosh is sustainability. So, from becoming a fair trade campus, to purchasing electricity from renewable sources, to being designated as a monarch waystation, to waste management, energy reduction, conservation, and efficiency projects, we came to the point where we said: "We have solid waste on this campus. "We have 14,000 students. "So what do we do with that waste?" Make sure I have that. The university decided to undertake a goal of increasing their use of renewable energy. So we have 14,000 students. We produce roughly 500 tons, and I'll throw out some numbers, and don't worry, this is not gonna be like class. There's no mathematics, and formulas, and anything else, but we produce about 500 tons of solid waste from our food service every year. And so the question came up, what can we do with that 500 tons of material that would not only fulfill our sustainability mission as a campus, but things that we could use as a learning tool as well? 

One of the interesting things about our campus, and the sustainability initiatives are it was started from the students. The students came to our former chancellor, and they said this is an important issue, not only in terms of environmental sustainability, but economic and what our new chancellor called political sustainability, and so they brought it to our administration. The administration bought into it. They said, well, let's see what we can do around the solid waste issue that we have on campus because that was one of the real areas on our campus that we hadn't been able to do much with. So the goal was to increase energy from renewable resources, and then also find a way to get rid of that 500 tons of solid waste that we produced, basically, leftover food service waste. And that brings us to where we are today. And I'm gonna talk about the three biogas facilities. So I call these, we call them our biogas enterprises. And the university is fortunate enough to have a progressive thinking foundation, and two of these complexes are owned by the UW-Oshkosh Foundation. And the first one that we'll talk about is the dry one on the top of the screen. 

I'll see if I can use this. And so this one processes food waste. This is a small farm, high solids, and I will go through this in more detail. This one is a continuously mixed wet system on the state's largest dairy. So, small family farm, large dairy. And this dry system, again, the one that we wanted to use to address our solid waste issues on campus. So we chose a partner through a process that our foundation used to vet technology providers. BIOFerm Energy Systems, located in Madison, and their parent company, the Viessmann Group of Germany, was selected as the technology provider, and at UW-Oshkosh we clearly are not very original because we named them BD1, BD2, and BD3. But the first one is located, just a little background before we talk about the specifics, was located in the city of Oshkosh, and it processes about a third food waste, 12% yard waste, and then crop bedding material from local small farms, and then some curbside municipal solid waste. In fact, we're the ones that piloted a trial with the city of Madison to bring curbside organic collection to our campus, which turned out to be a little bit more complicated because changing human behavior in how they dispose of their waste products is not as simple as one might think. 

BD2, on a 9,000-cow dairy farm. It's feedstock is really manure only. And the pretreatment is sand separation. So all 9,000 cows are bedded in sand, and you have to separate that out before you digest the liquid product. The Allen Farm is located in Allenville, Wisconsin. His family is the namesake for the town, and he's a third generation farmer with 120 to 130 cows. He has two sons that will take over the business from him at some point, so that farm will be in its fourth generation in not too distant future. That farm is basically solid manure, wash water from his milking operation, a little bit of bedding, and we do bring in a few co-substrates. The point, I guess, is that all three of these technologies, as you are gonna find out, are very, very different, and very different applications. We like to call them sort of the three biggest laboratory pieces of equipment that you can find. 

So we use them not only for the purpose that they were designed for, for producing biogas and energy and heat, and the things that we'll talk about, but we also use them as a teaching tool. After all, we're at a university, and we're not in the business of biogas. I mean, we are in the business of biogas, but we're really in the business of education, workforce development, and allowing students to sort of go through that journey, and find the things that they want to do. So all of these are fully open to students. In fact, we have students that work at all the facilities. And, in some cases, they operate the facility almost entirely much of the time. The categories that we put these in are dry, and I'll explain this. So the first one is a dry system, and what does it mean to be dry? Essentially, if you wanted to take the feedstock material, and you could hold it in your hand, or put it in a cup and, what is it, Dairy Queen, that you can turn the shake upside down and it stays, and they have to do that, or you get it free. If you can do that, it's really a dry system. 

So it's something that you can hold in your hand. It's like a snowball. Smells even better. But a wet system, again, something you put in a cup, and you can pour out. And so that's what we would consider what we're calling BD2. This is a completely mixed system. And the solids content is a little over 10%, where in the dry system we're at 30% or more. And then BD3, the small farm digester is really what we consider high solids in that it's liquid, viscous, we could pour it and spray it, but it's a much higher solids content, closer to 15% to 18%, than the completely mixed one. So they're really different applications, and different types of material. That's the take-home message. 

Each one of these processes is a different type of thing, and solves a different sort of problem. The first one is 370 kilowatts. So, not too large. We get about eight cents a kilowatt hour. So the power purchase agreements are negotiated with the utilities. And the end product is digested, and then we produce an organic compost from that, which I'll talk about again later. BD2, again, different utility, different agreement, but nine cents a kilowatt hour. And then we have fiber that's separated, and you'll see that, but that's 1.4 megawatts. Interestingly, the farm would be able to produce up to four megawatts of electricity, but the utility would not buy anymore, so the plant is really undersized for the size of the farm. So we only take a portion of the manure from the farm to generate electricity. 

The third one, the BD3, is a 64 kW. Originally it was designed as a 55 kW system. Then we decided we could co-feed that, so we made it a 64. Our previous chancellor was trying to come up with new names, you know how they're always trying to name things, and he was calling it the Titan, our mascot. He added the Titan 55, and then it was the Titan 64. And a student said to him one time, "Oh, I like Titan 64. "That sounds just like a beer." And that was the last time he mentioned it. So now we just call it the Allen Farm Digester. The first one we'll talk about is the dry system. 

And this was the first one in the United States, first one anywhere in the Americas, actually, to be put in. I know that sounds exciting, and everybody thinks being first is sexy, but really being first means there's a lot of work to do. And so this, again, is a picture of the system. It's installed just across the Fox River from our campus in Oshkosh. And we process 10,000 tons of organic waste. Did anybody remember what I said how much our campus produces? 500 tons. So we bring in 9,500 tons of organic waste product that would either go to a landfill, or some other non-value added destination in the Fox Valley. Most of it comes from within 40 miles of our campus. We produce the 375 kW, and we produce almost 500 kW of thermal value. 

So, all of these systems run a CHP, or a combined heat and power system. So as the engine combusts the biogas, it produces heat off that process, that heat is captured in a jacket, and then it's sent out for either use in the process, or heating other buildings, or other activities as we'll talk about. One other interesting feature, a unique feature of this plant, is it's located across the street from the Oshkosh Wastewater Treatment Plant. They do not co-generate at that plant, so they actually flare their biogas almost year round. And so being sort of stewards of sustainability, and watching, basically, the Olympic flame at the wastewater treatment plant year round, we went to them and said, "How would you like to come up with "a better solution for that biogas?" And they said, "What?" And we said, "Well, we'll put a biogas plant "and just pipe it in." And they said, "We're not really, "I don't know if we want to do that." We said, "We'll pay for it all." "Oh, yeah, sure, we'll do that." 

So we actually take all their excess biogas in our plant. So the size of our plant is about 175-180 kW is what we can produce just on the food waste that I'll show you, but because we take the biogas from the wastewater treatment plant, we're able to install a bigger engine, and produce 370 kW from basically gas that was just being flared at that time. It's a public/private collaboration. So between our foundation it's actually called Witzel, LLC. And so the foundation owns, and operates this, and contracts with the university and my staff to operate these facilities. When we started, we realized that this would be sort of our hypothetical feedstock. We'd start out with some food processing materials, some farm waste, we'd add some municipal yard waste. The city of Oshkosh yard collection site is right across the street, and it literally is sort of like at this confluence of four or five roads. So we have campus buildings next to it, we have a wastewater treatment plant, and we have the city's new municipal waste, and garage right across the street, so it's a pretty attractive location. But we thought we'd be able to keep adding food waste. 

And so we'd keeping adding municipal food waste over time as the plant sort of evolved. And, as I'll discuss, that doesn't exactly work. That's one of those sort of challenges, or lessons learned as we've sort of moved forward. But we also did find a number of companies, that one company, in particular, was actually trucking, because their corporate philosophy is sustainability. They were trucking organic waste from their processing facility from a small town outside of Oshkosh to Minneapolis-Saint Paul. And they were paying the trucking costs, and somebody who is into sustainability could calculate sort of the carbon footprint of doing that, which would be pretty significant, but they wanted to find a place to put that other than in a landfill, and now the material comes to our plant. So this gives you an idea of sort of the annual usage. Again, here's our bedding waste, and our food waste. Basically, about a third. In the other picture I showed, we talked about bringing food waste content up to close to 100%, but one of the challenges is, on the engineering and operation side, when you put too much food waste into these digesters, as you'll see, they turned into this gelatinous mass that really is nonfunctional. 

And it'll hopefully become clear why that is. So now, as owner/operators of this facility, we understand that we can't use only food waste. We have to put other material in there, too, to make what we call a recipe. And that recipe has to not only have organic content that we can provide biogas to our engine, but it also has to provide structure, and sort of end use, and then we'll also responsible for what goes in there because we sell the product coming out. So we have to have this sort of long chain of custody of all the material that goes into the site. So this shows a couple pictures of material. Of course, we work with students, and they look at this and they say, "Wow, look at all those vegetables. "Those are perfectly good." So, well, knock yourself out. In November, it's amazing, the first week of November, that pile will be all orange with pumpkins. 

So Walmart, all the organic collection companies that come from those large stores, we get a tremendous number of pumpkins in there. You'll see the yard waste. So here's some yard clippings. And that works great in the summertime. What is one problem that we might have with yard waste?

- 
[Voiceover]
 Winter.

- Yep, winter is a problem. Not a lot of source of that in January, so we have to come up with another solution. 

And here we have some sawdust, and some other smaller products that come in from other companies. These blue barrels here are from a company called Blue Barrel Waste. They're from Madison area. Essentially, it's FOG material that they needed to get rid of, and they would bring it in barrels. It looked a little sketchy at first, but I'm pretty sure we knew what was going in there. So, organic containers. One of the next evolutions of this facility is doing pilots in our area. And I know the city of Madison is looking at the same thing, whether it's curbside organics or working with, we have many restaurants in town that want to work on back-of-the-house, or front-of-the-house collection of organics. And the model that we use is if you're paying to dispose of it at some rate per ton, we will partner with you, and take that organic waste product, as long as it's a clean product, and save you at least half, if not more, of your tipping fees. So companies are very willing to do that, restaurants, small mom and pop shops, as well as national corporations, because, one, they're doing the right thing in terms of organic diversion, and, two, they're also saving their bottom line. 

And as long as it doesn't take too much work on their staff's part, they're very willing to do that. This looks like, well, not looks like, it is the pile of material. So all of those little individual piles you saw at the beginning that make up our recipe, it gets all mixed together. And I'd love to say we have some sort of complex-- We're a university, we're supposed to have really complex, fancy, scientific equipment, not really. This is all done with a front end loader. So I am the only person who has not run into anything with the front end loader. They won't let me drive it anymore, but it's pretty therapeutic. So you essentially use that front end loader to mix your recipe. And this is sort of what it looks like. Each week we have a four-bay system, and I'll show you the bay in just a second. 

We put in 400 tons of material into that bay every week. So 400 tons is loaded into the bay, and then sealed for 28 days. Each week when that 400 tons comes out of one of the four bays, we have four bays, so one week a month, 200 tons of the old, sort of used material is mixed with 200 tons of the new material. That 400 tons of mixed material then is put back in as a pile. The fermenter looks just like this. It's basically a concrete box. People always ask, what could you put in there? I tell them you want to park a bus in there. You could park a bus in there, and it'll be there in 28 days. You won't get any value out of the bus, but it'll still be there. 

We often, it's sort of like buying a lottery ticket. We talk about what other things we might want to digest. And so dealing in the water, and wastewater industry, you always see great slogans on the backs of trucks. And so the students have started a contest about putting names on these doors. And like "Used food hauler." "We're number one in the number two business." My favorite one driving down the highway was, "This truck is filled with campaign promises. "Stay back 200 feet." 
(laughter)
 But you have to have fun when you deal with these sorts of things. 

So you seal the chamber. As I mentioned, the chamber, and I'll have a cartoon in a minute, produces gas. There's a bag, a big gas bag on the top, and then a generator, or a CHP. And here's sort of a schematic of that. So there's just a static pile. Nothing moves. The pile is there. There's a percolate that's sprayed sort of over the top, it percolates through that pile, down through floor drains, into our percolate tank. And to give you a perspective, there's 400 tons of material in the system, and this is a pretty small plant, the percolate storage tank has 120,000-gallon capacity. So it's a pretty large amount of material. 

And that simply goes round and round and round. And between the four bays, there's a good buffering between the bays. And, really, the advantage to this type of system is that there's only really two moving parts. So, the pile sits there. There's a pump that pumps that percolate through, and there's what we call a RotoCut, or a large garbage disposer that grinds up any solid material that may percolate through the pile, and into the drains. And so there's really very low maintenance operation, and maintenance with this system because there's not any moving parts to really fail, just those two systems. So it's very simple. Again, I always wished I could tell somebody we're designing a nuclear reactor, but it's just like wastewater treatment. We're basically harnessing microbes that are naturally present, and putting them in a situation that allows them to do what they do best, that they've sort of evolved over eons to do, and then we're sort of capturing the bi-products of what they do, and that's gas. And then the end product. 

And just before I go on, the gas is stored. It's burned in the generator, or the CHP. And, again, we produce electricity and heat. The electricity is sold back to the grid. We do not use it directly on campus, and the reason for that is the power transfer equipment that we would have to install is too expensive. It's much more economical to just sell it back to the grid, and then use the income from that to operate the plant. The heat operates this entire system. So the entire plant that I showed you, and you'll see a picture of it again later, every therm of heat in that plant is produced by the process. We don't use any natural gas, or anything for heating. And, in fact, the plant is a completely closed loop. 

Aside from a bathroom in the control room, anything that goes down any drain ends up in the plant. And we've now connected our CHP to our campus services building, fleet vehicles, maintenance shops, and some of these other things right next to us, and so we'll provide heat for that building as well. So that will save the campus on utility costs. So, once that 400 tons comes out of the digester, it's then sent to a local partner, a composting site. And this is a picture of one of the trucks coming in. Again, from a student perspective, they're used to working in labs with test tubes, and beakers and burettes, and now we do qPCR and molecular biology, and you're dealing with nanograms of material, and here we are dealing with semi dump trucks of material, and getting them to understand the scale of these things. And, again, this is a small plant. So it's goes and it's composted, and we now produce, as I'll mention right at the end, a value added product that you may find in your stores relatively soon. And so the second biodigester is a little bit different. Again, biodigester 2. 

So this one is, in terms of technology, this was nothing new to Wisconsin, or nothing new to the United States. This is a continuously mixed, wet anaerobic digester, runs solely on manure. And, if you think about it, is manure really a very efficient thing to run in a digester? Not at all. It's already been digested once by an animal that's evolved over time to extract as much energy value as it can out of its food products, and we feed cows high protein diets. And so, really, it's a poor energy source for anaerobic digestion. The advantage is, when you have 9,000 cows, you have a lot of it. So it's an economy of scale. If you look at it from a per pound basis, or per gram of organic matter, the food waste is tremendously high value, where manure is tremendously low value. But, nonetheless, when you have 9,000 cows, you have a lot of opportunity to be creative. 

And so with the 9,000 cows, this is in Rosendale, it is a state-of-the-art farm. They have tours from people all over the world almost literally on a daily basis. They produce about 110,000 tons annually, and the plant is a 1.4 kW system, 1.4 megawatts. So a much larger system than the one we talked about before. And so this is one barn at the dairy. The 4,500 cows in this barn, and 4,500 cows in the barn down the way. They never leave the barn. They stay in the barn, and work toward a carousel milker. The manure from that barn travels via underground pipe to our digester. It then goes up to a solid separation system. 

The solid separation, this is a little bit novel aspect of this plant, so the higher the solids content you can have in your digester, just like your dry digester, the more organic material you have, the more biogas you'll produce. So instead of using a very dilute, low quality manure product, the material is then separated, and the solids are basically extracted out at the beginning of the process. Those solid materials then fed back over, and then remixed and then sent back to the anaerobic digesters. So each one of these is about a million gallons, and so instead of having, say, a 6% organic solution, we now have close to a 10% organic solution. So that extra 4% of solids give us a tremendous opportunity to produce more biogas. And then, with any of these systems, you have the opportunity should the farm be willing, and the operator of the digester be willing to add co-substrates to it again, any other waste products that would be in a liquid form that could be added that might boost production. The top of these are actually solid domes. There's a solid dome on the top, and there's a bladder inside that collects the biogas. But the biogas does not necessarily just appear on that white dome that you see. This is what the inside of the system looks like. 

I can only imagine it doesn't look exactly like this anymore, but I haven't went in to check. That's what we have freshmen for. No, I'm just kidding. But this paddle essentially stirs the tank, and allows that material to continuously mix, thus allowing most efficient biogas production. This is a picture of our CHP container. This is basically a dehumidifier. So, one of the concerns people always have with biogas is combustion. So whether it's in our first system in this gas bag, or in some other sort of accident, biogas is extremely difficult to ignite. So it's very, very safe because it is so wet. And so, what does that mean? 

It means the biogas is so wet that we can't put it into an engine. The engine would not run and function properly, so we have to dehumidify the gas, and we call this a chiller. Essentially, it's basically a dehumidifier for the gas. With the waste products, again, that are in manure, we also have to scrub out hydrogen sulfide, and other reduced sulfur compounds because they can be corrosive for the engine. From manure, we get very high levels of H2S. It's not uncommon. That's pretty typical. In the first system, the reason I didn't show you that, when you degrade organic material, food waste products, you get very little hydrogen sulfide. In fact, there's almost no reason to scrub the gas. The gas is extremely clean that you get out of those systems. 

This is what the engine looks like. So it's a big 20-cylinder, basically diesel engine that's converted to run on biogas. And so that sends electricity out to the grid. And then at times where we actually have too much biogas because we can't sell anymore due to our contract, it actually gets flared. And so we talked about the Olympics. You can imagine, you can see the background here, this is in the middle. So this big container is essentially a stainless steel cover around the flare. So at night, even if it's flaring, you won't actually see the flare. So it's just more aesthetically pleasing as you're driving through the countryside, and there's nothing around you except for this ginormous flare. So that's essentially what that is. 

The material, then, that comes out of this system, just like the other, you're left with a tremendous opportunity with the solid product. And this is one of those questions that everybody across the country has wondered what to do with this material. There are a number of options from the material, but no real gold standard as to what you do with it. The material comes out of the digester again, and then it's produced a fiber product. It's kind of extracted through another screw press. That fiber then is dropped outside the digester, and we produce five semi truck loads of that a day. So there's five semi truck loads of that fiber product a day, and when Europeans come and tour the plant, we give probably four to five tours a week for the different facilities, they look at this material and they call it black gold. They can't imagine, we tell them it's worth about $5 a ton as is, and they just can't believe it. In Germany or France or Italy or wherever, it would have tremendous value, and they just can't believe in the US. We try to explain to them how many dairy cows are in Wisconsin, and how much of this material there is, but one of the issues are that you have 9,000 cows, and now you have all this material in a very concentrated place, and how do you take that concentrated amount of material and distribute it sort of evenly to where it needs to go, and not just stay in one spot. 

And so that's a challenge that we're working through, and I'll talk a little bit more about that a little bit later. And then the last one, you know, true to our roots, the average farm in Wisconsin, we hear about farms of 9,000 cows. You hear about CAFOs, 5,000-cow farms. The average farm size in Wisconsin is about 111 cows, so it's very small. And we still have almost 10,000 farms in Wisconsin, so a large number. That number is declining fairly significantly, but it's still a lot of farms with an average that's really pretty small. And so the technologies that I showed earlier are really not applicable to those type of applications. And so, again, because we didn't learn our lesson with the first two, we decided we wanted to try to do something on a small farm. And we decided to put a small farm digester in at Dave Allen's farm to prove the technology. And with any of these systems, we're calling them sort of the version 1.0, and we view our role as one of technology development. 

And so how can we take version 1.0, work through a lot of the issues, and then when we get to version 2.0, company ABC, farm XYZ puts in this system, we've already been able to experiment with a lot of the issues that have come up. To give you an example, the first system that went in, I can operate that entire plant on my phone. There's literally every valve, and system I can control, with the exception of two major errors, on my phone. So what the plant wants to do is anytime there's a fault, there's a dialer, which is awesome, and it calls you. It doesn't matter if it's 2am or 3am If you've ever seen that State Farm commercial, this thing would call, and it would read off an error message. And I had to keep telling my wife, "Don't worry, it's the digester. "Sure, trust me." But it turned out that for a while we had to do a rotating call schedule because we were getting a lot of those calls as we worked through the bugs. But, nonetheless, the small farm, it's the same thing, we can control that. He has up to 4,000 tons of manure, and bedding waste. 

So he beds in crop residue that he produces on his farm. He right now has about 120 cows. We produce about 64 kW of electrical that's sold back to the grid again. And that revenue from the electrical sales is used to operate the facility. And then the 100 kW of thermal value, and you'll see how he benefits from that in just a second. So this is Dave, on the lower right, and his oldest son Cody. So, again, he's a very progressive thinking small farmer, and he realizes that he needs to do something to his farm to make it very sustainable, and to make it ready for his sons to take over, and one that they would be able to operate for some time and be profitable. So he allowed us to have access to his farm, and installed the system. I think there were times that he wishes he hadn't done that. For example, the time when we had a big pipe break on Christmas Eve, and we had 5,000 gallons of material oozing over the ground and it was 20 below. 

Let me tell you, it doesn't stay warm very long. And we affectionately call that the poopsicle. This is what the system looks like from the other side, and I'll show you some detail of this. This is what we call our pascal. That's with all the material, the solid material is loaded into the digester with the front end loader. It then goes into the actual digester unit itself. And this is sort of a two-chamber plug flow system. And the material flows through the system. And in all of these systems, roughly the retention time is between 21 and 28 days. So just slightly less than a month. 

And, depending on what you put in, and how you operate it, you can adjust that retention time, but we find with the material we're putting in, that gives us most of the gas value has been extracted out of the material, and operationally we can run pretty well. There's a small little gas bag on the top of this system. Nothing near like the dry digester we showed you earlier. But the gas then goes to an engine, which I'll show you in a second. This is a picture of the augers that actually feed the system. And one of the challenges you can imagine, so this one goes into the system, these next two go sort of counter to that, and it's supposed to allow it to become well mixed, and then feed into the system. This just shows them loading the pascal. You can imagine when you start talking to people, this was, again, first of its kind installed anywhere in the US, certainly anywhere that's cold. As Tom mentioned, I am a Madisonian, so I grew up in Wisconsin. And I think anybody that spends any time in Wisconsin understands what it is like in December, January, and February. 

And if you look at this picture in January or February, we tried to explain to our technology provider that things don't stay unfrozen in January. And so we've worked through some of those issues, and how can we still process material in those times of years. But, certainly, there's certain challenges that we have to address in northern climates that, if you were in Florida or California, you don't have to deal with. This shows just, in fact, it's been a little bit re-engineered, but this is a liquid line from his milking parlor. And so we have solid material that's fed through the pascal. Then we have liquid material that's fed through this line from his milking parlor. So we have a combination of solid and liquid material. The farmer and his sons load the material, so they're responsible for this. It's really throwing a couple bucketfuls into the pascal a day, and the pump is set to automatically meter in the amount of liquid we need. So it's really not a lot of work for him. 

This, again, shows the inside of the plant, or inside of the digester, and the mixing paddles. And this is sort of the small bag that's found in that little chamber. And so, in theory, we would be producing enough gas in any of these systems that those bags would be sort of continuously full. The reality is it doesn't really work that way. So we use the bag as sort of a buffering. As we produce more material, the bag sort of fills up. When the engine kicks on, and it's a variable intensity operation, so we can run at 100% capacity, we can run as low as 50% capacity on the engine, and we try to scale that to maximize the amount of electrical sales, and then it's all based on how much gas we've produced. Again, a similar operation to the last one. We have our chiller to dry the biogas, and then we have a scrubber again to take the hydrogen sulfide. And, in fact, we found you don't find people in my area and the art department talking very often, but I've come to find out, I've been on our campus about 16 years, and they have these huge kilns they use for all sorts of pottery and things. 

Well, it's a great way to regenerate activated carbon that we use in these filters. And so we sort of commandeered their ceramics lab for a couple of weeks. They said, "What is all this stuff? "You guys are crazy science people." Anyway, but it works pretty well. So it's a way a couple kind of unique departments collaborated. In this container is our CHP. Again, it's a simple system. And so, again, a small diesel engine that's set up to run on biogas. This just shows a picture of the pump and the RotoCut. 

Again, the only real two major parts, these would be almost identical only smaller to our dry system, and, again, showing the RotoCut, and then the pump that moves material back and forth. At the end, this is the odorous area. But, in fact, one of the great advantages of anaerobic digestion, whether it's a large farm or this farm, because a lot of that breakdown has already occurred in the decomposition process in the biogas production process, the material going into his manure pit, or into the large farm lacks a lot of the compounds that would be broken down in those pits, and then producing odor. So they really have much less of an odor footprint than they would have if there was no anaerobic digestion. He again then takes that material, and he spreads it on his fields. So he's able to reuse the nutrients that he's producing and it never leaves his farm. So all of it is self-contained. This is an aerial of his farm showing his old milking parlor. He keeps some cows in this barn. The square, this is where our digester is. 

This is the manure pit. And, in fact, he takes the heat off of the digester, and he runs, we ran a heat loop to his house, and we ran a heat loop to his workshop. And so this is a new milking parlor. So this is a robotic milking operation he just installed this summer, which was a challenge because we designed the system to operate with the existing farm, and our technology provider partners. That was our original intent. And so he said, "Well, no, I want to upgrade "my milking capabilities." So he put in an ultra-modern robotic milker, which produces a different kind of material and feedstock. So we had to make some adaptations to the system. But that now feeds to the digester. This is just a picture of us running our heat loops. 

And this shows it coming in, on the left into his workshop, and on the right coming into his basement. And at one point last winter, I think he had so much heat it was about 82 degrees in his workshop, and he said, "This is awesome, I can have a beach party, "and I don't have to buy any propane." And so you can imagine the cost savings for him. Remember a couple years ago when propane was $6 a gallon. So it's fairly significant if you're in rural areas, and not able to get natural gas. So, again, this is sort of a summary of the three. The dry one, the small one, and the large one. And I would love to tell you that everything with anaerobic digestion is wonderful, but there's certainly advantages to doing this and challenges. And so in the US, we have a number of challenges. The reality is natural gas prices are cheap. 

And natural gas, for the foreseeable future, will probably not be very expensive. And so it makes it very difficult, as utilities change their electrical generation from coal and other things to gas, they can produce very inexpensive gas. Power purchase agreements, there's no incentive. So in Germany, for example, they may get 32 cents a kilowatt hour for the energy they produce in a renewable fashion. We're getting eight. So if we got 32 cents per kilowatt hour, the plants would pay for themselves, and our foundation's model is any money that comes back for these facilities goes to student employment, and student scholarships on our campus. And so, at this point, we haven't got to a lot of those yet, but we're working that way. At 32 cents a kilowatt hour, we'd be there. So, essentially, the take-home message is nobody's obligated to buy the electricity from you, but if you can't install a digester, and think you're gonna make any money in the United States only on electricity. You have to have multiple revenue streams. 

And if you look at our dry digester, this is true of anybody's system, you have to have either a tipping fee at the beginning for organic waste products, you have to electrical sales, and then the most important thing out of those is you have to do something with the solid material that comes out of that system. And it has to have some sort of value that you can bring back to the sort of cost metrics of that plan. You also have to have feedstock stability. So in California, we could install that same dry digester, and have a pretty continuous feedstock year round. In Wisconsin, we have challenges because we have grass clippings, and other things that are yard waste that are wonderful feedstock, but in January we have to come up with alternate things. So our operators, our plant manager has to come up with a unique feedstock that he can supplement those material. The seasonality, transportation costs are a big one. Our climate, just the coolness. I'll give you an example, again, lesson learned in our dry digester. That mixing lobby where you saw the big piles of pumpkins and oranges, there was really no heat initially in there. 

And we thought, I think maybe our administrators thought, well, the students don't need any heat in there, they'll survive. But, really, what it turned out to be is the moisture in the air was so great it would basically cloud up in there. So drive a giant front end loader in a cloud. It was just dangerous. So we took a heat loop off of our CHP, and now we heat that enough, so it's a little bit safe. And I mentioned technology development. So, all of these systems, certainly we've learned a lot of lessons over the time that we've put them in, and we hope that the next generation of digesters will not only learn from us, but from others that have gone through the same thing. So, what are some benefits beyond electricity? Again, the thermal value. So, in European cities, they will install these in the center of a small community, and they're all very close to a number of buildings, and that heat's being able to be used. 

In small communities in Wisconsin, the buildings are not close enough to make it viable to use the heat energy from the digester. So, like in Dave's case, you have to have buildings right there on the farm that you're able to use that heat. Nutrient management is a huge one. In the Great Lakes, certainly this is a big, big issue. Water control and reuse. So in certain areas of Wisconsin, taking that water that comes out of the digester, cleaning it to the extent, and then being able to reuse it on the farm without having to go back and get new water, and dispose of the water. That's probably one of the single biggest challenges. Pollution control, value added products on the back end. And in our system, we hire a lot of students. So we have in our group, my group, the Environmental Research and Innovation Center Lab that operates the digesters. 

We hire about 48 students that have fully paid positions over the course of a summer or academic year, help put them through school, and they learn hands-on training, whether it's engineering technology, microbiology, environmental health, a bunch of other disciplines. They get really hands-on experience. And I won't tell you what campus this student came from, but he was a doubly, and he just graduated, was all excited, and he came to our plant manager and said, "I'm here to fix your electrical relay." And he said, "Oh, okay, it's upstairs." And the guy was gone for a little while, and our manager goes up there, and this younger professional is sitting there looking at stuff. And he says, "Oh, it's right there." And he's, "Oh, I studied these in books, "but I've never actually seen one." So we hope with our students they'll have a much more sort of, while it's necessary for those things, a very applied sense of how they can do things, and put their hands on a lot of this equipment before they leave. This is our newest product. So this Titan Gold product is the material that we bring out of our dry digester. 

So it's based on food scraps. We think this is an opportunity for our biodigester 2. Our partners here, they're not our partners, our sort of sister entity, Purple Cow, I think people have probably seen that product. There's Magic Dirt. And certainly one of the biggest biosolids products, these are digester products, but Milorganite. So that's been around, the biggest selling one in history from the city of Milwaukee. So Wisconsin has a long legacy of using these organic solids as they come out of treatment systems. And so we hope that this will be the first step in a number of them. But to sort of summarize things, all anaerobic digestion is not the same. So the fundamental microbial processes, that is the production of acids, and then the production of biogas, that's the same, no different. 

But each system is very different based on the type of feedstock, and the type of thing you're trying to break down. And you can only imagine, we're doing a project for a Canadian city right now where they're bringing us their curbside collection, and we have to deal with all the contamination. So in our first system, you saw all those pumpkins and apples, and things go into that system, there's no preprocessing. The material is mixed, it comes back out, it's digested, it's composted, and then it's put in those bags I just showed you. There's no removal of debris or material. The material we got from the city in Canada has needles, cans, prophylactics, I mean, you name it, it's in there. And so that takes a lot of, anything you put into the system is coming out of the system, if it doesn't break down. So in order to do anything with that material, you have to really be careful about how you're screening that feedstock going in. So you have to evaluate each site, what the feedstock is that's available, what's really the end goal, what's financially feasible, put the metrics to it, and will it work. People have to really understand electricity is not the only part of the feedback for these systems. 

A lot of, I've heard providers, technology providers say, "Oh, you'll make so much money in electricity, "the water when you come out of "the system will be so clean you can drink it." Well, that all may happen some day. I've never seen anybody willing to take that first drink out of the glass. And so we'll see. At some point I certainly hope we get to that point, but it's gonna take a lot of work for a lot of people. A lot of work to be done, but anaerobic digestion is alive, and well in Wisconsin. And there are a number of groups, there's a group in UW-Madison, there's certainly our group, some people at Green Bay, and then a number of technology providers. And I think it's not an accident that they all ended up in Wisconsin in that area because if you look at the number of farms in Wisconsin, Minnesota, Iowa, northern Illinois, it far eclipses what's available in Europe. And in Europe, they've found ways to install tens of thousands of these systems. And so I think the opportunity presents itself for all the reasons I mentioned earlier. 

We just need to get to that point. Every one of these systems that doesn't do well, it hurts everybody. And so if you read the newspaper about this or that happening at an anaerobic digester, that's not good for anybody because it let's people believe that the technology doesn't work, or that it can't work. And that's not, in fact, the case. It does, but you have to be very careful, and apply the right technology to the right situation. So, with that, I will say thank you, and take questions when I'm allowed. 
(applause)