(I am writing this 5 days after - it's been a busy week.)
We had a full day planned this day - 8am to 6pm, much of it (about 4 hours) on the bus. But the bus ride is an important part of the experience. In addition to hanging out with Sunny, it gave me time to get to know my students better, and I talked extensively with Michael, the Danish college student who will travel with us while we are in Thy. Michael is extremely knowledgeable about many things, especially Danish culture and history. He (like most of the other Danish we have me) also is a lot of fun - we have become good friends. We will hopefully see him in Copenhagen next Friday.
We got to the Siemen's factory around 10am. The only picture I have is from the front, as we were not allowed to take pictures inside. A few details about our trip:
We had a full day planned this day - 8am to 6pm, much of it (about 4 hours) on the bus. But the bus ride is an important part of the experience. In addition to hanging out with Sunny, it gave me time to get to know my students better, and I talked extensively with Michael, the Danish college student who will travel with us while we are in Thy. Michael is extremely knowledgeable about many things, especially Danish culture and history. He (like most of the other Danish we have me) also is a lot of fun - we have become good friends. We will hopefully see him in Copenhagen next Friday.
We got to the Siemen's factory around 10am. The only picture I have is from the front, as we were not allowed to take pictures inside. A few details about our trip:
- The Siemen's factory is in Brande, which is about 2 hours south of the Folkecenter. Siemen's got into the wind business in 2004 when they bought a Danish company named Bonus. You can still see Bonus turbines around Denmark. They bought the company, and expanded the existing plant from a dozen or so acres to 45 acres. They are now one of the leading turbine manufacturers in the world.
- You know that cliche about German efficiency? Well, it's not just a cliche - EVERYTHING about the tour and the plant is the height of efficiency. The walkways we were allowed to use are painted green (they give tours to about 20,000 people each year!), and the guide talked and walked very fast. He was extremely friendly, helpful, and candid, but he really moved quickly. He also explained a lot about the efficiency of the turbine manufacturing. For example, they have timers marked at prominent locations along the wall that show exactly how long a crew has been working on a turbine, and how long they have left to finish. It is difficult to quite put into words, but this sums it up: We each had a helmet and goggles for the tour. When we were going back to the room at the end of the tour, he instructed us to put our goggles in our right hand and helmet in our left hand before we walked into the room b/c the goggle bin is to the right of the door and the helmet shelf is to the left. He was serious! And you know what, it did make it more efficient.
- We got to see and learn about all four "platforms:" The G2 (2.3 MW), the D3 (3 MW and 3.2 MW direct drive), the G4 (4.2 MW and 3.6 MW offshore), and the D6 (6 MW direct drive). Direct drive turbines have no gearbox, and the shaft of the generator is turned directly by the rotor of the turbine. They also have permanent, instead of electro- magnets. This cuts down on maintenance and is the direction the industry is headed. They have about 50% fewer moving parts and are lighter than geared turbines.
- The 6 MW turbine was the largest in the world until this year (Vestas has a 8 MW now). The top of the turbine (the nacelle, which houses the generator and other mechanicals/electricals) is over 2 stories high! The whole top of the turbine, including the blades, weighs 360 tons! 360 tons! The blades are each about 75 meters long - that is wider than the span of a large jet airliner (about 240 feet)! The tower is about 140 m high (about 300 ft). The scale of these things is massive. Absolutely massive. We got to stand inside of a turbine blade. It is nearly unfathomable that these things sit a couple hundred feet in the air.
- The blades are seamless - they are made in one giant mold with layers of fiberglass, balsa wood, epoxy, and something else he could not tell us.
- They had a hovercraft-type machine inside the factory (floats an inch or two on air) that can lift 250 tons. "Much safer than using a crane," he said. Makes perfect sense, actually.
- Their turbines are so reliable that they will be operating over 95% of the time after they go up.
- They have a factory in the U.S., China, and other places, and are building one in England. 1/3rd of the cost of turbines is the logistics, so they are building factories where the most business is.
- We got to take a look at the 1 MW turbine on site (you can see this in the picture below).
Stop 2: Lemvig Biogas
After the Siemen's factory, we stopped at a nearby small town and had a picnic lunch with food from our host families. We were very concerned when we could not find coffee at the first cafe, but after walking around the town a bit, we found some. I also learned that our bus driver plays guitar and sings country music, which is pretty popular in Denmark. After about an hour, we headed off to Lemvig, which is a small town about an hour and a half away.
At Lemvig, we visited a biogas plant. Biogas is made by anaerobic (oxygen-free) digestion of organic material by bacteria. When organic material is digested anaerobically, it produces mostly methane (the main component of natural gas) instead of carbon dioxide,which is the byproduct of aerobic digestion. The biogas can be used like natural gas and burned for heat, electricity, or a vehicle that runs on natural gas. A few details about the plant:
The way this plant works:
The whole process is closed-looped - manure goes in, gas comes out, electricity and heat are generated and used, and the "waste" is put back on the farm fields. And on and on they go!
After the Siemen's factory, we stopped at a nearby small town and had a picnic lunch with food from our host families. We were very concerned when we could not find coffee at the first cafe, but after walking around the town a bit, we found some. I also learned that our bus driver plays guitar and sings country music, which is pretty popular in Denmark. After about an hour, we headed off to Lemvig, which is a small town about an hour and a half away.
At Lemvig, we visited a biogas plant. Biogas is made by anaerobic (oxygen-free) digestion of organic material by bacteria. When organic material is digested anaerobically, it produces mostly methane (the main component of natural gas) instead of carbon dioxide,which is the byproduct of aerobic digestion. The biogas can be used like natural gas and burned for heat, electricity, or a vehicle that runs on natural gas. A few details about the plant:
- The biogas is burned in a generator on site (see image below) to generate electricity. The "waste" heat (about 70% of the energy ends up as heat) is used to heat hot water, which is sent out through underground pipes to the local town for heating. This is called district heating, and is a fairly common way to heat homes in Denmark and other European countries. Not so much in the U.S., other than on college campuses and so forth.
- The hot water is in a closed loop, so is not used in the homes. The hot water is split into smaller pipes before going into homes, then runs through the house where the heat is radiated to warm the house. It is also used for household hot water: the tubing runs through hot water tanks, and heat is released into the water in the tank to heat it up.
- All of the heat in the town of Lemvig (not sure how big it is) is supplied by district heating from the plant, other than a little bit of supplemental heat.
- It is 100% cooperatively owned by the local farmers. About 25 farmers own the plant.
- The plant is non-profit, meaning all profits outside of operating costs and salaries of the employees must be used to reduce the price of heat to the local town.
- When the warm manure comes out of the other side of the process, the heat is used to preheat the manure that is coming in. It must be heated up to 50 C (about 122 F) before it is digested, This, like most other things here in Denmark, makes the process more efficient.
The way this plant works:
- Manure (pig and cow, mostly) is trucked in from the local farms. It is put into a holding tank (see picture) and constantly mixed.
- It is filtered to take out larger organic pieces and things that cannot be digested like plastic and rocks.
- It is pumped into the digesters, which are the large towers (4 of them) in the images below.
- After 26 days in the digesters, the gas is ready to use.
- The "waste" (the leftover material) is high quality composted manure that is then put back into the farmers fields. According to our guide Jane, one of the primary reasons that the farmers participate is because they get this product at the end.
- According to Axl (the farmer and board member who showed us around), the manure they get after the process is done is much better than the manure they put in.
- All in all, this process is 93% efficient. Awesome.
The whole process is closed-looped - manure goes in, gas comes out, electricity and heat are generated and used, and the "waste" is put back on the farm fields. And on and on they go!
Our last stop of the day was at another biogas plant, this time in Harboore (see below for correct spelling). Harboore is a different kind of biogas - it is "gasified." It also uses woodchips instead of manure. This is an entirely different process than Lemvig. I don't quite understand all of it, but this is basically how it works:
Like all other plants we have seen, the inside of the plant was basically spotless. Everything is clean. It also struck me that the dog was allowed to follow us around everywhere we went.
After we left, we took a ferry at Thyborn. It was a lot of fun! It was about a 15 minute ride, and the fjord was pretty rough. After that, we rode on the bus back to the Folkecenter and home to our host families (after one more ride on the electric bike of course).
- The wood chips (about 10,000 tons a year) are delivered. The wood chips are waste wood from the local national forest.
- Gasification is a two-part process: First, it is burned through pyrolisis, which means it is burned in a low oxygen environment. (This is where it gets hazy). It is then chemically processed somehow, and the byproducts are mostly carbon monoxide, hydrogen and methane. This is what is burned in the engine. According to our guide, this can be burned in a natural gas engine (see below).
- The gas is burned in an engine that drives a generator. The electricity is sent out to the grid. The "waste" heat is used for district heating. About 75% of the energy is made into heat, the rest as electricity.
- The water goes out to the local town. It goes out at 70 C (about 150 F), and comes back at 40 C (about 105 F).
- One of the byproducts of gasification is tar (about 4,000 tons per year). This is also burned and used for heat in the winter.
- The whole process is about 95% efficient.
Like all other plants we have seen, the inside of the plant was basically spotless. Everything is clean. It also struck me that the dog was allowed to follow us around everywhere we went.
After we left, we took a ferry at Thyborn. It was a lot of fun! It was about a 15 minute ride, and the fjord was pretty rough. After that, we rode on the bus back to the Folkecenter and home to our host families (after one more ride on the electric bike of course).