On May 27th the group spent its final day together in Frankfurt, Germany. Being sure to not spend too much time away from Meininger Hotels, we enjoyed the night before at the Frankfurt Meininger and had a great breakfast early on the 27th.
Following breakfast, we hopped in the cars and headed to the farm of Wolfgang and Stefan Bauer near Butterstadt, a small town northeast of Frankfurt. The group had dinner with Wolfgang the night before and now had an opportunity to follow up on some of our discussion with a tour. It was a gorgeous day for learning all about biogas. As you can see we were beyond excited.
Stefan led the group in a tour and began with the storage of corn silage on site. We then were able to see the mixing and pumping of corn silage and manure to be used in the digesters.
The resulting mixture of the corn silage, or compressed high-moisture corn stored in a silo, manure, and chemical additives, can be seen below. With this mixture we can begin gasification in the large digesters.
Following the production of gas the process is very simple. We walked through the controls room to see the pumping mechanisms and regulation equipment that allows the gas engine to run at optimal conditions. Finally we saw the switch panel and control box before entering the gas engine room. The plant operated two gas engines at roughly 300 kilowatts and 400 kilowatts, respectively.
At the farm the Bauer’s take advantage of combined heat and power. This ensures a very efficient generation cycle by capturing lost heat to be reused. An illustration of the process is below.
Wolfgang and Stefan were able from there to answer any and all questions the group had before saying their goodbyes. Mario made sure of course to not let Stefan go without a spartan hat and a few pens endorsing the trip.
Before we ultimately left, however, Wolfgang offered to show us the wind farm nearby. The farm consisted of 9 turbines with a 2 to 2.5 megawatt power output. Each tower supported a hub 150 meters high and 3 blades, each 60 meters in length. Wolfgang believed the turbines were manufactured by Nordic Windpower. You will notice that the turbines are direct drive units, meaning they use a larger generator as opposed to using a longer, more rectangular hub that uses a gearbox to increase revolution speed and drives a smaller generator. While the direct drive turbines typically have a higher capital cost and are heavier, they minimize conversion losses and reduce maintenance costs by removing the need for a gear box and only operating the generator at low revolution speed.
After our tour of the wind farm and final goodbyes with Wolfgang, the group returned to the hotel to wrap up the trip. We had a discussion to overview plans for the remaining 24 hours and a reflection on the trip as a whole. To round out the day, everyone caught a train to the middle of the city and spent a few hours downtown. We enjoyed some shopping, maybe for a few last minute gifts, and met up for dinner to have some schnitzel one last time. While shopping I found a quote that I believe all of us could apply to our trip.
Thank you very much to everyone who has followed us along the way and enjoyed the blog. For being such loyal readers, enjoy these pictures. From Germany, danke schön and tschüss.