Indeed the location did help draw attention from all over the world including the United States. Enbasys’ multifeedstock Enbaferm process was coupled with a hydrolysis system developed together with ATRES engineering biogas, a German company. The demonstration was not an attempt to prove the technologies, as they have already been deemed successful, but instead to show breweries that their waste streams can be used to produce energy for their own processes. “We know that with our technology, we can produce biogas, but to convince them, to see with their own eyes that, yes, I can produce biogas from my feedstock, is why we installed the demonstration plant,” Grasmug says.
“The idea from this demonstration plant was to show that our concept for using the spent grains from breweries for anaerobic digestion is a feasible project or a feasible idea,” says ATRES Owner Gunther Pesta, who has been working on the concept for more than 10 years.
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The Technology
The patented Enbaferm system consists of two phases: hydrolysis and methane, according to Grasmug. The process is being used at several locations with multiple feedstocks including organic portions of municipal solid waste. The only difference is the pretreatment for the different feedstocks. Enbaferm has a higher loading rate than conventional AD systems, making only two fermentors necessary, regardless of the volume of feedstock. “That means we can load three times more organics into the system with the same efficiency,” Grasmug explains.
Enbasys engineers were able to design the system to eliminate the problem of foaming in the fermentors, along with sediment settlement. Sediment accumulation means money and time spent on discharging, cleaning, refilling and restarting the fermentors, Grasmug says. Enbaferm also saves its owners and operators money because it requires no chemical additives. “A lot of systems need to blend the feedstock with other substrates to stabilize the process or for pH regulation,” he says, adding that the cost of transporting those chemicals to the plant can be burdensome.
On the other hand, the hydrolyser is a simple and ordinary process, Pesta says. “It’s just less or more a simple hydrolyser similar to other biogas processes,” he says. The system is smaller than others, however, has an optimized retention time and special procedural methods.
When integrated at the 1,000-year-old Weihenstephan brewery, the two processes were just as efficient as their developers had hoped. “It was very successful,” Grasmug says of the demonstration. “We had a lot of voices, even from the United States.” The demonstration was installed and operating for nine months, ending in late March/early April of this year and producing small amounts of biogas. “We didn’t heat the whole city with the energy,” Grasmug jokes, adding that the demonstration biogas, as it was in such small quantities, was not used for energy.
“If you install this system at a commercial scale at a brewery, you can use this energy, this biogas, for your own process,” he says. Between 4 and 5 liters of heating oil is required to produce 100 liters of beer. “If you use that residue coming from your process, you can substitute about 50 percent of this fossil energy,” he says. The system is applicable at any brewery in the world, both companies say, but as with any new process there are barriers to its widespread implementation.
Starting the First One
“The main challenge is to convince the brewery to install biogas,” Grasmug says. “In their minds, anaerobic digestion is always linked to agriculture.” The beer production industry is old and in many cases conservative, he says, so it is difficult to persuade companies to make such a big change.
“The thing is, one brewery has to start, just like in any business,” Grasmug says. That first brewery installation might be just around the corner at Heineken’s Gösser Brewery in Austria. If all goes well, the system could be operational next year, although Grasmug says 1,000 things could hinder development. “They should become the showcase plant to install such a process,” he says.
But even after convincing breweries of the system’s effectiveness, there’s another obstacle. Spent grains can be sold to the agriculture industry as animal feed for anywhere from €7 to €15 ($9 to $18) per metric ton, creating Enbaferm’s only competitor. Installing a biogas process does not always represent monetary gains for breweries as it might for other types of clients, but does help to build their reputations as green companies, Grasmug says. “It’s more for marketing,” he says. “A sign that they are doing something for environmental prevention; that they don’t use fossil energy.”
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