In early 2014, an update to Germany's renewable energy legislation brought abrupt changes to the nation's biogas market. agriKomp took advantage of the situation to give its biogas plants a decisive upgrade: a completely new control solution from B&R. The company is more than pleased with the results: scalable plants that are faster to develop and commission.

In 2014, agriKomp responded to changes in Germany's subsidy conditions by introducing a small-scale biogas plant, the agriSelect. The company selected an APROL control solution in combination with B&R hardware. That made adapting to the new and changed conditions exceptionally easy. The result: a biogas plant tailored entirely to the farmer's wishes and requirements.

Prior to 2014, Germany's farmers relied primarily on larger biogas plants with an output of at least 250 kWel to generate electricity from renewable feedstock and biowaste. Following the law change, however, demand shifted to 75 kWel systems. The reason for this sudden change was the amendment of the German Renewable Energy Sources Act, which brought a drastic reduction in the subsidy for new plants with an output over 75 kWel.

Only months before the details of the upcoming legal changes were made public, agriKomp had introduced a new B&R control solution for its popular 250 kWel plants. With the proprietary control software the company had previously used, it would have taken great effort to adapt the software to the heightened requirements.

"Both the more comprehensive safety requirements and the users' desire for more individually tailored system configurations were pushing our old control solution to its limits," says agriKomp's chief electrical engineer, Andreas Ströhlein. "The absence of a path for migrating to more efficient control hardware was growing increasingly problematic, not to mention the limited number of supported communication interfaces for integrating third-party systems such as solar panels or surveillance cameras."

More than 100 requirements specified

When the decision was made to introduce a new control system, Ströhlein and his team prepared a 75-page catalog specifying more than 100 requirements and obtained corresponding proposals from all the well-known automation suppliers in the German-speaking world. By the end of the evaluation, B&R had come out on top.

"It was B&R's integrated and comprehensive automation package in combination with the APROL process control system that convinced us. It enables us to meet all our requirements in an especially efficient manner," explains Ströhlein. "For us, it was important that the package contains an integrated safety solution and exceptional interface support. For every physical interface, B&R has a suitable counterpart. Another core criteria was for the control solution to be easily scalable."

One solution, multiple performance classes

This capability served agriKomp well when it came time to respond to the amended Renewable Energy Sources Act with a newly developed 75 kWel plant for biogas production from slurry and manure. To keep engineering and service costs down and simplify spare parts inventory, agriKomp decided to use the same control solution as in its large 250 kWel plants. "There are considerable differences between the two performance classes, both functionally and financially," says Ströhlein.

But the B&R solution helped agriKomp clear this hurdle as well. The fine-grained modularity of the X20 system allows the company to meet the tighter hardware budget by tailoring I/O channels, interfaces and CPU performance to each configuration of the 75 kWel plant. For larger systems, on the other hand, the company installs a uniform standard control station regardless of the system configuration in order to minimize inventory handling overhead.

The cockpit programmed with APROL gives the operator a quick overview of the status and efficiency of the biogas plant. (Source: agriKomp)

Efficient and convenient programming

Also exceptionally modular, the APROL software was easy to adapt to the new requirements – allowing the same software project to be used for the new 75 kWel plants as for their larger counterparts. Ströhlein and his team implemented their modular software solution with the help of the process control system's hyper macro technology. The hyper macros allow users to design their own libraries. Even the extensive standard libraries that B&R provides cannot cover every requirement of every user in every industry.

To automatically add a new tank, including the agitators and all the other components, all you need to do is change one variable in a hyper macro," explains Emmanuel Hahn, chief software engineer at agriKomp. "Overall, programming with APROL is very efficient and elegant. We can easily program the machine control application in the APROL development environment, for example, without having to use an extra tool." To configure the hardware and program safety functions, the agriKomp team uses the Automotion Studio development environment and its integrated SafeDESIGNER tool.

APROL gives plant manufacturers remote access to their plants in the field, so they can offer operators additional data-based services that help them optimize plant performance. (Source: agriKomp)

Transparency for plant operators and service teams

The software installed on agriKomp plants, including updates, can be managed, maintained and installed on any connected plant worldwide from a central location via a remote maintenance connection. User management can also be implemented centrally. At the same time, plant operators can permit agriKomp to collect data from the plant and use it to provide additional services.

"APROL offers a large number of comprehensive reports. In addition to that, we use the collected data to generate reports for documentation or plant optimization, which operators can view either on site or from their office PC," Hahn explains. "This includes, for example, a feeding plan that lists what materials the operator has introduced into the biogas plant."

"The comprehensive recording functions make it possible to trace all processes and activities," says Ströhlein. "This is particularly helpful when the operator contacts us to help solve a problem or answer a question. The ability to evaluate objective data about the plant's status over time allows us to provide more targeted, efficient support." For the user, this means less hassle and higher plant availability.

Faster commissioning

B&R's integrated safety technology also contributes to higher system availability. Before the new control solution was introduced, agriKomp relied on hardwired safety relays. "At the time, we had a lot of overhead going into safety technology. Just implementing the secure locks required for the plant's pumps can easily require 60 relays," says Ströhlein. "It adds up quickly, and all those relays have to be installed and wired." In addition to the time that takes, it also opens up lots of room for errors. As a result, installation and testing of the safety technology used to constitute a substantial portion of the overall commissioning process.

That's where integrated safety technology is a real game-changer, as Ströhlein reports: "We have significantly less wiring work, the error rate has been reduced considerably and very little testing is required during on-site commissioning."

Retrofit increases process reliability

The B&R solution has also proven useful for modernizing older systems. This is illustrated by the example of an existing plant in Germany, where errors had been growing increasingly frequent. The operator had been recording up to 200 errors per month. "Since switching to the new control solution, the plant now has fewer than 12 errors per month with a noticeable improvement in process reliability," reveals Ströhlein. "Our experience has shown that the retrofit can be completed quickly, even for large plants." This is made possible in part by the fact that existing third-party I/O modules can generally be reused, and only the signals of the safety-relevant components have to be transferred to the safety modules.

The flexibility and efficiency of B&R's technology have made an important contribution to agriKomp's market success, claims Hahn: "Product development has really picked up speed since we started using the B&R system. We've been bringing more new solutions to market at shorter intervals." In return, the market has rewarded this effort. By the end of 2019, the biogas plant manufacturer had delivered or retrofitted around 200 plants with B&R technology – in spite of further legislative changes in important markets such as France. With the B&R solution, agriKomp can now respond quickly to changing market conditions and offer customized solutions that are efficient and profitable to build.

Andreas Ströhlein

Chief Electrical Engineer, agriKomp GmbH

"It was B&R's integrated and comprehensive automation package in combination with the APROL process control system that convinced us. This enables us to meet all our requirements in an especially efficient manner."

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