Back on Stream after 58 Days

As a source of cooling water and hydroelectric power, the Alz Canal is the lifeline of WACKER’s Burghausen site. The canal has now undergone its first full renovation in 100 years, and the canal bed now incorporates a WACKER innovation: self-filling concrete.

“It was like open-heart surgery,” recalls Michael Stauber, one of the engineers responsible for maintaining infrastructure at the WACKER site in Burghausen. He was describing the late-2016 renovation of the roughly 17-kilometer Alz Canal – the lifeline of the largest WACKER plant in the world. “We use the water for cooling our chemical plants, for example, which allows us to cover 70% of our cooling needs,” the engineer explains. The canal also delivers 10% of the electrical energy consumed at the Burghausen plant: before plunging into the Salzach river some 60 meters below, the canal water passes through the Alzwerke hydroelectric power plant. The difference in height between the Alz and the Salzach – and thus the ability to generate hydroelectric power – was actually the reason why WACKER decided to build its chemical production facility in out-of-the-way Burghausen in 1916. The average annual output of the Alzwerke remains impressive to this day: this on-site hydroelectric power plant generates 266 million kilowatt hours of electricity each year – enough to power about 90,000 households, or a medium-sized city. If needed, the Alz Canal also provides the plant fire department with water for firefighting. The site’s hydrants are supplied with water from the canal as well.

In 2016, the Alz Canal was completely drained for the first time since it came into operation in 1922, and was closed down for 58 days.

“After nearly 100 years in operation, however, the canal bed, the tunnels and the buildings were all showing extensive signs of age,” Stauber explains. Algae had colonized the concrete walls over the decades, reducing the flow rate and hence the performance of the canal, but that was not the only issue: the building fabric had also suffered a great deal from the elements. “The structural components are nearly 100 years old, but repairs in recent decades have largely just been local,” notes the WACKER engineer. “The asphalt lining applied in 1984 only covered four kilometers of the channel. Large areas of spalling, defective coatings and rotten bits of old formwork made comprehensive renovation an absolute necessity.”

The 2016 Alz Canal renovation was a mammoth project, both for the maintenance team and for the WACKER Group as a whole – one that presented many challenges. During the construction phase, the canal would have to be drained and completely shut down, but industrial operations needed to continue unaffected. And, at just 10 weeks, the construction time frame was extremely tight, especially given that the canal was filled throughout the entire nearly four-year planning phase.