Green Manufacturer - November/December 2011

Biomass gets famous window-maker out of a logjam

Wood-fired steam, warm water recovery replace coal-fired predecessor

By Kate Bachman, Editor

As you cross the bridge over the St. Croix River on I-94 from Hudson, Wis., to Minnesota and head north on Route 95 along the river at night, you will see an imposing smokestack with red lights looming eerily in the distance.

The smokestack belongs to an Xcel Energy coal-fired electricity plant in Bayport, Minn. Until a few years ago, the Xcel plant was the source of steam for the heating and cooling needs of the 65-acre headquarters and main manufacturing plant of Andersen Corp. In fact, piping runs directly from the energy facility to the adjacent window manufacturer’s plant.

Then, in February 2005, Xcel notified Andersen that it could no longer supply the steam and that the manufacturer would need to find a new power source by April 2007.

That put the company in a bit of a jam.

Logjam

The relatively abrupt halt of the company’s steam source did not promote panic among the company’s leadership. After all, Andersen is a 108-year-old company. It has been in jams before. In fact, America’s largest window manufacturer was borne of a logjam. Literally.

In 1903 a mileslong logjam occurred on the St. Croix River that deadlocked all movement of the thousands of logs felled from the forests nearby that were on their way to lumber mills to become the building materials of future homes and businesses. An enterprising young man named Hans Andersen saw this as an opportunity and he seized it.

A mathematician, Andersen calculated how many and which logs needed to be removed to unwedge the jam. He offered to purchase the troublesome logs and remove them a

www.greenmanufacturer.net

few miles upstream from their original sawmill destinations. With the newly acquired wood, he opened his own sawmill, which was the precursor to today’s window and door manufacturing plant—which still houses its own lumber milling operation.

Just as Hans Andersen viewed the logjam as an opportunity, his successors viewed the steam source loss as an opportunity to find a more energy-efficient alternative and to eliminate reliance on coal-based steam.

As a result, the company built a new wood-fired boiler steam-generating plant and heat recovery system that provides all of the company’s steam and thermal demand for the 2.5-million-square-foot facility and powers some of its manufacturing equipment (see Figure 1).

With both the steam plant and the heat recovery systems, the manufacturer is using already-available resources.

The feedstock for the biomass steam plant is Andersen’s own sawdust and wood waste byproducts, reclaimed from its on-site milling operations.

The warm water recovery system accesses warm discharge water from the Xcel power plant.

The new steam plant became fully operational in April 2007 and has been hugely successful, garnering the company a number of awards along the way. But getting to that point was no log ride.

Evaluating Options

“When we received notice, we stepped back and said, ‘All right, this is inevitable; what are we going to do?’ said Chuck LeRoux, director, corporate safety, security, and environmental management for Andersen.