This photo shows woodchips from a saw mill in western Wisconsin that Gundersen will use as a fuel in its new biomass boiler. That project will supply 38 percent of the health system’s energy needs with a renewable source of energy. When you look for renewable energy sources it makes sense to search for the assets that are abundant in your region. The Upper Midwest region of the U.S. does not have oceans from which to capture tidal energy nor does it have an abundance of sunlight nor does it have geothermal steam near the surface of the earth’s crust. However, Wisconsin and neighboring states are blessed with numerous sources of biomass such as trees, grasses, animal waste, and agricultural crops.
New technologies have developed that enable cleaner combustion of biomass fuels as an alternative to fossil fuels. These fuel sources can become a significant source of renewable heat and electricity production in the United States which could allow our country to become more energy independent and reduce the negative effects of mining and burning fossil fuels.
Often, biomass fuels are commonly thought of as waste products or residues from other primary operations and can commonly be purchased at relatively low cost compared to other fuels. For instance, this particular sawmill processes hardwood logs from western Wisconsin such as red oak, white oak, walnut, hickory, etc. The milling machinery is very efficient at producing boards of lumber from the rough logs and various byproducts such as chips, fines, sawdust, and ground bark can be recovered and utilized in a clean and productive manner. In the past, byproducts such as these may have been sold into a lower value application such as animal bedding or landscaping material. In some cases, producers may have had to pay to have the byproduct removed. Utilizing these sources of fuel can improve the economics for both the producer of the biomass fuel and for the purchaser.
Some fuels classified as biomass may present challenges to boiler equipment and/or require expensive emissions control systems. It is important to consider the sources to make sure they are free of chemicals and treatments such as glues, paints, heavy metals, varnishes, etc. to avoid challenges and expense in minimizing emissions and optimizing boiler performance. Some natural sources of biomass may also contain high levels of sulfur or alkalinity, which may present other challenges, so a thorough review of the source is necessary before launching a project.
Standards and programs have also been developed in recent years to promote ethical harvesting techniques used for biomass fuels. One example is Wisconsin’s Woody Biomass Harvesting Guidelines.
A couple of great resources for understanding the best fit for your application and gaining help for a project are the U.S. Forest Service’s Wood Energy Resource Center.