Managing our inventory of biomass feedstock comes with its own unique set of challenges. We typically deal with baled biomaterials such as switchgrass, miscanthus, and corn stover as well as a number of chopped and milled energy crops. All of these feedstocks are subject to physical material losses which inevitably leads to economic losses. Therefore, paying close attention to the key contributors of material loss as well as other inefficiencies in the supply chain will make sure that your inventory does not bleed your operation dry. These four fundamentals are the first steps to best practices in biomass inventory management.
1) Moisture Management
When dealing with a biological material such as dedicated energy crops, moisture is enemy number one. If we are baling perennial grasses like switchgrass, we typically shoot for sub 18% moisture levels. When levels get into the high 20% and 30% range, we start to see rapid decomposition and dry matter loss. If this wet material is stored too long, you can easily lose a quarter of your material to decomposition, not to mention the inevitable complications that occur during processing. The best way to manage moisture is through careful planning, which leads to our next critical step.
2) Time
Time is certainly of the essence when managing biomass inventory. Crops need to be harvested at the optimal date to maximize the dry down of the plant. For example, switchgrass begins to dry down after the first killing frost which occurs around the beginning to middle of November in Tennessee. Once that ideal date is determined and crops have been harvested, it is then a race against the clock to get bales out of the field and into storage to avoid exposure to rain.
3) Packaging
In the biomass industry, feedstock typically comes in three general “package” types: round bales, square bales, and field chop. Each one has their pros and cons and those characteristics have to be carefully assessed to see which package (or combination of packages) is best suited for a project. Whether you are trying to maximize densities for transportation with square bales or if the weatherability of round bales is critical, feedstock packaging needs to be high on the priority list.
4) Handling
Lastly, careful planning and coordination is needed to make sure that bales are handled as little as possible. Not only is the operation of bale movement expensive, each time a bale is handled, the bale structure is compromised and material losses occur.
By Lance Stewart, Supply Chain Manager
