In many European countries, notably in Poland, there is a significant demand for space heating. This could be largely satisfied by biomass, particularly in rural areas, where biomass is locally available, mainly as agricultural residues. In Poland, this is mainly straw. It may become an environmentally friendly fuel for heating rural holdings, if burnt in dedicated biomass boilers.

Biomass is characterized by low-bulk density and low calorific value. Moreover, it is quite a problematic fuel due to the heterogeneity of the material. The usefulness of biomass for energy purposes depends on the humidity, type, and composition. However, the basic problem of using biomass as a fuel is moisture content, which is primarily influenced by the period of harvest and the conditions of its storage. Drying biomass for energy purposes could increase the energy efficiency of the combustion process, but this process is usually quite expensive. Most biomass dryers, as drying agents, use gases from the biomass combustion or process steam. This chapter presents the overview of the batch biomass dryers and a dedicated straw batch dryer.