Latvia has set a target to increase the gross final consumption of energy from renewable energy sources up to 40% by 2020. To reach this ambitious objective increasing of the amount of energy produced from locally available biomass is a priority. In Latvia, as in European Union, consumption of wood and wood waste has increased during the last decade. At the same time, export of pellets and briquettes produced in Latvia is a growing trend, therefore production amounts depend greatly upon export market demand. In the light of a foreseeable increase of the global market of solid biofuels the same trend would be respected in Latvia. Consequently and in the light of an increase in energy consumption this would result in shortages of the substrate biomass for the production of compressed biomass. To cover the growing biomass demand for both domestic consumption and export, potential biomass sources from agricultural and industrial sectors have to be investigated. The main objective of this paper is to determine the availability of potential herbaceous biomass sources for production of compressed biofuels in Latvia. In order to reach this target the available amounts of herbaceous agricultural and industrial by-products in Latvia have been evaluated and their energy potential has been calculated. In addition, the current use of these materials is described and sustainability aspects of various applications of such materials are discussed. This study intends to provide the necessary background information to select the most suitable and convenient sources (in terms of availability and energy value) for the production of compressed mixed biomass fuels at laboratory conditions and the consecutive determination of quality and physical, mechanical, thermo-chemical and combustion properties of such fuels.