Europe has increasingly utilised biomass as a renewable alternative to fossil fuels for combustion and heat production to meet climate targets. This shift has made the energy sector heavily dependent on primary wood biomass. However, recently implemented regulations have introduced restrictions on using primary wood in the energy industry. While low-quality biomass holds significant potential for combustion, there is limited information regarding the availability and quantities of non-wood biomass resources in Latvia. The authors used the Sankey diagram approach to evaluate the share of non-wood biomass resources that can cover roundwood consumption. None of the studied biomass resources in this article can individually cover the required energy demand. However, combining all the studied resources could potentially cover the required energy demand. Specially grown energy crops exhibit the highest potential, but other analysed biomass types are available locally and could be utilised in locally adapted boiler houses.