Limits to co-combustion of coal and eucalyptus due to water availability in the state of Rio Grande do Sul, Brazil

•Brazil holds reserves of high ash coal that can only be used in mine-mouth plants.•Water scarcity requires the use of wet or dry cooling systems in several regions.•The co-firing of 30 wt% eucalyptus is possible regarding the biomass availability.•Biomass cultivation would aggravate the water scarcity in several regions.

Brazil has favorable edaphoclimatic conditions for the cultivation of biomass for energy. On the other hand, the country plans to expand its thermal power park using fossil fuels, including Brazil’s high ash coal. This study estimates the potential of co-firing biomass from energy forests in power plants fired with Brazilian coal in the state of Rio Grande do Sul, Brazil, focusing on the limits given by biomass and water availability. Results show that the state holds coal reserves that could support a potential of approximately 8 GW. Referring to limits due to water availability, different outcomes were found for the various coal fields in Rio Grande do Sul. The Candiota coal field, which represents the most important coal field, holding a capacity of 4 GW, shows severe restrictions for water availability that would be aggravated by intense eucalyptus cultivation.