Several countries in the world have policies for increased use of biomass for energy and biomaterials. It is likely that such policies will lead to increased international demand for wood and increased pressure on the world’s forests. Concerns for forest sustainability have been expressed, especially in the EU and its biomass importing countries. As countries and companies search worldwide for new biomass sourcing areas, there is a need to review and compare the biomass potentials in different regions and the associated forest sustainability challenges. We reviewed the literature to assess, evaluate and compare forest biomass sourcing potentials and associated forest sustainability challenges in Europe, Russia, Africa, North and South America, under a scenario where international demand for energy wood continue to increase. We focused on environmental sustainability criteria (GHG emission reductions, ecosystem carbon, biodiversity, soil and water) and how well they are governed. We also addressed other issues of significant concern in a specific region, such as competition with food production. We propose and compare the most urgent short- and long-term forest sustainability and governance challenges in the different regions for consideration by institutions developing energy biomass sourcing polices and biomass sustainability criteria in the public and private sector.