A thermochemical processing route from biomass residues to light olefins (ethylene and propylene) is assessed by means of process simulation and cost analysis. A two-step process chain is proposed where (1) biomass residues are first converted to synthetic methanol in a gasification plant situated close to feedstock resources and (2) the produced methanol is transported to a steam cracking site where it is further converted in a methanol to olefins (MTO) plant. Possibilities for heat and product integration as well as equipment sharing with a steam cracking plant are discussed. Overall mass yields from dry biomass to light olefins range from 169 to 203 kg/t. Based on cursory capital cost estimates, the maximum methanol purchase price for such integrated MTO plants is estimated to be in the range of 420-450 /t.