Economic evaluation of decentralized pyrolysis for the production of bio-oil as an energy carrier for improved logistics towards a large centralized gasification plant

In the present study, the potential of biomass-to-bio-oil conversion as an intermediate process step to increase product energy density and subsequently decrease transport-related costs is examined. The scheme under investigation consists of two steps; (1) decentralized bio-oil production from biomass gathered from a certain area and (2) transportation of the produced bio-oil to a central destination (bio-refinery, power plant, etc.). The supply chain is compared to one based on direct solid biomass transportation from the circular source to the central plant. The best case scenario of the biomass-to-bio-oil conversion scheme involves an 80 dry t/h fast pyrolysis unit and utilization of the by-product char for electricity production, while the bio-oil is transported by pipeline. For central transportation distances ranging from 100 to 500 km, the centralized unit yard cost of woodchips-derived bio-oil is equal to 0.030-0.035 €/kWhth, while the respective cost for directly transported biomass varies between 0.015 and 0.024 €/kWhth. It can therefore be concluded that the capital and operating costs of fast pyrolysis units are still high, hindering any benefits from cost-effective transportation of the bio oil.