Lignite-fired power plants in Northern Greece produce about 50% of the electricity and account for nearly 60% of the allocated CO2 emissions. The implementation of biomass co-firingis considered a cost effective and efficient method for minimizing GHG emissions. However, despite a favorable legislative framework,co-firing in Greece has not progressed since low lignite costs and distance of power plants from harbor facilities limit access to internationally traded solid biomass. The improvement and optimization of local biomass supply chains is thus a strategic priority in the national context. The purpose of the present work is to present preliminary investigations of a wheat straw supply chain for a Greek lignite-fired power plant to be converted into biomass co-firing operation. On-field demonstration data are analyzed in order to estimate costs for supply chains involving either pelletized straw or straw bales. Information of energy consumption is also presented for different cases and GHG emissionscalculated according to the methodology of (COM 2010)11. Resultsindicate that the cost of straw delivered at the power plant varies depending on whether pelletization is included as a supply chain step. Overall, over short distances, transfer of baled biomass is more economic and results in lowerGHG emissions, however the increase in the cost ofthe supply chain suggest that a pelletization step should be considered for longer distances. The transport cost of the supply chain also depends on whether the vehicles are assumed to return empty at their starting point or loaded. Also, compared to imported or domestic wood pellets, straw pellets have lower prices and could be more attractive to plant operators. Long-term fuel contracts are essential in order to ensure the financial viability of co-firing, especially if a reduction in the feed-in tariff is expected.

Keywords: straw, logistics, cofiring, pelletization, sustainability criteria.