System expansion for handling co-products in LCA of sugar cane bio-energy systems: GHG consequences of using molasses for ethanol production

► A challenging issue in LCA is how to account for co-products' environmental burdens. ► The two most commonly used procedures are system expansion and allocation. ► System expansion appears to be more appropriate than allocation. ► Indirect land use change is a consequence of diverting molasses from feed to fuel. ► The inclusion of land use change worsens the GHG balance of molasses ethanol.