Sustainable development and availability of renewables based fuels are the key issues of chemical industry in the future.Focusing only to the CO2 emission reduction may however lead to wasting of renewable resources.Therefore more advanced sustainability methods are needed.The emergy method measures all resources (raw materials,energy,services and investments) by a single unit;solar energy.This allows evaluation and optimization of different manufacturing routes to be made on a single basis,which reflects the sustainability from point of view of the biosphere and its long time scale.In fact,emergy aims to be a memoryof how much work the biosphere has done to provide a product.