Co-combustion of Pulverised Coal/Biomass for Steam Production: eMergy Approach
Résumé
Emergy, also called Embodied energy, has been firstly defined by Odum. It is the energy required to make a service or product expressed in energy of one form (here solar energy). Emergy per mass or transformity (expressed as solar energy joule per gram [sej/g]) varies from 0.88 109 sej/g for wood to a high of 1.1 1015 sej/g for coal. This concept of eMergy is particularly relevant to compare on the same basis different fuels especially to analyse co-combustion of renewable and non-renewable combustibles. The cost of co-combustion, in term of emergy, makes it relevant if collection of biomass remains below the threshold distance of 400 km from the power plant. That threshold can be raised to 700 km when the calorific value of biomass feed stock is higher.