Estimating Transformity (UEV) with Economic Input-Output Models

Accurate and sufficient information on unit emergy values (UEVs) is very fundamental for emergy calculations and is also essential for the broad acceptance, application and further development of the emergy method. As an extension of matrix methods, an input-output model based framework was built in this paper, for estimating transformity (UEV) of products and services of a certain economy. Then UEVs of the Chinese economy in 2007 were calculated and analyzed with a 135-sector inventory, which can be transformed into transformities with the aid of corresponding prices. The results show that estimating transformity (UEV) with economic input-output models can achieve results relatively consistent with values reported in the literature. The input-output model based approach proposed in this study could produce reliable results and provide a sound and dynamic source of UEVs for emergy accounting that also contains necessary information on renewable and nonrenewable emergies and can be easily updated.