A review of LCA greenhouse gas emissions results for advanced biofuels: The use of meta-regression analysis

This article presents the results of a literature review performed with a meta-regression analysis (MRA). It focuses on the estimates of advanced biofuel Greenhouse Gas (GHG) emissions determined with a Life Cycle Assessment (LCA) approach. The mean GHG emissions of both second (G2) and third generation (G3) biofuels and the effects of factors influencing these estimates are identified and quantified by means of specific statistical methods. 47 LCA studies are included in the database, providing 593 estimates. Each study estimate of the database is characterized by (i) technical data/characteristics, (ii) author′s methodological choices and (iii) typology of the study under consideration. The database is composed of both the vector of these estimates—expressed in grams of CO2 equivalent per MJ of biofuel (gCO2eq/MJ) and a matrix containing vectors of predictor variables which can be continuous or dummy variables. The former is the dependent variable while the latter corresponds to the explanatory variables of the meta-regression model. Parameters are estimated by means of econometrics methods.