We estimate sectoral energy intensities and CO2 emissions for the Catalonian economy. In order to evaluate energy intensities, we use the SAM (Social Accounting Matrix) multiplier analysis applied to a SAM of the economy. CO2 emissions are estimated by means of the Leontief input-output submodel of the SAM, together with a table of coefficients of emissions per unit of monetary expenditures. This new methodology allows us to dispense with energy input-output tables for the base period. Our results are of the same order of magnitude as others obtained by physical measurement methods. We also simulate how changes in demand and energy energy efficiency parameters may affect CO2 emissions for the economy.