This study evaluates the overall effects of the present Italian Renewable Energy Supply of Electricity (RES-E) obligation and compares the contribution of each expected RES-E to the economic equilibrium mix resulting from computable economic equilibrium scenarios. The impact of the policies has been evaluated by means of a model of the Italian energy-environment system built with the MARKAL/TIMES methodology, which has been developed by the Energy Technology Systems Analysis Project of the International Energy Agency (IEA/ETSAP). Since the development of RES-E helps energy security, climate mitigation and the distribution of energy production revenues across the country, this study evaluates also an alternative scenario assuming a progressive increase of the RES-E obligation. Both scenarios are then compared with the targets fixed for each RES by the Italian White Paper on renewable energy source. Eventually the effectiveness of the RES-E policies implemented through the green-certificate mechanism are compared with the obligation to improve the efficiency of end-use devices fed by electricity and natural gas. Contrary to green-certificates policies, White certificates obligations increase energy security and GDP at the same time, because in principle they force end users to more rational choices. (c) 2006 Elsevier Ltd. All rights reserved.