The European Commission has proposed a new Renewable Energy Directive, which includes flexibility provisions allowing the cost-effective attainment of the ambitious target for renewable energy of 20% of energy consumption, which has been set for the year 2020. One of the flexibility provisions currently being considered is to allow countries to reach their individual targets by buying their renewable electricity deployment deficit from other countries with a surplus (i.e., with a renewable electricity deployment above their targets). This trade is likely to take the form of an exchange in guarantees of origin (GOs). GOs are currently implemented in Member States to fulfil the Renewable Electricity Directive requirement that each country has a system that allows the tracing of the source of each kWh of renewable electricity and informs on this source. Although the recent and tiny literature on the analysis of GO trading has focused on trade between firms, the exchange of GOs between governments has not received a comparable attention. This paper analyses the advantages and drawbacks of a system of government trading of GOs with respect to company trading. (C) 2008 Elsevier Ltd. All rights reserved.