Considerable argument about trading in green electricity certificates (GECs) preceded the publication of the proposed EU Renewables Directive in early 2008. The proposed Directive set a binding target of 20 per cent of EU energy to be derived from renewable energy by 2020 broken down into targets for each member state. Those arguing for trade in green certificates, called certificates of guaranteed origin (GO), included major electricity companies. However, the idea of mandatory trading was opposed by the main renewable energy industry lobby groups. The proposed Directive limited trading in accordance with the demands of the renewables industry pressure groups. Analysis suggests that if member states were forced to trade to achieve a mandatory target of 20 per cent target, then GEC prices would rise to high levels because the demand for tradeable certificates would be much higher than their supply. Trading is unlikely to improve the prospects for meeting the targets. A system of nationally based 'feed-in tariff systems would not face the problems of uncertain certificate prices faced by compulsory trading in GECs. (C) 2008 Elsevier Ltd. All rights reserved.