Finally, the effectiveness of the certification schemes can be reduced by their rising number. While it might create positive pro-competitive effects such as development in implementation and verification mechanisms, it could all the same generate confusion and inconsistency, hence reducing the confidence of E-64-c and final users (, p. 142).
A more general issue on the EU sustainability criteria for biofuel is its consistency with international trade rules. The unclear classification of biofuels for transport may generate difficulties for the introduction of incentives and tariffs linked to sustainability criteria. Economic, environmental and social restrictions need to comply with WTO conventions and country Most Favoured Nation obligations. Moreover, according to the GATT rules, domestically produced biofuels have to meet the same standards required for foreign producers, because peptides is not possible to distinguish between domestic and imported products . For example, the German draft biofuels law proposed the exclusion of imported biofuels made by soybean oil and palm oil from subsidy programmes and mandates until the compliance with sustainability criteria was demonstrated. But Germany had to drop this proposal because of EU objections concerning WTO/GATT compatibility  and .