Voluntary schemes verify compliance with the EU's biofuels sustainability criteria. They check that biofuel production did not take place on land with high biodiversity, that land with high carbon stock was not converted for biofuel production, and that the production of biofuels leads to a sufficient level of greenhouse gas emissions savings. Several schemes also take into account additional sustainability aspects such as soil, water, air protection and social criteria.
For the purpose of certification, the whole production chain from the farmer growing the feedstock up to the biofuel producer or trader is checked by independent auditors.
Schemes are mostly privately run but recognised as valid by the European Commission. Recognitions can last for a period of five years.