Global warming is linked to the reduction of green house gas emissions (GHG). The anaerobic digestion of animal manure and energy crops is a promising way of reducing GHG emissions. The increasing number of biogas plants involves a high consumption of energy crops and the needed of big agricultural area. In Italy, cereals silages are the main feedstock for biogas production and are commonly grown under two different crop systems: single crop (only maize) and double crops (maize later winter cereals). In this paper we present the results of experimental field tests carried out by monitoring the anaerobic biomethane potential (BMP) of different cereals silages commonly grown in the Padanian Plan. A laboratory device has been developed to measure the specific biomethane production of the different cereal silages. The different energy crops have been evaluated, in single and double crop systems, expressing the biomethane production per hectare. The maize hybrids show higher specific biomethane potentials respect to winter cereals. Maize FAO class 700 achieves the highest production per hectare as a single crop. Nevertheless, the highest biomethane productions per hectare are reached with double crop system in particular when maize FAO class 500 follows triticale (+12% respect the best single crop system). (C) 2014 Elsevier Ltd. All rights reserved.