Anaerobic digestion of spring and winter wheat: Comparison of net energy yields

ABSTRACT

Anaerobic digestion of wheat was investigated under batch conditions. The article compares the potential net energy yield between a winter wheat (sown in the autumn) and a spring wheat (sown in the spring) grown in the same year and harvested at the same growth stage in the same farm. The spring wheat had a slightly higher biochemical methane potential and required lower energy inputs in cultivation, but produced a lower dry biomass yield per hectare, which resulted in winter wheat providing the best overall net energy yield. The difference was small; both varieties gave a good net energy yield. Spring sowing may also offer the opportunity for growing an additional over-winter catch crop for spring harvest, thus increasing the overall biomass yield per hectare, with both crops being potential digester feedstocks.

KEYWORDS:

• Anaerobic processes
• biodegradation
• energy crop
• environmental preservation
• renewable energy production

Acknowledgments

Thanks are due to Peter King of King Bros for supplying wheat samples and crop information, and Dr. Yue Zhang of the University of Southampton for advice on interpretation of analytical data.

Funding

This research was partly funded by the UKRC RELU project RES 229-25-0022. The authors are grateful to the Secretaría de Estado de Universidades e Investigación from the Spanish Education and Science Ministry and the Fundación Española para la Ciencia y la Tecnología (FECYT) for supporting Dr. Rincón.