A quantitative assessment of crop residue feedstocks for biofuel in North and Northeast China

Crop residue resources may affect soil quality, global carbon balance, and stability of crop production, but also contribute to future energy security. This study was performed to evaluate the spatial and temporal variation in residue quantities of field crops in five provinces of North China (NC) and three provinces of Northeast China (NEC). The availability of biomass resources was derived from statistical data on crop yields for all crops on the provincial and even county level. We found that cereals – wheat, maize, and rice – were the biggest resource of crop residue feedstock. The ranking of these crops as a source of biomass for bioenergy is determined by the acreage in each region and the crop-specific yield. Annually, the average amount of total residue of 83.0 Mt (Mt = Mega tonnes) in NC (16.9 Million ha) comprised 76.6 Mt field residues and 6.4 Mt process residues on an air-dried basis. The average amount of total biomass residue of 105.7 Mt in NEC (19.8 Million ha) comprised 92.8 Mt field residues and 12.9 Mt process residues. Averaged for 2008, 2009, and 2010, the total standard coal equivalent (SCE) in NC amounted to 46.4 Mt, which comprised 42.4 Mt field residues and of 3.9 Mt process residues. In NEC, the SCE value of 57.0 Mt comprised 49.7 Mt field residues and 7.4 Mt process residues. The temporal availability of field residues was mainly concentrated in the period between July and September, followed by the period between October and December. In the period between July and September, the amount of field residue available amounted to 40.9 and 53.1 Mt in NC and NEC, respectively. An accurate assessment of field residues may guide policy makers and industry to optimize the utilization of the crop residue resource