Straw from agriculture could play an important role in the future energy mix, a newly released study from Germany says.
Up until now it has been underutilized as a biomass residue and waste material. These were the conclusions of a study conducted by the TLL (Thueringian regional institute for agriculture), the DBFZ (German biomass research centre) and the Helmholtz Center for Environmental Research (UFZ).
According to them, from a total of 30 million tons of cereal straw produced annually in Germany, between eight million and 13 million tons of it could be used sustainably for energy or fuel production.
This potential could for example provide 1.7 million to 2.8 million average households with electricity and at the same time 2.8 million to 4.5 million households with heating. These results highlight the potential contribution of straw to renewable sources of energy, scientists state in the peer-reviewed scientific journal Applied Energy.
For their respective study, scientists analyzed the development of residual substances resulting from German agriculture. Accounting for 58 per cent, straw can be regarded as the most important resource, and yet so far it has hardly been used for energy production.
From 1950 to 2000 there was a noticeable rise in the cultivation of winter wheat, rye and winter barley in Germany which then remained relatively constant. To remove any bias from weather fluctuations, the average values were taken from 1999, 2003 and 2007.
On average, approx. 30 megatons of cereal straw per year were produced in these years. Due to the fact that not all parts of the straw can be used and the fact that straw also plays an important role as bedding in livestock farming, only about half of these 30 megatons are actually available in the end.
It must be taken into consideration that cereal straw plays an important role in the humus balance of soils. For this reason some of the straw must be left scattered on the agricultural land to prevent nutrients from being permanently extracted from the soil.