|Greenhouse gas emissions of the individual ethanol production process steps. Red line is the German BioNachV basic value. Click to enlarge.
Bioethanol produced from grain (rye or wheat) by German biofuels producer VERBIO Vereinigte BioEnergie AG can emit up to 80% less CO2 than gasoline on a lifecycle basis, depending upon the feedstock and facility design, according to a study carried out by the Heidelberg IFEU Institute (Institute for Energy and Environmental Research) and commissioned by the VERBIO.
VERBIO is a leading producer and supplier of biodiesel and bioethanol in Europe, with nominal annual capacity of around 450,000 tonnes of biodiesel (~136 million gallons US) and 300,000 tonnes of ethanol (~100 million gallons US). The study examined ethanol production at VERBIO’s two facilities in Schwedt/Oder and Zörbig, with the aim of determining how much CO2 can be avoided under the prevailing production conditions. The results show that all the techniques and plants under investigation return significantly better CO2 savings than the 30% which are specified in the German Biomass Sustainability Ordinance (BioNachV).
For example, using the basic scenario based on the VERBIO AG business model, greenhouse gas reduction potentials between 40% (Schwedt DDGS rye) and 80% (Zörbig wheat) were determined. Even when disadvantageous values are used, as was the case in several sensitivity analyses, or when the framework conditions are changed, the basic value of 30% valid till 2010 is always achieved. With the exception of two cases, the basic value almost always fell below the 40% stipulated as of 2010.—“Greenhouse Gas Balances for VERBIO Ethanol”
As the Zörbig plant also produces biogas by using the waste products from the primary production process, and the straw is used as a source of energy as well, this is where the highest CO2 savings are achieved: more than 80% compared with fossil fuels. In its study, the IFEU included all factors influencing the overall energy balance, including the recovery of fertilizer from the plants used.
Other findings from the report include:
Compared to rye, ethanol production from wheat leads to lower greenhouse gas emissions because a relatively low specific quantity of nitrogen fertilizers is estimated for wheat cultivation (as per the BioNachV ordinance).
Plant concepts with biogas production (Zörbig and Schwedt biogas) yield significantly better results than those with DDGS production (Schwedt DDGS), because the provision of energy for drying the stillage sludge to DDGS causes high emissions.
The comparison of the two plants with biogas production (energy production in Zörbig compared to preparation and feeding into the gas network in Schwedt) shows clear advantages for the Zörbig concept. Among other reasons, this is due to the fact that the process steam required is produced from biomass (straw) whereas all the process steam in Schwedt is provided via fossil fuels.
Grain cultivation (mainly due to the use of fertilizer) and processing (mainly due to energy provision) have a major influence on greenhouse gas emissions in the production chain of VERBIO ethanol.
Compared to the default values specified in the BioNachV ordinance, the values for VERBIO ethanol are very good, since the greenhouse gases emitted both during cultivation (due to straw sales and returning of digestate) and those emitted during generation of the process steam (with default values based on the use of lignite) are significantly smaller.
Using the latitude resulting from the BioNachV ordinance’s specifications leads to results that are very different to those of the basic scenario, but VERBIO ethanol still achieves the basic value of 30% in all these cases.
In December 2007, the German government passed a draft for the Biomass Sustainability Ordinance (BioNachV) within the scope of a climate and energy program [BioNachV 2007]. The ordinance is intended to ensure that biofuels meet certain sustainability criteria, and that they reduce greenhouse gas emissions by at least 30% on a lifecycle basis.