Assessing the greenhouse gas emissions of waste-derived ethanol in accordance with the EU RED methodology for biofuels

Directive on the promotion of the use of energy from renewable sources in the European Union (EU), also called as RED, was published 5 June 2009 in the Official Journal of the EU (2009/28/EC). It establishes an overall binding target of a 20% share of renewable energy sources in the final energy consumption in the EU by 2020. In addition, a 10% binding minimum target for renewable energy sources in transport is set for each Member State. The RED also introduces environmental sustainability criteria for biofuels and other bioliquids. It states that the greenhouse gas (GHG) emission saving from the use of biofuels and other bioliquids taken into account for the national targets shall be at least 35% for current biofuels, at least 50% after 1 January 2017, and at least 60% after 1 January 2018 for biofuels produced in installations in which production started on or after 1 January 2017. The RED introduces a methodology to calculate the GHG emission savings of biofuels and other bioliquids compared to fossil fuels. In this report the methodology was tested with a case study based on commercial and industrial waste-derived bioethanol production integrated with a CHP plant in Finland. The aim of the report was to study whether the waste ethanol concept gains the 60% GHG emission savings according to the RED methodology or not. Four different interpretations of the RED methodology were considered possible for the studied concept. All these options were calculated with three different process values depending on the need of sterilisation of the waste material and the amount of urea used in the process. Within these four options differences in the system boundary setting and thus allocation of emissions took place resulting in differences in emission saving results. The key question was, whether the CHP plant and the biofuel process were supposed to be treated as one combined process or as two separated ones. The GHG emission savings over 60% were gained when the biofuel process and the CHP plant were assumed to be separate processes and the amount of heat and urea needed in the process were minor. The GHG emission saving of the waste ethanol was highly dependent on the emission factor given for the waste material combusted at the CHP plant. The emission factor was the higher the higher were the plastic and moisture contents of the waste. To gain results with over 60% emission savings, attention should be paid to minimization of the plastic content of waste material combusted. Over 60% emission savings could also be gained if carbon capture and replacement or storage were applied for the biogenic carbon dioxide released from the ethanol processing (fermentation).