Case Story Austria

GÖSSER BREWERY

The role of biogas in greening the brewing industry

December 2018

MISSION AND VISION

In 2015, the Austrian company BDI set up an anaerobic digestion unit at the site of one of the biggest breweries in Austria, the Gösser Brewery close to Leoben (figure 1). This facility has a yearly production of approximately 100 Million litres of beer. The Gösser Brewery, which is part of the Heineken Group, decided to establish a decarbonised beer production facility as their contribution to greening of the brewing industry.

During the brewing process several organic residues are generated, which can be used as feedstock for an anaerobic digestion process. Each hectolitre of beer (100 litres) produces approximately 20 kg of brewers’ spent grains. Furthermore, residual yeast, hot and cold break (a protein rich fraction from the brewing process), filter cake and waste water are residues which occur during the brewing process. Anaerobic treatment of waste water is currently realised on-site for most breweries. Different technologies are employed including for Upflow Anaerobic Sludge Blanket (UASB) and Expanded Granular Sludge Blanket (EGSB).

Brewers’ spent grains contain by far the biggest energy yield of the residues. During anaerobic digestion approximately 75 Nm³ CH4 can be produced from each tonne of brewers’ spent grains. Biogas can be used in a Combined Heat and Power (CHP) facility for electricity and thermal energy or in a boiler for thermal energy only (Table 1). In terms of the energy demand of a brewery, typically biogas from anaerobic digestion of the residues from brewing, storage and bottling processes when used in a CHP facility can cover between 50 and 60% of the electrical energy demand of the brewery and 60% of the thermal energy demand within the brewing process. Utilisation of biogas in a boiler should cover 100% of the heat demand in the form of saturated steam. Thus, the utilisation of biogas leads to the replacement of natural gas.