Life cycle assessment of measures towards a low-carbon flat glass production

The glass industry needs to decrease greenhouse gas (GHG) emissions to fulfill the GHG reduction target for 2030 set by the European Union. Therefore, several measures are discussed in the literature: increasing the energy efficiency, changing the heat supply to avoid combustion-related CO 2 emissions, and avoiding all direct CO 2 emissions, e.g., by carbon capture and storage (CCS). However, the literature misses a holistic environmental assessment of the proposed measures. An environmental assessment of these measures is necessary, as new technologies can also lead to a burden shift towards other parts of the value chain or other environmental impact categories. In this article, we present a comprehensive life cycle assessment for glass production including the following GHG reduction measures: usage of cullet, oxyfuel combustion, waste heat recovery, hybrid melting, hydrogen combustion, and CCS. The data for energy demands of the melting process is derived from an energy balance model. The material and energy demand for other glass production steps, water electrolysis, and CCS are based on an extensive literature review. When combining all GHG reduction measures, the climate change impact of glass production can be reduced by up to 75% compared to the benchmark technology with natural gas combustion, if low-carbon electricity is used. Within the transition towards a low-carbon energy supply, the measures should be implemented in the following order to minimize GHG emissions: CCS, hybrid melting, and hydrogen combustion. The GHG emissions can already be reduced nowadays by implementing CCS while hybrid melting and hydrogen combustion require a greener electricity mix to reduce GHG emissions. However, assessing other environmental impact categories shows a burden shift towards increased impacts, especially for eutrophication of freshwater, human toxicity and resource depletion of minerals and metals. • EU's GHG emission targets require fundamental transformation of industrial processes • Life cycle assessment of GHG reduction measures for the glass melting process • Analysis of boundary conditions to reduce overall GHG emissions of glass production • Implementation of GHG reduction measures can significantly reduce GHG emissions • Largest GHG emission reduction by CCS, hybrid melting, and hydrogen combustion • Low-carbon electricity needed to achieve GHG emission reduction of glass production • GHG emission reduction leads to a burden shift towards other environmental categories