Syngas from What? Comparative Life-Cycle Assessment for Syngas Production from Biomass, CO₂, and Steel Mill Off-Gases

Abstract

Syngas is an essential platform chemical for producing chemicals and fuels, whose market volume is expected to grow strongly. Today, syngas is mainly produced from fossil resources and thus emits large amounts of greenhouse gases (GHGs). The GHG emissions of syngas can be reduced by alternative feedstocks such as biomass, CO 2 , and steel mill off-gases (mill gas). However, since previous studies on alternative feedstocks differ in assumptions and methodological choices, their results are not comparable. Therefore, it remains unknown which feedstock is preferable from an environmental perspective. Herein, we present a consistent environmental assessment of alternative syngas pathways. We show that bio-based and mill gas-based syngas reduce GHG emissions the most, although the results strongly depend on the conventional feedstock use: if the feedstock is limited and already used elsewhere, its GHG mitigation potential decreases. Furthermore, producing syngas from mill gas or bio-waste leads to moderate environmental trade-offs, while other bio-feedstocks and CO 2 can significantly increase other environmental impacts than GHG. Our results demonstrate that a consistent assessment of alternative pathways is required to make informed decisions on syngas decarbonization and highlight the importance of considering the conventional use of limited feedstocks in life-cycle assessments.

Single carbon metabolism – A new paradigm for microbial bioprocesses?

“…Methane and syngas are way more abundantly available, however to a large extent from fossil resources. The renewable production of methanol and formate [ [85] , [86] , [87] ], as well as syngas [ 88 ] is on the rise, but still need to be massively upscaled to serve as feedstocks for a C1 biotechnology that has a relevant impact on the global carbon balance [ 89 ] ( Fig. 2 ).…”

Renewable Syngas Generation via Low-Temperature Electrolysis: Opportunities and Challenges

“…According to The International Energy Agency (2021), to meet current net-zero targets, the rapid deployment of appropriate carbon capture and utilization (CCU) technologies is required to stay on track with carbon emissions by 2050. Consequently, the production of low-carbon syngas on CO 2 basis, together with electrification and hydrogen mobility, is expected to significantly contribute to the decarbonization of both industrial and transportation sectors. − …”

“…Consequently, the production of low-carbon syngas on CO 2 basis, together with electrification and hydrogen mobility, is expected to significantly contribute to the decarbonization of both industrial and transportation sectors. 12 − 16 …”

Life Cycle Assessment of a Wood Biomass Gasification Plant and Implications for Syngas and Biochar Utilization

“…Typically, a blend of locally cultivated energy crops with imported biomass would constitute a viable strategy, also from the perspective of source diversification [15,16]. Among others, gasification is a promising and efficient way to convert biomass/waste into valuable energy carriers, such as synthetic natural gas [17] or syngas [18][19][20][21][22]. The production and chemical mixture of syngas are dependent on the process conditions, requiring a specific supply of oxygen to yield a fuel gas rich in hydrogen and carbon monoxide and the inflowing biomass.…”