Cost and Life-Cycle Greenhouse Gas Implications of Integrating Biogas Upgrading and Carbon Capture Technologies in Cellulosic Biorefineries

Abstract

Gaseous streams in biorefineries have been undervalued and underutilized. In cellulosic biorefineries, coproduced biogas is assumed to be combusted alongside lignin to generate process heat and electricity. Biogas can instead be upgraded to compressed biomethane and used as a transportation fuel. Capturing CO 2 -rich streams generated in biorefineries can also contribute to greenhouse gas (GHG) mitigation goals. We explore the economic and life-cycle GHG impacts of biogas upgrading and CO 2 capture and storage (CCS) at ionic liquid-based cellulosic ethanol biorefineries using biomass sorghum. Without policy incentives, biorefineries with biogas upgrading systems can achieve a comparable minimum ethanol selling price (MESP) and reduced GHG footprint ($1.38/liter gasoline equivalent (LGE) and 12.9 gCO 2e /MJ) relative to facilities that combust biogas onsite ($1.34/LGE and 24.3 gCO 2e /MJ). Incorporating renewable identification number (RIN) values advantages facilities that upgrade biogas relative to other options (MESP of $0.72/LGE). Incorporating CCS increases the MESP but dramatically decreases the GHG footprint (−21.3 gCO 2e /MJ for partial, −110.7 gCO 2e /MJ for full CCS). The addition of CCS also decreases the cost of carbon mitigation to as low as $52−$78/t CO 2 , depending on the assumed fuel selling price, and is the lowest-cost option if both RIN and California's Low Carbon Fuel Standard credits are incorporated.

Quantitative Sustainable Design (QSD) for the Prioritization of Research, Development, and Deployment of Technologies: A Tutorial and Review

“…For example, to mitigate GHG emissions and curb global warming within 1.5°C above the pre-industrial level, different scenarios, each consisting of varying technologies, have been evaluated for decarbonization. 61 Similar applications of scenario analysis can be found in other topics (e.g., water and wastewater treatment, 46,159,298,299 renewable energy, 217,260,279,300 waste management 232 ), or for a certain technique (e.g., using different scenarios of electricity mix in LCA to assess the environmental sustainability of electric vehicles 301 ). In essence, scenario analysis divides the entire problem space into discrete, representative sub-spaces.…”

“…254,255 The analysis of other systems has followed a similar workflow, transferring data among multiple tools used for different steps of QSD. 107,227,[256][257][258][259][260][261][262] Although programming languages can be used to facilitate data formatting and transfer, this nonetheless presents challenges in QSD execution when system simulation and sustainability characterization need to be repeated thousands of times or more to consider uncertainty (Section 5.2). Alternatively, there are ongoing efforts in tool development to integrate system simulation and sustainability characterization on a single, opensource platform (e.g., for sanitation and resource recovery systems, 230 biorefineries 215 ).…”

“…With uncertainty analysis, one can characterize sustainability indicators, identify the drivers of system sustainability, and set targets for future research and development. 19,62,108,258,260,269,[276][277][278] To summarize the results from Monte Carlo simulation, one can first characterize the sustainability indicators by reviewing their distributions and descriptive statistics of interest, which can help to understand the variability of these indicators and the likelihood of achieving a specific target (e.g., carbon-neutral or negative, To identify the drivers of system sustainability, values of key sustainability indicators (e.g., MSP) can be attributed across different sources (e.g., equipment, material, labor) based on their contributions (Figure 3B). Given that sources with the largest contributions exert the most influence toward indicator values, they may be prioritized in RD&D to advance system sustainability.…”

Conversion of High-Solids Hydrothermally Pretreated Bioenergy Sorghum to Lipids and Ethanol Using Yeast Cultures

“…Lignocellulosic materials are renewable resources used to produce bio-based fuels, platform chemicals, and value-added products through cost-effective biorefineries . Lignocellulosic biorefineries have been considered green processes because of their potential to reduce greenhouse gas emissions significantly . Cellulose and hemicellulose are major carbohydrates present in plant biomass.…”

“…1 Lignocellulosic biorefineries have been considered green processes because of their potential to reduce greenhouse gas emissions significantly. 2 Cellulose and hemicellulose are major carbohydrates present in plant biomass. After biomass deconstruction, fermentable sugars, including glucose, xylose, and arabinose, can be released by enzymatic hydrolysis.…”