Background/Objectives:

To fully grasp the environmental impacts and tradeoffs in different power system scenarios, it's essential to consider both direct and embedded emissions throughout the entire lifecycle, from creation to disposal. This entails examining emissions at each stage, including resource acquisition, construction, manufacturing, transportation, operation, and decommissioning in the power sector. Analyzing the spatial and temporal nuances in environmental impact and resource utilization metrics can uncover potential tradeoffs over time, in different locations, and across sustainability dimensions. Notably, the National Renewable Energy Laboratory's (NREL) power system studies have traditionally concentrated on system costs and direct CO2 emissions. Expanding the range of impact metrics poses challenges and requires significant time and effort, especially in major studies like 'Standard Scenarios.' Explicitly considering Scope 2 emissions on a regional and temporal basis will be crucial for studying future decarbonization scenarios and assessing the benefits of emerging low-carbon technologies.

Approach/Activities:

This study aims to enhance the efficiency of assessing environmental impacts and incorporating new metrics by leveraging the existing NREL code-based platform, Harmonized Impacts of Products, Scenarios, and Technologies across Environmental and Resource use metrics (HIPSTER). Unlike the current fragmented approach relying on disparate assumptions and inputs, HIPSTER is designed to harmonize variables in life cycle assessment (LCA) from cradle to grave. HIPSTER can assess Regional Energy Deployment System (ReEDS) scenarios, providing impacts per kilowatt-hour (kWh) by considering both direct and indirect emissions from resource extraction to electricity distribution. It has the capacity to distinguish among major power generation technologies in ReEDS across 134 spatial US regions, allowing for assessments at various scales, such as state, eGRID, NERC, or national levels. This flexibility facilitates the creation of time-step life cycle inventories for grid mixes at different spatial resolutions.

Results/Lessons Learned:

We have already performed environmental impact analysis of 134 regions from the ReEDS model across 70 different standard scenarios for 2020 through 2050. These updated life cycle inventory databases are available for use by LCA practitioners. Analyzing these standard scenarios across different environmental metrics provides a holistic understanding of the pathways the electricity generation sector in the US can evolve into the future.

Conversion of captured carbon dioxide (CO2) into valuable products for various applications can reduce greenhouse gas (GHG) emissions and support the achievement of net zero carbon emission goals. Photocatalytic conversion of CO2 is a promising carbon conversion pathway that utilizes solar irradiation and can be carried out at low temperatures and pressure and without high energy demand to convert CO2 into fuels or chemicals via photocatalytic reduction of CO2. However, the photocatalytic CO2 reduction process is still at a low technology readiness level, mostly at the lab/pilot scale. Life cycle analysis/assessment (LCA) can help to determine the potential environmental impacts and net life cycle GHG reductions of conversion technologies from a consistent and unbiased viewpoint, which is crucial for the commercialization and acceptance of CO2-derived products in the marketplace. Current literature mostly focuses on the development of photocatalysts and photocatalytic CO2 reduction processes to enhance CO2 conversion efficiency. However, only a few consider the LCA of photocatalytic carbon conversion. This study demonstrates an LCA of the photocatalytic CO2 conversion process to produce methanol using a TiO2 - based photocatalyst to evaluate the potential environmental impacts and capabilities of CO2 utilization. The LCA model considers solar irradiation as a parameter to explore changes in LCA results due to different solar irradiation values and different methods for separation of produced methanol from unreacted CO2 and H2O. It also includes the recycling of CO2 and H2O and photocatalyst degradation in the LCA models. This study uses openLCA 2.0 to develop the LCA model and utilizes the NETL-modified TRACI 2.1 impact assessment method to calculate the potential impacts in different categories. The potential impact of photocatalytic conversion of CO2 to methanol is compared to conventional methanol production via a steam methane reforming process. The study also includes scenario analysis to compare LCA results considering different technology scales, changes in key parameters, and electricity mix. This presentation describes the modeling approach, scenario analysis, key results, and uncertainty associated with this LCA.

A core drawback of conventional life cycle assessment (LCA) is its failure to account for the temporal dynamics of the technological and environmental background in which a technology is assumed to operate. The temporal implications of the background system can be particularly relevant when evaluating systems in an early stage of development as they usually require time-intensive research and development effort. The use of static life cycle inventory databases can also result in the misrepresentation of the environmental impacts of technologies with operational lifetimes spanning decades since temporal changes in the background system, such as the decarbonization of the electrical grid, are not commonly accounted for. In a context where achieving near-term climate targets depends heavily on advancing technologies currently at a low technology readiness level, capturing the systematic changes in background dynamics and supply chains is critical for the accurate assessment of technology potential and effective decision-making.

This study explores the application of prospective LCA (pLCA) to evaluate the environmental impacts of sustainable aviation fuel pathways. Specifically, the research focuses on comparing two pathways: one involving the conversion of corn grain-derived ethanol to a jet fuel blendstock and the other converting algal oil to jet fuel through hydrotreating esters and fatty acids. The pLCA model leverages data on shared socioeconomic pathways (SSPs) and representative concentration pathways (RCPs) to transform life cycle inventories of key sectors, such as power, cement, steel, and transportation fuels, across different futuristic scenarios. Data for life cycle inventory transformation includes outputs from a “middle of the road” SSP, which aligns with the objectives of the Paris Agreement, and a RCP assuming a global mean surface temperature of 1.6°C (RCP 2.6) by 2100. The transformed pLCA database is then coupled to engineering process models of the SAF systems to simulate the well-to-wake life cycle greenhouse gas (GHGs) emissions over their lifetime. Moreover, potential tax credits derived from reducing GHGs over time will be evaluated through techno-economic analysis.

The preliminary pLCA underscores the significance of incorporating supply chain dynamics into LCA. Results reveal that conventional (static) LCA methods may provide a distorted view of environmental impacts compared to dynamic LCA. For instance, results challenge the notion that algal-based jet fuel has a higher global warming potential (58 g CO2E MJ-1) than the ethanol-to-jet pathway (53 g CO2E MJ-1), if static LCA methods are used. Results from the pLCA demonstrate that algal jet fuel eventually achieves a lower life cycle carbon intensity than corn-derived jet fuel, with estimated GHG emissions of 27 g CO2E MJ-1 ¬¬¬and 39 g CO2E MJ-1 by 2050 respectively. The change in emissions observed in the algal pathway is primarily due to reductions in the carbon intensity of the electrical grid. Based on reductions in GHG emissions, both pathways are potentially eligible for tax credits under current policies. In conclusion, preliminary work emphasizes the importance of considering background system dynamics when evaluating energy-intensive technologies such as SAF pathways and underscores the importance of comprehensive and dynamic LCA methodologies in shaping informed decision-making and policy development.

Packaging significantly benefits society by helping to enable modern life through the transportation and storing of goods, playing an essential role in product protection and preservation, and influencing consumer buying decisions. Materials, including plastics, metals, glass, paper, and combinations thereof, play important roles in packaging design for industrial, medical, agricultural, food, and non-food packaging applications. However, the increasing consumption of packaging materials that can be associated with economic growth and prosperity have raised interest in assessing the sustainability of these materials and mitigating their potential environmental impacts. This study presents a comprehensive life cycle assessment comparing the potential environmental impacts of polyethylene-based (PE) packaging and alternative materials such as metals (steel and aluminum), glass, paper, and combinations. Nineteen packaged products were assessed across five prevalent PE packaging applications (collation shrink film, stretch film, heavy-duty sacks, non-food bottles, and flexible food pouches) based on five environmental footprint indicators, Global Warming Potential with and without biogenic carbon, Fossil Resource Use, Water Scarcity, and Mineral Resource Use. Data was gathered from physical samples and supplier specifications. Life cycle inventory models were developed in EcoImpact-COMPASS software, which integrates ecoinvent as its primary background data source. The results show that for the five potential impact categories and 19 alternative solutions considered, PE-based packaging had a lower potential environmental impact in 77 of 95 (81%) packaged product comparisons. The study highlights the material efficiency of PE-based packaging as a significant factor in its reduced environmental impact and suggests that the environmental impacts are a function of packaging weight, design, and the inclusion of non-paper components in paper-based alternatives. This panel reviewed ISO 14040/44 complaint LCA study provides valuable insights for stakeholders and decision-makers in the packaging industry and beyond, contributing to a greater understanding of the potential environmental impacts of various packaging materials.