Our LCA Methodology
The methodology section serves as the foundation for a comprehensive understanding of the Life Cycle Assessment (LCA) calculations in Scaler. This structured approach ensures transparency and consistency in evaluating the environmental impact of the product throughout its life cycle.
Base Case LCA
- Scope of Analysis: The Base Case Life Cycle Assessment (LCA) focuses on evaluating the environmental impact of a product, encompassing the entire life cycle from raw materials to the packaged product at the facility. However, certain exclusions are made, and the analysis does not account for:
- Transportation from the facility
- Secondary processing for consumer product creation
- Product use and/or disposal
- Treatment of Biogenic CO2: Biogenic CO2 refers to carbon in the feedstock that was originally removed from the atmosphere by photosynthesis and under natural conditions, eventually cycles back into the atmosphere. Biogenic CO2 is considered neutral and therefore, is not included in the analysis. This includes the CO2 removed from the atmosphere by the feedstock, as well as CO2 released back to the atmosphere via the fermentation process.
- Default Emission Factors: Default emission factors are sourced from publicly available databases such as GREET.net 2022 and EPA emission factors hub.
- Site-Dependent Feedstock and Energy Emission Factors: Emission factors for feedstock and energy are site-dependent, with the default basis set as Iowa, United States. Users have the flexibility to modify these factors in the advanced tab to better align with specific production locations.
- "Other" Category Inclusions: The "Other" category within the analysis encompasses a range of factors, including:
- Other raw materials
- Material transportation
- Cleaning materials
- Water and wastewater processing
- Declared Unit: Results are expressed on a per kilogram (kg) of product basis. The declared unit considers the final moisture content and impurities as specified by Scaler inputs, providing a standardized metric for comparison.
- Lower Carbon Dextrose: The tool incorporates the concept of Lower Carbon Dextrose, assuming a feedstock with a 25% lower carbon footprint compared to the default dextrose carbon emissions factor. An illustrative example is Green Plains dextrose, known for its claim of a 40% lower Carbon Intensity (CI) than industry competitors (Green Plains Dextrose).
- Renewable Energy: The methodology considers the use of solar energy, assuming an average embodied greenhouse gas (GHG) emissions factor of 36 g CO2e per kilowatt-hour (kWh) for utility-scale solar electricity in the U.S. (Reference).
- Biogas: The tool incorporates Biogas as an improvement strategy, assuming the utilization of Renewable Natural Gas (RNG) derived from food waste via anaerobic digestion for thermal energy. The emissions factor is sourced from GREET.net 2022.
- Lower Carbon N2: Incorporating Lower Carbon N2 strategies, the tool assumes the production of ammonia through steam methane reforming (SMR) of natural gas with carbon capture and storage (CCS). The emissions factor is obtained from the World Resources Institute (WRI).
- Lower Carbon Methanol: The tool integrates Lower Carbon Methanol strategies, using emissions factors from the Methanol Institute for Blue Methanol. Blue Methanol is produced through steam methane reforming (SMR) of natural gas with carbon capture and storage (CCS).
- Displacement/Substitution Credit If the co-product usage is known, then a substitution credit can be applied. An example of this is shown in the improvement strategies waterfall chart. The “waste biomass to feed” credit assumes that the cell mass co-product is a substitution for high protein animal feed. For this calculation the assumption is that 1 kg of biomass by-product (including 10% moisture) displaces 1 kg of animal feed with a carbon footprint of 1.13 CO2e/kg. For this scenario, the cell mass co-product is dried to 90wt% dried solids which may require more natural gas consumption than the base case. Both the increased natural gas usage and the animal feed credit are included in the calculation. Displacement/Substitution credit can not be applied on top of economic or mass allocation.
A precision fermentation process not only yields the intended final product but also generates a co-product in the form of cell mass. The allocation method employed for attributing greenhouse gas (GHG) emissions to this co-product significantly influences the calculated product carbon intensity value. In the base case result, no emissions are allocated to the cell mass, treating it akin to a waste stream. However, three distinct methods can be contemplated concerning the treatment of the cell mass co-product. The selection of an allocation method in Life Cycle Assessment (LCA) is contingent upon the study's objectives, data accessibility, and the unique context of the assessment. The decision on how to allocate emissions to the co-product is crucial, impacting the overall environmental footprint analysis of the precision fermentation process.
In economic allocation, the environmental impacts are allocated to co-products in proportion to their economic value. This means that products with higher market value receive a larger share of the environmental burdens in the LCA. This approach is based on the idea that the economic value of a product reflects its contribution to environmental impacts.
In mass allocation, environmental burdens are allocated to different products or co-products based on their mass or weight. In mass allocation, the environmental impacts are distributed amongst the products in proportion to their mass. In the calculation the GHG emissions are allocated to the co-product in proportion to its dry mass (excluding moisture).