Dataset associated with the publication "Absolute Sustainability Assessment of Flue Gas Valorization to Ammonia and Synthetic Natural Gas" by Sebastiano C. D'Angelo, Julian Mache, and Gonzalo Guillén-Gosálbez, available at https://doi.org/10.1021/acssuschemeng.3c05246. The dataset includes the numeric data required to plot all the figures embedded in the main manuscript and in the Electronic Supplementary Information (ESI). The dataset contains two Excel files with the raw numerical data and two pieces of code to generate the associated plots included in the publication: Impacts_InputFile_v1: numerical values associated with the total share of safe operating space for all the assessed control variables of the seven planetary boundaries quantified in the study, for all the considered scenarios. The results are presented for the two different downscaling approaches considered in the study. The ReCiPe 2016 (hierarchist approach) midpoint and endpoint impacts for all the scenarios are here reported, as well. The single sheets are organized as follows: LCI: tables with life cycle inventories for all the reported scenarios. PB-LCIA: life cycle impact assessment results for the quantified planetary boundaries, using the nonegalitarian downscaling. ReCiPe16-MP: life cycle impact assessment results for the ReCiPe 2016 midpoints. ReCiPe16-EP: life cycle impact assessment results for the ReCiPe 2016 endpoints. Results_NotAggr: life cycle impact assessment results for all the quantified planetary boundaries, with full breakdown, using the nonegalitarian downscaling. Results_NotAggr_PopDS: life cycle impact assessment results for all the quantified planetary boundaries, with full breakdown, using the egalitarian downscaling. Results-NotAggr_ReCiPe16-MP: life cycle impact assessment results for the ReCiPe 2016 midpoints, with full breakdown. Results-NotAggr_ReCiPe16-EP: life cycle impact assessment results for the ReCiPe endpoints, with full breakdown. Environmental_plots_v1: code to generate plots associated with environmental results. Note that the path in the first jupyter cell needs to be adjusted to match the user's local working folder. Economics_InputFile_v1: numerical values associated with the breakdown of the economic impacts reported in the main manuscript and in the Supplementary Information, for all the assessed scenarios. The single sheets are organized as follows: Revenue: calculations to determine the revenues from (synthetic) natural gas and ammonia. CAPEX: breakdown of capital expenditure for all the components of all the investigated scenarios. OPEX: breakdown of operating expenditure for all the components of all the investigated scenarios. LCA: global warming impacts of the investigated scenarios (used to calculate the carbon abatement cost). Wind_CapacityFactors: wind capacity factors used for the economic calculations. Economic_plots_v1: code to generate plots associated with economic results. Note that the path in the first jupyter cell needs to be adjusted to match the user's local working folder.