Abstract: The invention includes a method for energy usage and green-house gas inventory management including: entering input data and input source descriptions for the input from green-house-gas-producing processes at a field site into a computer-readable file; passing the input data to a green-house-gas calculating module; outputting green-house-gas emissions based on the input data; passing the input, input source descriptions, and the output over a network to an output integration program; integrating the output with a plurality of other output from at least one other field sites; mapping the integrated output into a relational database schema; and storing the mapped integrated output in a relational database.