The Acton 2020 plan, published in 2011, has a section on carbon footprint. The results are used throughout the report, but the basic calculations are shown starting on page 209 of Volume 2, which is also page 16 of Chapter 9 (Sustainability). These pages are also in this PDF.
To summarize, the calculations show one way to measure these aspects of Acton’s carbon footprint:
Residential / Electric
Residential / Natural Gas
Residential / Oil
Residential / Gasoline for Vehicles
Commercial+Industrial / Electric
Commercial+Industrial / Natural Gas
Town+School / Electric
Town+School / Natural Gas
The report used a mix of utility data, census data, MAPC data (for transportation) and Town data to come up with amounts of various fossil fuels consumed for these purposes, and then uses EPA conversion factors to calculate