We are conducting a study on some textile factories and we have the energy usage data (diesel, natural gas, electricity) of those factories. Is there any possible way to calculate the amount of CO2 or other GHG emission from these energy data? Is there any empirical equation or anything?
It all depends on the accuracy. Burning of diesel and natural gas is all about chemistry. Stoichiometric amounts of CO2 will be produced. And the energy yield for selected fuels is available in the literature, to determine the initial amount of these raw materials. So yes, I think it can be backward calculated, however the precision will be only moderate. The same applies to the electricity, if you can determine the source - if it is renewable energy or from charcoal plant, etc.
Dear:
You can read the publications of the IPCC i. e the intergovernmental panal on climate change 2007, you will find the required equations for calculation GHG emission from energy.
EPA has provided a calculator on their website, where you can calculate GHG emissions by either emission data or your energy consumption.
https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator