I need to assess CO2 emission factors (KgCO2/ Kwh of energy input) for a gas boiler, a steam reformer, anaerobic digester, fuel cell and an water electrolysis.
In United States, the CO2 emission factors for different type of power sources are published based on power grid region. For example, EPA have published air emissions rates of the electricity generation in any U.S. region (lbs/MWh).
I have used the public data to calculate "Energy Emissions Factors" for electricity and natural gas production in the following paper:
Conference Paper Environmental Impact of Housing Retrofit Activities: Case Study