Quote:
Originally Posted by Street Pharmacist
I think that's assuming 100% efficiency as the best estimates I can find are 200-400 for home heating. And that's not including the gCO2 of methane escape.
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It's for delivered energy to the building. A cruddy old furnace could have an combustion efficiency as low as 50-60%: 180/0.5=360 + misc losses (leaks, pilot light, etc.) easily gets you to 400. Electricity is a bit different in that it basically operates at 100% efficiency once it's delivered to the building.
Source (it's outdated for electricity but NG rates are stable):
https://www.energystar.gov/buildings...-source-energy
e: I took another look and GHG from extracting the fuel source are not included in these numbers (so methane leak during natural gas extraction is really going to skew that number). I must have remembered wrong. These numbers are often used to make cases for reducing emissions and you make a better argument with higher emission rates. Then again, actually pinning down the fuel extraction GHG emissions is difficult and is a different kind of problem to solve.