I found this handy emission calculator that goes beyond tailpipe at Fueleconomy.gov. For now, it only has Leaf and Volt to choose from. They should add Prius PHV in there soon. From the site: GHG emissions vary based on how the electricity is produced. For example, electricity produced from coal will likely result in significantly higher GHG emissions than electricity produced from renewable sources like wind. This graph shows how the emissions rate for this vehicle where you live compares to the national average. Also shown is the total CO2 emissions rate for the average gasoline car. *Total emissions rate includes tailpipe emissions and the emissions associated with the production and distribution of fuel. You can enter your own zip code and it'll show you the total greenhouse gas emission. For reference, I am including the Prius Liftback. I expect Prius PHV to have lower GHG emission than the Liftback. My estimate is between 200-222 gram/mile. Prius 50 MPG: 222 gram/mile (178+44) Leaf National Average: 230 gram/mile Volt National Average: 260 gram/mile Prius (50 MPG gasoline): Leaf in Hawaii: Volt in Hawaii:
Thanks. Reminds me of some charts I was posting in the past. It will be interesting to see what utility factor they will use for the Prius PHV, compared to 0.64 they use for the Volt.
Thanks for pointing to the calculator. Wish it showed power plant emissions beyond CO2 though. Here in eastern Pennsylvania, where some still use coal for home heating, the Volt was 230g/mi and the Leaf 190g/mi. Why the need for posting the cars' numbers for Hawaii? The state with a power grid most reliant on fossil fuels. Vermont is another state that could have been used. There (05904 zip) the Volt is rated 210g/mi and the Leaf 140g/mi.
This calculator uses eGRID 2010 data. It includes CO2 equivalent (CO2e) from Methane and Nitrous Oxide emission. See the summary table (p.1) for the breakdown. The data is not city or state level but from subregion. Eastern Pennsylvania should be in RFCE subregion. Here is the subregion map: The summary table also has a breakdown by state on p.11. It said 54.3% of PA electricity is from Coal. If you want state level, you can use p.10 and p11 to manually calculate it. In PA, 137,165,994.3 tons of CO2e generated from 225,840,098.3 MWh of electricity. 124,434,896,876,382 grams / 225,840,098,300 kWh That come out to 551 gram/kWh. (551 g/kWh * 12.9 kWh) / 35 miles = 203 g/mile using electricity. Volt running on gas emit 299 g/mile. Using 0.64 utility factor from J1711, the composite comes out to 238 g/mile. 1) I had to pick a zip code to get the URL 2) Hawaii is a subregion by itself.
The summary table link is corrupted, at least for me. Or you can just go here: How clean is the electricity I use? - Power Profiler | Clean Energy | US EPA My town is under the national average for coal, and over double for nuclear. Thus I could do better than average with a plug-in, once a I run new electric service out to the detached garage. Western Pa's percentage of coal pulls up the state average. Hawaii's grid is 77.4% oil. It's mix is an outlier. Better to just use a continental US locality to have a better chance of nearing the national average.
That gives you subregion average, not state level. If the summary PDF does not work for you, get all the files in a zip.
My real world Chevy Volt CO2 emissions calculate out to 144g per mile using this methodology but with more locally specific data for Northern California. Total mileage of 18,377 with 7,000 of that in charge sustaining (hybrid) mode at 42 mpg and 30 kWh / 100 miles electric (annualized average efficiencies) and a utility grid that is an average 238g CO2 per kWh.
Good job Jeff. You are a heck of efficient driver. Your local electricity is very clean (238 vs 590 gram/kWh) compare to the national average.
Thanks. My overnight grid average is probably lower than 238g/kWh based on the fuel source data but that number isn't published by PG&E. I could do better by charging at 240V which seems to be around 7% more efficient (28 kWh/100 instead of 30 kWh/100).
