Author Topic: Computing CO2 emissions, now with my real world data  (Read 760 times)


  • Brammovangelist
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Computing CO2 emissions, now with my real world data
« on: March 24, 2012, 04:04:01 PM »
Not counting the first 20 miles or so where I was trying the bike out, I have 311.4 miles on the bike and 39.36 kWh measured at a killowatt meter.

That works out to 126.4 Wh / mile - not bad, considering I would say my average speed is 50 and I often hit 60-65 at least for a few miles each ride.

The EPA has an easy-to-use tool that will show you how much CO2 is produced in your area by your zipcode in lbs per MWh. The data is somewhat old - from eGRID2010 containing 2007 data - but it's a starting point.

My region is 1541 lbs of CO2 per MWh, vs 1293 lbs of CO2 per MWh for the national average. We burn way more coal (66.1% vs 48.5% of power) and less natural gas than the national average, which is largely responsible for our cheap electricity. Although I wouldn't be surprised if that balance has shifted somewhat, natural gas is pretty cheap now.

1541 lbs (CO2) / MWh works out to 699 g (CO2) / kWh. The eastern grid has 6.471% transmission loss, which means the electricity delivered to my house is 747.3 g (CO2) / kWh.

Since each mile requires 126.4 Wh at the wall, I'm responsible for 94.5 g CO2 / mile, or 58.7 g CO2 / km.

A gas motorcycle like my GS500 gets about 50 mpg in my typical riding. Since combustion of a gallon of gas produces 8.8 kg of CO2, the gas bike gets about 176 g CO2 / mile.

This isn't exactly a 1 to 1 comparison, since we're not considering emissions resulting from harvesting, refining, and transporting fuel to the power plants, nor are we considering emissions resulting from harvesting, refining, and transporting fuel to the gas station, nor emissions resulting from additional travel incurred to the pump. This is a significant distinction, and probably results in a comparison slightly biased towards gas - most gas is shipped from abroad, refined, and trucked to various gas stations, where most fuel for power plants is produced domestically and is transported by train or pipeline.

Nevertheless, the ebike does quite well in a coal-heavy state.


Most states have a green- or renewable-backed energy program. TVA's program is called Green Power Switch, and allows you to buy blocks of energy guaranteed to be produced from renewables. I'm a little squeamish of such programs, since a) grid energy is completely fungible and b) it feels a bit like self-flagellation. Nevertheless, TVA's program is relatively inexpensive and it's at least a step in the right direction, so I support it in the interim. Most of TVA's GPS energy comes from landfill methane - I'd much rather buy energy backed by wind or solar power. Or install my own solar power. But that's another post : P
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