The carbon foot print of an ebike vs. a normal bike

[auraslip]

The information below is the summary of a paper I wrote for my government class. Please see the attached paper and sources on my website for a more in depth explanation.

When comparing a bicycle and an electric bike making the average American commute of 30 miles per day (15 miles round trip) at a speed of 15 miles per hour the bicycle produces around 8.5 times more carbon emissions.

The bicycle

A cyclist can travel 30 miles in an hour using only 200 watt hours (Wright)
200 watt hours is only 174 calories, but humans are at best only 25% efficient at converting food calories to useable energy.
This means it would take at least 700 calories from food to travel 30 miles a day.
The average American Diet produces .005lbs of CO2 per calorie. (Martin)
700 calories translates to 3.5lbs of CO2 a day and 1,278lbs a year.

The electric bicycle

500 watt hours is the high end end average for traveling at 15mph for 30 miles with one of the more popular electric conversion kits. This includes the loss of power from inefficiency in the electrical components.
Inefficiencies and power losses in the grid and battery charger are 93.5% and 90% respectively. (Lemire-Elmore, Justin)
This comes out to 585 watt hours produced at the power station per day.
Per kilowatt hour coal produces .7lbs of CO2. ("Carbon Trust")
.585 kilowatt hours per day produces .41lbs of CO2 and a total of 149.5lbs a year.

Variables and counter-points

The environmental costs of producing and electric bike over a normal bicycle

The environmental impact of production is almost meaningless when compared to life time operating cost. The extra components on an electric bike do add to the environmental impact, but not much: "The li-ion battery plays a minor role regarding the environmental burdens of e-mobility irrespective of the impact assessment method used." (Notter 6550-6556)

The impact of diet

This exercise assumes the average American diet. A vegetarian diet cuts the carbon footprint of the cyclists in half. (Pimental)

The use of carbon neutral energy sources

Wind, solar, hydo, and nuclear make up 27.5% of Americas domestic energy production.

Cost in dollars

200 calories from white pasta costs $0.21 or $0.00105 per calorie. This comes out to $0.735 a day and $268.26 a year.
At $0.13 per kilowatt hour the electric bike costs $0.076 a day and $27.76 a year.




"Resources - conversion factors ." Carbon Trust. Carbon Trust, n.d. Web. 6 Apr 2011. <http://www.carbontrust.co.uk/cut-carbon-reduce-costs/calculate/carbon-footprinting/pages/conversion-factors.aspx>.

Martin, Pamela. "Diet, Energy, and Global Warming." Earth Interactions. 10.9 (2006): 3. Print.

Notter, Dominic. "Contribution of Li-Ion Batteries to the Environmental Impact of Electric Vehicles." Environ. Sci. Technol.. 44.17 (2010): 6550–6556. Print.

Pimentel, David. "Sustainability of meat-based and plant-based diets and the environment." American Journal of Clinical Nutrition. 78.3 (2003): 660-663 . Print.

Wright, Chuck. "Bicycling Energy Calculator." Chuck Wright Consulting. Chuck Wright Consulting, n.d. Web. 5 Apr 2011. <http://chuck-wright.com/calculators/bicycle.html>.

Lemire-Elmore, Justin. "The Energy Cost of Electric and Human-Powered Bicycles ." Grin Tech. ebikes.ca, April 13, 2004. Web. 6 Apr 2011. <http://www.ebikes.ca/sustainability/Ebike_Energy.pdf>.

 

[auraslip]

Thanks to Justin for inspiring this paper and for also providing me with some help writing it!

 

[Joseph C.]

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[neptronix]

Heh, 30 miles using only 174 calories?

All the online calculators i look at show around 200-600 calories per hour for 12-15mph

Are we talking about a 50 pound teardrop shaped human here?

http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=cycling+calories+per+hour

I think eBikes are way cheaper than you calculated.
Not that we need to beat a dead horse though. We already know ebikes are cheaper to operate.
Even when you add 25 cents per 30 miles to figure in battery replacement costs.

 

[MikeFairbanks]

I don't see the reason for promoting e-bikes over human-powered bikes and vice versa.

Besides, I know exactly where the electricity is coming from for my E-trike: Coal-fired electrical plant.

For me it was never about saving the planet (as if we created it or could truly destroy it...that's arrogant thinking).


For me it's about having fun and being different. It's a cool thing, and people admire it. I meet more people. I see my town better (because I'm in the fresh air and going slower), and it makes me smile.

I have no illusions about saving a planet that can't be destroyed by the ants we call human beings.

Sure, we can put a scar or two on it, but the planet will continue spinning and will continue to revolve around the sun for 4.5 billion more years until the sun swells up and vaporizes our earth.

Humans destroy the planet! Absurd.

 

[REdiculous]

lbs CO2 per 20k miles...

ebike; 691
escooter; 2594
bike; 4000
75mpg scooter; 5216
ecar; 8819
30mpg car; 13,040

I used neptronix's numbers for the ebike (0.8kWh for 30 miles), your numbers for the bike (3.5lbs CO2 for 30 miles) and carbonfund.org for the CO2 per kWh and CO2 per gallon of gas. The escooter is Current Motor's 'Economy', the ecar is the Leaf and I used the best case scenario for both. I didn't count oil changes on the gas vehicles or the cost to extract/refine/transport the fuel since I didn't know if that was included in the figure from carbonfund.org.

Fun stuff.

Heh, 30 miles using only 174 calories?

The next line down says 700 calories.

edit; I changed the figure for the bike - using 1200 calories (instead of 700) for every 30 miles.

 

[neptronix]

Oh, he's including the efficiency loss.

Still, 700 calories isn't right, 30 miles is about 2 hours of cycling, or 1000-1200 calories at a very slow pace for a skinny person.

Or for the average 200lb American it is more like 1500lb.

Go look at online calorie calculators! They all seem to agree that 500-ish is what we use to go at a moderate pace for an hour.

 

[REdiculous]

I think you're right.

He used Wright's calculator...

The equations were given to me by Mike Landrus, and he's not sure where he got them, so have fun but don't take the answer too seriously (though most of the calculations look reasonable, it makes many unchecked assumptions).

If you put in 30 miles and 15mph it says you need 797.5 calories regardless of what you and the bike weigh. You can put 500lbs in those slots and it still says 797.5 calories.

 

[neptronix]

It also doesn't calculate the bike's weight.
It also gives NaN values meaning the programming is a bit suspect to begin with ( i program for a living )

I have looked at about 10 online calorie counters to get an idea of how many were needed before i wrote the article i made, just so i could get a general idea.

I never encountered one that was this optimistic.

I wonder how these numbers are provided anyway. All i know is that after a 20-30 mile ride even on flats, i am effing starved as if i had skipped a meal.

 

[REdiculous]

NaN is ok (better than crashing) but 0 is better for UI since non-programmers may not know that NaN stands for not a number. I've worked on a few programs but I was always most interested in UI design...not much money there. Anyway...

If you put in an elevation change I think it factors in the bike and rider weight but that doesn't mean it's getting it right. You can see the source since it's just some javascript. I haven't messed w/ javascript in ages but it doesn't look too complicated.

 

[Joseph C.]

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[Joseph C.]

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[auraslip]

OOOOOOOOPS that cycling calculator is a bit off. I guess I was in a rush to finish the paper in time and just went with the first cycling calculator I could find. I will edit the thing tomorrow.

 

[nuevomexicano]

...I believe what we really mean when we use that phrase is all human life anyway...

You don't even need to destroy human life, just screw things up enough to make it damn uncomfortable for us.