It's still dwarfed by the carbon impact of manufacturing the bike. On average, a cheap bike takes around 240 KGs of CO2 to manufacture. I couldn't find any data on high end mountain bikes, but it's probably more due to all the fancy suspension components, fat tires, dropper posts, etc. To be conservative, we'll go with a cheap bike.
The 18650s in the battery pack are the "carbon heavy" component of an ebike. 18650s average between 30 KG CO2 and 50 KG CO2 of emission per 500 WH for their mining, manufacture, shipping etc, and has been dropping. This means adding a battery pack to a cheap bike would only add an extra 16% CO2 emissions.
To put this in perspective a carbon frame takes around 60KG of CO2 to manufacture, while an aluminum frame takes 170KG to manufacture. This means the choice between carbon and aluminum frame matters more than whether the bike is an ebike. It's 40KG of CO2 for the battery, but an extra 110KG for an aluminum frame vs a carbon frame.
On top of this, 18650 cells are highly recyclable, because they are standard cells used everywhere from laptop batteries to electric cars, and demand for their raw materials is high. The same cannot be said about most other bike components.
In terms of energy mix, BC in 2018 generated 74 TWH with 95% of that clean energy. We exported 8.7 TWH and imported 9.6 TWH, giving a net import of 0.9 TWH. This puts our energy mix at 93.8% clean energy. That puts charging an ebike from completely empty in BC at 0.031 KG of carbon emissions worst case. This is less than eating 1/100th of a Big Mac.
Now consider that a person will typically use his ebike to offset some shuttle laps, or use it to bike to the trail head instead of taking their car. It only takes a couple of skipped shuttle laps to put you in the green. Now your ebike is considerably more green than your non-ebike.
There are some reasonable arguments against ebikes, but extra emissions is not one of them.
April 24, 2020, 8:36 p.m. - aegli214
It's still dwarfed by the carbon impact of manufacturing the bike. On average, a cheap bike takes around 240 KGs of CO2 to manufacture. I couldn't find any data on high end mountain bikes, but it's probably more due to all the fancy suspension components, fat tires, dropper posts, etc. To be conservative, we'll go with a cheap bike. The 18650s in the battery pack are the "carbon heavy" component of an ebike. 18650s average between 30 KG CO2 and 50 KG CO2 of emission per 500 WH for their mining, manufacture, shipping etc, and has been dropping. This means adding a battery pack to a cheap bike would only add an extra 16% CO2 emissions. To put this in perspective a carbon frame takes around 60KG of CO2 to manufacture, while an aluminum frame takes 170KG to manufacture. This means the choice between carbon and aluminum frame matters more than whether the bike is an ebike. It's 40KG of CO2 for the battery, but an extra 110KG for an aluminum frame vs a carbon frame. On top of this, 18650 cells are highly recyclable, because they are standard cells used everywhere from laptop batteries to electric cars, and demand for their raw materials is high. The same cannot be said about most other bike components. In terms of energy mix, BC in 2018 generated 74 TWH with 95% of that clean energy. We exported 8.7 TWH and imported 9.6 TWH, giving a net import of 0.9 TWH. This puts our energy mix at 93.8% clean energy. That puts charging an ebike from completely empty in BC at 0.031 KG of carbon emissions worst case. This is less than eating 1/100th of a Big Mac. Now consider that a person will typically use his ebike to offset some shuttle laps, or use it to bike to the trail head instead of taking their car. It only takes a couple of skipped shuttle laps to put you in the green. Now your ebike is considerably more green than your non-ebike. There are some reasonable arguments against ebikes, but extra emissions is not one of them.