Discussion

So, a few friends & associates started asking; “…isn't an eBike less efficient than a regular bike, isn't it less environmentally friendly…doesn't it defeat the purpose of a bike?”

My answer was simple: “…for me, NO, but it depends on your usage patterns…”

Rationale

Energy Consumption

A human powered vehicle uses the human metabolism to convert food into energy, at a conversion efficiency of about 25%. That's the first part of the picture.

Next, you need to consider supply chain differences:

  • Human energy (aka: food) is often grown with machinery & chemical fertilizers, and then transported, processed, packaged, re-transported, sold, transported again, and finally cooked before consumption. Afterwards your unused food waste still must be discarded through sewer systems. In the end, roughly 10 times more primary energy went into your food, than is actually stored in the food itself. The net effect is that for every unit of human energy used on a bike, about 40 times that much was consumed.
  • Bike energy is delivered directly from your power grids at between 60-80% efficiency, stored in batteries, and then put to work through an electric motor with roughly 90% efficiency (older eBike technologies drops efficiency to ~75%). Once you account for the battery manufacturing and recycling energies, e-bikes end up consuming between 5-10 times less fossil fuel energy than their human-powered equivalents.

Want proof?

Cycling Audiences

eBikes open cycling to an entirely new audience; people people who'd otherwise be on a bus, or driving a car or truck. Many people would often like to, but find it impractical or impossible because of time commitments, hills, distance, health (knees, aging, etc…), or simply the impossibility of showering & changing at a destination.

While it's wrong for cyclists to assume anyone can ride a bike, eBikes suddenly make biking far more accessible to the non-biking 98% of our population.

powerassistbenefits.txt · Last modified: 2014/05/16 12:35 (external edit)
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