Originally Posted by
cyccommute
That is stretching "greener alternative" to the breaking point. Electric bikes are a greener alternative and can't really be called "polluting" in any terms. Without a battery the bicycle is even greener.
While there are a few people who may need the assistance, the vast majority of people don't need that kind of power assist. I've ridden with old people all of my life up to the point where I am an old people. I haven't run across that many old people before electric bikes came along that couldn't propel a bike down the road for from short to extended periods.
That was thought-provoking enough to start me looking up info. None of what follows addresses the specific instance of a bicycle with a Supercapacitor (capitalization courtesy the Bike Forums spellchecker), unfortunately.
From
this page:
Energy Density: Supercapacitors store much less energy per unit volume or weight compared to conventional batteries. In EVs, energy density translates to mileage per charge. Thus, batteries are more suitable in applications requiring large energy storage.
- Power Density: Supercapacitors can deliver large energy in a short time, making them ideal for applications requiring rapid power usage. Fast acceleration of electric vehicles and camera flashes are such applications.
- Self-Discharge: Batteries have much lower self-discharge rate compared to supercapacitors. Thus, batteries are more suitable for applications requiring long-term energy storage without frequent recharging.
- Lifetime: In batteries, the chemical reaction corrodes the components – so while supercapacitors can handle more than 1,000,000 charge/discharge cycles, a normal battery can only withstand about 2,000 to 3,000 cycles.
- Cost: Supercapacitors typically have a higher cost per watt, due to the cost of the components and the fact that the power is discharged very quickly and therefore sometimes inefficiently.
- Sustainability: Mining the lithium, nickel, and cobalt required for a Li-ion battery comes with environmental concerns around waste and pollution. In contrast, supercapacitors can use more sustainable materials, such as activated carbon from biomass sources that are more renewable, less harmful to the environment, and easier to recycle.