How much electric can I generate with a bike, and what is it worth.?

I have seen various web-sites that show that someone pedaling a bike that is hooked to a a generator can power various appliances. These web-sites say things like if you pedal for an hour you can power a laptop for three hours. Or they say that you can charge a 12 volt battery. [...]

Is it worth buying an electric bike?

I don’t drive and soon I will not be able to get to work by public transport anymore – my shifts start very early. I am reasonably fit and would need to cycle 8 miles on flat road, at a time when there is very little traffic. Does having an electric bike significantly increase speed/make [...]