I live 25 miles from work.  Too far for me to cycle on a regular basis, since I really can’t spend 4 hours a day on the bike, arriving at home totally exhausted.  But then I saw a kit online for an electric conversion that could be applied to my old recumbent road bike.  It comes from Eco-Speed, and is a 600 watt motor that sits between the pedals and the wheel, providing extra power as I pedal.  To improve on aerodynamics and carrying capacity I got a front fairing from Zzipper, and a tailbox from Angletech.  The battery is a 22Ah 36V LiFeSo cell from Cycle9, which provides enough power for about a 40 mile range on the terrain between work and home.