Supercapacitors are new components ale to store a high energy density aven if this energy is still lower than the energy batteries can store. This paper shows how supercapacitors can be used to supply electric vehicle such as busses and tramways. The "on-board" supercapaitors need a fast loading at some stations. This needs a high power, not always suitable when a distribution network is too weak, or when the power supplied by a network must be limited. Such type of limitations will hav o be more considered by the planning of transportation in the next decades. In a second part, we propose a mehod foer loading energy in supercapacitors with a high power by taking low power on a distribution network, using also supercapacitors as energy buffers.