During the last ten or twenty years, the costs of fuels have become higher than in the past, about this there is a discussion because it is though that more the price of fuels will rise, less it will be consumed, and, consequently, it will be possible to soften the pressure on this kind of resources. In my opinion, this is not the way to reach the aims we talked before, in fact, petrol and fuel are too strictly conneceted to our lifes to let us renounce them so easily.