Whilst pedal cycles represent the most energy efficient form of transport ever devised (an ordinary bicycle uses 110J/km, which equates to 0.321 L/100 km, and a velomobile is five times better still), data centres are notorious for using a lot of energy. That means they are potentially responsible for a lot of carbon dioxide emissions. Push Bikes' servers are managed by Midlands Data, which has truly green ethics and aims to become carbon-negative by the end of this year.