In the last century, there has been rapid urbanization leading to increased energy demand with an ever increasing load on nonrenewable resources and subsequent escalation of pollution. A viable solution to these two problems can be a power supply technology that is able to produce energy with minimum or zero pollutant emission into the environment. Fuel cells appear to be an eco-friendly power supply technology. Main advantage of fuel cell technology is represented by direct conversion of fuels into electrical energy, with zero emissions, when hydrogen is used as fuel. This article describes the basic overview of fuel cell technology in order to better understand the construction and also the working principle of this eco-friendly technology. © 2017, Springer International Publishing AG.