Renewable and Sustainable Energy Reviews 6 (2002) 297–306 www.elsevier.com/locate/rser Fuel cells, an alternative to standard sources of energy A. Boudghene Stambouli * , E. Traversa University of Roma, ‘Tor Vergata’, Department of Chemical Science and Technology, Via della Ricerca Scientifica-00133, Roma, Italy Received 18 October 2001; accepted 23 October 2001 Abstract Three E’s are the national energy policy drivers of any country of the world, Energy secur- ity, Economic growth and Environmental protection. A fuel cell is an energy conversion device that produces electricity by electrochemically combining fuel (hydrogen) and oxidant (oxygen from the air) gases through electrodes and across an ion conducting electrolyte. The principal characteristic of a fuel cell is its ability to convert chemical energy directly into electrical energy giving much higher conversion efficiencies than any conventional thermo-mechanical system thus extracting more electricity from the same amount of fuel, operate without combus- tion so they are virtually pollution free and have quieter operation since there are no moving parts. The emission of fuel cells running on hydrogen derived from a renewable source will be nothing but water vapour. Fuel cells are presently under development for a variety of power generation applications in response to the critical need for a cleaner energy technology. This paper reviews the existing or emerging fuel cells technologies, their design and operation, their limitations and their benefits in connection with energy, environment and sustainable development relationship. Few potential applications of fuel cell will be discussed.  2002 Elsevier Science Ltd. All rights reserved. Contents 1. Introduction .......................................... 298 * Corresponding author. Fax: +39-06-7259-4328. E-mail address: aboudghenes@yahoo.com (A. Boudghene Stambouli). 1364-0321/02/$ - see front matter  2002 Elsevier Science Ltd. All rights reserved. PII:S1364-0321(01)00015-6