The International Energy Agency (IEA) Hydrogen Implementing Agreement (HIA) established in 2004 a task (Annex 18) on the topic of "Integrated Systems: Evaluation of Hydrogen Demonstration Projects". During 6 years, divided in two phases, this annex has been working in order to search and provide information on progress in the hydrogen economy around the world. Spain is one of the 15 member countries since the phase 1. The task has followed three main targets: To develop a database that includes national documents, national capabilities and a compilation of demonstration projects of each member country. To evaluate several hydrogen demonstration systems deployed within the participating countries. These projects have in common that modeling tools are used to help guide, assess, and evaluate the overall design and performance. To find best practices, trends and lessons learned with respect to realization and operation of integrated hydrogen systems. The participation of INTA in this Annex, as a national member and the coordination of a capability analysis work group inside the Spanish Hydrogen and Fuel cell Platform (PEHFC), has helped to complete and update a database on the State of the art of hydrogen activities in Spain. (C) 2010 Published by Elsevier Ltd on behalf of Professor T. Nejat Veziroglu.