Most offshore wind farms built thus far are based on waters below 30 m deep, either using big diameter steel monopiles or a gravity base. Now, offshore windfarms are starting to be installed in deeper waters and the use of these structures—used for oil and gas like jackets and tripods—is becoming more competitive. Setting aside these calls for direct or fixed foundations, and thinking of water depths beyond 50 m, there is a completely new line of investigation focused on the usage of floating structures; TLP (tension leg platform), Spar (large deep craft cylindrical floating caisson), and semisubmersible are the most studied. We analyze these in detail at the end of this document. Nevertheless, it is foreseen that we must still wait sometime before these solutions, based on floating structures, can become truth from a commercial point of view, due to the higher cost, rather than direct or fixed foundations. In addition, it is more likely that some technical modifications in the wind turbines will have to be implemented to improve their function. Regarding wind farm connections to grid, it can be found from traditional designs such as radial, star or ring. On the other hand, for wind generator modeling, classifications can be established, modeling the wind turbine and modeling the wind farm. Finally, for the wind generator control, the main strategies are: passive stall, active stall, and pitch control; and when it is based on wind generation zone: fixed speed and variable speed. Lastly, the trend is to use strategies based on synchronous machines, as the permanent magnet synchronous generator (PMSG) and the wound rotor synchronous generator (WRSG).

In this paper the publications from Spanish institutions listed in the journals of the Construction & Building Technology subject of Web of Science database for the period 1997- 2008 are analyzed. The number of journals in whose is published is 35 and the number of articles was 760 (Article or Review). Also a bibliometric assessment has done and we propose two new parameters: Weighted Impact Factor and Relative Impact Factor; also includes the number of citations and the number documents at the institutional level. Among the major production Institutions with greater scientific production, as expected, the Institute of Constructional Science Eduardo Torroja (CSIC), while taking into account the weighted impact factor ranks first University of Vigo. On the other hand, only two journals Cement and Concrete Materials and Materials de Construction agglutinate the 45.26% of the Spanish scientific production published in the Construction & Building Technology subject, with 172 papers each one. Regarding international cooperation, include countries such as England, Mexico, United States, Italy, Argentina and France.