Looking behind, the O&G industry has made a considerable contribution for worldwide population by allowing to gain mineral resources that could not be accessible in the past. At the same time, the increasing warming and pollution forced the O&G industry to become more competitive by cutting costs, streamlining project execution focusing of a most profitable assets maintaining the emphasis and cutting down the pollution. Nowadays, the environmental impact reduction is going to play an increasingly important role in everyday life. On the other hand, the pursuit of new goods with sustainability characteristics different from the past driven by the increasing energy demand, lay the basis for clean energy. Jackets are the most common structure in the Adriatic Sea for extracting natural gas. The structural typologies are suitable for relative low water depth and flat sea floors. Most of them have been built in the last 50 years. When the underground source finishes, these structures should be moved to another location or removed if they reached their design life. Nevertheless, another solution might be considered: change the future working life of these platforms by involving renewable energy and transforming them into offshore wind towers (1). The present research proposal aims to investigate the possibility of converting actual structures for gas extraction to offshore platforms for wind turbine towers. This research proposal is something completely different and innovative from the previous studies, because it is a purely transversal research activity which touches several important engineering aspects that have a common thread: green economy. Developing this research on offshore wind towers means make a big step forward, a significant contribution in this increasingly strong new green world coming.
The overwhelming policy based on renewable energies are making the offshore wind resources an increasingly viable option for electricity generation harnessing the more consistent gusts of wind available than onshore solutions. The growth of offshore wind realises potential synergies with the offshore oil & gas hydrocarbon sector. The North Sea oil & gas industries are already testing some possible matches between the two sectors (2). The target is to find new uses for existing offshore structures once they reach the limit service life. In order to make the transformation of Oil & Gas platform into offshore wind tower possible, it is reported the feasibility study of 3 retrofitted configurations. The analysis covers a basic approach to modelling the ultimate loads on the structure like analysis of wind loads, wave loads and current loads. The analytical derivation of response spectra that give as output the limit displacement of all the structure and consequently all the tools to understand the behaviour of each retrofitted configuration and why.