For now, Italian offshore counts for more than 100 fixed installations, including oil and gas production platforms and loading and offloading terminals. Decommissioning of these structures is normally not imposed upon the completion of their project life but on the exhaustion of the oil or gas bed or dismantelment/conversion of the refinery or power plant supplied by the terminals. If the remaining project life of an offshore structure is greater than ten years, a conversion can be evaluated as an alternative to decommissioning. Following the last Italian and European directives, issued to limit co2 emission and to increase the proportion of renewable energy in the global energy balance, conversion of existent offshore structures in renewable energy power plants has become a contentious issue of great topical interest. Recent experiences in north European countries have certainly demonstrated that offshore environmental conditions are optimal for the location of wind farms. In terms of production, offshore wind turbines are 40% more efficient than onshore ones and, obviously, have a very low visual impact. The conversion of existing structures would reduce investment and simplify the acquisition of necessary permits (surrounding waters are always forbidden to commercial fishing, navigation and anchoring). The General Project Assessment (GPA) for the conversion of existing structures estimates the energy sources available at site (wind/waves/sea current/sun radiation) and the characteristics of the existing structure to determine the dimensions of the generators to be installed. This quality/quantity evaluation will be expressed in the GPA as a yearly expected power production. GPA will also include a detailed NDT inspection to evaluate the structure's conditions at the time of conversion and to confirm the structure's remaining project life. An engineering study to verify the structure's capability to support the generator(s), an Environmental Impact Assessment (EIA) and a feed study for the power cable dimensioning and installation will also be implemented in the GPA.

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