Feasibility analysis for floating offshore wind energy

Purpose The assessment of the economic feasibility of foating ofshore wind farms (FOWFs) plays an important role in the future possible spreading of this challenging technology in the wind power industry. The use of specifc economic analyses is fundamental to point out the potential of FOWFs and to sustain their technical value. Within this topic, the implementation of the FOWF life cycle cost model and producibility analysis in a geographic information system is developed, with the aim of carrying out a feasibility analysis at the territorial scale, for diferent types of foater. Moreover, a simplifed model for a quick life cycle cost assessment is proposed and calibrated. Methods The available cost model is frst validated comparing the costs of FOWFs based on diferent foaters (Semi-Submersible Platform—SSP, Spar Buoy—SB and Tension Leg Platform—TLP) with corresponding results available in the literature. Then, it is implemented in QGIS to be used for territorial-scale analyses and sensitivity analyses of the cost parameters. A feasibility analysis is developed through the main fnancial parameters. Finally, the results are then used to calibrate a simplifed version of the cost model that depends on three main parameters, namely distance to shore, distance from the port of operation and bathymetry. Results and discussion The FOWF cost values are found to be in good agreement with those coming from analytical methods similar to the one from the authors. However, some discrepancies with those based on average costs are observed. Then, the results of the sensitivity analysis are presented as life cycle cost maps, giving an overall picture of the variation of the total cost of FOWF installations on a reference domain. The results show that among the three types of foaters considered here, the SSP proved to be the most promising one, giving lower costs than the SB and the TLP. Moreover, a good agreement between the results in terms of total cost of FOWFs calculated with the analytical and simplifed models for SSPs, SBs and TLPs is observed. Finally, the feasibility analysis showed that the fnancial parameters are more infuenced by the wind speed than by the cost of the farm. Conclusions The paper aims to provide guidance on how to carry out feasibility analyses of a specifc site for FOWF installation, thus supporting decision-making procedures. The approach and the results presented here are meant for use in the early stage of the decision-making process, as a tool for the assessment of the economic feasibility of FOWFs installation

Sensitivity analysis of cost parameters for floating offshore wind farms: An application to Italian waters

Floating offshore wind farms represent the next frontier in wind power industry. However, the development of this technology is strongly dependent on its economic feasibility. There follows that the development of economic analyses is crucial to highlight the possible greater potential of floating offshore wind farms and to support their sustainability and technical value. In this context, the purpose of this paper is to present a sensitivity analysis of the main cost parameters for floating offshore wind farms, namely the distance from the coast, the distance from the closest port and the sea depth. It can give specific information on which parameters are more important, and how much they affect the total cost. To this aim, a comprehensive life cycle cost assessment of floating offshore wind farms has been developed. In this study the cost model has been applied to the Italian waters. The results shown should provide guidance on how to preliminary assess the quality of a given site for floating offshore wind farm installation, and should be helpful for future development of decision-making procedures in the offshore wind sector

Wind energy into the future: The challenge of deep-water wind farms

In 2019, 5.6% of the total energy produced worldwide came from wind. Offshore wind generation is still a small portion of the total wind generation, yet its growth is exponential. Higher availability of sites, larger producibility and potentially lower environmental impacts make offshore wind generation attractive. On the other hand, as the water depth increases, fixed foundations are no more viable, and the new frontier is that of floating foundations. This paper brings an overview of why and how offshore wind energy should move deep water; it contains material from the Keynote Lecture given by the first author at the ACEM20/Structures20 Conference, held in Seoul in August 2020. The paper is organized into four sections: the first giving general concepts about wind generation especially offshore, the second and the third considering economic and technical aspects, respectively, of offshore deep-water wind generation, in the fourth, some challenges of floating offshore wind generation are presented and some conclusions are drawn

Long term effect of biochar on soil plant water relation and fine roots: Results after 10 years of vineyard experiment

Biochar is widely suggested to improve soil physical properties and soil-water-plant interactions. Furthermore, the application of biochar to the soil can alter the dynamics of the roots and, in turn, affect the performance of the plant. Nevertheless, the long-term evolution of these effects is unknown and of critical importance because biochar persists in soil for centuries. The results of this work are part of a long-term study in the vineyard started in 2009 and still ongoing. In this work, the effect of applying biochar to soil on the plant-water relationships of Vitis vinifera, soil properties and fine root traits is evaluated 10 years after application. Even after 10 years, the ecophysiological measurements indicated an increase in soil water content and a significant increase in the water status of the plants in the plots treated with biochar. Independently of the diameter class considered, both doses of biochar led in the entire 40 cm of soil to a general reduction of the fine-root standing biomass and length, which is probably due to the lower need for fine root foraging. Moreover, the SRL did not show differences among different treatments. When fine-root traits were analysed along the soil depth at 10 cm intervals, we noted that both length and biomass were significantly higher in the control plant only in the upper soil layers (20 cm) and SRL was significantly higher only in the upper 10 cm of soil. These findings underscore how control plants plastically respond to the lower content of water in the soil by decreasing the fine-root cost-to-benefit ratio, especially in the topsoil layer. Research on the effect of biochar in viticulture can provide an effective contribution to the mitigation of climate change by increasing the water status of the soil and plants even 10 years after its application

Management of infants with neural tube defects (NTDs) in NICU

Neural tube defects (NTDs) are a group of congenital malformations of the central nervous system, which derive from an altered embryological development during neurulation. The different types of NTDs are closely related to their onset in the embryonic period; precocity is an index of greater severity of clinical manifestation. The myelomeningocele is one of the most common pathological conditions which is included into the spectrum of NTDs. It is characterized by the lack of fusion of the vertebral arches, resulting in eversion of the meninges and medullary content; it is the condition which clearly needs more assistance in the neonatal intensive care unit. The management of patients with NTDs is divided into different levels and particularly neonatologists have to monitor all the infants\u2019 vital signs, to perform a careful neurological examination for the evaluation of motor and sphincterial functions and to recognize orthopedic abnormalities. Furthermore, concerning the open defects, which maintain a communication between the spinal cord and the outside, it is essential to prevent infections of the central nervous system through a broadspectrum antibiotic therapy. The diagnosis includes x-ray of the spine, which allows to locate the exact level of the vertebral defect and ultrasound scan of the region involved; also magnetic resonance imaging plays a very important diagnostic role. All this exams guarantees to every newborn affected by NTDs a comprehensive care approach, but also useful informations for diagnosis and prognosis

Small bowel obstruction after caesarean section: Laparoscopic management. Two case report

Introduction: Caesarean section is the most common abdominal surgery performed on women worldwide. Adhesions represent a severe complication of cesarean section and can cause different degrees of bowel obstruction. Case reports: We report two unusual cases of small bowel obstruction treated with laparoscopic approach after caesarean section performed for gynecological pathologies. In the first one small bowel obstruction was due to volvulus caused by a severe pelvic adhesion syndrome; in the second one, occlusive picture was related to presence of multiple adhesion phenomena between the sigmoid colon and the right ovary as result of abdominal hysterectomy. Discussion: The incidence of small bowel obstruction after caesarean section is very low and postoperative adhesions represent the main cause. Diagnosis was established by clinical signs, radiological and intraoperative findings. Laparoscopic approach can be the treatment of choice only in selected patients. In presence of dense adhesions, inability to visualize the site of obstruction, iatrogenic intestinal perforation, bowel necrosis and technical difficulties, conversion to open surgery is mandatory. Conclusion: In selected patients with small bowel obstruction laparoscopy is a safe and feasible procedure if conservative measures fail