EnerGoConsult (Czechia)

The planned phase-out of coal power plants connected to transmission and distribution networks 110 kV is associated with the task of substitution of current active and reactive sources with new ones, based on an innovative technology. The new connected sources are mainly decentralized, renewable and are based on the non-synchronous power modules connected particularly to distribution networks (MV and LV). This influences their capability for reactive power operation. Improvement recommendations for the reactive management in distribution and interface transmission/distribution systems are presented based on wider technical studies in cooperation with TSO and DSOs in the Czech Republic.

Abstract Due to a recent mooring shackle failure within the offshore industry, focus has been directed toward existing in-service facilities that have similar manufactured shackles installed in the mooring systems. An in-service deep water facility was identified as having similar mooring components by the same manufacturer that failed in-service. A subsequent assessment of the material properties was undertaken on readily available spare shackles that identified Charpy impact toughness values below the original material specification. Consequently, a fitness-for-service assessment was carried out that included the assessment of the shackle fracture toughness, a finite element analysis of the shackle and associated mooring components, and a deterministic analysis procedure that assessed the structural capacity of the shackle by considering the response of the shackle to the presence of a crack or flaw located at a shackle stress hot spot coupled with a significant return period event. Finally, full-scale structural testing of spare shackles was performed to enable verification of actual shackle load capacity with a flaw located at the shackle stress hot spot. The focus of this paper is on presenting an overview of the fit-for-service methodology and the results of the structural integrity assessment. While a full quantitative risk assessment of the effect of a low fracture toughness shackle in the mooring system would have been ideal, due to the level of data available and the timeframe required for a probabilistic assessment, it was deemed appropriate to undertake a deterministic assessment of the mooring shackles under realistic scenarios representative of service and severe loads that may accompany the service. The results of the deterministic assessment on an actual in-service deepwater floating facility will be presented. The fit-for-service methodology presented in this paper provides a robust method to assess in-service floating facilities that have been identified or suspected of having below-specification mooring components. It has successfully been applied to a number of Chevron in-service floating facilities in different geographical locations. Introduction Following the early failure of a mooring shackle on a new deepwater floating facility, attention has been directed to other new and existing assets that have similar manufactured mooring shackles installed in the mooring system. Additionally, the release of Safety Alert No. 256 from the U.S. Department of the Interior (Minerals Management Service), provided recommendations to operators to review their current specification and testing requirements for mooring systems to ensure that the mooring components are adequate for the proposed or current usage.

Analysis of Potential Conservatism in Foundation Design for Offshore Platform Assessment Robert B. Gilbert; Robert B. Gilbert University of Texas at Austin Search for other works by this author on: This Site Google Scholar J.Y. Chen; J.Y. Chen The University of Texas at Austin Search for other works by this author on: This Site Google Scholar B. Materek; B. Materek HNTB Search for other works by this author on: This Site Google Scholar Frank Puskar; Frank Puskar Energo Engineering Search for other works by this author on: This Site Google Scholar S. Verret; S. Verret Energo Engineering Search for other works by this author on: This Site Google Scholar J. Carpenter; J. Carpenter Geoscience Earth & Marine Services Inc. Search for other works by this author on: This Site Google Scholar Alan G. Young; Alan G. Young Geoscience Earth & Marine Services Inc. Search for other works by this author on: This Site Google Scholar James Donald Murff James Donald Murff Texas A&M University Search for other works by this author on: This Site Google Scholar Paper presented at the Offshore Technology Conference, Houston, Texas, USA, May 2010. Paper Number: OTC-20861-MS https://doi.org/10.4043/20861-MS Published: May 03 2010 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Gilbert, Robert B., Chen, J.Y., Materek, B., Puskar, Frank, Verret, S., Carpenter, J., Young, Alan G., and James Donald Murff. "Analysis of Potential Conservatism in Foundation Design for Offshore Platform Assessment." Paper presented at the Offshore Technology Conference, Houston, Texas, USA, May 2010. doi: https://doi.org/10.4043/20861-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentAll ProceedingsOffshore Technology ConferenceOTC Offshore Technology Conference Search Advanced Search AbstractThere is a common perception that the design method for pile foundations in offshore platforms is conservative. However, we found no direct evidence of excessive conservatism in detailed analyses of thirteen case study platforms where the foundation systems were loaded to near or beyond their capacities. In eight cases, the foundation systems, including piles and well conductors, survived as they were predicted to do. In the one case we do have of a foundation failure occurring in a hurricane (a pile pull-out failure in clay), the failure was predicted. In two cases, the survival in a hurricane is consistent with realistic (not conservative) assumptions for the lateral capacities of piles and well conductors. In the last two cases, a potential overturning failure of the foundation system was predicted but not observed, most likely due to the lack of a site-specific soil boring to predict foundation capacity. Due to the small number of cases analyzed, these results do not preclude the possibility of foundation capacities being greater than expected based on design, particularly for piles tipping in sand layers.The perception of conservatism appears to be related to the common analysis methods used by the offshore industry. The assessment of existing foundations is different from new design and needs to be treated accordingly. Recommendations to improve the practice of platform foundation assessments include the following:When the foundation controls the assessment, include a geotechnical engineer familiar with platform assessments on the analysis team.Include well conductors and jacket leg stubs realistically and explicitly in the structural analyses.Consider using average rather than nominal yield strength for steel piles and well conductors.Use static versus cyclic p-y curves for lateral soil resistance.Be careful in specifying the input parameters for sand layers.Be careful when relying on a soil boring that was not drilled at the location of the platform or was not drilled using modern methods of sampling and testing, particularly when sand layers are present.Try to obtain pile driving records as well as soil boring logs to help estimate axial pile capacities.When the pile foundation system is governing the capacity of the platform in a pushover analysis, check the sensitivity of the foundation system capacity to the lateral and axial capacities of the piles independently.Do not arbitrarily increase the shear strength of the soil to account for perceived conservatism in foundation design.Provide specific guidance for characterizing pile foundations in platform assessments into a code format suitable for the American Petroleum Institute Recommended Practices.In the future, detailed analyses of platforms that were destroyed by hurricanes could provide valuable information about how pile systems and the jackets they support performed under extreme loading conditions. Keywords: assessment, hurricane, base shear, fine sand, conductor, foundation system, platform 1, pushover analysis, platform assessment, shear strength Subjects: Offshore Facilities and Subsea Systems, Information Management and Systems This content is only available via PDF. 2010. Offshore Technology Conference You can access this article if you purchase or spend a download.

SS: Offshore Wind Energy Special Session: Inspection Guidance for Offshore Wind Turbine Facilities Robert Edward Sheppard; Robert Edward Sheppard Energo Engineering Search for other works by this author on: This Site Google Scholar Frank Puskar; Frank Puskar Energo Engineering Search for other works by this author on: This Site Google Scholar Chris Waldhart Chris Waldhart Energo Engineering Search for other works by this author on: This Site Google Scholar Paper presented at the Offshore Technology Conference, Houston, Texas, USA, May 2010. Paper Number: OTC-20656-MS https://doi.org/10.4043/20656-MS Published: May 03 2010 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Sheppard, Robert Edward, Puskar, Frank, and Chris Waldhart. "SS: Offshore Wind Energy Special Session: Inspection Guidance for Offshore Wind Turbine Facilities." Paper presented at the Offshore Technology Conference, Houston, Texas, USA, May 2010. doi: https://doi.org/10.4043/20656-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsOffshore Technology ConferenceOTC Offshore Technology Conference Search Advanced Search AbstractWith the expected introduction of wind turbine facilities for the generation of electricity to the US Outer Continental Shelf (OCS) waters, there is a need to evaluate how the long term operations of these facilities can be ensured through Integrity Management (IM) activities, particularly inspections. There is a long operational history of IM in the Gulf of Mexico, offshore California and Alaska, and around the world for fixed and floating oil and gas platforms. Both prescriptive and Risk- Based Inspection (RBI) methodologies have been established and implemented. This experience provides a foundation for implementing similar integrity management programs for offshore wind turbine facilities. This paper describes a guidance document developed to assist operators and regulators in developing IM programs for offshore wind farms, the incorporation of existing guidance for subsea structures, above-water structures and access systems, along with guidance from subject matter experts regarding critical inspection areas, inspection techniques, and inspection intervals that are unique to wind turbine facilities. This work was funded by the US Department of the Interior, Minerals Management Service (MMS).Development ApproachAn integrity management program is designed to ensure the safe and efficient operations of a facility over its service life. It is comprised of three primary activities:Inspection activitiesContinuous monitoring activitiesEngineering evaluation and data managementThis basic framework has been used extensively with offshore oil and gas platforms worldwide. Coupling this with inspection and monitoring practices unique to wind turbine facilities (both onshore and offshore) provides a basis for developing guidelines for an offshore wind turbine integrity management program.These guidelines and the approach used in their development are documented in MMS TA&R Project 627, " Inspection Methodologies for Offshore Wind Turbine Facilities?? [1]. Information from regulatory standards, industry recommended practices, and subject matter experts was used to divide a typical offshore wind turbine facility into specific systems and structures with similar inspection scope, frequency and approach. The highlighted critical inspection locations were coupled with practical inspection realities (e.g., what can be accessed and how can areas be inspected) important to developing a successful integrity management program.This paper provides an overview of the MMS TA&R Project 627 [1] including:Description of a typical offshore wind turbine facilityPotential failure modes and inspection techniquesRecommended integrity management guidelines Keywords: offshore wind turbine facility, otc 20656, guidance, corrosion management, assessment, subsea structure, wind turbine facility, offshore projects planning and execution, visual inspection, renewable energy Subjects: Production Chemistry, Metallurgy and Biology, Pipelines, Flowlines and Risers, Offshore Facilities and Subsea Systems, Facilities and Construction Project Management, Materials and corrosion, Platform design, Offshore projects planning and execution, Corrosion inhibition and management (including H2S and CO2) This content is only available via PDF. 2010. Offshore Technology Conference You can access this article if you purchase or spend a download.

Factors causing an extremely negative situation with respect to the environment in cities of Russia that has been created continuously over the last 40 years by numerous storage sites of domestic wastes, which at the same time are a considerable resource of renewable (inexhaustible) fuel, are considered. A combustion theory for multicomponent and high-moisture domestic wastes as nontraditional fuel is developed, and technology for their thermal reprocessing is developed on the basis of this theory.

Abstract This paper presents a probabilistic study of various Gulf of Mexico (GoM) MODU mooring systems that was performed as part of the MODU Mooring JIP (Joint Industry Project). The intent was to determine the relative changes in reliability between different types of MODUs, with different mooring systems, in different water depths, designed for different hurricane conditions and located at different regions in the Gulf. In addition, the effects of assuming reduced mooring line strength were investigated. Twenty cases were selected which cover four different classes of MODUs, four different types of mooring systems, three different numbers of mooring lines, as well as three different water depths. These base cases were chosen so that trends or differences between different hull shapes and mooring systems could be identified. These twenty base cases are further expanded into sixty cases according to location in the Gulf as well as the return period used to design the mooring system. The results indicate that on average the " notional?? (i.e., relative) annual failure probability of mooring line failure decreases by one order of magnitude when increasing the MODU mooring system design return period from 10-yr to 50-yr. Two orders of magnitude decrease are observed if the design return period is increased from 10-yr to 100-yr. In addition to the above findings, reliability sensitivity to four different GoM Metocean regions is also provided. Redundancy of the mooring system for 8, 12 and 16-lines is also examined in terms of the additional reliability gained by the extra lines. Introduction The probabilistic reliability approach was performed using an updated procedure that was originally developed in prior work by DeepStar [1]. The results can be used by operators, drilling contractors, API work groups and regulators alike to understand, on a comparative basis, the performance of various MODUs and mooring systems. A base set of 20 separate MODU and associated mooring cases were evaluated as shown in the first twenty cases of the matrix in Table 1. These selected twenty base cases cover four MODUs (or MODU classes), four types of mooring systems, three numbers of mooring lines and three water depths. The footnotes of Table 1 provide definitions of these cases. These base cases were chosen so that trends or differences between different hull shapes and mooring systems can be identified. This base set of cases was then further defined into a larger set of 60 according to location in the Gulf as well as the return period used to design the mooring system. The Gulf locations were defined as the Central, West Central and West according to MODU JIP metocean study [5] and the latest API guideline [6], and the design return periods were defined as 10, 25, 50 and 100 year. The remainder of Table 1 shows the resulting matrix of cases studied. The full set of 60 cases was initially evaluated for reliability using 100% CBS (Catalogue Break Strength) for the mooring line. The entire set of 60 was then re-evaluated using 80% CBS to determine the sensitivity of the results to lower than expected mooring line strength. For the 8-10 mooring line cases, the first and second line failures were determined. The second line failure was used to represent the mooring system failure. For the 12 and 16 line cases, the third line failure was also determined, with the third line failure representing the mooring system failure. This allowed a comparison of the effect of mooring line redundancy in terms of the first line failure, versus the mooring system failure.

Abstract The 2005 U.S. Gulf of Mexico hurricane season validated the industry's practice of "shut-in and evacuate". Successful application of this practice resulted in no fatalities or serious injuries as well as limited pollution events related to Jackup operations. However, infrastructure (hull) losses in regards to the Jackup fleet were unprecedented and demanded operational alterations by industry in advance of the 2006 hurricane season. Prior to the 2006 Hurricane Season, Jackup owner/operators did not have a consensus on a recommended practice or specification document to utilize in order to adhere to minimum operational requirements to mitigate hurricane damage. The International Association of Drilling Contractors' (IADC) Jackup Rig Committee has been diligently engaged in producing the Gulf of Mexico Annex to the Society of Naval Architects and Marine Engineers' (SNAME) Technical and Research Bulletin 5-5A, Guidelines for Site Specific Assessment of Mobile Jack-up Units [1]. The committee was not at a stage where scientific studies had been completed and a consensus had not been achieved, consequently the document was not available for general use. Because of this, an interim operational-based solution was necessary. Shortly after the conclusion of the 2005 hurricane season, industry met with its government partners, Minerals Management Service (MMS) and U.S. Coast Guard to preliminarily determine the primary causes of the losses, the impact on the fleet population and to assess opportunities for performance improvement in advance of the 2006 Gulf of Mexico hurricane season. This strategic partnership led to the development of API Recommended Practice (RP) 95J, Interim Guidance for Jackup Operations in the Gulf of Mexico During Hurricane Season [2]. Use of the RP essentially became mandatory as the MMS adopted the operational recommendations and promulgated its Notice to Lessees (NTL) No. 2006-G09 [3] in advance of the 2006 hurricane season. The results of the operational alterations have not been tested as the 2006 Gulf of Mexico hurricane season was unusually mild. MMS has advised industry that it intends on reissuing the NTL in same or similar form for the 2007 Gulf of Mexico hurricane season. Introduction As reflected in Figure 1, hurricanes Katrina and Rita severely impacted the Central Gulf of Mexico, which contained much of this nation's offshore energy infrastructure, including the majority of the domestic Jackup fleet. Historically, Jackup operators have sustained minimal hull losses due to hurricanes. Between 1992 and 2005, three (3) units lost stationkeeping in Gulf of Mexico hurricanes. In recent years, deeper prospects, increased drilling rig demands, customer demands, and jackup water depth working capacity have placed units in deeper water depths throughout the Gulf of Mexico area. In retrospect, this trend, in certain instances, placed jackups at or near their maximum water depth capacity and outdated metocean criteria, contributed to the loss of stationkeeping of eight (8) such units during the 2005 hurricane season. Preliminary analysis of the losses to the Jackup fleet and those units that survived indicates the likely causes to be wave inundation and/or foundation failure leading to hull wave inundation.

Abstract Hurricanes Ivan, Katrina and Rita passed through over 3,000 platforms in the Gulf of Mexico during 2004 and 2005. While most structures performed adequately, 123 were destroyed and over 183 had major above and or below water damage. There was no life loss and no significant pollution, which is a tribute to the Minerals Management Service (MMS) oversight and American Petroleum Institute (API) design codes, specifically API RP2A (RP2A) for the structural design of fixed offshore platforms. RP2A has evolved considerably over the past 38 years since its first edition in October 1969. Some of this is attributable to changes in engineering practice and the results of experimental studies. Some is attributable to the experiences and lessons learned in large storms and hurricanes. These three recent hurricanes resulted in the largest number of destroyed and damaged platforms in the history of Gulf of Mexico operations. There are several industry, API and MMS studies underway to understand what went right and what went wrong, and to update industry guidelines and practices accordingly. This paper presents the initial results of a study performed for the MMS on the performance of fixed platforms in these hurricanes. The paper also ties-in findings of the work and its correlation to RP2A design practices. Background While hurricanes are not a welcome sight in the Gulf of Mexico, they do provide opportunity to observe how platforms perform in the storms and if required, an opportunity to update design codes accordingly. In fact, development of RP2A was in part driven by several hurricanes in the late to mid 1960's including Carla (1961), Hilda (1964), Betsy (1965) and in particular hurricane Camille (1969), which was one of the largest hurricanes to impact platforms in the Gulf of Mexico. All of these hurricanes damaged or destroyed platforms and the industry responded with the development of RP2A. In the 1970's, RP2A further evolved and the platforms were tested by hurricanes Carmen (1974) and Frederic (1979). The 9th edition of RP2A was issued in November 1977 and contained the first industry accepted wave load "recipe" including the use of 100 year return period conditions and consistent hydrodynamic drag and inertia coefficients. The 9th edition represents a substantial improvement in platform design, and is in fact demonstrated by the better performance of 9th edition and later RP2A designs in these hurricanes, as describe later. In 1985 hurricane Juan spawned in the Gulf of Mexico as a "Sudden Hurricane" and the industry was not able to evacuate all of the platforms. Several manned platforms were severely damaged, including several that toppled during the storm. Fortunately, there was no direct life loss associated with the fixed platform failures. Later investigation determined that the platforms were older vintage and in need of repair prior to Juan. It was clear that specific guidelines were required for assessment of existing offshore platforms for fitness of purpose. The industry, including significant support from the MMS, began a series of joint industry and special projects, as well as API initiatives to develop an assessment standard for existing platforms. The result was RP2A Section 17, developed in the early 1990's and originally published in 1996 as a supplement to the 20th edition. Interestingly, in 1992 during the development of Section 17, hurricane Andrew damaged or destroyed dozens of older Gulf of Mexico platforms. A hurricane the size of Andrew had not occurred since Camille and provided an opportunity to both test and then calibrate Section 17 during its development. In 2002 hurricane Lili damaged and destroyed several older platforms, something that had not been see