2015 SNAME_Schellstede_2014DEC05 (1)

FUTURE OFFSHORE TECHNOLOGY AND SUSTAINED
RELIABILITY
HERMAN J. SCHELLSTEDE
PRESIDENT, HERMAN J SCHELLSTEDE AND ASSOCIATES, INCORPORATED
Proceedings of the 20th Offshore Symposium, February 2015, Houston, Texas
Texas Section of the Society of Naval Architects and Marine Engineers
Copyright 2015, The Society of Naval Architects and Marine Engineers
ABSTRACT
The coastlines of the United States, both eastern and western, and the Gulf of Mexico have
excellent wind resources. The wind resources are near major population areas whereby power
can be generated having a minimum distance to the end user. The continental shelves that
surround the U.S. allow placement of wind power systems in both state and federally controlled
waters. Employing the technologies generated for oil and gas offshore operations as well as the
advancements of large megawatt class generators, will allow great flexibility to provide efficient
offshore wind farms. The choice of support of the platform is discussed in the paper. The means
and methods for installation of the platform, including cost comparisons are also included in this
paper.
Wind farms have an expected useful life of 25 to 30 years. This paper discusses the design of
the wind farm to accommodate the necessary maintenance required during the useful life of the
wind farm. The cost of offshore maintenance is also illustrated in comparison to long-term power
purchase agreements. This report illustrates the types of structures, installation costs and
maintenance costs which the wind farm developer will be subjected to. The future of offshore
technology is discussed regarding the use of ocean bottom conditions to be the most efficient and
reliable type of renewable energy.
Keywords: SNAME, offshore, symposium, renewable energy, technology, wind, power,
platform, installation, maintenance, cost, efficiency, solar, biomass, natural gas, ocean,
wave, current, hydrothermal, geothermal
INTRODUCTION
The oceans of the world provide an excellent area for the production of renewable energy. Renewable energy
production equates to a very small percentage of the world's power requirements. Various studies have reported that
renewable power availability surpasses the needs of the world’s present and future requirements.
The advent of renewable energy has had very humble beginnings. In recent years, the quest for low cost, clean

Proceedings of the 20th
Offshore Symposium, February 2015, Houston, Texas
2
energy has grown greatly. Global climate changes have been experienced throughout the globe. Many choose to
attribute the climate changes to the use of fossil fuels. The production of power employing renewable sources has
been the focus of inventors, engineers, developers and governmental agencies. Billions of dollars have been
directed towards the vast array of methods to harvest energy.
This paper outlines the present development status of renewable energy projects and the cost to develop and
provide power for sale.
Renewable energy cannot be expected to supply the world's power requirements unless there is a major
transition in the methodology that will allow a practical use of renewable energy. In the past, Americans have
excelled in the development of industry-changing innovations. Nuclear power was developed in a two-year program
resulting in the construction of a nuclear weapon. Americans constructed the Empire State Building (New York
City) in 18 months. The basic question that must be asked is "Why does it require seven years and millions of
dollars for an offshore wind farm to be permitted?" The permitting process system must be revisited and
streamlined in the development of obtaining energy from the world's renewable energy sources.
The oceans of the world constitute over three-fourths of the earth's surface. Governmental and environmental
officials must decide that the offshore waters of the world are vital sources for the development of renewable
energy. The officials must provide a reasonable path to follow regarding the use of offshore water areas. Therefore,
it is mandatory that governments, stakeholders and financial groups be willing to support the offshore energy
developers.
This paper projects the future of offshore power development and lists the milestones that will be reached in this
century.
METHODOLOGY
Renewable Energy Conversion Methods Being Developed
The direction that has been taken concerning the development of renewable energy involves many methods.
The following listing describes several development programs.
 Wind
 Solar
 Biomass
 Ocean Current
 Ocean Wave
 Enhanced Geothermal Systems
In most cases, available power from the above-listed programs cannot produce predictable power levels. Power
storage is also being considered as a method to allow these technologies to be cost efficient. The power storage
methods being developed are as follows:
 Batteries
 Underground Storage Caverns
 Undersea Vessel Storage
 Pumped Water Systems

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 Production of Potable Water
 Production of Nitrogen
 Flywheel Power Storage Systems (Grid Interconnect Service)
Renewable energy being developed has many pathways which require major support systems to produce
dependable power at high demand rates. Each of the above-listed items illustrating conversion and storage has major
limitations such as project costs, low-efficiency power production as well as environmental and permitting matters.
The renewable energy industry must transform the power production plan to consider the replacement of present site
specific projects to larger and more acceptable projects which will allow a greater return on investment and provide
a low cost of energy. The historical power cost of renewable energy compared to conventional electrical power
produced by coal or gas-fired plants illustrates a marked increase.
Technology has improved the efficiency of both wind and solar translating systems. However, an increase in
cost has been encountered in recent years. One of the major cost components is related to governmental regulations,
environmental concerns and the overall permitting time schedule.
In North America, there are no offshore operational wind farms; therefore, the actual costs are only projections.
Based on the offshore power cost, a substantial sales price must be received to consider the project economically
viable. The locations that are ideal for renewable energy facilities are located in offshore waters.
The author of this paper obtained the first offshore wind farm lease in the U.S. and has leased 94,000 offshore
acres offshore the Texas coastline. The leases were obtained from the Texas General Land Office. The process was
very simple, direct and affordable. State, federal and international renewable power leases can be structured and can
be one of the development components that require the least amount of time and funding. The offshore oil and gas
industry has produced the technology to supply suitable platforms to support renewable energy operations in the
open ocean. The offshore oil and gas industry has operated in shallow and deep waters throughout the world. It can
be stated that offshore technology and the support of offshore operations is well established and will assist in
renewable power operations offshore.
The offshore wind power operations are supported by platforms which are employed in the offshore oil and gas
industry. The platforms are modified to accommodate support for wind systems, transformer facilities and security
stations. Table 1 illustrates typical offshore platforms that will be employed for offshore wind power operations.
The platform systems illustrated in Table 1 have been employed in global operations.
Platform Type Platform Description Operating
Water
Depth
Installation
Method
Tripod Platform
(Caisson)
Bottom attached by driven
piles
8' - 350' Liftboat or derrick
barge
Tripod Platform
(3 or 4 pile unit)
Bottom attached by driven
piles
20' - 250' Liftboat or derrick
barge
Jackup Vessel Tubular or lattice leg units 10' - 450' Self-Installation
Spar Vessel Tension leg to bottom 50' - 4,700' Self-Installation
Truss Spar Tension leg to bottom 200' - 8,500' Self-Installation
Ultra-Deep Platform Lattice Type Platform -
Bottom Attached
1500' - 2100' Derrick Barge
Table 1 Typical Offshore Platforms

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Figure 1 illustrates a typical jacket unit designed for shallow water. Figure 2 illustrates a typical deck unit. The
jacket and deck units were installed offshore Galveston, Texas USA in 2007.
Figure 1 Typical Shallow Water Jacket Unit
Figure 2 Typical Deck Unit

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Figure 3 illustrates a typical jackup drilling vessel.
Figure 3 Jackup Platform Outfitted for Drilling
Figure 4 illustrates a spar outfitted for drilling production - deep water service.
Figure 4 - Spar Unit

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Figure 5 illustrates ultra deep bottom-attached platforms operating in 2,100’ water depth.
Figure 5 – Petronius Ultra Deep Water Depth Offshore Platform

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Figure 6 illustrates a lower section of a hybrid platform constructed of concrete. The upper drilling platform is
constructed of steel.
Statfjord B. Illustration: Statoil
Figure 6 - ConDeep Platform - Stratfjord B
Global classification societies have approved the above illustrated platform design. The developer has the
freedom to choose various platforms for a specific use. Therefore, minimal design and engineering efforts are
required.
Table 2 illustrates the installation equipment which is required to install platforms as illustrated in Table 1.
Installation Vessel Operating Water
Depth
Installation Vessel General Design Features
Derrick Barge 20' - 1,500' Crane Capacity 1,000 T
Mooring System: 8-point anchor spread
Derrick Barge 500' - 5,000' Crane Capacity 3,000 T
Mooring System: driven pile / tether system
Liftboat 8' - 250' Crane Capacity 2 T - 250 T
Mooring System: Legs extended and pontoons lowered
Table 2 Platform Installation Equipment

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Figure 7 illustrates a typical derrick barge used for installation of platform.
Figure 7 Typical Derrick Barge
Figure 8 illustrates a typical liftboat.
Figure 8 Typical Liftboat Vessel

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The offshore platform and support vessels can accommodate the offshore renewable energy developers’
requirements. The platforms and support vessels are operated by trained personnel. The specific infrastructure is in
place and can support the demands of the offshore developers on a global basis.
Figures 1-8 illustrate developments provided by the offshore oil and gas industry. The support equipment
which operates in concert with the platform structures has also been developed and provided by the offshore oil and
gas industry. It can be stated that with minor adjustments, offshore platforms, i.e., shallow and deep water, can be
employed to advance the offshore renewable industry greatly and remove high risk concerns of operating in harsh
offshore waters.
Renewable Energy Translation Options
The offshore waters support many of the present developments such as wind, solar, ocean currents, ocean wave
and geothermal methods. Most of the renewable sources must be supported by power storage methods. Therefore,
the power cost is increased due to the capacity factors of the various processes.
One of the major considerations regarding the choice of renewable energy sources is capacity factor. Power
storage is expensive and not efficient at this time. The renewable energy sources that require no power storage and
have a high degree of sustained reliability is thermal energy translated from heated structures existing throughout the
world’s ocean floor. The following study illustrates an order of magnitude of the cost of produced energy.
Renewable Energy Costs
The cost of electric energy produced by renewable sources vary due to translating methods, location, efficiency
of methods, sales points and governmental investment plans. The following costs illustrate a cross-section of a
renewable energy price structure.
Wind
Onshore Minimum 63.4$/MWH
Average 73.1$/MWH STORAGE REQUIRED
Maximum 82.9$/MWH
Offshore Minimum 140.9$/MWH
Maximum 225.3$/MWH
Solar
In recent years, solar power has made outstanding advancements in efficiency which has lowered the solar
price. The solar price structure illustrated below is dependent on the location, capacity factors, etc.
Solar PV Minimum 86.5$/MWH
Maximum 170.2$/MWH

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Onshore Solar Thermal
Minimum 148.6$/MWH
Maximum 325.6$/MWH
Biomass
Biomass fuels have been a source of renewable energy for many years. Due to the power generating plant
location, various sales prices are noted. The following illustrates typical sales prices of electrical power.
Average 97$/MWH
Maximum 118.8$/MWH
Dispatchable Technologies
The cost of conventional standard power is as follows:
Conventional Coal
Minimum 78.4$/MWH
Average 87.0$/MWH
Maximum 106.7$/MWH
Natural Gas-Fired
Conventional Combined Cycle
Minimum 75.8$/MWH
Average 81.2$/MWH
Maximum 94.0$/MWH
Advanced Combined Cycle
Minimum 73.4$/MWH
Average 77.8$/MWH
Maximum 89.4$/MWH
Advanced Nuclear
Minimum 80.2$/MWH
Average 83.0$/MWH
Maximum 87.6$/MWH
NOTE: The values illustrated above are for comparison purposes only. The values stated relate to early 2014
values. The intent of the cost values is to illustrate the present cost range of renewable energy. The potential to
achieve renewable energy rated at dispatchable technologies illustrate that enhanced geothermal systems approach
the present standard commercial energy prices. The projected price of all power generating systems must consider
the length of transmission lines as well as environmental considerations, useful life and maintenance costs.

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Ocean Current/Ocean Wave
The two ocean-based technologies are now in the development stages and firm cost data is not available
Hydrothermal (Ocean Depth Differential System)
Hydrothermal systems based on ocean temperatures are not commercialized at this time.
Minimum 340$/MWH
Maximum 540$/MWH
Enhanced Geothermal Systems
The advanced thermal systems possess the greatest source of renewable energy reserves considering global
offshore areas. The translating methods have been tested and proven. The following prices are recent estimates.
Average 67.8$/MWH
Maximum 81.3$/MWH
Offshore Minimum 140.9$/MWH
Average 170.3$/MWH Note: (Projected Values)
Maximum 225.3$/MWH
Maintenance Cost and Useful Life of Systems
The equipment of various power translating systems, i.e., wind, solar, biomass, ocean power, hydrothermal,
and enhanced geothermal systems require maintenance or replacement of major items. Initial renewable energy
projects that were developed over 20 years ago focused their studies on initial capital costs. Projection of return on
investments was made without adequate knowledge of maintenance and repair costs. Many projects entered into
power purchase agreements without a good definition of maintenance costs.
Present development programs have considered maintenance costs. The following are estimates of maintenance
costs related to a specific translating system.
Costs being employed from developer's data regarding different renewable energy methods are as follows:

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Maintenance Cost of Translating Methods
The following maintenance costs for the various renewable energy systems.
Renewable Energy Power Maintenance Cost Based on:
Wind Onshore 60 $/kW-yr
Fixed O&M Cost
(2010)
Wind Offshore 100 $/kW-yr
Fixed O&M Cost
Fixed Bottom Platform
Solar 50 $/kW-yr
Fixed O&M Cost
Commercial PV w/ 100 kW (DC)
(2010)
Biomass 95 $/kW-yr
Fixed O&M Cost
Stand alone Biomass Power Plant
(50 MW Net)
Ocean Tidal Current 198 $/kW-yr
Fixed O&M Cost
(2015)
Ocean Wave 474 $/kW-yr
Fixed O&M Cost
(2015)
Hydrothermal 31 $/MWh
Variable O&M Cost
Enhanced Geothermal 31 $/MWh
Variable O&M Cost
Table 3 Maintenance Cost for Renewable Systems
The values are within reason regarding maintenance costs but will have a direct effect on the profitability of the
program and must be included in planning. Offshore maintenance pertaining to wind, ocean currents and ocean
waves is greatly affected by the availability of vessels, crane barges and offshore technologies and has an
exponential effect on the cost of maintenance if major maintenance or equipment replacement of components is
required.
The present designs of offshore wind turbine systems include fixed hub heights. The turbine towers support
massive equipment and blades at hub-height. Therefore, for general maintenance of offshore facilities, access to the
equipment located at the tower top is required. In the case of major repairs or replacement, high lift marine cranes
are required. The "call out" of major marine equipment is very expensive and, in some cases, will exceed the budget
of annual maintenance by 100% considering one event.
The offshore oil and gas industry has provided many methods to "replace" major items instead of conducting
offshore repairs. This system has been very efficient and trouble-free. Renewable methods must implement
maintenance programs to avoid major failure of equipment. Offshore developers must demand that the renewable
energy manufacturers provide design engineering which will prevent unexpected failure of equipment based on
warranty arrangements. It can be observed that major offshore emergency maintenance and repairs must be avoided
at all costs. .
Major maintenance programs must be in place and implemented to avoid offshore equipment failure. Table 4
illustrates typical maintenance programs which will be required regarding offshore platforms and renewable energy
translating devices.

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Table 4 illustrates an industry standard equipment maintenance schedule.
Typical Offshore
Translating System
Projected
Useful Life
Remarks
Conventional Wind
Turbine with Gear Box
Drive (Low Speed)
25 yrs High Maintenance prone to
experience gear box failure
Conventional Wind
Turbine with Medium
Ratio Gear Box
25 yrs Medium Maintenance less
gear box problems
Conventional Wind
Turbine with Direct
Drive System
25 yrs Low Maintenance wind
system
Solar Driven Power 25 yrs Low Maintenance Cost
Solar Powered
Arrangement
25 yrs Low Maintenance Cost
Ocean Wave / Current
Power
Hydrothermal (Ocean)
Power
Enhanced Geothermal
Systems
Table 4 Typical Maritime Maintenance Programs
In support of the cost to produce energy, power storage is required. Figure 9 illustrates the typical capital cost
to provide power storage. Three energy storage technologies are being developed, i.e., compressed air energy
storage, pumped storage hydropower technology and battery energy storage technology
Figure 9 Capital Cost of Compressed Air Energy System

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Figure 10 illustrates pumped storage hydropower technology.
Figure 10 Capital Cost of Pumped Storage Hydropower Technology
Figure 11 illustrates battery energy storage technology.
Figure 11 Battery Energy Storage Technology
Energy storage systems have a high capital cost and substantial operational and maintenance costs.
It is studied opinion of the author of this paper that total and timely efforts be directed towards the development
of enhanced geothermal system technology operating from offshore facilities. It is important to maintain the
momentum of the present technologies, however, the present technologies should be in commercialized. New
developments must be directed towards the geothermal system which supply power to meet global needs.

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Summary of Renewable Energy Methods
Upon reviewing the renewable power methods, it can be concluded that renewable methods in present form
cannot be expected to replace conventional electric production means. It can also be concluded that the price
structure of renewable energy does not compete with power produced by conventional means due to the renewable
process capacity factors. New development funding must be directed toward offshore enhanced geothermal
systems. Within 20 years, a major source of the world’s power requirements can be supplied by the ocean’s bottoms.
Future Developments
Renewable energy which is considered to be environmentally acceptable must be supplied on a large scale to
accommodate the global power requirements. It is the opinion of the author of this paper that a departure from the
present, well established renewable technologies should be implemented. It is further recommended that the bulk of
research funding be directed towards the development of offshore enhanced geothermal systems.
Recently, scientists have revealed a new map of the world’s sea floor. Thousands of previously uncharted areas
have been identified. Thousands of “sea mounds” have emerged from the new mapping technology. Most sea
mounds were once active volcanoes. The new mapping gravity anomaly and satellite images determined that many
of the sea mounds are covered with one mile of sediment.
Figure 12 illustrates the north Atlantic (vertical gravity gradient).
Figure 12 North Atlantic - Vertical Gravity Gradient

16
Figure 13 illustrates the Central Indian Ocean (vertical gravity gradient).
Figure 13 Central Indian Ocean - Vertical Gravity Gradient
Figure 14 illustrates the general activity in the Caribbean Sea and the west coast of South and Central America.
Figure 14 Caribbean Sea - Vertical Gravity Gradient

17
The near shore location of the ocean provides an excellent area to obtain power from the ocean bottom by use of
shallow and deep enhanced geothermal programs.
The technology necessary to produce electrical power from the vast oceans employing standard geothermal
sources is available at this time. The primary providers that are prepared for service and commercialization of
E.P.S. are as follows:
 Offshore structures are available to support the enhanced shallow and deep geothermal process.
 Drilling contractors who operate jack-up rigs, drill ships, platform rigs and semi-submersible units are prepared
to serve both onshore and offshore operations. Drilling is being conducted in offshore waters of 12,000’ and
drilling depths to 30,000’ with present equipment designed for high-temperature service.
 The formation fracking process is well established onshore for the enhancement of oil and gas reserves. The
identical procedures can be employed to expand the formation’s contact surfaces for power from thermal
energy.
 Steam generation of power has been greatly improved in the past decade. Equipment to transfer the thermal
process to electrical power is well established and has been proven to be very efficient.
 Electrical transmission of power in deep, underwater locations is being conducted throughout the world. New
cable designs are being provided to greatly reduce power losses in cables. Nano technology is being researched
to improve the design of new transmission cables.
 Underwater, fully automated oil and gas wells have been developed to operate in water depths of over 10,000’.
These systems are designed for the production of oil and gas. These automated systems can be employed in
thermal energy transfer.
 Management and personnel are available in both the drilling and production phases of offshore services.
Therefore, the work force is trained to conduct offshore services.
As can be seen, the proposal to obtain energy from the ocean floor is not a far-reaching concept, but can be
implemented in less than 10 years. Future developments implementing advanced offshore processes can successfully
meet the goal of providing the world with energy at an affordable rate with a very high capacity factor and without
harm to the environment.
The development of geothermal renewable energy is reliable and economical operating from offshore
installations. Consult Figure 15 for a typical directional fracked well.

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Figure 15 Typical Horizontal Fracked Well
CONCLUSION
Global renewable energy groups must depart from the present translating systems, i.e. wind, sales, waves,
currents, biomass and move forward for the development of geothermal energy employing new proven offshore
platforms and drilling methods.
Geothermal energy is distributed in vast areas of the earth. In many cases, the sites are very near major ports
and cities. It is envisioned that a typical bottom-fixed platform can provide large quantities of power very near the
end user.
Enhanced geothermal programs have technical procedures that are being addressed. The advent of horizontal
well development and the ability to expose more surface area is being conducted on a regular basis.
The fracking process will allow one well drilled horizontally and fracked to produce tenfold power capacity.
Therefore, one platform may drill a 12 well thermal program in a horizontal mode as compared to 120 conventional
wells being drilled with conventional straight hole drilling. Figure 16 illustrates this comparison
Figure 16 Traditional Wells vs. Horizontal Fracked Wells

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Horizontal wells are being completed with a horizontal leg over 9000'. This technology is not in the
development stages; it has been pioneered and commercialized. Included in this new direction for the development
of an efficient renewable energy source, the universities, colleges, governmental agencies and research labs should
be asked for solutions to problems which still exist in the use of enhanced geothermal methods.
It is the studied conclusion that the earth has provided many natural resources of which humanity has
survived and progressed. The earth's sub-bottom renewable energy source must be employed to preserve the quality
of living which exists and to provide an environmentally-friendly form of energy.
REFERENCES
Black & Veatch, National Renewable Energy Laboratory, "Cost Report: Cost and Performance Data for Power
Generation Technologies", Feb. 2012
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IRENA (International Renewable Energy Agency), "Renewable Power Generation Costs in 2012: An
Overview", 2013
Jansen, Robin, "All Hands on Deck", web: robinjansen.wordpress.com, Photo compliments of nt.gov.au
Lawver, L., Dalziel, I. and Sandwell, D., "Antarctic Plate: Tectonics from a Gravity Anomaly and Infrared
Satellite Image", GSA Today, Geological Society of America, v. 3, n. 5, 1993.
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Renewable Energy Technical Potentials: A GIS-Based Analysis", DE-AC36-08GO28308, July 2012
Massachusetts Institute of Technology (MIT), "The Future of Geothermal Energy: Impact of Enhanced
Geothermal Systems (EGS) on the United States in the 21st Century", 2006
Marine Data from Satellite Altimetry, http://topex.ucsd.edu/grav_outreach/, Institute of Geophysics and
Planetary Physics, Scripps Institution of Oceanography, Univ. of California, San Diego, Updated Oct 2014
National Science Foundation, "New Map Uncovers Thousands of Unseen Seamounts on Ocean Floor", PR 14-
133, 2014
Rigzone, "How do Spars Work?", web: https://www.rigzone.com/training/insight.asp?insight_id=307&c_id=12
Sandwell, D, et al, Science 346, "New Global Marine Gravity Model from CryoSat-2 and Jason-1 reveals
buried tectonic structure", Oct. 2014
Stratfjord, Norsk Oljemuseum, web: http://www.norskolje.museum.no/modules/module_123/proxy.asp?D=2&
C=266&I=3160
Texas Natural Gas Now, "Hydraulic Fracturing and Horizontal Drilling", web: texasnaturalgasnow.com
US Department of Energy, "2013 Wind Technologies Market Report", August 2014
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Resources in Annual Energy Outlook 2014", April 2014

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