NO20210632A1 - Offshore uninteruptable power supply system - Google Patents

Offshore uninteruptable power supply system Download PDF

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Publication number
NO20210632A1
NO20210632A1 NO20210632A NO20210632A NO20210632A1 NO 20210632 A1 NO20210632 A1 NO 20210632A1 NO 20210632 A NO20210632 A NO 20210632A NO 20210632 A NO20210632 A NO 20210632A NO 20210632 A1 NO20210632 A1 NO 20210632A1
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NO
Norway
Prior art keywords
power supply
supply system
hydrocarbon producing
hcpi
energy storage
Prior art date
Application number
NO20210632A
Other versions
NO347202B1 (en
Inventor
Eystein Borgen
Håkon Klepsvik
Original Assignee
Odfjell Oceanwind As
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Odfjell Oceanwind As filed Critical Odfjell Oceanwind As
Priority to NO20210632A priority Critical patent/NO347202B1/en
Priority to BR112023024309A priority patent/BR112023024309A2/en
Priority to PCT/EP2022/063116 priority patent/WO2022243211A1/en
Priority to GB2318534.1A priority patent/GB2621798A/en
Publication of NO20210632A1 publication Critical patent/NO20210632A1/en
Publication of NO347202B1 publication Critical patent/NO347202B1/en

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/062—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for AC powered loads
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D13/00—Assembly, mounting or commissioning of wind motors; Arrangements specially adapted for transporting wind motor components
    • F03D13/20—Arrangements for mounting or supporting wind motors; Masts or towers for wind motors
    • F03D13/25—Arrangements for mounting or supporting wind motors; Masts or towers for wind motors specially adapted for offshore installation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D9/00—Adaptations of wind motors for special use; Combinations of wind motors with apparatus driven thereby; Wind motors specially adapted for installation in particular locations
    • F03D9/10—Combinations of wind motors with apparatus storing energy
    • F03D9/11—Combinations of wind motors with apparatus storing energy storing electrical energy
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/40—Synchronising a generator for connection to a network or to another generator
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
    • B63B35/44—Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices
    • B63B2035/4433—Floating structures carrying electric power plants
    • B63B2035/446—Floating structures carrying electric power plants for converting wind energy into electric energy
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
    • B63B35/44—Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices
    • B63B2035/4473—Floating structures supporting industrial plants, such as factories, refineries, or the like
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
    • B63B35/44—Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices
    • B63B2035/448—Floating hydrocarbon production vessels, e.g. Floating Production Storage and Offloading vessels [FPSO]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2220/00—Application
    • F05B2220/61—Application for hydrogen and/or oxygen production
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2240/00—Components
    • F05B2240/90—Mounting on supporting structures or systems
    • F05B2240/93—Mounting on supporting structures or systems on a structure floating on a liquid surface
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/28—The renewable source being wind energy
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2310/00—The network for supplying or distributing electric power characterised by its spatial reach or by the load
    • H02J2310/10—The network having a local or delimited stationary reach
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B10/00—Integration of renewable energy sources in buildings
    • Y02B10/70—Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • General Engineering & Computer Science (AREA)
  • Emergency Management (AREA)
  • Business, Economics & Management (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Control Of Eletrric Generators (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Description

FIELD OF THE INVENTION
The present invention relates to an uninterruptable power supply system for an offshore, hydrocarbon producing installation.
BACKGROUND OF THE INVENTION
Offshore hydrocarbon producing installations are today typically supplied with electric power from one or more gas turbines located on the hydrocarbon-producing installation. As the power consumption of such installations are relatively high, and the efficiency of the gas turbines are often poor, the emissions of CO2, NOx and other gases are relatively high.
Alternative ways of supplying such installations with electric power have been discussed. One alternative is to supply electric power from land via cables. Such cables are expensive, and redundancy based on such cables will rarely be an option. The cable therefore represents a single point of failure. However, as the startup time for the gas turbine is approximately 30 minutes, there will be a risk of a black-out during this time. Emergency generators may be installed on the offshore hydrocarbon producing installations, but these will also require a certain start-up period during which time there would be no electricity available. Such emergency generators can also become non-operational or impossible to use due to a sudden incident, like an explosion, fire, gas leakage or other accidents.
Another alternative is to supply electric power to the installations from offshore wind turbines. It should be noted that the power produced by wind turbines will fluctuate over time due to variations in available wind. Hence, the gas turbines will be running in parallel with the wind turbines as a redundancy, as an interruption in the electrical power supply during some operations could have major consequences.
One known such project is the Hywind Tampen project, which will supply electric power to several installations. The gas turbine(s), will here be running in parallel with the wind turbines as spinning reserve to ensure a stable local grid, keeping both the voltage and frequency within specified limits at all times and also to immediately take over all the power supply if the wind turbine should experience a sudden shut-down.
One disadvantage with the above prior art technology is that there is a risk of a sudden black-out, i.e. interruption in the power supply, for the scenario when running a power system on gas turbines on board the offshore hydrocarbon producing installations, or the power supply is via a cable to shore, or the power supply is combined with locally produced wind or solar power.
Another disadvantage with the above prior art technology is that the gas turbines onboard the platforms have to run in an idling mode as a redundancy and to ensure a stable voltage and frequency level on the platform, typically at minimum 4-5MW for each gas turbine, even if there is theoretically enough wind energy available to temporally supply 100% of the load. It should be noted that the gas turbine has considerable emissions even when operating in idle mode.
NO 20191054 describes an energy system for supply of power to a Mobile Offshore Drilling Unit. The energy system comprises: - a first storage and supply device, - a second storage and supply device, - a remote power generation source for supplying power to the first and/or second storage and supply device via one or more electrical cables. The first storage and supply device are configured to store and provide sufficient power for one or more end users onboard the Mobile Offshore Drilling Unit. The second storage and supply device as a minimum is configured to store and provide sufficient power to secure a well in case of a combined situation of a well control incident and loss of the remote power generation source. The second storage and supply device may be a battery or battery bank located on the Mobile Offshore Drilling Unit.
One way of reducing the risk of a black-out on an offshore hydrocarbon producing installation is to install a battery storage onboard the offshore hydrocarbon producing installation. However, the risk of fire or an explosion in the storage system is a disadvantage that limits this possibility.
Another way of increasing redundancy in the power supply to an offshore hydrocarbon producing installation is to install diesel generators, which has a considerably shorter startup time than the gas turbines. This is currently the standard method but has its disadvantages in that the diesel generators can have a start-up time of several minutes and will not be able to supply the power immediately, hence the risk of a total black-out is still considerable.
Yet another way of increasing the redundancy in the power supply to an offshore hydrocarbon producing installation is to import power from shore via a subsea cable. However, a cable to shore is expensive, and if the gas turbines are stopped, there is still a risk of a total black-out in the case of a fault in long electrical cables to shore.
One objective of the present invention is to provide a safe and reliable uninterruptable power supply system for an offshore hydrocarbon producing installation, wherein the uninterruptable power supply system having a reduced risk of malfunctioning in case of an interruption in the power supply.
SUMMARY OF THE INVENTION
The present invention relates to an uninterruptable power supply system for an offshore hydrocarbon producing installation, wherein the uninterruptable power supply system comprises:
- an offshore foundation separate from the hydrocarbon producing installation; - an energy storage located on or inside the offshore foundation;
wherein the energy storage is electrically connected to the hydrocarbon producing installation for supplying electric power to the hydrocarbon producing installation during an interruption of a power supply of the hydrocarbon producing installation.
In one aspect, the power supply of the hydrocarbon producing installation is a fuel powered power plant. The fuel powered power plant may be a gas turbine, a diesel generator etc. The fuel powered power plant is typically located on the hydrocarbon producing installation.
In one aspect, the power supply of the hydrocarbon producing installation is a wind turbine system. The wind turbine system is typically located on foundations separate from the hydrocarbon producing installation.
In one aspect, the power supply of the hydrocarbon producing installation is an onshore power supply transferred offshore by means of a power supply cable.
The power supply of the hydrocarbon producing installation may also comprises solar power and/or combinations of the above.
According to the invention, the operation of the hydrocarbon producing installation may continue even if there is an unexpected interruption in the power supply of the hydrocarbon producing installation, due to the capacity of the energy storage to immediately supply power to the hydrocarbon producing installation. Hence, safety will be improved and equipment for backup power supply to the hydrocarbon producing installation, such as diesel generators, may be removed from the hydrocarbon producing installation HCPI.
According to the invention, as the offshore foundation is separate from the hydrocarbon producing installation, space and/or weight restrictions of the hydrocarbon producing installation will not negatively affect the uninterruptable power supply system. In particular, dimensions of the energy storage system will not be negatively affected by the space and/or weight restrictions of the hydrocarbon producing installation.
According to the invention, as the offshore foundation is separate from the hydrocarbon producing installation, safety and/or security restrictions of the hydrocarbon producing installation will not negatively affect the uninterruptable power supply system. Similarly, safety and/or security restrictions of the uninterruptable power supply system will not negatively affect the hydrocarbon producing installation. As an example, there has been some safety and/or security restrictions related to fire-prevention of Lithium-types of batteries commonly used in energy storage systems. In a worst-case scenario, should a fire start on the hydrocarbon producing installation, the risk of fire propagating to the energy storage system is considerably reduced. Similarly, should a fire start in the energy storage system, the risk of fire propagating to the hydrocarbon producing installation is considerably reduced.
In one aspect, the energy storage is electrically connected to the hydrocarbon producing installation for supplying electric power to the hydrocarbon producing installation during a sudden and/or unexpected interruption of a power supply of the hydrocarbon producing installation.
In one aspect, the energy storage comprises a first storage capacity dimensioned for a sudden and/or unexpected interruption of the power supply of the hydrocarbon producing installation. The first storage capacity may be dimensioned to supply power for a startup period the power supply of the hydrocarbon producing installation. The first storage capacity may be dimensioned to other properties of the power supply of the hydrocarbon producing installation.
The entire energy storage may be dimensioned for such sudden and/or unexpected interruptions of the power supply of the hydrocarbon producing installation.
In one aspect, the energy storage comprises a second storage capacity dimensioned to handle fluctuations in the load and/or fluctuations in the power supply of the hydrocarbon producing installation. Equalization of fluctuations in load may allow fuel powered power plants to achieve higher power efficiency. Equalization of fluctuations in the power supply will contribute to a more stable and robust power supply for the hydrocarbon producing installation.
Hence, the first storage capacity provides for uninterruptable power in case of sudden and/or unexpected interruptions, while the second capacity provides for equalization of fluctuations in load and/or the power supply of the hydrocarbon producing installation.
In one aspect, the offshore foundation is located spaced apart from the hydrocarbon producing installation, and wherein the energy storage is electrically connected to the hydrocarbon producing installation via a power cable.
The present invention also relates to a uninterruptable power supply system to any one of the above claims, wherein the offshore foundation is a floating foundation comprising buoyancy members, wherein the energy storage is located on or inside the at least one buoyancy members.
In one aspect, the floating foundation comprises at least three buoyancy members; wherein:
- the energy storage is located on or inside a first buoyancy member and/or on or inside a second buoyancy member.
In one aspect, a ballast of the floating foundation is at least partially provided by the weight of the energy storage.
In one aspect, at least 5 %, preferably at least 10 %, of the ballast of the floating foundation is provided by the weight of the energy storage.
In one aspect, the energy storage is a rechargeable battery or a plurality of rechargeable batteries.
In one aspect, the energy storage is dimensioned according to a property of the power supply of the hydrocarbon producing installation.
In one aspect, a property of the power supply of the hydrocarbon producing installation is a start-up period for the power supply of the hydrocarbon producing installation and wherein the energy storage is dimensioned to supply power to the hydrocarbon producing installation for a period of time corresponding to at least the start-up period.
In one aspect, a property of the power supply of the hydrocarbon producing installation is a maximum power for the power supply of the hydrocarbon producing installation.
In one aspect, a property of the power supply of the hydrocarbon producing installation is a short circuit capacity for the power supply of the hydrocarbon producing installation.
In one aspect, the uninterruptable power supply system comprises a frequency reference generator for generating a frequency reference for the electric power supplied to the hydrocarbon producing installation.
In one aspect, the frequency reference generator is provided in communication with, and is synchronized with, a frequency generator of the hydrocarbon producing installation.
In one aspect, the uninterruptable power supply system comprises a cooling system for cooling the energy storage, wherein the cooling system comprises:
- a cooling fluid circulation pump for circulation of cooling fluid through a cooling fluid circuit;
- a heat exchanger connected to the cooling fluid circuit, wherein the heat exchanger is submerged in ballast water.
In one aspect, the cooling system further comprises a valve for controlling the flow of the fluid in the cooling fluid circuit.
In one aspect, the heat exchanger is submerged in the ballast water in one of the buoyancy members.
In one aspect, the uninterruptable power supply system comprises a power management system for controlling power supplied to prioritized loads of the hydrocarbon producing installation based on a presently available short circuit capacity of the energy storage.
In one aspect, the uninterruptable power supply system comprises:
- a wind turbine installed on the offshore foundation;
- a first power converter for converting power produced by the wind turbine to energy stored in the energy storage.
In one aspect, the uninterruptable power supply system comprises a cable terminal connectable to the power cable, wherein the cable terminal is electrically connected to AC terminals of the first power converter.
Alternatively, in case there is no wind turbine installed on the offshore foundation, the uninterruptable power supply system may comprise the first power converter for the purpose of converting power produced by the power supply of the hydrocarbon producing installation, typically AC power, to DC power used to recharge the rechargeable batteries of the energy storage. The first power converter is also used converting DC power from the rechargeable batteries of the energy storage to AC power supplied via the AC power cable to the hydrocarbon producing installation during an interruption.
In one aspect, the foundation is a floating foundation and wherein the wind turbine is located on at least one buoyancy member of the floating foundation.
In one aspect, the wind turbine is forming at least a part of the power supply of the hydrocarbon producing installation.
During periods of high winds, the power produced by the wind turbine will be sufficient to recharge the energy storage and to supply power to the hydrocarbon producing installation. During periods with low wind or no wind, the energy storage is preferably also dimensioned to supply sufficient electric power to the hydrocarbon producing installation.
Periods with low wind or no wind may be predicted, for example based on a weather forecast and gas turbines may be safely started to take over the power generation. However, the wind turbine or the wind turbine system may suffer a sudden technical fault and shut down within seconds, or at least within one minute. Also other interruptions of the power supply may be sudden, for example an explosion or fire on board the offshore hydrocarbon producing installation, a sudden reduction in the power generating equipment supplying power to said installation due to a failure etc. The uninterruptable power supply system will be able to supply power to the offshore, hydrocarbon producing installation in all of the above situations.
In other aspects, the wind turbine together with a fuel powered power plant are forming the power supply of the hydrocarbon producing installation. Here it may be possible to turn off the fuel powered power plant of the hydrocarbon producing installation in time periods when renewable energy is produced by the wind turbine, and to increase the time until the gas turbines will have to be re-started as some of the energy in the storage system may be used to even out fluctuations in the available wind energy. This will reduce emissions considerably, as a gas turbine has considerable emissions even when operating in idle mode.
In one aspect, the buoyancy member on which the wind turbine is located is different from the buoyancy member on or in which the energy storage is located.
In one aspect, the floating foundation comprises three buoyancy members in a triangular configuration.
In one aspect, the floating foundation comprises four buoyancy members in a rectangular configuration.
In one aspect, the floating foundation is a semi-submersible platform. Alternatively, the floating foundation may be a spar type of platform.
In one aspect, the first power converter is a bidirectional power converter for converting AC power produced by the wind turbine or by the power supply of the hydrocarbon producing installation to a DC power supplied to the battery and for converting DC power stored in the battery to an AC power supplied to the hydrocarbon producing installation.
In one aspect, the uninterruptable power supply system is configured to supply electric power to the hydrocarbon producing installation simultaneously from the wind turbine and the energy storage.
In one aspect, the maximum current supplied by the energy storage and the wind turbine in total is at least two times, preferably four times, the rated maximum current of the power supply located on the hydrocarbon producing installation.
In one aspect, the maximum power supplied by the energy storage and the wind turbine in total exceeds the rated maximum power of at least one of the generators or gas turbines of the power supply located on the hydrocarbon producing installation.
In one aspect, the uninterruptable power supply system comprises a second power converter connected between the wind turbine and the cable terminal.
Alternatively, the first power converter is a hydrogen plant for producing hydrogen and the energy storage is a hydrogen storage for storing the hydrogen produced by the hydrogen plant. The first power converter may also here comprise an AC-DC converter, possibly in combination with a transformer, for converting the AC power produced by the wind turbine to a suitable electric power for the hydrogen plant. Electric power may be produced by fuel cells fuelled by the hydrogen from the energy storage and transferred via the power cable to the hydrocarbon producing installation. Alternatively, the hydrogen may be used as fuel on the hydrocarbon producing installation. The hydrogen is here transferred from the energy storage to the hydrocarbon producing installation.
As used in the description herein, the term “offshore hydrocarbon producing installation” is here referring to one offshore platform or a group of platforms located nearby each other. The term “platform” may typically be a structure standing on the seabed, but may also be a floating structure anchored to the seabed. In addition to the one or the group of platforms, the installation may also comprise subsea units, such as separators, pumps etc. Such subsea units may also require electrical power.
DETAILED DESCRIPTION
Embodiments of the invention will now be described in detail with reference to the enclosed drawings, wherein:
Fig. 1 illustrates a perspective view of a first embodiment of a power supply system;
Fig. 2 illustrates a schematical perspective view of the first embodiment;
Fig. 3 is a diagram of the first embodiment;
Fig. 4 illustrates the content of the first power converter;
Fig. 5 illustrates the cooling system schematically;
Fig. 6 illustrates the frequency control system;
Fig. 7 illustrates a power management system;
Fig. 8 is a diagram of a second embodiment;
Fig. 9 is a diagram of a third embodiment;
Fig. 10 is a diagram of a fourth embodiment.
First embodiment
Initially, it is referred to fig. 1, wherein an uninterruptable power supply system 1 is shown. The uninterruptable power supply system 1 is connected to an offshore hydrocarbon producing installation HCPI via a power cable PC. The installation HCPI may be a drilling platform type of installation (floating types, seabed fixed types), a FPSO (a floating production, storage and offloading) type of installation, an oil and/or gas production platform or any other type of offshore installation involved with production of hydrocarbons.
In the present embodiment, the installation HCPI is a drilling platform.
The offshore hydrocarbon producing installation HCPI comprises a power supply 120 located on the platform. In the present embodiment, the power supply 120 is a fuel powered power plant 120, such as a gas turbine, a diesel generator etc.
It is now referred to fig. 1 and fig. 2. Here it is shown that the uninterruptable power supply system 1 comprises a floating offshore foundation 10 comprising three buoyancy members 11a, 11b, 11c in a triangular configuration. As shown in fig. 2, the uninterruptable power supply system 1 comprises an energy storage 30 in the form of rechargeable batteries inside the first buoyancy member 11a and inside the second buoyancy member 11b. The weight of the energy storage 30 is used as part of the ballast of the floating foundation 10.
The uninterruptable power supply system 1 further comprises a wind turbine 20 located on the third buoyancy member 11c. As used herein, the term “wind turbine” refers to the entire system needed to produce electric energy from wind, i.e. a mast with a nacelle containing a shaft connected to rotor blades and a generator. The wind turbine may further comprise mechanical and/or electrical equipment such as gearboxes, brakes, frequency converter, transformer, and controllers for controlling the electrical and/or mechanical equipment etc. The wind turbine 20 is considered known for a skilled person and will not be described in detail herein.
It is now referred to fig. 2, fig. 3 and fig. 4. Here it is shown that the uninterruptable power supply system 1 further comprises a first power converter 40, which in the present embodiment is located together with the energy storage 30 inside the first buoyancy member 11a and inside the second buoyancy member 11b.
The uninterruptable power supply system 1 further comprises a cable terminal 60 connectable to the power cable PC. In the present embodiment, the cable terminal 60 may be considered to be a bus bar, wherein the energy storage 30 is connected to the cable terminal 60 via the first power converter 40 and the wind turbine 20 is connected directly to the cable terminal 60.
The first power converter 40 has two main purposes in the present embodiment. The first purpose is transfer power from the wind turbine 20 to the energy storage 30, i.e. to recharge the battery of the energy storage 30. The second purpose is to transfer power from the energy storage 30 to the installation HCPI in case of interruptions in the power supply of the installation HCPI.
In the present embodiment, the battery of the energy storage 30 has a nominal voltage of 1 kV DC, while the nominal voltage of the cable terminal 60 is 11kV AC. Hence, the first power converter 40 has DC terminals connected to the energy storage 30 and AC terminals connected to the cable terminal 60.
As shown in fig. 4, the first power converter 40 is a bidirectional converter comprising a bidirectional DC/DC, a bidirectional DC/AC converter and a transformer. It should be noted that there may be many alternative embodiments of the first power converter 40.
As shown in fig. 1, the uninterruptable power supply system 1 is separated from the hydrocarbon producing installation HCPI by a distance D. This distance D may be from 150m and up to several kilometres.
In fig. 3, the fuel powered power plant 120 may be a gas turbine with a start-up period Tstartup of ca 30 minutes. In practice, this start-up period is so long that the gas turbine is kept idling.
In the present embodiment, the energy storage 30 is dimensioned to supply power to the hydrocarbon producing installation HCPI for a period of time Tload corresponding to at least the start-up period Tstartup for the fuel powered power plant 120. Hence, the gas turbine may be turned completely off in periods with high winds, in which periods the hydrocarbon producing installation HCPI is supplied with power from the wind turbine 20. Consequently, emissions can be reduced considerably.
In the first embodiment, the maximum current which can be supplied by the energy storage 30 and the wind turbine 20 in total is at least two times, preferably four times, the rated maximum current of the power supply 120 located on the HCPI alone. Accordingly, the uninterruptable power supply system 1 may handle a typical level of short circuit current in case of a fault incident at the HCPI.
In the first embodiment, the maximum power which can be supplied by the energy storage 30 and the wind turbine 20 in total exceeds the rated maximum power of at least one of the fuel powered power plants 120 located on the HCPI.
Preferably, the maximum current which can be supplied by the energy storage 30 and the wind turbine 20 in total is at least two times, preferably four times, the rated maximum current of the wind turbine 20 alone. Accordingly, the uninterruptable power supply system 1 may handle a short circuit current in case of a fault incident at the HCPI.
Preferably, the maximum power supplied which can be supplied by the energy storage 30 and the wind turbine 20 in total exceeds the rated maximum power of the wind turbine 20 alone.
The cooling system 70
It is now referred to fig. 5, wherein the above uninterruptable power supply system 1 is shown to comprise a cooling system 70. In the buoyancy member 11a of the foundation 10, the weight of ballast water BW is used in addition to the weight of the energy storage 30 as ballast.
The purpose of the cooling system 70 is to cool the batteries and /or other electrical components of the energy storage 30. The cooling system 70 comprises a cooling fluid circulation pump 71 for circulation of cooling fluid through a cooling fluid circuit 72. In fig. 5, the cooling fluid circuit is illustrated as arrows, where dashed arrows indicate heated fluid heated by the energy storage 30 and solid arrows indicates cool fluid. The cooling system 70 further comprises a heat exchanger 73 connected to the cooling fluid circuit 72, wherein the heat exchanger 73 is submerged in the ballast water BW. The cooling system 70 further comprises a valve 74 for controlling the flow of the fluid in the cooling fluid circuit 72.
Typically, the valve 74 will be temperature controlled. If the temperature of the heated fluid returning from the energy storage 30 is below a predetermined threshold value, the fluid is not circulated via the heat exchanger 73. However, if the temperature of the heated fluid returning from the energy storage 30 is above a predetermined threshold value, the fluid, or some of the fluid, is circulated via the heat exchanger 73 to reduce the temperature of the fluid.
As the ballast water BW typically will be fresh water, exposure of the cooling system 70 to seawater can be avoided, hence reducing corrosion and build-up of salt deposits on the heat exchanger.
The frequency reference generator 50
It is now referred to fig. 6, wherein the above uninterruptable power supply system 1 is shown to comprise a frequency reference generator 50 for generating a frequency reference for the electric power supplied to the hydrocarbon producing installation HCPI. The frequency reference generator 50 is provided in communication with, and is synchronized with, a frequency generator 150 of the hydrocarbon producing installation HCPI.
In one embodiment of the invention the uninterruptable power supply system 1 imitates the spinning reserve function of one or more gas turbines onboard the HCPI. In another embodiment of the invention the uninterruptable power supply system 1 further comprises a synthetic frequency reference generator system for generating a frequency and phase reference for the converter(s) located on the floating offshore foundation(s) 10 and the power generators, i.e. gas turbines, onboard the HCPI. When the gas turbine(s) is running the frequency may be dictated by the governor of the gas turbine. The synthetic frequency reference generator (50) at the floating offshore foundation(s) 10 may be equipped with a separate smaller battery or other separate power supply which is not influenced by a fault in the rest of the electrical system. The HCPI may be equipped with a similar frequency reference system 150 which also may comprise its own separate smaller battery system. Both frequency reference systems 50, 150 may communicate with each other via a fiber optic cable or by other means of communication. Both SFRG systems may be synchronized on a regular basis or continuously during normal operation. One or both SFRG systems may be synchronised with the gas turbine’s frequency onboard the HCPI. In the case of a fault onboard the HCPI, onboard floating offshore foundation(s) 10 or in any of the cables between them, both the HCPI and the floating offshore foundation(s) 10 will have an operating SFRG system, hence both sides of the fault will have continues information of the phase and frequency of each other and will be able to continue operation of the spinning equipment (and generator(s) in phase even if the two sides of the system is temporarily disconnected from each other. So in the case of the two parts of the system (HCPI and floating offshore foundation(s) 10) is temporarily disconnected from each other, they will continue with separate SFRG systems comprising a governor to give frequency and phase information for controlling the operation. This ensures that the rotating equipment and generators can continue to run on both sides of the fault and be quickly and smoothly re-connected in phase as soon as the fault is repaired or the fault has been isolated from the grid. As an example, if both a gas turbine and a energy storage at the floating offshore foundation(s) 10 is supplying the local grid in parallel, and the gas turbine is suddenly disconnected due to a fault, the energy storage will automatically switch to its own SFRG system, comprising a governor for frequency and phase, to continue to supply the grid at the same frequency and phase as before the fault occurred. Another scenario could entail a sudden fault in the signal communication (for instance the optical cable) between the HCPI and the wind turbine(s). Another scenario could entail a temporary disconnection at the energy storage side due to a fault. The energy storage, and a wind turbine if included, would then be able to continue to operate, maintain its rotational inertia, by supplying an energy storage or simply dump the energy via a dump load. As soon as the fault has been isolated from the grid the frequency delivered via the wind turbine, if included, and/or the energy storage’s frequency converters will be in perfect phase with the grid on the HCPI side even before the mains are re-connected. Hence the transition time to re-engage normal operation will be reduced.
The power management system 80
It is now referred to fig. 7, wherein the above uninterruptable power supply system 1 is shown to comprise a power management system 80.
It is also shown schematically that the installation HCPI comprises electric loads 106a, 106b, 106c. These loads are given priority in the power management system 80. As an example, in case there is not sufficient power available to supply power to all three loads, it is first evaluated if there is sufficient power available to supply power to loads 106a and 106b. If this is the case, then the power management system 80 will turn off power to load 106c. However, in case there is not sufficient power available to supply power to these two loads 106a, 106b, it is evaluated if there is sufficient power available to supply power to load 106a If this is the case, then the power management system 80 will turn off power to load 106b and 106c.
Second embodiment
It is now referred to fig. 8, wherein a second embodiment of the uninterruptable power supply system 1 is shown. The second embodiment is in many ways similar to the first embodiment described above, and only differences between the first embodiment and the second embodiment will be described in detail herein.
In the second embodiment, the uninterruptable power supply system 1 comprises a second power converter 45 connected between the wind turbine 20 and the cable terminal 60 for converting the power from the wind turbine 20 to a suitable power for the power cable PC. A suitable power here refers to a suitable voltage level or a suitable frequency. It should be noted that the second power converter 45 may be connected to the frequency reference generator 50 of fig. 6.
It should be noted that in many cases, the features of the second power converter 45 are considered to be a part of the wind turbine 20 itself. However, in some cases, the second power converter 45 is needed to operate the wind turbine 20 together with other parts of the uninterruptable power supply system 1.
Third embodiment
It is now referred to fig. 9, wherein a third embodiment of the uninterruptable power supply system 1 is shown. The third embodiment is in many ways similar to the first embodiment described above, and only differences between the first embodiment and the third embodiment will be described in detail herein.
In the third embodiment, the uninterruptable power supply system 1 does not comprise a wind turbine 20 and hence no second power converter 45.
In fig. 9, the power cable PC is a bidirectional power cable, and the power supply of the hydrocarbon producing installation HCPI is a fuel powered power plant 120.
The fuel powered power plant 120 is used to recharge the battery of the energy storage. In case of an interruption in the fuel powered power plant 120, the energy storage 30 will supply electric power to the hydrocarbon producing installation HCPI during this interruption. As the power cable is an AC power cable, the uninterruptable power supply system 1 will also here comprise a bidirectional power converter 40 for converting power between the AC power cable and the energy storage (30).
Fourth embodiment
It is now referred to fig. 10, wherein a fourth embodiment of the uninterruptable power supply system 1 is shown. The fourth embodiment is in many ways similar to the third embodiment described above, and only differences between the third embodiment and the fourth embodiment will be described in detail herein.
In the fourth embodiment, the uninterruptable power supply system 1 does not comprise a wind turbine 20 and hence no second power converter 45.
In the fourth embodiment, the power supply of the hydrocarbon producing installation HCPI is a wind turbine system 120A, typically comprising one or a plurality of wind turbines located on one or a plurality of foundations separate from the hydrocarbon producing installation HCPI and separate from the uninterruptable power supply system 1.
In fig. 10, the power cable PC is a bidirectional power cable and the wind turbine system 120A is used to recharge the battery of the energy storage. In case of an interruption in the wind turbine system 120A, the energy storage 30 will supply electric power to the hydrocarbon producing installation HCPI during this interruption.

Claims (22)

1. Uninterruptable power supply system (1) for an offshore hydrocarbon producing installation (HCPI), wherein the uninterruptable power supply system (1) comprises:
- an offshore foundation (10) separate from the hydrocarbon producing installation (HCPI);
- an energy storage (30) located on or inside the offshore foundation (10); wherein the energy storage (30) is electrically connected to the hydrocarbon producing installation (HCPI) for supplying electric power to the hydrocarbon producing installation (HCPI) during an interruption of a power supply (120; 120A) of the hydrocarbon producing installation (HCPI).
2. Uninterruptable power supply system (1) according to claim 1 , wherein the offshore foundation (10) is located spaced apart from the hydrocarbon producing installation (HCPI), and wherein the energy storage (30) is electrically connected to the hydrocarbon producing installation (HCPI) via a power cable (PC).
3. Uninterruptable power supply system (1) to any one of the above claims, wherein the offshore foundation (10) is a floating foundation (10) comprising buoyancy members (11a, 11b, 11c), wherein the energy storage (20) is located on or inside the at least one buoyancy members (11a, 11b, 11c).
4. Uninterruptable power supply system (1) according to claim 3, wherein the floating foundation (10) comprises at least three buoyancy members (11a, 11b, 11c); wherein:
- the energy storage (30) is located on or inside a first buoyancy member (11a) and/or on or inside a second buoyancy member (11b).
5. Uninterruptable power supply system (1) according to any one of the above claims, wherein a ballast of the floating foundation (10) is at least partially provided by the weight of the energy storage (30).
6. Uninterruptable power supply system (1) according to claim 5, wherein at least 5 %, preferably at least 10 %, of the ballast of the floating foundation (10) is provided by the weight of the energy storage (30).
7. Uninterruptable power supply system (1) according to any one of the above claims, wherein the energy storage (30) is a rechargeable battery or a plurality of rechargeable batteries.
8. Uninterruptable power supply system (1) according to any one of the above claims, wherein the energy storage (30) is dimensioned according to a property of the power supply of the hydrocarbon producing installation (HCPI).
9. Uninterruptable power supply system (1) according to claim 8, wherein a property of the power supply of the hydrocarbon producing installation (HCPI) is a start-up period (Tstartup) for the power supply of the hydrocarbon producing installation (HCPI) and wherein the energy storage (30) is dimensioned to supply power to the hydrocarbon producing installation (HCPI) for a period of time (Tload) corresponding to at least the start-up period (Tstartup).
10. Uninterruptable power supply system (1) according to any one of the above claims, wherein the uninterruptable power supply system (1) comprises a frequency reference generator (50) for generating a frequency reference for the electric power supplied to the hydrocarbon producing installation (HCPI).
11. Uninterruptable power supply system (1) according to claim 10, wherein the frequency reference generator (50) is provided in communication with, and is synchronized with, a frequency generator (150) of the hydrocarbon producing installation (HCPI).
12. Uninterruptable power supply system (1) according to any one of the above claims, wherein the uninterruptable power supply system (1) comprises a cooling system (70) for cooling the energy storage (30), wherein the cooling system (70) comprises:
- a cooling fluid circulation pump (71) for circulation of cooling fluid through a cooling fluid circuit (72);
- a heat exchanger (73) connected to the cooling fluid circuit (72), wherein the heat exchanger (73) is submerged in ballast water.
13. Uninterruptable power supply system (1) according to claim 12, wherein the heat exchanger (73) is submerged in the ballast water in one of the buoyancy members (11a, 11b, 11c).
14. Uninterruptable power supply system (1) according to any one of the above claims, wherein the uninterruptable power supply system (1) comprises a power management system (80) for controlling power supplied to prioritized loads (106a, 106b, 106c) of the hydrocarbon producing installation (HCPI) based on a presently available short circuit capacity of the energy storage (30).
15. Uninterruptable power supply system (1) according to any one of the above claims, wherein the uninterruptable power supply system (1) comprises:
- a wind turbine (20) installed on the offshore foundation (10);
- a first power converter (40) for converting power produced by the wind turbine (20) to energy stored in the energy storage (30).
16. Uninterruptable power supply system (1) according to claim 15, wherein the uninterruptable power supply system (1) comprises a cable terminal (60) connectable to the power cable (PC), wherein the cable terminal (60) is electrically connected to AC terminals of the first power converter (40).
17. Uninterruptable power supply system (1) according to claim 15 or 16, wherein the foundation (11) is a floating foundation and wherein the wind turbine (20) is located on at least one buoyancy member (11c) of the floating foundation.
18. Uninterruptable power supply system (1) according to claim 15, wherein the first power converter (40) is a bidirectional power converter for converting AC power produced by the wind turbine (20) or by the power supply (120; 120A) of the hydrocarbon producing installation (HCPI) to a DC power supplied to the battery and for converting DC power stored in the battery to an AC power supplied to the hydrocarbon producing installation (HCPI).
19. Uninterruptable power supply system (1) according to claim 15, wherein the uninterruptable power supply system (1) is configured to supply electric power to the hydrocarbon producing installation (HCPI) simultaneously from the wind turbine (20) and the energy storage (30).
20. Uninterruptable power supply system (1) according to any one of the above claims, wherein the maximum current supplied by the energy storage (30) and the wind turbine (20) in total is at least two times, preferably four times, the rated maximum current of the power supply (120; 120A) of the hydrocarbon producing installation (HCPI).
21. Uninterruptable power supply system (1) according to any one of the above claims, wherein the maximum power supplied by the energy storage (30) and the wind turbine (20) in total exceeds the rated maximum power of at least one of the generators or gas turbines of the power supply (120) located on the hydrocarbon producing installation (HCPI).
22. Uninterruptable power supply system (1) according to claim 16, wherein the uninterruptable power supply system (1) comprises a second power converter (45) connected between the wind turbine (20) and the cable terminal (60).
NO20210632A 2021-05-21 2021-05-21 Offshore uninteruptable power supply system NO347202B1 (en)

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NO20210632A NO347202B1 (en) 2021-05-21 2021-05-21 Offshore uninteruptable power supply system
BR112023024309A BR112023024309A2 (en) 2021-05-21 2022-05-16 UNINTERRUPTED POWER SUPPLY SYSTEM FOR AN OFFSHORE HYDROCARBON PRODUCTION FACILITY
PCT/EP2022/063116 WO2022243211A1 (en) 2021-05-21 2022-05-16 An uninterruptable power supply system for an offshore, hydrocarbon producing installation
GB2318534.1A GB2621798A (en) 2021-05-21 2022-05-16 An uninterruptable power supply system for an offshore, hydrocarbon producing installation

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US20200006938A1 (en) * 2017-03-10 2020-01-02 Equinor Energy As Power supply system for an offshore platform
NO20191054A1 (en) * 2019-09-02 2021-03-03 Odfjell Drilling As An energy system for a Mobile Offshore Drilling Unit (MODU), a MODU and a method of supplying power to the MODU

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WO2022243211A1 (en) 2022-11-24

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