WO2023102595A1

WO2023102595A1 - Liquified gas power vessel

Info

Publication number: WO2023102595A1
Application number: PCT/AU2022/051447
Authority: WO
Inventors: Christopher Stirling
Original assignee: Charlie Six Pty Ltd
Priority date: 2021-12-07
Filing date: 2022-12-02
Publication date: 2023-06-15

Abstract

The invention provides a floating liquified gas power station vessel comprising: liquified gas cargo tanks for storage and transport of liquified gas; a regasification converter for converting liquified gas into gas; wherein liquefied gas is pumped from the cargo tanks to a combined-cycle power plant through the regasification converter such that the liquified gas is pressurised and vaporised to gas at ambient temperature. The combined-cycle power plant comprises at least one gas turbine and at least one steam turbine, wherein the pressurised gas drives the gas turbine, and waste heat from the combined-cycle power plant produce steams to drive the steam turbine. The steam turbine and the gas turbine are connected to an electrical power generator; connected to an electrical grid onshore. The combined-cycle power plant generates 130 MW to 1.35 GW of electrical power. The vessel can burn liquified gas supplied by gas carriers.

Description

LIQUIFIED GAS POWER VESSEL

TECHNICAL FIELD

[0001] The present invention relates to power supply and, in particular, sustainable power supply from clean energy sources.

BACKGROUND

[0002] Global demand for energy and power generation continues to grow at an exponential rate. In the face of growing deficits across the world in power generation capacity, and calls for cleaner, more sustainable energy sources, liquefied natural gas (LNG) is increasingly considered as an option for adding significant, sustainable capacity to the power grid.

[0003] Due to large volumes, it is not practical to store natural gas in a gas phase at atmospheric pressure. When liquefied, natural gas can be stored in a volume l/600th as large. However, in order to maintain the liquid state, natural gas must be kept at a temperature at or below -162 °C (-260 °F). Once liquefied, LNG is then stored in a specialized double wall insulated tank at atmospheric pressure ready for transportation and/or use.

[0004] The most important infrastructure needed for LNG production and transportation is an LNG plant consisting of one or more LNG trains, each of which is an independent unit for gas liquefaction. LNG is loaded onto ships for transportation and delivered to a regasification terminal, where the LNG is allowed to expand and reconvert into gas. Regasification terminals are usually connected to a storage and pipeline distribution network to distribute natural gas to local distribution companies (LDCs) or independent power plants (IPPs).

[0005] In terms of cost, the per-ton construction cost of an LNG liquefaction plant fell steadily from the 1970s through the 1990s. The cost reduced by approximately 35 percent. However, from the early 2000 ’s, the cost of building liquefaction and regasification terminals has reportedly doubled due to increased cost of materials and a shortage of skilled labour, professional engineers, designers, managers and other whitecollar professionals.

[0006] Korean Patent Publication 10-2014-0119997 discloses a floating refueling equipment device, comprising: a floating refueling vessel moored in the sea at a certain distance from the land; an LNG storage tank installed in the floating oil tanker and storing LNG supplied from the LNG carrier; a gas production facility that regasifies the LNG stored in the LNG storage tank to produce gas; Evaporative gas generated during the loading and unloading process of regasified gas and LNG Electricity production facility that produces electricity using boil-off gas (BOG) as a fuel; a refueling facility for supplying LNG stored in the LNG storage tank to an LNG bunkering vessel; a subsea gas delivery pipe for supplying the gas produced by the gas production facility to land; a subsea transmission line for supplying electricity produced by the electricity production facility to land; and a fuel storage tank for receiving and storing fuel for propulsion from a fuel supply ship, and a fuel delivery pipe for supplying fuel stored in the fuel storage tank to an LNG carrier or an LNG bunkering ship. Accordingly, it is possible to refuel the fuel for propulsion with the LNG carrier supplying LNG and the bunkering vessel receiving the LNG, so the time and effort required to move the LNG carrier and the LNG bunkering vessel to another place to receive the fuel for propulsion. There is an effect that can significantly reduce the work efficiency and further improve the work efficiency.

[0007] In recent years, the technology and commercial viability of floating storage and regasification units (FSRUs) has been established. FSRUs can now present a simpler and potentially more flexible solution to the provision of gas storage and regasification facilities than alternative land-based facilities. Indeed, in recent times, FSRUs have been brought into operation in countries including Brazil, Lithuania, Indonesia, Kuwait (replacing a smaller FSRU), Egypt, Jordan and Pakistan. Many opportunities for gas to power are also emerging across Africa. Proposals under consideration in Morocco reportedly include two 1,200 MW Combined Cycle Gas Turbine (CCGT) gas-to-power project. The 1,300 MW Ghana 1000 project led by Endeavor is looking to develop a CCGT in several phases, with the later phases being fuelled by LNG supplied by the Ghana National Petroleum Corporation. South Africa also has ambitious plans to add over 3,000 MW of gas-fired capacity based around LNG fuel supply. Closer to Europe, Malta Gas and Power Limited is reportedly developing a 200 MW gas- fired power plant at the Delimara power station near Marsaxlokk. In Chile, sponsors including EDF and Cheniere are reportedly developing an LNG receiving terminal and an associated 640 MW CCGT.

[0008] A feasibility study on a floating LNG power station in Thailand was completed in March 2019 by IHI Corporation. The floating LNG Power Station consists of an LNG tank, an LNG vaporization facility, and a power generation system. The capacity of the power generation facility is assumed 600 MW at the maximum, and the generated power is transmitted to the substation on land by the submarine transmission cable and is to be supplied to the distribution system,

[0009] Japanese company MODEC has expanded its product range to include FSRWP (Floating Storage Regasification Water-Desalination & Power-Generation) and its associated systems for Power only (FSR-Power and Water only (FSR-Water). MODEC’ s power & water solutions make use of LNG as a fuel source to provide clean water and/or electrical power in a reportedly more efficient process using a floating vessel when compared to conventional land-based solutions. LNG storage tanks on the floating vessel are used by combined-cycle gas turbine systems to produce electricity. Electricity can be sent directly to the grid via cable if the vessel is moored to the jetty. If the vessel is moored near shore, the electricity sent via submarine cables then to the grid. The power generation of MODEC ’s floating systems is 160MW to 1,000 MW depending on the size of system.

[0010] Siemens SGT-8000H based combined-cycle power plant in multi shaft arrangement has been optimized for SeaFloat application, i.e. it can be installed on floating devices such as barges or platforms. The design is based on Siemens' land-based reference power plant. The SeaFloat adaption of the SGT-8000H is designed to withstand typical maritime conditions such motions (roll & pitch, accelerations), hull deflections and environmental conditions such as spray water. SCC-8000H SeaFloat multi shaft plants can be arranged in 1+1 arrangement i.e. one (1) gas turbine, one (1) HRSG routed to one (1) steam turbine, as well as in a 2+1 arrangement which consists of two (2) gas turbines and two (2) HRSGs routed to one (1) steam turbine. The power density of the 2x1 and 1x1 configurations is from 460 MW (1x1 60Hz) up to 1,330 MW(2xl 50Hz) However, the Siemens SGT-8000H based combined-cycle power plant operates from barges or platforms, and does not have regasification or storage capacity on board the barge or platform.

[0011] Power Barge Corporation is a privately held company established in 2000, providing turnkey engineering, procurement and construction contracting, as well as aftermarket and consulting service to developers, owners and operators of barge mounted power plants with both gas turbines, medium speed engines and energy storage system. The diesel and gas turbine power barges sold by Power Barge Corporation range from 9 to 800MW power capacity (http://www.powerbargecorp.com/worldwide.html).

However, these combined-cycle power plants also do not have regasification or storage capacity on board the barge or platform.

[0012] WO2018139997 to PCORE ENERGY LLC discloses a floating liquid natural gas storage, regasification, and generation vessel comprising a boat having liquid natural gas (LNG) storage tanks, a regasifier, a power plant, and an electrical power offloader. The power plant produces between 150 MW and 650 MW of electrical power. http://pcoreenergy.com/lng-to-power/. It is noted in paragraph [0046] that a majority of space on the ship is used for storing LNG 30. The LNG 30 is kept at -160 C°, and is combustible, very hazardous if it comes in contact with people or some equipment, and usually requires handling systems. The majority of the middle and front of the LNG carrier is designated Hazardous Areas and Gas Dangerous Areas, basically all area around the LNG containment system. There is limited space to work around, without reducing the LNG storage capacity and without building major side sponsons, which would increase the cost substantially. The inventors used the stem 58 of the ship to place the power plant 10 equipment, but that meant competing with space for the ship propulsion system, including the engine room and accommodations. The regasifier 8 was located in space on the front or bow 60 of the ship, spaced from the power plant 10 for safety. This highlights the challenges in converting an LNG carrier into a floating storage, regasification and generation vessel and the limitations for effectively incorporating the necessary equipment on an existing LNG carrier vessel.

[0013] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.

SUMMARY

[0014] PROBLEMS TO BE SOLVED

[0015] It is an aim and objective of the present invention to provide a floating vessel to generate and deliver low-cost, clean energy to the grid.

[0016] It is an aim and objective of the present invention to provide a floating vessel for storage, regasification and power generation using clean energy sources such as liquid natural gas or hydrogen.

[0017] It is an aim and objective of the present invention to provide a floating vessel having a multifunction role encompassing transport, storage, base load electricity and gas supply to the market.

[0018] It is an aim and objective of the present invention to provide a relocatable floating vessel to generate and deliver low cost, clean energy, based on an existing LNG carrier vessel or from a new build vessel.

[0019] It is an aim and objective of the present invention to provide a floating vessel to generate and deliver low cost, clean energy, the vessel having lower capital costs and low shore-based infrastructure costs in comparison to current, new land-based power stations. [0020] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0021] MEANS FOR SOLVING THE PROBLEM

[0022] According to a first aspect, the invention provides a floating liquified gas power station vessel comprising: liquified gas cargo tanks for storage and transport of liquified gas; a regasification converter for converting liquified gas into gas; wherein liquefied gas is pumped from the cargo tanks to a combined-cycle power plant through the regasification converter such that the liquified gas is pressurised and vaporised to gas at ambient temperature; wherein the combined-cycle power plant comprises at least one gas turbine and at least one steam turbine, wherein the pressurised gas drives the gas turbine, and wherein waste heat from the combined-cycle power plant produce steams to drive the steam turbine, wherein both the steam turbine and the gas turbine are connected to an electrical power generator; a connection to provide electrical power generated by the electrical power generator to an electrical grid onshore; wherein the combined-cycle power plant generates 130 MW to 1.35 GW of electrical power, and wherein the vessel can burn liquified gas supplied by gas carriers while moored in near-shore areas, or can navigate independently to different locations or to transport liquified gas.

[0023] Preferably, the liquified gas is liquid natural gas (LNG) or up to 98% hydrogen (H2) or a combination thereof. The gas turbine in the combined-cycle power plant maybe driven by a combination of 50% pressurised natural gas and 50% stored hydrogen.

[0024] Excess power generation from the combined-cycle power plant may be diverted into a shore-side hydrogen generation plant for storage and delivery into a national gas grid.

[0025] The combined-cycle power plant preferably generates about 1.0 to 1.2 GW of electrical power in some applications. [0026] The combined-cycle power plant may be added to an extension of an existing LNG carrier vessel. Preferably, the extension of the existing LNG carrier vessel is a stern extension and the extension geometry conforms to an overall length limit of about 350m. The vessel propulsion equipment is preferably located in the extension. The regasification converter is located on the vessel midbody and/or bow.

[0027] The extension may be added to the existing LNG carrier vessel by removing an existing stern comprising existing propulsion machinery at an aft end of a deckhouse, and adding an extended stern comprising the combined-cycle power plant and propulsion equipment room. The vessel preferably further comprises an engine room, and an aft mooring system in a new aft hull. Preferably, the vessel further comprises fresh water generating systems and a sea water supply pump room. The vessel may comprise gas turbine generators for propulsion and electrical power, replacing the existing LNG carrier vessel engine and gensets to enable a low carbon footprint from vessel operations.

[0028] Propulsion for the vessel may be provided using at least two podded propulsors at the stern and bow thrusters to aid low-speed manoeuvrability, or the vessel can maintain a set position using a dynamic position systems (DP).

[0029] The combined-cycle power plant may comprise at least one gas turbine generator or an LNG / Hydrogen powered reciprocating generator, at least one heat recovery steam generator, at least one steam turbine generator, and at least one steam condenser. Preferably, the propulsion power plant comprises at least one azimuth podded propulsors, at least one gas turbine generator and at least one bow thruster. The propulsion/ship power gas turbine gas generators may be located in the space occupied by ship power generators in the existing LNG carrier vessel. A propulsion room is preferably located inside a new hull at the aft end of the vessel to accommodate the podded propulsors.

[0030] The regasification system preferably comprises at least one sea water supply pump, at least one sea water/water cooling agent heat exchangers for open loop regasification, at least one steam/water cooling agent heat exchangers for closed loop regasification, and at least one water cooling agent circulation pump, wherein the regasification system can reuse waste heat generated by the combined-cycle gas turbines.

[0031 ] Battery storage may be used on board the vessel to maintain system integrity and as a hybrid power source and on shore to maintain supply to the grid during transition loads or vessel operational requirements.

[0032] In the context of the present invention, the words “comprise”, “comprising” and the like are to be construed in their inclusive, as opposed to their exclusive, sense, that is in the sense of “including, but not limited to”.

[0033] The invention is to be interpreted with reference to the at least one of the technical problems described or affiliated with the background art. The present aims to solve or ameliorate at least one of the technical problems and this may result in one or more advantageous effects as defined by this specification and described in detail with reference to the preferred embodiments of the present invention.

BRIEF DESCRIPTION OF THE FIGURES

[0034] Fig. 1 is a side view of the outboard profile view of a preferred liquefied gas power vessel embodiment of the present invention;

[0035] Fig. 2 is an inboard profile view of the preferred embodiment of Fig. 1 showing a power plant in the stern extension in way of a port gas turbine;

[0036] Fig. 3 is a centreline elevation view of the preferred embodiment of Fig. 1;

[0037] Fig. 4 is a top plan view of the upper deck of the preferred embodiment of Fig. 1 ;

[0038] Fig. 5 shows partial plans of the 2^nd deck aft, the 3^rd deck and the 4^th deck of the preferred embodiment of Fig. 1; [0039] Fig. 6 shows partial plans below the 4^th deck of Fig. 1 showing a notional condenser seawater supply;

[0040] Fig. 7 shows partial plans at 2^nd deck forward, 9900 ABL forward and 4400 ABL forward of Fig. 1.

[0041] Fig. 8 shows estimated weight (red) and buoyancy (green) curves for the converted vessel.

[0042] Fig. 9 shows the closed shear force and still water bending moment curves of the converted vessel.

DESCRIPTION OF THE INVENTION

[0043] Preferred embodiments of the invention will now be described with reference to the accompanying drawings and non-limiting examples.

[0044] Referring to Fig. 1, there is provided a liquefied gas power vessel 1 which may be converted from an existing LNG carrier 2 by housing a combined-cycle power plant 3 within a stern extension 4. Liquified gas from storage tanks 5 is used to power the power plant 3 and deliver high voltage power from the vessel 1 to an on-shore grid via an umbilical connection 6. The vessel 1 can be moored in sheltered near-shore areas, burning liquefied gas supplied by gas carriers. However, the liquefied gas power vessel 1 will also be able to navigate independently to different locations or to transport liquified gas . The liquified gas power vessel 1 can also be used for secondary applications such as generating and offloading fresh water.

[0045] The operational equipment on the liquefied gas power vessel 1 can fit into the length and width of the space available in the extended stern section 4 and elsewhere on the parent carrier vessel 2. The weight and trim of a converted liquefied gas power vessel 1 is compatible with the combined-cycle power plant operation as well as secondary applications such as generating fresh water and hydrogen generation. The hull 7 of the liquefied gas power vessel 1 has sufficient strength to withstand bending loads due to the increased length and weight of added operational equipment.

[0046] Liquefied gas power vessels 1 can provide electrical power to the on-shore grid, replacing land-based, coalfired power plants. Each existing LNG carrier 2 will be converted from an approximately 140,000 m3, depending on the port requirements, four- tank Moss type LNG carrier, or membrane LNG tanker, and modified to accommodate a 1.2 GW (to 1.35GW) combined-cycle (gas turbine and steam) electrical power plant 3 on a new, extended aft hull section 8. In operation, each liquefied gas power vessel 1 can be spread-moored in a sheltered coastal area and can supply power to the on-shore grid by an electrical umbilical connection 6. It is possible that other shore-side connections, such as cooling water may also be required. The liquefied gas power vessel 1 can also supply liquefied gas to shore via shuttle tankers, and generate and offload potable water. The liquefied gas power vessel 1 is designed to be capable of navigating under its own power to reposition, avoid weather, or transport liquefied gas .

[0047] Referring to Eig. 2, sufficient space is created to accommodate the required equipment and systems by cutting the candidate ship hull 7 just aft of the accommodation block 9 and providing a new hull section 8 of approx. 110 m length. A preferred embodiment of the invention includes a 1.2 GW (to 1.35 GW) combined-cycle power plant 3 including its major components and auxiliary systems/equipment (with a customized design being applied to some components. The combined-cycle power plant 3 also includes a propulsion plant 10 and auxiliary systems 11 (existing and new) in a new engine room 12; propulsion equipment 13 and aft mooring system 14 in the new aft hull 8; and spaces 15 required for the utilities and services of the ship and power plant.

[0048] In a preferred embodiment, the overall length of the liquefied gas power vessel 1 is about 350m. The existing LNG carrier 2 is typically about 280m in length. In the liquefied gas power vessel 1, about 175m of length remains from the existing vessel and the remaining length of the vessel is modified and extended. [0049] The forward water ballast and heavy fuel oil tanks in the existing LNG carrier 2 can be converted into machinery spaces 16 to create sufficient space for a larger bow thruster room 17, regasification and fresh water generating systems 18, sea water supply pump room 19, regasification and fresh water generating systems electrical equipment 20; and spaces 21 required for the utilities and services related to regasification system. The regasification system can also use waist heat from the combined-cycle gas turbine system. The regasification and combined-cycle power plant function in a closed loop during operation, with the exception of an emergency.

[0050] The following equipment can be installed in a modular construction on elevated platforms at the forward end of the vessel 1 or between the cargo tanks: regasification system heat exchangers 22; fresh water generating equipment 23; regasification equipment 24; fuel gas storage, transfer and flow measuring equipment 25.

[0051] Initial estimates of the converted vessel’s weight and draft indicate that, with liquefied gas tanks 5 full, the draft amidships 26 is estimated to be approximately 9.0 m, which is within the requirement of a 10.5 m draft limit. The available hydrostatic data suggests that the converted vessel 1 will trim level in the full load condition with additional ballast added forward in the ship. Based on structural drawings from a representative parent vessel, the existing hull structure 7 of the existing LNG carrier 2 should be within Class limits and strong enough to withstand environmental bending loads for restricted service when the added stern and equipment and the increased overall hull length are considered. An initial calculation has determined that a service factor of 0.63 or less would achieve a sea-going solution with sailing limitations. Increasing the liquid or permanent ballast carried in the cargo section 27 is likely to improve the structural result and permit a higher service area factor to be applied.

[0052] To allow hydrogen to be used as a fuel for the liquefied gas power vessel 1, hydrogen storage is a key enabling technology. Hydrogen has the highest energy per mass of any fuel. However, hydrogen has a low energy per unit volume, requiring advanced storage methods for achieving high energy density. Such storage methods may include compressed gas storage, potentially using advanced pressure vessels made of fibre reinforced composites that are capable of reaching 700 bar pressure. Cold or cryocompressed hydrogen storage with increased hydrogen density and insulated pressure vessels, or materials-based hydrogen storage technologies, including metal hydrides, may also be considered.

[0053] The following key requirements have been defined for the liquefied gas power vessel 1 : Maximum Length 28 of 350 m; Maximum Draft 29 of 10.5 m; Maximum Beam 30 of 48 m (same as current vessel)

[0054] Additional requirements, such as the service speed, the ability to manoeuvre in harbour without tug assistance, and accommodation standards will also be considered. The liquefied gas power vessel 1 is powered with gas turbine generators 31 for propulsion and electrical power, replacing the parent vessel’s engine and gensets to enable a low carbon footprint from vessel operations. Propulsion will be provided by two podded propulsors 32 at the stern and bow thrusters 33 will be added to aid low-speed manoeuvrability. The converted vessel’s electrical system 34 will also be fully renewed and an intention at this time to have all ship service equipment replaced with new items.

[0055] A summary of the planned conversion scope for the liquefied gas power vessel 1 from the existing LNG carrier 2 is as follows: (1) Cut off existing stern at the aft end of deckhouse, including propulsion machinery. (2) Add new, extended stern 4 holding new combined-cycle power generation 3 and ship’s propulsion equipment 10; (3) Add new bow thrusters 33, regasification system 18, fresh water generating equipment 23, spread mooring equipment 35, etc. to the parent vessel’s midbody and bow 36.

[0056] Figure 1 presents an illustration of a converted vessel.

[0057] Based on information available for an existing Moss-type LNG carrier 2, ship data from multiple vessels has been combined to represent a typical Moss carrier with approximately 140 000 m3 capacity. A summary review of applicable rules regulations has been performed based on a typical Lloyd’s Register (LR) notation as follows: +100 Al LIQUEFIED GAS CARRIER, SHIP TYPE 2G, METHANE (LNG) IN INDEPENDENT SPHERICAL TANKS TYPE B, MAXIMUM VAPOUR PRESSURE 0.25 BARG, MINIMUM CARGO TEMPERATURE MINUS 163 DEGREES C, SHIPRIGHT(SDA), *IWS, LI, EP +Lloyd’s RGP +LMC, UMS, ICC, NAVI, IBS. Initial studies indicate that the current LR requirements would be viable for such an LNG power vessel 1 conversion.

[0058] POWER GENERATION SYSTEM SPATIAL INTEGRATION STUDY

[0059] Fig. 2, 3, 4 and 5 disclose power system equipment and support systems of the LNG power vessel 1. Components include the following: a. External power plant 37- approx. 1.2 GW power output, efficiency approx. 60% (General Electric): b. 2 x gas turbine generators 31 (9HA.01/H84) c. 2 x air intake filters/ducting for gas turbines 38; d. 2 x lubrication oil modules 39; e. 2 x heat recovery steam generators 40 with scrubber and exhaust gas stack; f. l x steam turbine generator 41 (D602/H84); g. l x steam condenser 42 - approx. 800 MW heat transfer capacity.

Heat can be reused from gas turbine generators 31 to provide energy to other systems in the power plant 3.

[0060] The information and input documents related to the power plant were specially focused to main components, with provisional data available on power plant auxiliary systems as expected. It is assumed that most of the auxiliary systems and equipment are integrated in equipment “package” modules and do not require additional space.

[0061] Given that the space on liquefied gas power vessel 1 is limited compared with a similar land-based power plant, the requirement has been identified for customization and special design for some components (e.g., the length of the exhaust gas diffuser connecting the gas turbines with the heat recovery steam generators, and the duct connecting the steam turbine exhaust to the condenser). Sea water shall be required for the steam condenser 42 where initial study findings are indicating an external supply will be required.

[0062] PROPULSION AND ELECTRICAL SYSTEM SPATIAL INTEGRATION STUDY

[0063] Locations have been identified and arrangements developed for the following propulsion and electrical equipment:

[0064] Propulsion power plant 10: a. 2 x azimuth podded propulsors 32 - approx. 10 MW each; b. 4 x gas turbine generators 31 - approx. 8 MW each; c. 2 x bow thruster 33 - approx. 2 MW each. d. Electrical equipment: Medium / low voltage switchboard for the ship power plant; Transformers and UPS’s

[0065] The arrangement of the equipment is shown in Fig. 2, 3 and 5. As per the combined-cycle plant 3, provision of sufficient access and maintenance clearance, and compatible with the required space for equipment foundations, piping, cabling, ducts, and ventilation systems is provided.

[0066] 4.5 CONCEPT MACHINERY ARRANGEMENT

[0067] A new engine room 43 arrangement has been an element of conversion design to maximize efficient placement of all systems and equipment required for LNG power vessel 1. The new propulsion/ship power gas turbine gas generators 31 are located at the 3rd deck level of the engine room, as shown in Fig. 5, in the space currently occupied by the ship power generators, while the cooling system/equipment 44 currently located at the 4th deck level of the engine room was retained and adjusted for the new installations.

[0068] A propulsion room 45 has been created inside the new hull 8 at the aft end of the vessel 1 to accommodate the podded propulsors 32 and their ancillaries as well as the hydraulic and electrical systems for the aft mooring equipment 35 located at the 2nd deck level, just above the propulsion room 45.

[0069] The machinery arrangement is shown in Fig. 5.

[0070] MAJOR VENDOR SYSTEM SPATIAL INTEGRATION

[0071] Regasification system 18 - approx. 210 tonnes/day: a. 4x sea water supply pumps 46 with necessary filtration equipment; b. 2 x sea water / water cooling agent heat exchangers 47 for open loop regasification; c. steam / water cooling agent heat exchangers 48 for closed loop regasification; d. 2 x water cooling agent circulation pumps 49; e. 2 x regasification trains 50 including LNG booster pumps, natural gas vaporizers and trim heaters; f. l x LNG suction drum 51 and “in-tank” LNG supply pumps 52; g. Fuel gas module 53; h. Buffer tanks 54 for power plant and propulsion gas turbines fuel; i. Flow meters 55 for power plant and propulsion gas turbines fuel. Cooling agents such as glycol are preferably used in the regasification system.

The provided information on mooring equipment is broadly like the equipment shown in existing ship drawings. HIGH-LEVEL WEIGHT ESTIMATE

[0072] The weight of the converted vessel has been estimated using representative lightship data for a parent vessel, parametric weights for the new stern section 4, and point weights for the added major equipment.

[0073] The lightship weight was estimated using graphical loading condition data (lightship, longitudinal weight distribution) from similar LNG carrier vessels. A weight per unit length value for the midbody was developed from this data and used to estimate the weight of the new stern section. Power plant equipment weights were assembled from several vendor-supplied documents, including drawings, catalogues, calculations, and vendor e-mails. Additional equipment weights were harvested from vendor data or estimated based on similar equipment used in previous projects. A 4% margin was included in all weight groups to account for these aggregations during IFS. A summary of the weight estimate is given in Table 4. The lightship weight for the converted vessel is estimated as 68 580 mt, and the full-load weight as 133 334 mt. For reference, a typical 140 000 m3 LNG carrier has a lightship weight of approximately 35 000 mt and a full load displacement of approximately 110 000 mt.

[0074] Table 4: Conversion weight estimate

[0075] 4.8 HYDROSTATICS AND STILL WATER BENDING MOMENT ESTIMATE

[0076] Hydrostatic properties were undertaken where the hull-form was defined using the hull-form of a similar LNG carrier’s 3D model in combination with the new stern section. The hydrostatic data was estimated for discrete drafts with zero trim rather than calculate free-floating drafts and trims for the converted vessel 1.

[0077] The total buoyant force for the hull at a draft of 10.5 m was calculated as 157 390 mt. Comparing this force to the full-load weight in the previous section suggests that the draft of the converted vessel will be approximately 9.0 m, within the limiting draft value. [0078] Figure 8 shows estimated weight (red) and buoyancy (green) curves for the converted vessel, with the zero-trim buoyant force distribution for 10.5m draft scaled down to equal the weight. The net load at each section is shown in blue. The distribution shows that the stern aft of the HRSGs and condenser appears to contribute net buoyancy to the hull, because the weight of the water it displaces exceeds the weight of the added machinery aft. This explains why the draft of the converted vessel is less than that of the parent LNG carrier.

[0079] Integrating the net load curve in Figure 8 shows that the load condition shown is unbalanced, and that the converted vessel will actually trim down by the stern unless ballast is added forward. The exact amount of trim cannot be determined without a more accurate hull-form model that will be defined in CDP and designed during detailed and Production design phases. By adjusting the buoyant force curve, the closed shear force and still water bending moment curves in Figure 9 are obtained. The maximum still water bending moment amidship, estimated as 59 900 mt-m or 587 620 kN-m, is used in the bending strength assessment in the next section.

[0080] HULL GIRDER BENDING STRENGTH ASSESSMENT

[0081] To assess the converted vessel hull girder bending strength and its need to withstand environmental loads, the bending strength has been assessed in accordance with the Lloyds Register Rules and Regulations for the Classification of Ships, July 2020, Part 3 Chapter 4, Section 5.

[0082] The LR requirements consider the effect of combined still water and wave bending moments, with the still water moment calculated from the vessel’s loading and the wave moment calculated using empirical formulas. The early assessment has considered one location on the hull and the full load condition defined in the previous sections. Other locations and loading conditions will be assessed as required by Class.

[0083] The midship section modulus has been estimated using the midship scantlings of a similar Moss carrier, with dimensions modified to the beam and depth of a proposed parent design. The section modulus calculation was based on a section in way of a Moss tank, with reduced width of strength deck plating. The strength deck and bottom shell were assumed to be constructed from H36 high tensile steel with a yield strength of 355 N/mm2, giving a Rule allowable bending stress sp of 243 N/mm2. The calculation assumed no hull wastage or damage that would reduce the hull girder strength from the as-delivered condition.

[0084] The still water bending moment for the full load condition was estimated as described in the previous section. The design hull vertical wave bending moments for hogging and sagging were calculated using a rule length of 337.84 m and a ship service factor fl of 0.63 for restricted service. Bending stresses were calculated at the strength deck for hogging wave loads and at keel for sagging wave loads.

[0085] As shown by the results in Table 5, the hull amidship has sufficient strength to meet Rule requirements.

[0086] Table 5: Midship bending strength calculations

[0087] By designing ballast in midbody ballast tanks in the full load condition, or by installing solid ballast in the cargo area and bow during conversion, a reduction in the still water bending moment is to be anticipated, improving the margin of compliance or increasing the service area factor.

[0088] Due to the preliminary nature and limited extent of the hull girder strength calculations, the analysis will be repeated during further assessment using actual weights, loading conditions, and scantling data for the selected parent vessel. The strength of the hull in locations other than amidships should also be evaluated, especially in way of the superstructure, which may have been designed with reduced stern scantlings for the parent vessel but will be in the amidships region of the converted vessel. The suitability of the ship service factor used will be confirmed with LR Class society for the conversion’s expected operation. The initial study has successfully identified space and located the equipment in the stern extension and in the modified or unconverted forward hull, demonstrating that spatial integration is possible.

[0089] With LNG tanks full, the draft amidships is estimated to be approximately 9.0 m, which is less than the limiting draft specified.

[0090] Using structural drawings from a representative parent vessel, the study has determined that the existing hull structure of the parent ship is strong enough to withstand the bending loads from the added stern and equipment and the increased overall hull length. Assumptions on ballast will impact the final service area factor.

[0091] Transitional product from LNG to hydrogen

[0092] The liquefied gas Power vessel 1 is initially designed for use with LNG. However, all of the equipment on the vessel 1 is ultimately designed for use with hydrogen as a power source. The vessel will commence operating with LNG but is designed to convert to 98% H2. The existing parent vessel 2 may be a Moss-type LNG carrier or a membrane LNG tanker. Alternatively, a tanker section may be built for only hydrogen.

[0093] The vessel 1 is designed to be self-reliant for operational power. Scrubbers etc have been included for carbon capture to improve clean environmental operation targets.

[0094] A key goal of the development of LNG power vessel 1 was to streamline and deliver low-cost clean energy to the market by creatively combining new and existing technologies.

[0095] The stage one project consisted of developing LNG powered 1300MW LNG power stations by converting LNG tankers into a multirole power station. These LNG power stations will be deployed in Australia.

[0096] Seven locations have been identified around the coast of Australia that could enable up to 8.4GW of power potential equivalent to the full load of Victoria. By 2024- 2025, it is anticipated that 4 locations can be supplied for an output of 4.8GW. This could be upscaled to 7.2GW by 2028 using these 4 ports.

[0097] The multi-role function of the vessels 1 would encompass transport, storage, base load electricity and gas supply to the Australian domestic markets.

[0098] The advantages of this multi-role function is to reduce transport cost, reduce infrastructure costs, direct delivery and to provide 3 key functions for the Australian market which is currently in demand, while producing a low carbon output alternative. The 3 key functions include base load power; LNG Gas and Large Capacity Storage

[0099] The integration of transport, storage, and supply of power into one asset enables the Applicant to create a completive advantage for a lower base line entry cost also not available to any other energy provider worldwide. [00100] The greatest advantage to this project is each vessel is self-sustaining, low capital costs in compared to current new power stations and shore-based infrastructure cost are very low.

[00101] Projected timelines are to fill the energy gap for the closure of Liddell Power stations in 2022, and the scheduled national forecast generation loss of coal generation will decrease by 13GW between 2022 to 2035.

[00102] Hydrogen Generation-

[00103] Times of low load excess power generations that cannot be shed can be diverted into a shore side hydrogen generation plant for storage and delivery into the national gas grid. The stored Hydrogen can be used for clean power generation. The GE 9HA gas turbines that are planned to be used on the LNG Power vessel 1 can operate on a mixed Hydrogen/Natural Gas 50%/50% cycle. This ratio could be as high as 98% hydrogen.

[00104] Battery Storage

[00105] One of the key redundancies that will be built into the system will be the addition of battery storage at each supply base and on each vessel is to maintain system integrity and as a hybrid power source on board the vessel and maintaining supply to the grid on-shore during transition loads or vessel operational requirements.

[00106] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms, in keeping with the broad principles and the spirit of the invention described herein.

[00107] The present invention and the described preferred embodiments specifically include at least one feature that is industrial applicable.

Claims

23 THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A floating liquified gas power station vessel comprising: liquified gas cargo tanks for storage and transport of liquified gas; a regasification converter for converting liquified gas into gas; wherein liquefied gas is pumped from the cargo tanks to a combined-cycle power plant through the regasification converter such that the liquified gas is pressurised and vaporised to gas at ambient temperature; wherein the combined-cycle power plant comprises at least one gas turbine and at least one steam turbine, wherein the pressurised gas drives the gas turbine, and wherein waste heat from the combined-cycle power plant produce steams to drive the steam turbine, wherein both the steam turbine and the gas turbine are connected to an electrical power generator; a connection to provide electrical power generated by the electrical power generator to an electrical grid onshore; wherein the combined-cycle power plant generates 130 MW to 1.35 GW of electrical power, and wherein the vessel can burn liquified gas supplied by gas carriers while moored in near-shore areas, or can navigate independently to different locations or to transport liquified gas.

2. The floating liquified gas power station vessel according to claim 1 wherein the liquified gas is liquid natural gas (LNG) or up to 98% hydrogen (H2) or a combination thereof.

3. The floating liquified gas power station vessel according to claim 1 or claim 2 wherein the gas turbine in the combined-cycle power plant is driven by a combination of 50% pressurised natural gas and 50% stored hydrogen.

4. The floating liquified gas power station vessel according to any one of claims 1 to 3 wherein excess power generation from the combined-cycle power plant can be diverted into a shore-side hydrogen generation plant for storage and delivery into a national gas grid.

5. The floating liquified gas power station vessel according to any one of the preceding claims wherein the combined-cycle power plant generates about 1.0 to 1.2 GW of electrical power.

6. The floating liquified gas power station vessel according to any one of the preceding claims wherein the combined-cycle power plant is added to an extension of an existing LNG carrier vessel.

7. The floating liquified gas power station vessel according to claim 6 wherein the extension of the existing LNG carrier vessel is a stern extension and the extension geometry conforms to an overall length limit of about 350m.

8. The floating liquified gas power station vessel according to claim 6 or claim 7 wherein the vessel propulsion equipment is located in the extension.

9. The floating liquified gas power station vessel according to any one of the preceding claims wherein the regasification converter is located on the vessel midbody and/or bow.

10. The floating liquified gas power station vessel according to any one of claims 6 to 9 wherein the extension is added to the existing LNG carrier vessel by removing an existing stern comprising existing propulsion machinery at an aft end of a deckhouse, and adding an extended stern comprising the combined-cycle power plant and propulsion equipment room.

11. The floating liquified gas power station vessel according to claim 10 wherein the extended stern further comprises an engine room, and an aft mooring system in a new aft hull.

12. The floating liquified gas power station vessel according to any one of claims 6 to 11 wherein the extension further comprises fresh water generating systems and a sea water supply pump room.

13. The floating liquified gas power station vessel according to any one claims 6 to 12 wherein the extended vessel comprises gas turbine generators for propulsion and electrical power, replacing the existing LNG carrier vessel engine and gensets to enable a low carbon footprint from vessel operations.

14. The floating liquified gas power station vessel according to any one of the preceding claims wherein propulsion for the vessel is provided using at least two podded propulsors at the stern and bow thrusters to aid low-speed manoeuvrability, or the vessel can maintain a set position using a dynamic position systems (DP).

15. The floating liquified gas power station vessel according to any one of the preceding claims wherein the combined-cycle power plant comprises at least one gas turbine generator or an LNG / Hydrogen powered reciprocating generator, at least one heat recovery steam generator, at least one steam turbine generator, and at least one steam condenser.

16. The floating liquified gas power station vessel according to any one of claims 14 to 15 wherein the propulsion power plant comprises at least one azimuth podded propulsors, at least one gas turbine generator and at least one bow thruster, 26

17. The floating liquified gas power station vessel according to claim 16 wherein the propulsion/ship power gas turbine gas generators are located in the space occupied by ship power generators in the existing LNG carrier vessel.

18. The floating liquified gas power station vessel according to claim 16 or claim 17 wherein a propulsion room is located inside a new hull at the aft end of the vessel to accommodate the podded propulsors.

19. The floating liquified gas power station vessel according to any one of the preceding claims wherein the regasification system comprises at least one sea water supply pump, at least one sea water/water cooling agentcooling agent heat exchangers for open loop regasification, at least one steam/water cooling agentcooling agent heat exchangers for closed loop regasification, and at least one water cooling agentcooling agent circulation pump, wherein the regasification system can reuse waste heat generated by the combined- cycle gas turbines .

20. The floating liquified gas power station vessel according to any one of the preceding claims wherein battery storage is used on board the vessel to maintain system integrity and as a hybrid power source and on-shore to maintain supply to the grid during transition loads or vessel operational requirements.