Technical and Economic Feasibility Analysis of a Conceptual Subsea Freight Glider for CO2 Transportation
Abstract
:1. Introduction
1.1. General Background
1.2. Previous Work
2. Description of a Novel Subsea Freight Glider
- A half-scaled version of the baseline SFG;
- A doubled-scaled version of the baseline SFG.
- Cargo tank: Seven main and six auxiliary tanks are placed symmetrically in the SFG, as shown in Figure 4. The tanks have a rounded shape with hemispherical heads.
- Buoyancy tanks: To make the SFG neutrally buoyant, eight buoyancy tanks are distributed in the upper part of the mid-body to make the SFG neutrally buoyant. All tubes have the same volume and are attached to the front and back bulkhead.
- Compensation tanks: Two compensation tanks provide the weight and trimming moment to give the SFG neutral buoyancy under different hydrostatic loads. One of the compensation tanks is placed in front of the vessel and another is placed in the back, as presented in Figure 4.
- Trim tanks: There are two trim tanks inside the SFG. These tanks make the vessel neutrally trim by placing the centre of gravity below the centre of buoyancy. The trim tanks are located in the front and back of the SFG. Both tanks are inaccessible flooding compartments. They do not interact with the open sea, so they are free from external hydrostatic pressure and only have to deal with the internal hydrostatic pressure.
2.3. Structural Desing
2.3.1. Materials
2.3.2. External Hull
- The acceptable stresses in the nominal diving depth are 203 MPa, in the test diving depth are 418 MPa, and in the collapse depth are 460 MPa;
- The pressure hulls in the free-floating compartment are subjected to hydrostatic pressure. Stress at the collapse depth, nominal diving depth, and test diving depth for the flooded and free-flooding sections are computed and compared to the permissive stresses required in the DNVGL Rules for Classification for Naval Vessels, specifically in Part 4 Sub-Surface Ships, Chapter 1 Submarines (DNVGL-RU-NAVAL-Pt4Ch1) [15];
- The design of the flooded mid-body module uses the same procedure as for the free flooded compartments. Nonetheless, the flooded mid-body does not handle the hydrostatic pressure. Therefore, this section uses 20 bar (200 m) for the collapse pressure to avoid mechanical failure in unintentional load cases.
2.3.3. Internal Hull Design
- The cargo tanks that are used for the storage of CO2 are subjected to internal and external hydrostatic pressure. The tanks are designed for a burst pressure of 55 bar, which is the worst case scenario if the SFG must emerge from the water. Due to the external pressure being 0 bar gauge, the pressure difference equals 55 bar. A PCS (pressure compensation system) can be used to avoid failure caused by the collapse pressure. Detailed work on the PCS can be found in the studies by Ma et al. [18] and ** a subsea project are generally referred to as the capital expenditure (CAPEX) and operational expenditure (OPEX). The capital expenditure is the total investment required to put a project into operation. It includes the initial design, engineering, and construction of the facility. The term OPEX refers to the expenses incurred by a facility or component during its operation. These expenses include labour, materials, and utilities. Aside from these, other costs such as testing and maintenance are also included in the OPEX [12].The economic analysis was performed based on two publicly available cost models from the MUNIN [20] and ZEP [21] reports. The MUNIN D9.3 [20] report presents a complete study of autonomous ship development, economic effects, security and safety effects, and relevant areas of law. In this paper, the data from the MUNIN report [20] related to autonomous ships are used for the economic impact assessment cost analysis. The ZEP report [21] shows an analysis of CO2 transportation in the deployment of carbon capture and storage (CCS) and carbon capture and utilisation (CCU) systems. Data provided in the ZEP report [21] were provided by members of maritime organisations, including stakeholders and essential players in marine transportation, such as Teekay Ship**, Open Grid Europe, and Gassco. The analysis is very detailed and covers all components. For instance, the cost of the actual coating is specified and considered for the offshore pipeline. The present work uses cost models from the ZEP report [21] for the cost estimations, including the OPEX and CAPEX, ship capacities, and electricity prices, for offshore pipelines.This paper considers transport distances of 180, 500, 750, and 1500 km with CO2 ship** capacities of 0.5, 1, and 2.5 million tons per annum (mtpa). The CO2 is carried from a capture plant at ambient temperature and a pressure of 110 bar. The following assumptions for the CO2 transportation are made:
- The SFG and ship offload straight to the well without the usage of an intermediate buffer storage space;
- In cases of large CO2 volumes or long distances, there is a need for more than one transportation vessel; for instance, in a 180 km transport distance and 1 mtpa transport volume scenario, 6 SFGs measuring 2430 m3 or 11 SFGs measuring 1194 m3 are required;
- The cost of the subsea well-head is not considered in the following study;
- The rate of currency exchange is 0.87 EUR/USD;
- The discount rate is 8% and the project lifetime is 40 years.
The procedure and computations for the economic study of autonomous/crew tanker ships, offshore pipelines and SFGs are presented in Appendix B.3.1. SFG, Crewed and Autonomous Tanker Ship
The ship transporting the CO2 is equipped with semi-refrigerated liquefied petroleum gas (LPG) tanks. The liquefied gas is transported at a temperature of −50 °C. During the transportation, the tanker ship requires refrigeration and liquefied gas, which is transported at 7–9 bar and close to −55 °C to avoid the risk of the formation of dry ice. During transportation, the temperature of the CO2 will increase, initiating a boil-off and increasing the internal pressure of the ship. Therefore, the cargo pressure at the end of the loaded journey will typically be around 8–9 bar.The properties of the tanker ship are displayed in Table 10.The minimum number of SFGs and tanker ships required to fulfil the mission is calculated using the following equation:The calculated parameters to find the number of SFGs (baseline design—1194 m3) needed to complete the mission of transporting 2.5 mtpa of CO2 for a distance of 180 km are displayed in Table 11.The capital expenditure (CAPEX) is calculated based on the price per ton of structural steel weight. According to the ZEP report [21], the maximum and minimum costs for a ton of steel are calculated at 11,631–28,888 € per ton. As presented in Table 12, it is assumed that an autonomous tanker ship has a CAPEX of 110% of a crew tanker ship. The vessels should be modern and equipped with submerged turret offloading buoy capabilities and dynamic positioning.The CAPEX values of the SFGs and the tanker ships are calculated using the following equation:The discount rate is estimated to be 8% and the lifetime to be 40 years. Based on these assumed parameters, the annuity is calculated using the below equation.The tanker ship is powered by marine diesel oil or LNG. For both fuels, the price per ton is the same. The data used to calculate operating expenditure (OPEX) are displayed in Table 13.The OPEX values of the SFGs and tanker ships are calculated using the following equations:Based on the data provided in the ZEP report [21], the crew tanker ship’s capital expenditure is approximately 60–149 m€. Accordingly, the CAPEX for the autonomous tanker ship is about 66–164 m€.3.2. Offshore Pipelines
Overall, the offshore pipeline costs are controlled by the CAPEX, and they are proportional to the pipe’s length. In the design of offshore pipelines, the essential factors are the pipeline diameter, wall thickness, transport capacity, outlet and inlet pressures, and steel quality. Additionally, factors such as the corrosion protection, design against trawling, installation method, dropped object protection, and bottom stability should be considered.In this study, the manifold cost for the well and the injection well drilling are not considered. The capital expenditure is estimated based on the steel market price, pipeline installation cost, trenching, and pipeline coating. The CO2 is sent through the pipelines at 55–88 bar in the supercritical phase. In this case, the pressure boosters and the related costs are required, and they are contained in the calculation of the CAPEX. Furthermore, the pressure of the CO2 in the pipeline is determined by the storage conditions. In this analysis, the cost of the pre-transport CO2 compression is included in the price of the capture facility.In this study, the lowest volume (1 mtpa of CO2) for the offshore pipelines is not considered. This is because offshore pipelines are too expensive due to their small transportation capacity, and it is not economical to use this method of transfer.The components’ properties and pricing for the offshore pipelines are displayed in Table 14 and Table 15.The CAPEX values for an offshore pipeline are shown in the ZEP [21] report. The maximum and minimum values are expected to be 120% and 80%, respectively.The average OPEX values for an underwater pipeline are shown in the ZEP [21] report. The minimum and maximum OPEX values are approximately 80% and 120%, respectively. The pipeline’s CO2 volume is expected to be around 2.5 million tons per year.The offshore pipeline annuities are calculated based on the design definitions, and the related costs are included in Table 14 and Table 15, respectively. A 2.5 million tons of transport capacity offshore pipeline will take the cost to about 20.986–126.961 m€. All calculated data are displayed in Table 16. All operational costs and aspects of maintenance are included in the OPEX. The operating expenditures equal 2.35 m€/a.4. Results and Discussion
The technical and economic feasibility analysis results are discussed in this section. The analysis includes detailed technical–economic studies of modern transportation submarines, namely the SFGs, used for CO2 transport with comparisons with crew and autonomous tanker ships, offshore pipelines, and SST values.4.1. Number of Vessels
The minimum number of vessels required to perform the mission is illustrated in Figure 7.4.2. CAPEX and OPEX Results
The CAPEX results for all transportation methods are displayed in Figure 8. Overall, can obviously be seen that the SFG CAPEX increases significantly with the size. This implies that the SFG is not an economical solution if large transportation capacities are needed.The SFG was designed based on DNV-RU-NAVAL-Pt4Ch1 [15], and was initially created for military submarine designs. Due to the high safety requirements, the SFG has a very heavy structural weight, making the CAPEX value very high. For a specific SFG, a potential solution to reduce the weight and CAPEX is to reduce the design safety factors that are suggested in the design code for general SFGs.The OPEX/CAPEX ratios are displayed in Figure 9. It can be seen that OPEX dominates among the costs for crew and autonomous tanker ships. For these vessels, the CAPEX/OPEX ratios range between 2.59 and 7.28. On the other hand, the highest CAPEX and lowest OPEX results are for offshore pipelines, and the OPEX/CAPEX ratio range is 0.06–0.38. For the SFGs, the OPEX is comparable with the CAPEX, and their CAPEX/OPEX ratio range is 1.07–1.39.4.3. Economic Analysis
Figure 10 displays the results for the average cost per ton of CO2. Overall, the subsea shuttle tanker and offshore pipelines have the lowest costs for short distances with large capacities. In contrast, the tanker ships (crew and autonomous) have the lowest prices for longer distances. The SFG is economical for small CO2 volumes of 0.5–1 mtpa and short distances of 180–500 km. It is noted that with increasing CO2 volumes, the cost per ton of CO2 decreases. This is because of the better economies of scale.4.3.1. Short Distances (<180 km)
For the small CO2 capacity of 0.5–1 mtpa, the SFG has the lowest cost. The major reason for having the lowest price is the small number of vessels needed to complete the mission. In contrast, the crew tanker ship with the smallest capacity is oversized. As a result, the SFG has a lower CAPEX and OPEX than the other vessels.In the 0.5 and 1 mtpa volume cases, the offshore pipelines are not considered. Overall, offshore pipelines are not economical for transferring small volumes of CO2. They are most profitable for large transport volumes (10–20 mtpa).4.3.2. Intermediate and Long Distance (500–1500 km)
Due to travelling at low velocity, the SFG requires more vessels to meet the requirements for transporting CO2 at larger than 1 mtpa capacity. This results in higher capital expenditures and a significantly higher cost per ton of CO2 than for a crew or autonomous tanker ship. For instance, if the amount of CO2 is 2.5 mtpa for 516 or 1500 km, the SFG approach requires 103–530 ships. The SFG CAPEX range is 1827.33–1982.95 million euros, while 298.71 million euros is the CAPEX for crew ships. As a result, the average cost of the SFG per ton of CO2 is in the range of 82.93–94.13 million euros, while it is 15.47 million euros for crew ships. Nevertheless, the SFG is economical for smaller CO2 volumes (0.5 and 1 mtpa).Table 17 presents the economic feasibility analysis results, along with the lowest costs.5. Conclusions and Future Work
This study deals with a technical–economic feasibility analysis for a novel subsea freight glider, which consists of two steps. The first step involves investigating the design limits of the SFG, while the second step focuses on performing an economic analysis. The SFG is designed based on the procedure provided in international standards of the DNV-RU-NAVAL-Pt4Ch1 and ASME BPVC. The Marine Unmanned Navigation through Intelligence in Network (MUNIN D9.3) and Zero Emission Platform (ZEP) cost models are used for the economic analysis.The presented research demonstrates that the SFGs with a cargo volume of 469 m3, 1194 m3, and 2430 m3 are able to fulfil the mission requirements. The scenarios considered for this study involve the transport of CO2 volumes of 0.5, 1.0, and 2.5 million tons per year over distances of 180, 500, 750, and 1500 kilometres. The cost per ton of CO2 for the SFGs is compared with the cost of transporting the same volume on a tanker ship or via offshore pipelines. This study indicates that the use of SFGs is technically feasible for short distances of up to 500 kilometres and smaller CO2 volumes of less than 1 million tons per year. The SFG approach is also a cheaper solution than the use of crew and autonomous tanker ships due to the lower OPEX and CAPEX. Additionally, because of its slow-moving speed and the advantage of having no liquefaction cost, the SFG can transport CO2 in a saturated state, which significantly reduces the total price.The performed technical–economic analysis of the SFG shows that the small underwater vehicle is technically feasible and economically profitable to complete the mission presented here. Moreover, the research shows that the SFG is an attractive alternative for CO2 transportation. It is shown that the solution is cost-competitive for low-volume and short-distance transport. With this, the authors hope this will engage the research and engineering community to further consider and evaluate the concept, resulting in a final working concept that will eventually be a preferred alternative for low-volume and short-distance transport. However, there is still work that can be done in the future. In this study, the design-by-rules method was applied. There is still a need to perform a design-by-analysis approach with an elastic and plastic stress analysis. In addition, this analysis included only small sized submarines. It is essential to carry out an economic study for SFGs with drastically increased sizes.Lastly, this research started at the University of Stavanger in 2019 in collaboration with Equinor [11]. This research has its roots in Norway and has focused so far on the Norwegian Continental Shelf, where there are many marginal fields within 200 km of the coast. Even so, the authors expect that the vessel can also be applied to other suitable fields in other regions in the world.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
Appendix A
Appendix A.1. External Hull Design Calculation for the Baseline Design SFG (1194 m3)
Parameter | Symbol | Free Flooding Compartment | Flooded Compartment | Units | Equation No. in DNVGL-RU-P4C1 Appendix A | ||
---|---|---|---|---|---|---|---|
Design Pressure Type | Nominal Diving Depth | Test Diving Depth | Collapse Depth | Collapse | |||
Design pressure | p | 20 | 25 | 40 | 20 | [bar] | User input |
Hull thickness | s | 0.03 | 0.03 | 0.03 | 0.013 | [m] | User input |
Hull radius | Rm | 2.75 | 2.75 | 2.75 | 2.75 | [m] | User input |
Frame web height | hw | 0.165 | 0.165 | 0.165 | 0.165 | [m] | User input |
Frame web thickness | sw | 0.003 | 0.003 | 0.003 | 0.003 | [m] | User input |
Flange width | bf | 0.08 | 0.08 | 0.08 | 0.08 | [m] | User input |
Flange thickness | sf | 0.03 | 0.03 | 0.03 | 0.03 | [m] | User input |
Frame spacing | Lf | 1.0 | 1.0 | 1.0 | 1.5 | [m] | User input |
Frame cross-sectional area | Af | 0.0074 | 0.0074 | 0.0074 | 0.0074 | [m2] | User input |
Inner radius to the flange of the frame | Rf | 2.53 | 2.53 | 2.53 | 2.53 | [m] | User input |
Young’s modulus | E | 206 | 206 | 206 | 206 | [GPa] | User input |
Poisson’s ratio | v | 0.3 | 0.3 | 0.3 | 0.3 | - | User input |
Poisson ratio in elastic-plastic range | vp | 0.44 | 0.44 | 0.44 | 0.44 | - | (A48) |
Frame distance without thickness | L | 0.97 | 0.97 | 0.97 | 0.97 | [m] | (A9) |
Effective length | Leff | 0.447 | 0.447 | 0.447 | 0.294 | [m] | (A10) |
Effective area | Aeff | 0.0076 | 0.0076 | 0.0076 | 0.0077 | [m2] | (A11) |
The radial displacement in the middle between the frames | wM | −0.002 | −0.0025 | −0.0042 | −0.0047 | [m] | (A15) |
The radial displacement at the frames | wF | −0.0021 | −0.0027 | −0.0041 | −0.0032 | [m] | (A16) |
The reference stress is the circumferential stress in the unstiffened cylindrical pressure hull | σ0 | 183 | 229 | 367 | 423 | [MPa] | (A13) |
The equivalent stresses are composed of the single stresses in longitudinal and circumferential directions in the middle between frames | σmv,m | 156 | 196 | 318 | 360 | [MPa] | (A14) |
The equivalent stresses are composed of the single stresses in longitudinal and circumferential directions in the frames | σmv,f | 164 | 203 | 317 | 268 | [MPa] | (A14) |
Average membrane stress in longitudinal direction | σmx | 91 | 115 | 183 | 212 | [MPa] | (A17) |
Membrane stress in circumferential direction in the middle between the frames | σm φ, M | 181 | 227 | 367 | 416 | [MPa] | (A18) |
Membrane stress in circumferential direction in the frames | σm φ,F | 189 | 235 | 366 | 301 | [MPa] | (A19) |
Bending stresses in longitudinal direction in the middle between the frames | σxφ,M | 52 | 67 | 117 | 27 | [MPa] | (A20) |
Bending stresses in longitudinal direction in the frames | σbx,F | 11 | 11 | 16 | 221 | [MPa] | (A21) |
Bending stresses in circumferential direction in the middle between the frames | σbφ,M | 16 | 20 | 32 | 8 | [MPa] | (A22) |
Bending stresses in circumferential direction in the frames | σbφ,M | 3 | 3 | 5 | 66 | [MPa] | (A23) |
Tangential module | Et | 206 | 206 | 206 | 206 | [MPa] | (A38) |
Secant module | Es | 204 | 204 | 204 | 204 | [GPa] | (A39) |
Elastic buckling pressure | pelcr | 82 | 82 | 82 | 62 | [GPa] | (A28) |
Theoretical elastic–plastic buckling pressure | picr | 93 | 93 | 93 | 70 | [bar] | (A29) |
Reduction factor | R | 0.75 | 0.75 | 0.75 | 0.75 | [bar] | (A43) |
Elastic–plastic buckling pressure | p’cr | 60 | 60 | 60 | 56 | [bar] | (A45) |
Type of Stresses | At the Frame | In the Middle of the Field | ||||
---|---|---|---|---|---|---|
Circumferetial | Equivalent | Axial | Circumferential | Equivalent | Axial | |
Membrane stress | 189 MPa | - | 92 Mpa | 181 Mpa | - | 92 Mpa |
Membrane equivalent stress | - | 156 Mpa | - | - | 164 Mpa | - |
Bending stress | 3 Mpa | - | 11 Mpa | 16 Mpa | - | 52 Mpa |
Normal stress outside | 192 Mpa | - | 102 Mpa | 196 Mpa | - | 144 Mpa |
Equivalent normal stress outside | - | 166 Mpa | - | - | 176 Mpa | - |
Normal stress inside | 192 Mpa | - | 102 Mpa | 196 Mpa | - | 144 Mpa |
Equivalent normal stress inside | - | 166 Mpa | - | - | 176 Mpa | - |
Type of Stresses | At the Frame | In the Middle of the Field | ||||
---|---|---|---|---|---|---|
Circumferetial | Equivalent | Axial | Circumferential | Equivalent | Axial | |
Membrane stress | 235 MPa | - | 115 MPa | 227 MPa | - | 115 MPa |
Membrane equivalent stress | - | 196 MPa | - | - | 203 MPa | - |
Bending stress | 3 MPa | - | 11 MPa | 20 MPa | - | 67 MPa |
Normal stress outside | 238 MPa | - | 126 MPa | 247 MPa | - | 182 MPa |
Equivalent normal stress outside | - | 206 MPa | - | - | 221 MPa | - |
Normal stress inside | 238 MPa | - | 126 MPa | 247 MPa | - | 182 MPa |
Equivalent normal stress inside | - | 206 MPa | - | - | 221 MPa | - |
Type of Stresses | At the Frame | In the Middle of the Field | ||||
---|---|---|---|---|---|---|
Circumferetial | Equivalent | Axial | Circumferential | Equivalent | Axial | |
Membrane stress | 366 MPa | - | 183 MPa | 367 MPa | - | 183 MPa |
Membrane equivalent stress | - | 318 MPa | - | - | 317 MPa | - |
Bending stress | 1 MPa | - | 2 MPa | 35 MPa | - | 117 MPa |
Normal stress outside | 366 MPa | - | 185 MPa | 402 MPa | - | 301 MPa |
Equivalent normal stress outside | - | 317 MPa | - | - | 362 MPa | - |
Normal stress inside | 366 MPa | - | 185 MPa | 402 MPa | - | 301 MPa |
Equivalent normal stress inside | - | 317 MPa | - | - | 362 MPa | - |
Type of Stresses | At the Frame | In the Middle of the Field | ||||
---|---|---|---|---|---|---|
Circumferetial | Equivalent | Axial | Circumferential | Equivalent | Axial | |
Membrane stress | 301 MPa | - | 212 MPa | 416 MPa | - | 212 MPa |
Membrane equivalent stress | - | 360 MPa | - | - | 268 MPa | - |
Bending stress | 66 MPa | - | 221 MPa | 8 MPa | - | 27 MPa |
Normal stress outside | 368 MPa | - | 433 MPa | 424 MPa | - | 238 MPa |
Equivalent normal stress outside | - | 404 MPa | - | - | 368 MPa | - |
Normal stress inside | 368 MPa | - | 433 MPa | 424 MPa | - | 238 MPa |
Equivalent normal stress inside | - | 404 MPa | - | - | 368 MPa | - |
Case | Depth | Maximum Equivalent Stress | Permissible Stress (Ref. Section. 4.3 in DNVGL RU P4C1) | Criterion Fulfilled? |
---|---|---|---|---|
Nominal diving depth | 200 m | 196 MPa | 203 MPa | Yes |
Test diving depth | 250 m | 247 MPa | 418 MPa | Yes |
Collapse depth | 400 m | 402 MPa | 460 MPa | Yes |
Flooded Compartment | - | 432 MPa | 460 MPa | Yes |
Appendix A.2. Internal Tank Design Calculation for the SFG Baseline Design (1194 m3)
Parameter | Symbol in ASME BPVC Section VIII Div. 2 | Value | Equation Number in ASME BPVC Section VIII Div 2. |
---|---|---|---|
Outer diameter | D0 | 0.346 | User input |
Thickness | t | 0.004 | User input |
Unsupported length | L | 1 m | User input |
Minimum yield strength | Sy | 414 MPa | User input |
Young’s modulus | Ey | 200 GPa | User input |
Design factor | FS | 2 | (4.4.1) |
Predicted elastic bucking factor | Fhe | 71 MPa | (4.4.19) |
Factor | Mx | 45 | (4.4.20) |
Factor | Ch | 0.01 | (4.4.22) |
Predicted buckling stress | Fic | 71 MPa | (4.4.27) |
Allowable external pressure | Pa | 8 bar | (4.4.28) |
Appendix A.3. Computation of the Reference Area of the Wing
- H is the nominal operating depth, which is set to be 200 m;
- BF is the ballast fraction, which is estimated to be 0.15%;
- Dton is the weight of the cargo;
- ξ is the gliding angle, which is 30°.
Appendix A.4. Power Consumption Estimation
- The power of the pump is approximated based on the flow of the pump duration taken to load and unload the freight. It takes 4 h to load and reload the cargo because the pumps give 3 bars of differential pressure. Every SFG design has different volumetric flow rates to guarantee the same loading and offloading intervals. The efficiency of the pumps is assumed to be no lower than 75% [27].
Appendix B
Appendix B.1. Offshore Pipelines—CAPEX
SFG | OP | CS | AS | Units | |
---|---|---|---|---|---|
Autonomous ship factor | - | - | - | 110% | - |
Price per ton of vessel steel | 18,896 | 18,896 | 18,896 | 18,896 | [€/ton] |
Structural volume | 489 | - | 5170 | 5170 | [ton] |
CAPEX | 255.61 | 250.25 | 97.69 | 107.46 | [m€] |
Annuity | 21.44 | 20.99 | 8.19 | 9.01 | [m€] |
Appendix B.2. Offshore Pipelines—OPEX
SFG | OP | CS | AS | Units | |
---|---|---|---|---|---|
CAPEX | 255.61 | 250.25 | 97.69 | 107.46 | [m€] |
Fuel price | - | - | 573.33 | 573.33 | [€/ton] |
Fuel consumption | - | - | 9.13 | 9.13 | [ton/day] |
Fuel cost | - | - | 1.91 | 1.91 | [m€/year] |
Electricity price | - | - | - | 0.11 | [€/kWh] |
Electricity consumption | - | - | - | 2044 | [kWh/day] |
Electricity cost | - | - | - | 0.24 | [m€/year] |
Liquification cost for 2.5 mtpa | - | - | 13.28 | 13.28 | [m€/year] |
Crew cost | - | 0.64 | - | - | [m€/year] |
Vessel maintenance cost | - | - | 1.95 | 2.15 | [m€/year] |
Vessel maintenance | - | 2% | 2% | 2% | |
OPEX | 7.33 | 2.35 | 17.78 | 17.33 | [m€/year] |
Appendix B.3. Cost of CO2 Per Ton
SFG | OP | CS | AS | |
---|---|---|---|---|
OPEX | 7.33 m€ | 2.35 m€ | 17.78 m€ | 17.33 m€ |
Annuity | 21.44 m€ | 20.99 m€ | 8.19 m€ | 9.01 m€ |
Total CO2 per annum | 2.5 | 2.5 | 2.5 | 2.5 |
Cost of CO2 per ton | 11.51 m€ | 9.33 m€ | 10.39 m€ | 10.54 m€ |
References
- Middleton, R.S.; Bielicki, J.M. A comprehensive carbon capture and storage infrastructure model. Energy Procedia 2009, 1, 1611–1616. [Google Scholar] [CrossRef]
- Global CCS Institute. The Global Status of CCS 2015: Summary Report; Global CCS Institute: Docklands, Australia, 2015. [Google Scholar]
- Trading Economics. Steel-2022 Data-2016-2021 Historical-2023 Forecast. 2022. Available online: https://tradingeconomics.com/commodity/steel (accessed on 28 May 2022).
- Rackley, S.A. Carbon Dioxide Transportation; Butterworth-Heinemann: Boston, MA, USA, 2017; pp. 595–611. [Google Scholar] [CrossRef]
- Equinor ASA. Equinor Aims to Cut Emissions in Norway towards Near Zero in 2050. 07 January 2020. Available online: https://www.equinor.com/news/archive/2020-01-06-climate-ambitions687norway (accessed on 28 May 2022).
- Jacobsen, L.R. Subsea Transport of Arctic Oil-A Technical And Economic Evaluation. In Offshore Technology Conference; OTC-1425-MS; OnePetro: Houston, TX, USA, May 1971. [Google Scholar] [CrossRef]
- Taylor, P.; Montgomery, J. Arctic Submarine Tanker System. In Offshore Technology Conference; OnePetro: Houston, TX, USA, 1977. [Google Scholar] [CrossRef]
- Jacobsen, L.; Lawrence, K.; Hall, K.; Canning, P.; Gardner, E. Transportation of LNG from the Arctic by Commercial Submarine. Mar. Technol. SNAME News 1983, 20, 377–384. [Google Scholar] [CrossRef]
- Brandt, H.; Frühling, C.; Hollung, A.; Schiemann, M.; Voß, T. A Multi-Purpose Submarine Concept for Arctic Offshore Operations. In OTC Arctic Technology Conference; OTC-25501-MS; OnePetro: Copenhagen, Denmark, 2015. [Google Scholar] [CrossRef]
- Equinor ASA. Subsea Shuttle: The World’s First Drone to Transport CO2. 2020. Available online: https://www.equinor.com/en/magazine/here-are-six-of-the-coolest-offshore-robots.html (accessed on 7 May 2022).
- **ng, Y.; Ong, M.C.; Hemmingsen, T.; Ellingsen, K.E.; Reinås, L. Design Considerations of a Subsea Shuttle Tanker System for Liquid Carbon Dioxide Transportation. J. Offshore Mech. Arct. Eng. 2020, 143, 045001. [Google Scholar] [CrossRef]
- **ng, Y.; Santoso, T.A.D.; Ma, Y. Technical–Economic Feasibility Analysis of Subsea Shuttle Tanker. J. Mar. Sci. Eng. 2021, 10, 20. [Google Scholar] [CrossRef]
- **ng, Y. A Conceptual Large Autonomous Subsea Freight-Glider for Liquid CO2 Transportation. In Proceedings of the International Conference on Ocean, Offshore and Arctic Engineering, Virtual, 21–30 June 2021. [Google Scholar] [CrossRef]
- Ahmad, U.N.; **ng, Y. A 2D model for the study of equilibrium glide paths of UiS Subsea Freight-Glider. IOP Conf. Series Mater. Sci. Eng. 2021, 1201, 012022. [Google Scholar] [CrossRef]
- DNV GL AS. Rules for Classification: Naval Vessels Part 4 Sub-Surface Ships Chapter 1 Submarines. 2018. Available online: http://www.dnvgl.com (accessed on 28 May 2022).
- The American Society of Mechanical Engineers ASME. ASME Boiler and Pressure Vessel Code an International Code R ules for Construction of Power Boilers SECTION I; The American Society of Mechanical Engineers ASME: New York, NY, USA, 2017. [Google Scholar]
- Ahmad, U.; **ng, Y.; Ma, Y. UiS Subsea-Freight Glider: A Buoyancy-Driven Autonomous Glider. In Technology and Applications of Autonomous Underwater Vehicles; Taylor and Francis: London, UK, 2022. [Google Scholar]
- Ma, Y.; **ng, Y.; Ong, M.C.; Hemmingsen, T.H. Baseline design of a subsea shuttle tanker system for liquid carbon dioxide transportation. Ocean Eng. 2021, 240, 109891. [Google Scholar] [CrossRef]
- Ersdal, G. An Overview of Ocean Currents with Emphasis on Currents on the Norwegian Continental Shelf. 2001. Available online: https://www.semanticscholar.org/paper/An-overview-of-ocean-currents-with724emphasis-on-on-Ersdal/e90fcf6fcade300b540190ab57071f8961b125c9 (accessed on 28 May 2022).
- MUNIN. D9.3: Quantitative Assessment; MUNIN: Singapore, 2015. [Google Scholar]
- ZEP. The Costs of CO2 Capture, Transport and Storage. 2011. Available online: www.zeroemissionsplatform.eu/library/publication/168-zep740cost-report-storage.html (accessed on 28 May 2022).
- Graver, J.G. Underwater Gliders: Dynamics, Control and Design; Princeton University: Princeton, NJ, USA, 2005. [Google Scholar]
- Hoerner, S.F. Fluid-Dynamic Drag: Practical Information on Aerodynamic Drag and Hydrodynamic Resistance; Hoerner Fluid Dynamics: California, CA, USA, 1965. [Google Scholar]
- ITTC. Procedures and Guidelines Testing and Extrapolation Methods Resistance Uncertainty Analysis, Example for Resistance Test; ITTC: London, UK, 2002. [Google Scholar]
- Wärtsilä. WSD50 30K 30,000 m3 LNG Carrier-Datasheet. Wärtsilä: Helsinki, Finland, 2017. [Google Scholar]
- Kretschmann, L.; Burmeister, H.-C.; Jahn, C. Analyzing the economic benefit of unmanned autonomous ships: An exploratory cost-comparison between an autonomous and a conventional bulk carrier. Res. Transp. Bus. Manag. 2017, 25, 76–86. [Google Scholar] [CrossRef]
- Hall, S. Rules of Thumb for Chemical Engineers; Butterworth-Heinemann: Oxford, UK, 2018. [Google Scholar]
Properties | Value | Units |
---|---|---|
Operating depth (nominal diving depth) | 200 | [m] |
Collapse depth | 400 | [m] |
Operating speed | 2 | [knots] |
Cargo pressure | 35–55 | [bar] |
Current speed | 1 | [m/s] |
Cargo temperature | 0–20 | [°C] |
Maximum range | 400 | [km] |
Properties | Material | Yield Strength | Tensile Strength |
---|---|---|---|
Bulkhead | VL D37 | 360 MPa | 276 MPa |
External hull—Bow compartment | VL D47 | 460 MPa | 550 MPa |
External hull—Aft compartment | VL D47 | 460 MPa | 550 MPa |
External hull—Mid-body | VL D47 | 460 MPa | 550 MPa |
Internal hull—Main cargo tank | SA-738 Grade B | 414 MPa | 550 MPa |
Internal hull—Compensation tank | SA-738 Grade B | 414 MPa | 586 MPa |
Internal hull—Auxiliary cargo tank | SA-738 Grade B | 414 MPa | 586 MPa |
Internal hull—Buoyancy tube | SA-738 Grade B | 414 MPa | 586 MPa |
Internal hull—Trim tank | SA-738 Grade B | 414 MPa | 586 MPa |
Component | Symbol | Value | Units |
---|---|---|---|
Frame web thickness | sw | 30 | [mm] |
Frame web height | hw | 165 | [mm] |
Inner radius to the flange of the frame | Rf | 2532 | [mm] |
Flange width | bf | 80 | [mm] |
Frame spacing | Lf | 1000 | [mm] |
Flange thickness | sf | 30 | [mm] |
Frame cross-sectional area | Af | 73,500 | [mm2] |
Parameter | SFG 469 m3 | SFG 1194 m3 | SFG 2430 m3 | Units | |
---|---|---|---|---|---|
Free-floating bow compartment | Thickness | 0.025 | 0.030 | 0.036 | [m] |
Length | 6.625 | 8.750 | 11.50 | [m] | |
Steel weight | 21.899 | 43.877 | 87.510 | [ton] | |
Material | VL D47 | VL D47 | VL D47 | ||
Design collapse pressure | 40 | 40 | 40 | [bar] | |
Flooded mid-body | Thickness | 0.009 | 0.013 | 0.026 | [m] |
Length | 25.00 | 33.75 | 42.00 | [m] | |
Steel weight | 34.049 | 80.850 | 222.749 | [ton] | |
Material | VL D47 | VL D47 | VL D47 | ||
Design collapse pressure | 20 | 20 | 20 | [bar] | |
Free-floating aft compartment | Thickness | 0.025 | 0.030 | 0.036 | [m] |
Length | 10.625 | 14.00 | 18.00 | [m] | |
Steel weight | 27.412 | 54.581 | 105.942 | [ton] | |
Material | VL D47 | VL D47 | VL D47 | ||
Design collapse pressure | 40 | 40 | 40 | [bar] |
Parameters | SFG 469 m3 | SFG 1194 m3 | SFG 2430 m3 | Units | |
---|---|---|---|---|---|
Main Cargo Tank (Total No. = 7) | Diameter | 1.20 | 1.62 | 2.20 | [m] |
Length | 25.00 | 33.75 | 42.00 | [m] | |
Thickness | 0.014 | 0.018 | 0.025 | [m] | |
Hemisphere head wall thickness | 0.007 | 0.009 | 0.012 | [m] | |
Steel weight | 68.688 | 168.998 | [ton] | ||
Total volume | 190.376 | 468.395 | 1073.411 | [m2] | |
Allowable burst pressure | 55.0 | 55.0 | 55.0 | [bar] | |
Material | SA-738 Grade B | SA-738 Grade B | SA-738 Grade B | ||
Auxiliary Cargo Tank (Total No. = 6) | Diameter | 0.45 | 0.70 | 0.80 | [m] |
Length | 24.25 | 32.83 | 40.60 | [m] | |
Thickness | 0.005 | 0.008 | 0.009 | [m] | |
Hemisphere head wall thickness | 0.003 | 0.004 | 0.005 | [m] | |
Steel weight | 8.153 | 26.670 | 43.115 | [ton] | |
Total volume | 22,478 | 73.568 | 118.894 | [m2] | |
Allowable burst pressure | 55.0 | 55.0 | 55.0 | [bar] | |
Material | SA-738 Grade B | SA-738 Grade B | SA-738 Grade B | ||
Compensation Tank (Total No. = 2) | Diameter | 3.0 | 3.5 | 5.5 | [m] |
Length | 1.7 | 2.5 | 5.0 | [m] | |
Thickness | 0.006 | 0.010 | 0.014 | [m] | |
Steel weight | 20.224 | 72.063 | 96.214 | [ton] | |
Total volume | 17.34 | 61.25 | 75 | [m2] | |
Allowable burst pressure | 8.0 | 8.0 | 8.0 | [bar] | |
Material | SA-738 Grade B | SA-738 Grade B | SA-738 Grade B | ||
Trim Tank (Total No. = 2) | Diameter | 1.6 | 1.8 | 3.00 | [m] |
Length | 2.24 | 2.50 | 6.3 | [m] | |
Thickness | 0.006 | 0.008 | 0.022 | [m] | |
Steel weight | 12.479 | 14.702 | 78.728 | [ton] | |
Total volume | 10.0 | 45.00 | 60.0 | [m2] | |
Allowable burst pressure | 10.0 | 10.0 | 10.0 | [bar] | |
Material | SA-738 Grade B | SA-738 Grade B | SA-738 Grade B | ||
Buoyancy Tube (Total No. = 8) | Diameter | 0.30 | 0.35 | 0.40 | [m] |
Length | 24.1 | 32.5 | 40.2 | [m] | |
Thickness | 0.003 | 0.004 | 0.005 | [m] | |
Hemisphere head wall thickness | 0.002 | 0.002 | 0.002 | [m] | |
Steel weight | 4.816 | 8.845 | 14.300 | [ton] | |
Total volume | 13.572 | 24.910 | 40.279 | [m2] | |
Allowable burst pressure | 20.0 | 20.0 | 20.0 | [bar] | |
Material | SA-738 Grade B | SA-738 Grade B | SA-738 Grade B |
Component | Weight (Tons) | |||||
---|---|---|---|---|---|---|
SFG 469 m3 | SFG 1194 m3 | SFG 2430 m3 | ||||
Machinery | 9.610 | 2.00% | 24.474 | 2.00% | 49.798 | 2.00% |
Permanent ballast | 9.610 | 2.00% | 24.274 | 2.00% | 49.798 | 2.00% |
Structure | 187.999 | 39.12% | 476.361 | 38.93% | 962.768 | 38.67% |
Mid-body seawater | 69.051 | 14.37% | 179.381 | 14.66% | 277.306 | 11.14% |
Compensation ballast | 0.804 | 0.17% | 0.999 | 0.08% | 11.994 | 0.48% |
Payload | 200.082 | 41.64% | 509.446 | 41.63% | 1120.768 | 45.01% |
Trim tank | 3.364 | 0.70% | 8.566 | 0.70% | 17.429 | 0.70% |
SUM | 480.520 | 100% | 1,223,700 | 100% | 2489.914 | 100% |
SFG 469 m3 (Half-Scaled) | ||||
Submerged (CO2 Filled) | Submerged (SW Filled) | Submerged (CO2 Filled) | Submerged (SW Filled) | |
CoG(x,y,z) | [−0.58, 0.00, 0.33] | [−0.52, 0.00, 0.33] | [−0.52, 0.00, 0.33] | [−0.60, 0.00, 0.51] |
CoB(x,y,z) | [−0.67, 0.00, 0.00] | [−0.67, 0.00, 0.00] | [−0.67, 0.00, 4.10] | [−0.67, 0.00, 3.50] |
M(x,y,z) | [0.00, 0.00, 0.00] | [0.00, 0.00, 0.00] | [0.00, 0.00, 0.00] | [0.00, 0.00, 0.00] |
BG | 0.330 | 0.330 | 3.770 | 2.990 |
GM | 0.330 | 0.330 | 0.330 | 0.510 |
Result | BG > 0.32 == OK | BG > 0.32 == OK | GM > 0.2 == OK | GM > 0.2 == OK |
SFG 1194 m3 (baseline design) | ||||
Submerged (CO2 filled) | Submerged (SW filled) | Submerged (CO2 filled) | Submerged (SW filled) | |
CoG(x,y,z) | [−0.60, 0.00, 0.35] | [−0,54 0.00, 0.36] | [−0.70, 0.00, 0,37] | [−0.66, 0.00, 0.36] |
CoB(x,y,z) | [−0.83, 0.00, 0.00] | [−0.84, 0.00, 0.00] | [−0.84, 0.00, 5.50] | [−0.84, 0.00, 4.20] |
M(x,y,z) | [0.00, 0.00, 0.00] | [0.00, 0.00, 0.00] | [0.00, 0.00, 0.00] | [0.00, 0.00, 0.00] |
BG | 0.347 | 0.361 | 5.126 | 3.844 |
GM | 0.347 | 0.361 | 0.374 | 0.356 |
Result | BG > 0.32 == OK | BG > 0.32 == OK | GM > 0.2 == OK | GM > 0.2 == OK |
SFG 2430 m3 (doubled-scaled) | ||||
Submerged (CO2 filled) | Submerged (SW filled) | Submerged (CO2 filled) | Submerged (SW filled) | |
CoG(x,y,z) | [−0.60, 0.00, 0.37] | [−0.56, 0.00, 0.39] | [−0.56, 0.00, 0.39] | [−0.65, 0.00, 0.39] |
CoB(x,y,z) | [−1.00, 0.00, 0,00] | [−1.00, 0.00, 0.00] | [−1.00, 0.00, 5.10] | [−1.00, 0.00, 7.30] |
M(x,y,z) | [0.00, 0.00, 0.00] | [0.00, 0.00, 0.00] | [0.00, 0.00, 0.00] | [0.00, 0.00, 0.00] |
BG | 0.372 | 0.388 | 4.712 | 6.13 |
GM | 0.372 | 0.388 | 0.388 | 0.387 |
Result | BG > 0.35 == OK | BG > 0.35 == OK | GM > 0.22 == OK | GM > 0.22 == OK |
Parameter | Value | ||
---|---|---|---|
SFG 469 m3 | SFG 1194 m3 | SFG 2430 m3 | |
Lightweight [ton] | 197.609 | 500.835 | 962.819 |
Lightweight [m3] | 192.789 | 488.619 | 939.336 |
Deadweight [ton] | 282.911 | 722.866 | 1527.094 |
Deadweight [m3] | 276.011 | 705,235 | 1489.848 |
Length [m] | 42.25 | 56.50 | 71.50 |
Beam [m] | 4.00 | 5.50 | 7.00 |
Displacement [ton] | 480.520 | 1223.701 | 2489.914 |
Displacement [m3] | 468.800 | 1193.854 | 2429.184 |
Total power consumption [kW] | 6450 | 9545 | 14,533 |
Power consumptions [kWh/day] | 1381 | 2044 | 3112 |
Speed [knots] | 2.00 | 2.00 | 2.00 |
Travel distance [km] | 400.00 | 400.00 | 400.00 |
The Cost Model Shown in MUNIN D9.3 | The Cost Model Presented in ZEP |
---|---|
Autonomous ship capital expenditure | Offshore pipeline capital expenditure |
Fuel price | Offshore pipeline operating expenditure |
Ship fuel consumption | Electricity price |
Discount rate | Discount rate |
Ship capacity | |
Vessel loading and offloading durations | |
Vessel transport velocity | |
Ship capital expenditure | |
Ship operating expenditure | |
Transport distance cases | |
Transport volume cases | |
Liquefaction price | |
Project lifetime |
Crew and Autonomous Tanker Ship Properties | ||
---|---|---|
Liquefaction 2.5 mtpa | 5.31 | €/ton |
Liquefaction 10 mtpa | 5.09 | €/ton |
Loading/offloading time | 12.00 | h |
Speed | 14.00 | knots |
Fuel consumption, ship 22,000 m3 | 9.13 | ton/day |
Payload | 80.00 | % |
Parameters | Value | Units |
---|---|---|
Total CO2 capacity | 2.5 | [mtpa] |
Transport distance | 180 | [km] |
Loading and offloading time | 4 | [hours] |
The velocity of the SFG | 2 | [knots] |
Cargo volume | 723 | [m3] |
CO2 density | 940 | [kg/m3] |
Number of required vessels | 27 |
Inputs to CAPEX of Crew and Autonomous Tanker Ships | ||
---|---|---|
Steel price (max) in ZEP report | 28,888.50 | €/ton |
Steel price (min) in ZEP report | 11,631.45 | €/ton |
Steel price (average) in the ZEP report | 18,896.04 | €/ton |
Residual value | 0 | € |
Autonomous ship price | 110% crew ship price |
Inputs to the OPEX for Crew and Autonomous Tanker Ships | ||
---|---|---|
Fuel price | 573.33 | €/ton |
Electricity price | 0.11 | €/kWh |
Crew Price | 640,180.80 | €/year—20 crews |
Maintenance | 2 | % |
Properties of the Offshore Pipelines | ||
---|---|---|
Pressures | 250 | [bar] |
Outlet pressure | 60 | [bar] |
Inlet pressure | 200 | [bar] |
Pipeline internal friction | 50 | |
External coating | 3 | [mm] |
Pipeline material | Carbon steel | |
Concrete coating (pipeline above 16”) | 70 mm; 2600 kg/m3 |
Component Pricing of the Offshore Pipelines | ||
---|---|---|
Trenching cost | 20–40 | €/meter |
Installation cost | 200–300 | €/meter |
Pipeline OPEX for 2.5 mtpa | 2.35 | m€/year |
Contingency | 20% | |
Steel price for pipeline 16” | 160 | €/meter |
Steel price for pipeline 40’ | 700 | €/meter |
External coating for pipeline 16” | 90 | €/meter |
External coating for pipeline 40” | 200 | €/meter |
Trenching cost | 20–40 | €/meter |
CO2 Volume | Offshore Pipeline Length | |||
---|---|---|---|---|
180 km | 500 km | 750 km | 1500 km | |
0.5 mtpa | - | - | - | - |
1 mtpa | - | - | - | - |
2.5 mtpa | 20.986 m€ | 48.688 m€ | 69.412 m€ | 126.961 m€ |
180 km | 500 km | 750 km | 1500 km | |
---|---|---|---|---|
0.5 mtpa | SFG | SFG/SST | SST | CS/AS |
1 mtpa | SFG/SST | SST | AS/CS/SST | CS/AS |
2.5 mtpa | OP/SST | CS | CS | CS/AS |
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. |
© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Share and Cite
Klis, P.; Wang, S.; **ng, Y. Technical and Economic Feasibility Analysis of a Conceptual Subsea Freight Glider for CO2 Transportation. J. Mar. Sci. Eng. 2022, 10, 1108. https://doi.org/10.3390/jmse10081108
Klis P, Wang S, **ng Y. Technical and Economic Feasibility Analysis of a Conceptual Subsea Freight Glider for CO2 Transportation. Journal of Marine Science and Engineering. 2022; 10(8):1108. https://doi.org/10.3390/jmse10081108
Chicago/Turabian StyleKlis, Pawel, Shuaishuai Wang, and Yihan **ng. 2022. "Technical and Economic Feasibility Analysis of a Conceptual Subsea Freight Glider for CO2 Transportation" Journal of Marine Science and Engineering 10, no. 8: 1108. https://doi.org/10.3390/jmse10081108