Technical–Economic Feasibility Analysis of Subsea Shuttle Tanker

Abstract

This paper presents the technical and economic feasibility analysis of the subsea shuttle tanker (SST). The SST is proposed as an alternative to subsea pipelines and surface tankers with the primary purpose of transporting CO2 autonomously underwater from onshore facilities to subsea wells for direct injection at marginal subsea fields. In contrast to highly weather-dependent surface tanker operations, the SST can operate in any condition underwater. The technical–economic analysis is performed in two steps. First, the SST’s technical feasibility is evaluated by investigating designs with lower and higher capacities. The purpose is to observe the appearance of technical limits (if present) when the SST is scaled down or up in size. Second, an economic analysis is performed using the well-reviewed cost models from the publicly available Zero Emissions Platform (ZEP) and Maritime Un-manned Navigation through Intelligence in Networks (MUNIN) D9.3 reports. The scenarios considered are CO2 transport volumes of 1 to 20 million tons per annum (mtpa) with transport distances of 180 km to 1500 km in which the cost per ton of CO2 is compared between offshore pipelines, crewed/autonomous tanker ships, and SST. The results show that SSTs with cargo capacities 10,569 m3, 23,239 m3, and 40,730 m3 are technically feasible. Furthermore, the SSTs are competitive for short and intermediate distances of 180–750 km and smaller CO2 volumes of 1–2.5 mtpa. Lastly, it is mentioned that the SST design used the DNVGL Rules for Classification for Naval Vessels, Part 4 Sub-surface ships, Chapter 1 Submarine, DNVGL-RU-NAVAL-Pt4Ch1, which is primarily catered towards military submarine design. It is expected that a dedicated structural design code that is optimized for the SST would reduce the structural weight and corresponding capital expenditure (CAPEX).

Instability and Failure of Subsea Structures

“…The resistance of the SST at an operating forward speed, when subjected to an incoming current, was computed using a delayed, detached, eddy-simulation method, which combines features of Reynolds-averaged Navier-Stokes simulation in the attached boundary layer parts at the near-wall regions, and large-eddy simulation at the unsteady, separated regions near the propeller [13]. The technical-economic feasibility analysis of SST was further performed in [14].…”

Carbon Storage Tanker Lifetime Assessment

“…SSTs considered in ref. [ 5 ] have been designed, following state‐of‐art DNV submarine design code. [ 6 ] The use of design optimizations should increase the economic allure of SST.…”

Dynamic design and analysis of subsea CO2 discharging flowline for cargo submarines used for CCS in low-carbon and renewable energy value chains

“…Since then, several research works on the SST have been performed. These included maneuvering studies (Ma et al, 2021a;Ma et al, 2022), structural analysis (Jamissen et al, 2022), computational fluid dynamics analysis (Xing et al, 2021a), CO 2 design considerations (Ma et al, 2021b), and technical and economic feasibility studies (Xing et al, 2021c).…”

“…The SST is fully electrically powered and therefore has zero carbon footprint during operations. This can help reduce the greenhouse gas emission from the maritime sector, which occupies roughly 3.3% of fossil-fuel-related emissions worldwide (Xing et al, 2021c) (Papanikolaou, 2014). According to the techno-economic analysis performed by Xing et al (2021c), the SST also makes it possible for large fields and those fields with marginal profits located away from the coast to be utilized as offshore CO 2 storage sites.…”

“…The baseline SST design (Ma et al, 2021c) allowed for detailed research studies such as evaluating the technicaleconomic feasibility of the SST (Xing et al, 2021c). Such an analysis is impossible without a fully defined SST baseline design, as pricing exercises require design details at the component level.…”