At what Pressure Shall CO2 Be Transported by Ship? An in-Depth Cost Comparison of 7 and 15 Barg Shipping

Abstract

The pipeline has historically been the preferred means to transport CO2 due to its low cost for short distances and opportunities for economies of scale. However, interest in vessel-based transport of CO2 is growing. While most of the literature has assumed that CO2 shipping would take place at low pressure (at 7 barg and −46 °C), the issue of identifying best transport conditions, in terms of pressure, temperature, and gas composition, is becoming more relevant as ship-based carbon capture and storage chains move towards implementation. This study focuses on an in-depth comparison of the two primary and relevant transport pressures, 7 and 15 barg, for annual volumes up to 20 MtCO2/year and transport distances up to 2000 km. We also address the impact of a number of key factors on optimal transport conditions, including (a) transport between harbours versus transport to an offshore site, (b) CO2 pressure prior to conditioning, (c) the presence of impurities and of purity constraints, and (d) maximum feasible ship capacities for the 7 and 15 barg options. Overall, we have found that 7 barg shipping is the most cost-efficient option for the combinations of distance and annual volume where transport by ship is the cost-optimal means of transport. Furthermore, 7 barg shipping can enable significant cost reductions (beyond 30%) compared to 15 barg shipping for a wide range of annual volume capacities.

Dimethyl ether/CO2 – a hitherto underestimated H2 storage cycle

“…61,63 At such low temperatures, it is key to avoid the formation of solid CO 2 (as dry ice or hydrates) to prevent blockages. 64 First vessels specialized for application under such conditions are currently under construction, e.g. by Mitsubishi Heavy Industries, Kawasaki Kisen Kaisha and Equinor.…”

Imaging measurement technologies for CCS

“…Ship transport of CO 2 normally takes place in 10000m 3 -capacity ships and is presently routinely performed at operational conditions of around 1.5 MPa and 247 K. However, the economic feasibility of larger-scale ships mandates lower pressure transport (0.6-0.7 MPa) [37]. A crucial safety and operational aspect, particularly at low transport pressures, is the possible dryice formation while venting CO 2 [4], during liquefaction [38], or due to other transient pressure drops.…”

CO2 Marine Transportation from a Techno-Energetic Perspective

“…CO 2 transportation by ship is anticipated to assume a significant role in the initial phases of CCS development, especially for modest capacities and/or for long-distance transportation [11]. The Global CCS Institute [12] states that CCUS technological advances facilitate both the capture and transportation of CO 2 within maritime operations.…”