Is High-Cost Onboard Carbon Capture Reliable？

Li Yaner

The Ship Energy Efficiency Index(EEXI), the Ship Energy Efficiency Management Plan (SEEMP) and the Operating Carbon Intensity Indicator(CII) rating mechanism will take effect on January 1, 2023, and the IMO plans to revise the greenhouse gas （GHG）emission reduction strategy at the 80th session of the Maritime Environmental Protection Commission (MEPC 80) in June 2023.

An industry insider said the ship decarbonization trend is advancing irresistably, encountering a lot of uncertainties though, especially the leading player remains unknown in the R&D of a variety of alternative fuels in full swing. By comparison,carbon capture and storage (CCS) on conventional fuel ships may be a first option for the shipbuilding and offshore engineering industries.

Onshore to offshore:Mature tech, high cost

At present, the land-use CCS technology has been quite mature,mostly used in oil refineries, power stations and other industries with high carbon dioxide emission concentration.The mainstream technologies of CCS include chemical adsorption, physical adsorption, adsorption separation,membrane separation, biological carbon sequestration, etc. It is widely believed in the industry that chemisorption is the most suitable technical route for ships. It uses the alcohol amine solution absorption method to capture carbon dioxide in the exhaust gas, store it on the ship, and finally unload it ashore.

Many CCS test projects that have been tried by the shipbuilding and offshore engineering industries basically continue the previous ideas of nitrogen reduction and desulfurization, and transfer the onshore CCS technology to the ship.

In August 2021, the CC-Ocean project, a collaboration between Kawasaki Kisen Kaisha, Mitsubishi Shipbuilding and Nippon Kaiji Kyokai(NK), entered the real ship test phase.The project team installed a small carbon dioxide capture device on the Corona Utility bulk carrier, whose tech emerged from a power plant project of Mitsubishi Heavy Industries (MHI).In October of the same year, MHI announced that they had successfully separated and recycled carbon dioxide from ship emissions, whose quantity,proportion and purity met the target requirements and whose purity of carbon dioxide captured reached 99.9%, testifying the feasibility capturing carbon dioxide from marine engine flue gas different from the land operating conditions. MHI pledged to develop compacter CCS equipment further in line with the needs of the stable operation of ships, and to explore the possibility of commercial use.

Nevertheless, due to the cost of the equipment itself and the reduction of cargo space caused by the complex system, the high cost is the biggest obstacle to CCS embarkation.

At the recently held academic annual conference of SSNAME, Cai Qianya, chief technical officer of CSSC Jiangnan Shipbuilding, used a large container ship as a model and made rough calculations. A 14000 TEU container ship with heavy oil as fuel adopts the CCS and scrubber integrated design, SMCR is 42000 kW and MCR is 4300 kW, CCS design is calculated as per 75% SMCR and 85%MCR. If the carbon dioxide capture rate is 40%, and the GHG emissions are reduced by about 35%, it can meet the current emission reduction requirements in 2050. If a single voyge operates continuously for 30 days, it can produce about 5000 tons of carbon dioxide, the storage capacity needs 6000 m3, according to the physical characteristics of carbon dioxide,two type-C tanks with a capacity of about 3000 m3 each can be arranged at the bottom of the cargo hold, the absorption tower and separation tower are separately arranged inside the expanded chimney; the liquefaction device and related electrical equipment and control units are arranged above the central control room. CCS’s additional power load is about 3000 kW, and a PTO is provided to meet the power requirements; With several CCS related devices and large storage space demand, the container position loss is about 470TEU.

Hu Keyi, director of the Jiangnan Shipbuilding Science and Technology Committee, said that even if the CCS technology is relatively mature on land, it is not an easy process to embark the onshore mature CCS tech.The particularity of ship navigation determines that the captured carbon dioxide must be stored onboard first. If stored in the form of gas, it will occupy the space on the ship and thus lose a large amount of cargo space; if stored in liquid or even solid, a large amount of cold energy is needed, which will increase the ship energy consumption and increase operating costs. In addition, the unloading, transport and treatment of carbon dioxide stored in liquid or even solid form after arrival is also a big problem. It is easier to install a CCS system on an oil tanker or bulk carrier with sufficient space on the upper deck or quarterdeck and a gas carrier with ready-to-shelf cooling system than a container ship.

In fact, even for onshore projects,carbon capture costs have been high. Previous reports stated that domestic power plants and refineries often invest tens of millions or even more than a hundred million of yuan in CCS, which is difficult to achieve emission reduction benefits. The operation and maintenance costs caused by carbon capture devices are equivalent to an additional 140-600 yuan per ton of carbon dioxide. According to the Annual Report on China's Carbon Dioxide Capture,Utilization and Storage (CCUS) (2021) released by the Institute of Environmental Planning of the Ministry of Ecology and Environment, it is expected that by 2030, the carbon dioxide capture and storage cost will be 90-390 yuan / ton by 2030, and 20-130 yuan / ton by 2060. The figures suffice to illustrate the high cost of carbon capture.

Fossil fuel + CCS: Transition plan?

“The shipping fuel market will be more diversified in the future.” In September, DNV released its latest version of Maritime Outlook for 2050. In the report, DNV identified the technology maturity of various alternative energy sources and possible application domains and ship embarkation timing, and noted, “Mature CCS technology and infrastructure can also make CCS on board a viable alternative to the continued use of fossil fuels on board.”

While the cost issue remains to be resolved,the combination of conventional fuel with the CCS still radiates a bit of pragmatism compared to other immature energy alternatives. The shipping industry has always been good at finding a compromise between strict regulations and existing technology,examplified by the popularity of LNG-powered ships. Hu Keyi said LNG remains a good solution for the shipping industry in a long transition period,however, the shipping industry's energy transition has already started, and the required zero-carbon fuel technology may not be fully available in several years or ten years.

DNV's latest report estimated 24 scenarios by two reduction routes: if following the current IMO’s GHG emissions strategy, that’s a reduction of 50% in total emissions by 2050, then the three fuel options -- heavy fuel oil (HFO) + desulfurization tower, low sulfur fuel oil (LSFO) + marine gas oil(MGO), and LNG -- total up at least more than 50%of the global fleet.

So, according to IMO's existing emission reduction plan, is CCS embarkation a possible option if a large number of traditional fuel tankers are to achieve decarburization in the future?

In this regard, in addition to Japan's “CCOcean” project, there are many international attempts worth paying attention to. In September,LR issued an AiP certification for the Dutch Value Maritime’s “Filtree” carbon capture and storage system, and the Filtree system will be installed on two Eastern Pacific Shipping MR-type tankers.LR says the Filtree system is a prefabricated gas purification system that filters sulfur and 99%particulate matter. The system also includes a carbon capture module, which can use a special chemical substance to capture carbon dioxide, the chemical will be stored in a large tank on the ship, the filled-up chemicals will be unloaded to the port receiving device, carbon dioxide will be released and collected,for carbon dioxide customer’s reuse or injected into the carbon storage network. Currently, Value Maritime's CCS technology can capture 40% of a ship’s carbon dioxide emissions, and the figure is expected to exceed 90% in the future.

Information released by Value Maritime indicate the company's CCS equipment has received a good market response. In October, Dutch intermodal carrier Samskip announced that it would install “Filtree” systems for two of its container ships, scheduled to operate in early 2023. with the project,a gas cleaning unit is installed behind the ship's chimney, and the recovered carbon dioxide will be pumped into a 10-megawatt carbon dioxide battery pack installed in a standard tank container. Carbon dioxide battery is a storage facility that can indefinitely charge and discharge carbon dioxide,the size is 20 feet standard container,convenient for loading and unloading,and the pack can be directly replaced after the ship draw alongside, Value Maritime will haul the filled batteries to the farm greenhouse for release,for planting crops, flowers, etc., to achieve closed loop. At Samskip,Erik Hofmeester, director of ship management, noted that Value Maritime's logistics solutions that return the collected carbon dioxide to natural absorption are attractive.Looking for more breakthroughs in the whole carbon dioxide industry chain will open the door for equipment boarding.

Wartsila is developing a CCS system on the basis of the desulfurization scrubber. The company has installed a 1MW onshore carbon capture and storage pilot device in Moss, Norway, after test in a series of scenarios and conditions, the CCS system has reached the goal of collecting 70% carbon dioxide.System design will be further optimized in the future to ensure the safety of equipment. Kashif Javaid,sales director of Wartsila vent gas disposal department, previously said in an interview with the media, due to the price difference between high sulfur oil and ultra-low sulfur oil,the scrubber market prospect is still bullish, and the equipment is an ideal platform for further realizing onboard carbon capture; CCS system depends on special solvent, hence a separate carbon dioxide removal stage, but this stage can be integrated into the traditional scrubber. As planned,Wartsila's CCS system will be verified on board Solvang's 20,000-ton ethylene carrier “Clipper Eos” in 2023.

An industry insider said that with the implementation of EEXI and CII in 2023, the decarbonization process of the shipping industry will be further accelerated, so will the application of various decarbonization technologies.In the application process, the upgrading of technologies may solve the cost and technical difficulties of relevant solutions to a certain extent.