FUELS & LUBRICANTS
VOC MEASURES HAMPERED WITHOUT TERMINAL INVESTMENT
Credit: Wärtsilä Gas Solutions
Norway and Canada have proposed onboard measures for reducing volatile organic compound (VOC) emissions from tankers, but some in the industry argue that more action is needed by terminals
Canada and Norway submitted a paper to the Intersessional meeting of the Working Group on Reduction of GHG Emissions from Ships in August (ISWG-GHG9) calling for changes to regulation 15 of MARPOL Annex VI for oil and chemical tankers that carry volatile cargo. As well as having GHG potential, these emissions can be harmful to human health and contribute to the formation of tropospheric ozone, a component of smog. The submission is based on a report by DNV that found that approximately 70% of VOC emissions are generated during cargo loading. Around 20-30% are generated during laden voyages. Currently Marpol Annex VI Regulation 15 regulates the control of specific VOC emissions for oil tankers and at ports and terminals. (Methane is excluded from the definition of VOC.) Where required, both the shipboard and shore arrangements are to be in accordance with MSC/Circ.585 “Standards for vapour emission control systems”. A second aspect of the regulation, regulation 15.6, requires that all tankers carrying crude oil have an approved and effectively implemented ship specific VOC Management Plan. The proposal Norway and Canada, based on an analysis by DNV, propose amendments to MARPOL that they consider to be feasible, practical and economically viable: 1. installation of pressure control systems in way of the mast riser for the purpose of automatic maintenance of tank pressure on voyage and during loading. 2. increased settings of pressure/vacuum (P/V) valves from current standard at 0.14 bar to 0.2 bar. 3. requirements to P/V valve type in terms of blow-down. DNV notes that the ability to load cargo against a controlled back-pressure has been shown to reduce the quantity of VOCs in the ullage space with a VOC emission reduction potential of approximately 10%. Additionally, an investigation
20 | OCTOBER 2021
8 Using a VOC recovery system (pictured) for loadings would yield net CO2 equivalent (CO2e) savings of 1,200-1,500 metric tonnes per loading of a VLCC
of shuttle tankers in the North Sea indicates that maintaining the cargo tank pressure could reduce the emissions by 3040% depending on tank design pressure. The submission notes that a vapour return system used during terminal loading would send all cargo vapours to shore for processing with no VOC emissions to air. However, currently only few terminals are requiring loading with vapour emission control systems. Industry responds Dragos Rauta, Technical Director at INTERTANKO, says the involvement of the shore terminals is the key element to success. “The proposed amendments in the DNV Study, forwarded to ISWG-GHG9 by Canada and Norway do suggest tankers contain onboard VOCs but there is no indication what tankers can do with these VOCs. Therefore, one cannot see a net environmental benefit without assistance from shore facilities.” Christian Bækmark Schiolborg, BIMCO Manager, Marine Environment, notes: “This proposal - by Canada and Norway is the first step on the path to reduce emissions of VOCs which by itself is a welcomed and positive step towards decarbonisation. The fundamental problem related to VOCs, however, is that the majority of tankers have had costly vapour emission collection systems installed since the MARPOL regulations came into force in 2010, but many port and terminals still don't have vapour emission collection systems installed and are therefore not capable of receiving VOCs from tankers. The problem will not be solved by continuing to regulate oil tankers if the ports and terminals are not mandated or incentivised to catch up with the oil tankers.” Jahn Viggo Rønningen, Director - Head of Ship Safety for the Norwegian Shipowners' Association, says members can agree to the proposed control measures, but says: “By far the largest effect during loading at the terminal would be to fully utilize the VECS (vapor return line) onboard. To which degree
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