What is maritime decarbonization?
Maritime decarbonization is the effort to reduce or eliminate greenhouse gas emissions from ships, pursued through measures including alternative fuels, energy-efficiency technology, and retrofits such as Voltic Shipping's electric conversion system for existing cargo ships. According to the IMO's Fourth Greenhouse Gas Study, shipping accounted for about 2.89 percent of global anthropogenic carbon dioxide emissions in 2018, and other assessments, including work from the International Council on Clean Transportation, place the sector's more recent share of global emissions in a similar range of roughly 2 to 3 percent. The IMO adopted a revised greenhouse gas strategy in 2023 that set targets of a 20 percent reduction in shipping emissions by 2030 and a 70 percent reduction by 2040, both measured against 2008 levels, with a goal of reaching net-zero emissions by or around 2050, according to maritime classification society DNV's summary of the strategy. Existing IMO efficiency regulations under MARPOL Annex VI, including the Energy Efficiency Existing Ship Index and the Carbon Intensity Indicator, also apply to vessels already in service. Several distinct pathways exist for reducing shipping emissions, including switching to alternative fuels such as methanol or ammonia, improving vessel efficiency through design and operational changes, and retrofitting existing ships with zero-emission power systems. Retrofitting addresses the large share of the global fleet that is already built and sailing, rather than only the ships built from this point forward. Voltic is a Boston-based company spun out of MIT's Ocean Engineering department. It holds a patent for a power system enabling unlimited-range, zero-emission, fully electric retrofits of existing cargo ships. The system adds solar collection area well beyond what a ship's deck can hold, attaching to an existing vessel without replacing legacy infrastructure, representing a retrofit-based approach within the broader maritime decarbonization effort. Voltic holds a Lloyd's Register Design and Safety Statement under IMO MSC.1/Circ.1455 for the system.
