Shell Charts Course for Decarbonised Shipping
Shell views biofuels and LNG and later, hydrogen and fuel cells, as the way to decarbonise shipping, it said in a report on September 29.
In Decarbonising Shipping: Setting Shell's Course, Shell said it believed liquid hydrogen was "advantaged over other potential zero-emissions fuels for shipping, therefore giving a higher likelihood of success." It said clean hydrogen produced from either water using renewables or gas if carbon emissions are captured and stored, is expensive. But the shipping industry should "stand ready" to take advantage of hydrogen production.
"The properties of hydrogen are well understood and although there is much to do, Shell considers that safe designs can be developed for marine use," it said.
Hydrogen can also be switched in to use with fuel cells that have been developed first for LNG. These cells are "a key technology to unlock the use of future fuels," Shell said. They could replace the internal combustion engine technology, converting a range of fuel types into electricity, and can improve energy efficiency to over 60% or even 80% if waste heat is exploited.
"This efficiency means a reduced need for significant auxiliary power plant which in our view could lead to improved ship design with additional space for cargo," Shell said. Fuel cells are more expensive than internal combustion engines at present but Shell said it was not deterred as manufacturing costs can improve, and their operating expenses are already low.
"In this way, shipping could lay the foundations for future fuels while securing immediate emissions reductions," the company said.
Shell also praised biofuels, noting they could be blended with conventional fuels, delivered using existing infrastructure and used in existing vessels, offering a low-cost and practical solution.
"In this way biofuels can be used in the engines of today's ships during the years it will take for these vessels to be fully phased out," Shell said. "To play their full role biofuels must be produced using sustainable feedstocks and processes while also meeting energy security and local development needs."
However, Shell said biofuels were unlikely to become the dominant future fuel for shipping, as the sector would need significant volumes and aviation and road transport would be better able to cover its costs.
Meanwhile Shell was critical of methanol, electric batteries and nuclear power, citing potential problems with long sea voyages requiring large-scale battery units, methanol's less efficient path to zero emissions and social anxiety about nuclear energy. Its position on ammonia was neutral, saying the fuel's role would depend on cost-competitive it proved to be.
Ammonia's higher energy density could free up more cargo space than hydrogen, but toxicity, emissions and high-ignition energy are challenges. Saudi Aramco however has shipped an experimental cargo of blue ammonia to Japan, for power generation.
"We will step up our efforts on hydrogen research and development and drive new understanding of the role fuel cells can play," Shell said. "We are growing our LNG, biofuels and offsets offers, and developing lubricants which help our customers achieve improved engine efficiency and performance."
Shell called on the International Maritime Organisation to use its 2023 strategy review "to set the trajectory for the sector to move to net-zero emissions by 2050."