The first commercial-scale trial of an innovative technology for onboard capture of carbon dioxide emissions from shipping vessels has been slated for later this year.
Seabound, a U.K. startup, will install a unit around the size of a shipping container on the deck of the UBC Cork, a 5,700-metric-ton vessel that carries cement from Heidelberg Materials, one of the world’s largest producers of the building material. The vessel’s exhaust will be routed over CO2-absorbing material in the container, safely locking away a portion of the vessel’s emissions.
The trial comes at a time of mounting pressure on the maritime shipping industry, which generates around a billion tons of CO2 annually, or roughly 3 percent of the global total. The International Maritime Organization, the United Nations agency that regulates the sector, recently announced plans for emissions-intensity rules that would force large vessels to cut emissions by up to 43 percent by 2035.
Additional advantage
Onboard carbon capture appeals because existing vessels can be retrofitted relatively quickly and cheaply, said Lars Erik Marcussen, logistics project manager at Heidelberg Materials Northern Europe. In the coming tests, the system will capture 25 percent of the CO2 emitted by the vessel, but the technology can achieve up to 95 percent capture, according to Seabound.
Onboard capture has an additional advantage for Heidelberg: the process involves reacting pebbles of calcium hydroxide, commonly known as lime, with CO2 to produce calcium carbonate, or limestone, which is an input into cement production.
“We can take the limestone pebbles and put them straight into our cement kilns,” said Marcussen.
The UBC Cork is one of nine vessels that Marcussen oversees. If the trial is successful, he hopes to install the carbon capture technology on an additional vessel every year. The work complements capture technology that Heidelberg has installed at its cement plant in Brevik, Norway, which now captures 400,000 tons of CO2 annually.
Energy expenses
One challenge to be surmounted before the technology scales is the production of low-carbon lime. The issue is serious enough to give some experts doubts about Seabound’s approach.
“There are systems that regenerate limestone back into calcium oxide [a precursor of calcium hydroxide], but this is a very energy-intensive process that incurs significant costs, even with 100 percent green electricity,” said Felix Klann, maritime transport policy officer at Transport & Environment, a nonprofit that works across Europe. “Shipping companies should focus instead on avoiding their emissions altogether by investing in green e-fuels, electrification and designing efficient ships.”
The technology is not yet cost-competitive, but Alisha Fredriksson, Seabound’s co-founder and CEO, expects costs to come down to around $150 per metric ton of CO2 capture as the technology scales. She added that once the cost of complying with the IMO rules and the European Union’s Emissions Trading Scheme are factored in the process will produce savings that pay back upfront costs within one to five years.
Seabound also needs to identify sources of low-carbon lime. At present, the emissions associated with producing and transporting the lime more than outweigh the benefits of capturing CO2 from the ship’s exhaust.
“We’re working with lime companies to ensure that there is a supply of green lime for our full-scale deployments,” said Fredriksson. “We want to team up with lime companies to develop dedicated kilns as close to the port as possible, so we can reuse the material over and over and then either sequester or sell that pure CO2.”