How ocean shipping goes green, from wind power to liquid hydrogen

The shipping industry accounts for nearly 3% of the world’s total greenhouse gas emissions, producing as much manmade carbon dioxide as all the coal-fired power plants in the U.S. combined. Still, it’s a relatively small output within the overall transportation sector, which is responsible for 37% of annual global greenhouse gases.

Yet as international trade continues to grow and heavily rely on oceangoing vessels to move cargo — they currently carry more than 80% of it — some scientists warn that by 2050 shipping could account for 17% of greenhouse gases.

That’s why, after years of lackluster efforts to decarbonize, the industry’s regulatory body is getting on board. In 2018, the International Maritime Organization, or IMO, a London-based United Nations agency comprising 175 member countries — many with delegates directly tied to businesses resistant to curbing emissions — adopted a strategy to reduce greenhouse gases by 50% by 2050 compared to the 2008 level.

Critics say that goal is too little and too late, insisting the IMO reset its target to 100% decarbonization by mid-century, or preferably sooner.

“The IMO has been rather late to the party, in terms of developing climate measures and coming up with a strategy,” said Lucy Gilliam, shipping policy officer at Seas at Risk and a board member of the Clean Shipping Coalition, both environmental NGOs. She cited the fact that international shipping is not included in the Paris climate accord. Plus, a recent study found that only 33 out of the 94 largest shipping companies have a clearly expressed policy to achieve net-zero emissions by 2050 and/or have committed to the IMO’s goal.

Nonetheless, the private sector is undertaking some initiatives to lessen its climate impact. The simplest solution would be for ships to simply slow down, thus using less carbon-emitting fuel. Shipbuilders are also experimenting with hulls coated with air bubbles to reduce drag, as well as sleeker bows, more efficient engines, propellers and thrusters, and AI-assisted navigation systems.

Meanwhile, the industry is beginning to establish green corridors, or specific shipping routes and ports that support zero-emission solutions and policies. The financial world is joining the decarbonization movement as well, with 29 institutions signing onto the Poseidon Principles, an agreement to consider efforts to cut greenhouse gas emissions when lending to shipping companies. The signatories represent more than $185 billion in loans to international shipping — nearly half of the global ship finance portfolio.

But with a global supply chain designed for speedy deliveries, the big breakthrough bets are being made on the development of low-emission or zero-emission fuels — including green methanol, hydrogen, liquid natural gas (LNG) and ammonia —…