Can Cargo Ships Use Hydrogen Power to Become Carbon Neutral?

A high-speed passenger ferry running on hydrogen power is coming to San Francisco. Yes, the boat will give tourists a nice tour of the bay, but the purpose reaches further than that. The ultimate goal of the SF-BREEZE is to test the viability of hydrogen-fueled shipping vessels.

The design, from the size of the ship to the fuel cells onboard, is a prototype for future zero-emissions cargo ships. The ferry is expected to be finished this fall. When it is completed it will be the first hydrogen-powered maritime vessel operating in the United States.

“This kind of boat has never been built before,” said mechanical engineer Curt Leffers, the project manager for Elliott Bay Design Group, in a press statement. “Hydrogen fuel cells are heavier than diesel engines for a given power output, so achieving the right power-to-weight ratio for the vessel was tricky.”

The project comes at a time when cargo ships are being forced to cut their emissions. The International Maritime Organization (IMO), the branch of the United Nations that regulates global shipping, has created new rules for sulphur oxide emissions. Starting Jan. 1, 2020, the global sulphur cap will become 0.5 percent m/m (mass by mass). The current limit is 3.5 percent. Unfortunately, cleaner oil means more expensive oil, and fuel prices are widely projected to increase by 50 percent during 2020.

Despite the initial costs of shifting to alternative fuel sources, some shipping companies are making ambitious promises for a clean future. For example, the biggest container shipping company in the world, Maersk, pledged last year to become either carbon neutral or use 100 percent renewable energy by 2050, although how it will accomplish this is not yet completely clear.

"An easy way to become carbon neutral . . . would be to make not-very-smart business decisions," Ole Graa Jakobsen, Maersk’s head of fleet technology, told NPR. "Then we would very fast be out of operation and emit no carbon."

Currently, shipping fuel is not sustainable

So in general, what’s the big deal with the fuel cargo ships that are currently in use?

They are incredibly dirty.

The primary fuel used in maritime shipping since the 1960s has been heavy fuel oil, a byproduct of refining oil. Heavy fuel oil has historically been cheap, but it leaves a large health and environmental footprint. To give a visual: If global shipping were a country, it would be the sixth largest greenhouse gas emitter—sitting squarely between Germany and Japan.

Another concern with heavy fuel oil is sulphur oxide emissions, which, according to the IMO, are harmful to human health and the environment. Sulphur oxide can contribute to acid rain, which harms forests and crops and contributes to the acidification of the oceans.

In an attempt to decrease their carbon impact, some shipping companies have been diversifying their energy sources with solar panels and wind kites, and scrubbers have helped make ship exhaust cleaner by capturing 99 percent of sulphur emitted.

Lloyd’s Register projects that heavy fuel oil will still occupy 40 percent of fuel use by 2030 in its report, Global Marine Technology Trends 2030. Diversifying energy sources and increasing energy efficiency are effective ways to transition toward carbon neutrality until energy sources like hydrogen power become available at large scales.

Hydrogen power is a promising alternative

Hydrogen fuel cells work by combining hydrogen and oxygen atoms. While hydrogen has historically been sourced from natural gas, today this fuel is increasingly coming from renewable sources—namely, from "splitting" water molecules using an electric current.

In addition, hydrogen runs cleaner than conventional fuels because it leaves neither toxins nor waste behind—its only byproduct is water. Plus, these fuel cells are two to three times more efficient than engines that run on gasoline.

Cost-wise, would a cargo ship want to transition to hydrogen-power? Joe Pratt, who initiated the SF-BREEZE with his then-research partner, would say not yet. The fuel cell system is quite costly. Even the hydrogen ferry will cost around twice as much as a conventional diesel ferry.

“Right now, we can’t achieve economic parity with a comparable diesel ferry,” Pratt said in a 2016 press statement. “But this is a question we need to explore further. Is economic parity necessary from the outset? Lessons from the automotive market tell us maybe not.”

Electric vehicles have shown us that pioneers, or early adopters, need to acquire these new products at first to bring down prices for others.

Attention, Maersk! Here’s a chance to invest in a solution that just might get you to your 2050 goal and push you ahead of mounting regulations, limits and taxes on carbon. The rest of the shipping community is sure to follow your lead.

Image credit: Pixabay