Marine fuel cells better suited for auxiliary power than propulsion – MMMCZCS
"It appears unrealistic to assume that fuel cells will compete with or entirely replace onboard internal combustion engines in the near future," Mærsk Mc-Kinney Møller Center for Zero Carbon Shipping (MMMCZCS) said in report, according to Engine Technologies.
The high price tags for proton exchange membrane (PEM) fuel cells and solid oxide fuel cells (SOFCs) for marine applications might hinder the installation of these fuel cells on ships in the near future, the study found.
Marine SOFCs are estimated to cost around $5,500 per kilowatt (kW) in 2025, whereas marine PEM fuel cells are expected to cost roughly $4,000/kW in 2025, according to MMMCZCS. For example, based on the study findings, a 2000-kW SOFC fuel cell stack will cost around $11 million, while a 2000-kW PEM fuel cell stack will cost around $8 million.
Costs are expected to reduce towards 2040, MMMCZCS added. PEM fuel cell costs will significantly reduce by 2035, and SOFC costs will reduce by 2040. The study projected SOFCs and PEM fuel cell costs to come down to $1,000/kW around 2040.
Apart from the initial cost of fuel cells, the replacement costs will also increase the burden on fuel cell installations.
“Replacement costs for fuel cells are expected to be significant, with approximately 30-40% of the initial system being replaced every 3-4 years,” the report said.
As an example, based on a replacement cycle of four years, the replacement cost for a 2000-kW PEM fuel cell system in 2035 would be $800,000, the study explained.
Significant adjustments would also be required in the ship's engine room design and standard operating procedures for crew members when fuel cells are installed on ships. This will further complicate the feasibility of widespread adoption, the report argued.
The authors of the report proposed that fuel cells should be used to power vessel's auxiliary operations rather than for primary propulsion.
Typically, onboard auxiliary power is generated by four-stroke engines, which are slightly less efficient than the ship's two-stroke main engines used for propulsion.
According to the study, PEM fuel cells have an energy efficiency of 45-60%, SOFCs have around 50-65% and alkaline fuel cells (AFCs) have around 60-70%. Energy efficiency means using less energy to do the same tasks.
As two-stroke internal combustion engines in large ships have a 50% energy efficiency, combining fuel cells with ICEs “could help ship owners to make the most of existing technologies while phasing in fuel cells and, in turn, potentially lower vessels’ emissions,” the report concluded.
