Life cycle assessment of Fuel Cells onboard ships

Abstract

This report is a comparative life cycle assessment (LCA) of a fuel cell and a gas engine. It includes emission release over a lifetime, and recommendations to which system to install in operating vessels today.

IMO and MARPOL are the main regulators of emission at sea. An increased focus on the marine environment has provided new regulations to limit the impact from ships. Emission to sea has lately been given much attention; dangerous substances have been trapped in local food chains and disturbed the eco-systems. It is assumed that regulations today are to be followed up by stricter limits in the future. Both the fuel cell and the gas engine are solutions which reduce emission to air.

The results of the study show a large impact from fuel cell materials. This is mainly harmful to the various ecosystems, and the marine ecosystem is the largest impact category. The fuel cell is a more efficient solution with lower fuel consumption. Because of the electrolyte reaction, there is no combustion process. This gives low CO2 and NOx emissions and approximately zero SOx and PM emissions. This result in a 30% global warming potential reduction compared to the gas engine.

Evaluating the results we found the gas engine to be the best solution at the moment. This is based on an overall evaluation of the environmental impact. In addition to this, the capital cost is low. Fuel cell technology is not developed enough to meet today’s standards. To be able to install a fuel cell delivering energy supply to a whole ship, the volume per kW output has to decrease and the lifetime has to be increased. Increased lifetime does not only reduce the environmental impact, it reduces the capital cost as well. The fuel cell has better operational qualities, especially when it comes to global warming impact. In the future the use of fuel cells can be an important tool to reduce the CO2 emission and other emissions to air.