Emission Reduction in Shipping Using Hydrogen and Fuel Cells
Chapter, Peer reviewed
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Despite various technical and operational improvements, shipping remains a contributor to global emissions of greenhouse gases, nitrogen oxides, and sulphur oxides, among others. As a part of its efforts to limit adverse health and environmental impacts of shipping, the International Maritime Organization (IMO) has enforced regulations to control these emissions. In addition, some countries, such as Norway have imposed additional regulations to control emissions further. Environmental regulations and concerns call for an improved environmental profile within shipping, which motivates this study. Alternative fuels and power systems are required for a substantial reduction in emissions from shipping. Hydrogen and fuel cells are among the most promising solutions from an environmental perspective. A fuel cell is an electrochemical conversion device, which produces electricity through the reaction of an oxidant with hydrogen or another hydrogen-rich fuel, such as a hydrocarbon fuel. Since the electricity production does not entail fuel combustion, emissions are reduced substantially. When hydrogen gas is used as the fuel, only water is formed as the byproduct. In addition to emitting ultralow or zero emissions, fuel cells offer high energy conversion efficiency, low noise level, and low vibration. The Norwegian energy system is based on electricity from renewable energy sources and mainly hydropower. Renewable energy output is strongly affected by the weather conditions, among other factors, and the supplies fluctuate accordingly. There is a need for a means to store and use the renewable energy surplus. In addition, from a technical point of view Norway still has potential to further develop hydro and wind power. Excess power can be used for production of hydrogen through water electrolysis, which in turn can fuel different means of transportation, such as shipping. This paper aims at contributing to the research body on the use of hydrogen and fuel cells in shipping. First, a short introduction to hydrogen fuel and fuel cells is given. Then, an elaboration on pros and cons of powering vessels with fuel cells is presented. After providing an overview of current marine applications of fuel cells, the paper discusses potential vessels, which can benefit from this technology. Finally, the environmental benefits of using fuel cells are shown through a preliminary case study. Data from the Automatic Identification System (AIS) in the Norwegian waters is used for estimating operational profile of a vessel, its current emissions, and potential emission reduction by using hydrogen and fuel cells. The results of this study show the potential of hydrogen and fuel cells in reducing emissions of shipping and set forth the research gaps.