Alternative Brennstoffe in der Schiffahrt – Welche Trends gibt es wirklich in den nächsten Jahren?
Die Liste potentieller Alternativen zu den bislang verwendeten Schiffsbrennstoffen ist lang. Sie reicht von LNG, Methanol über Biokraftstoffe bis hin zu Wasserstoff und Nuklearantrieben. Doch für welche Kraftstoffe ist die Zukunft so nahe, dass Sie in heutigen Investitionsentscheidungen für den Bau von Seeschiffen berücksichtigt werden sollten?
Das DNV GL white paper ASSESSMENT OF SELECTED ALTERNATIVE FUELS AND TECHNOLOGIES liefert hierzu Informationen und Zusammenhänge.
Environmental and price challenges are driving the interest in alternative ship fuels, but the number of realistic candidates is small. DNV GL believes LNG, LPG, methanol, biofuel and hydrogen to be the most promising candidates. Among them, LNG has already overcome the hurdles related to international legislation, and methanol and biofuels will follow suit very soon. It will be a while before LPG and hydrogen are covered by appropriate new regulations within the IMO IGF Code, as well.
The existing and upcoming environmental restrictions can be met by all alternative fuels using existing technology. However, the IMO target of 50% GHG emissions reduction within 2050 is ambitious, and will likely call for wide-spread uptake of zero-carbon fuels, in addition to other energy efficiency measures.
Fuel cells can use all available alternative fuels and achieve efficiencies comparable to, or better than those of current propulsion systems. However, fuel cell technology for ships is still in its infancy. The most advanced developments to date have been achieved by the projects running under the umbrella of the e4ships lighthouse project in Germany, with Meyer Werft and ThyssenKrupp Marine Systems heading the projects for seagoing ships. Wind-assisted propulsion could potentially reduce fuel consumption, especially when used for slow ships, but the business case remains difficult. Batteries as a means to store energy can be considered as an alternative fuel source in the widest sense. They have major potential for ships running on short distances and can be used to boost the efficiency of the propulsion system in any ship. However, in deep-sea shipping batteries alone cannot substitute fuel. With low- sulphur and alternative fuels becoming more widely available, the well-known gas and steam turbine combined cycle technology represents a viable alternative for high-power ship propulsion systems.
All fuel alternatives discussed here could meet the foreseeable volume requirements for shipping over the coming years. A major increase in consumption would require an appropriate increase in production capacity; the only exception is LNG, which is available in sufficient quantities today to meet the potential requirement of the shipping industry for many years. Without taxation or subsidies, renewable fuels will find it difficult to compete with the prices of conventional fossil fuels. LNG and LPG are the only fossil fuels capable of achieving a CO2 reduction. CO2-neutral shipping seems possible only with fuels produced from regenerative sources. If the shipping sector resorts to synthetic fuels produced from hydrogen and CO2 using regenerative energy, the available alternatives will be liquefied methane (which is very similar to LNG) and diesel-like fuels.