Page - 7 - in options, Volume winter 2019

News in brief The transport sector is responsible for around a quarter of global CO2 emissions caused by humans. Of these emissions, 3% come from cargo ships, but it is expected to increase by between 50% and 250% by 2050. It is clear that we will have to find new approaches to transporting cargo with a lower demand for energy and lower CO2 emissions. This conundrum led a team of IIASA researchers to look to the first half of the 20th century, when airships were widely used for the long-range transport of cargo and passengers. Following the catastrophic Hindenburg crash of 1937, their use was discontinued almost overnight, but since then, considerable advances in material sciences, our ability to forecast the weather, and the urgent need to reduce energy consumption and emissions, have steadily been bringing airships back into political, business, and scientific conversations as a viable transportation alternative. Inspired by the possibilities offered by these giant, lighter than air aircraft, the researchers started exploring how an airship- based transport industry could be developed using the jet stream – a core of strong winds that flows from west to east high above the Earth’s surface. The jet stream would contribute most of the energy required to move the airship between destinations, enabling it to haul tons of cargo around the world in around two weeks, which is considerably faster than current maritime shipping routes allow. Apart from presenting a more environmentally friendly way of delivering goods, the authors propose that airships could also contribute to the establishment of a sustainable hydrogen economy. One of the challenges to implementing a hydrogen- based economy is cooling the hydrogen to below -253°C to liquefy it. The process consumes almost 30% of the embodied energy, with additional energy required for transport. The authors say that instead of using energy in liquefaction, hydrogen could be carried inside the airship as a gas and transported by the jet stream with a much lower fuel requirement. Another possibility is for the liquefaction process to happen on board the airship where much less energy would be required for cooling due to the already low temperature of the stratosphere. Any additional energy required for further cooling could be generated using the hydrogen in the airship. “Airships were used in the past and provided great services to society. Due to current needs, airships should be reconsidered and returned to the skies. Our study presents results and arguments in favor of this. The development of an airship industry will reduce the costs of fast delivery cargo shipping, particularly in regions far from the coast. The possibility to transport hydrogen without the need to liquefy it would reduce the costs for the development of a sustainable hydrogen-based economy, ultimately increasing the feasibility of a sustainable world,” concludes study lead- author and IIASA postdoc, Julian Hunt. Julian Hunt: hunt@iiasa.ac.at Further info: pure.iiasa.ac.at/16010By Ansa Heyl Reintroducing airships into the world’s transportation-mix could potentially contribute to lowering carbon emissions and play a role in establishing a sustainable hydrogen-based economy. A sustainable future through a new age of airships © Rosa | U.S. Air Force Polar and European jet stream © NASA's Scientific Visualization Studio 7Optionswww.iiasa.ac.at Winter 2019/20