Bottom of the table, unsurprisingly, are petrol vehicles, but coming in a close second last are hybrid vehicles that can run on compressed natural gas or petrol. Top of their league are fuel cell powered vehicles using hydrogen gas obtained from natural gas methane.
Karl Høyer of Oslo University College and Erling Holden of Western Norway Research Institute, Norway, and reported in Inderscience's International Journal of Alternative Propulsion their analysis of fuel chains including petrol, natural gas, and alternative fuel sources such as methanol and ethanol, hydrogen and biofuels.
"Alternative fuels are not in themselves a road towards sustainable mobility," the researchers say. However, their analysis places petrol and hybrid vehicles firmly at the bottom of the league table when all energy factors from source to consumer use are taken into account. "Any alternative fuel we considered is better than the cars that are used mostly today," they add.
Currently, there is no consensus regarding sustainable transport development. Even if a particular energy reduction goal is set for the transport sector there is no agreement on actions that should be taken to achieve this goal. Different lobbying groups have different approaches to the problem and opponents of any particular approach can usually find evidence to suggest a particular approach is not sustainable. The ongoing biofuel debate is a case in point.
Nevertheless, there are several factors that must be considered in assessing a particular alternative fuel: the efficiency route, the substitution route and the reduction route. Each has its strong defenders, say Høyer and Holden, but in reality there are substantial grey areas between them. One important facet of the debate that is often overlooked, is to ensure the three impact categories - energy use, carbon emissions, and nitrogen oxide pollution - are considered together. "This is a highly problematic task and should only be carried out with great care," the team adds.
They used a simple ranking system to create their league table, based on giving each energy form a weight from 1 to 16 depending on its impact in these three areas. When the weights are added up from well to wheel, they provide an overall value for each energy chain. For example, extraction of natural gas, processing into liquefied hydrogen, storage, and end use in a fuel cell car. The energy chains giving the lowest sum-figures are the highest in the league table and those with largest figures are considered potentially the most environmentally harmful.
Interestingly, the team's analysis puts a fossil-based alternative, natural gas conversion into hydrogen for fuel cells at the top of the list. In contrast the direct use of natural gas in hybrid cars is lower down the list in terms of efficiency, energy, and pollution. Biological methanol for use in fuel cell vehicles is way down the list despite biomethanol being a potentially renewable resource unlike natural gas. "It must be emphasised that no single chain comes out with the best score on all impact categories," the researchers say, "There are always some sorts of trade offs involved. Thus, there are no obvious winners; only good or bad trade offs between different impact categories."
Jim Corlett | alfa
When corals eat plastics
24.05.2018 | Justus-Liebig-Universität Gießen
Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences