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Fraunhofer Institute for
Systems and Innovation Research ISI

New study compares different electric mobility concepts

Press Release 19.05.2010

Electricity is an established final energy source, which will become even more important in the future. Hydrogen, in contrast, does not play any role as a final energy source at the moment, although its use is constantly being debated for climate protection and supply security reasons. In the current study “Comparing Electricity and Hydrogen as Carbon-Free Final Energy Sources”, the Fraunhofer Institute for Systems and Innovation Research ISI is comparing and evaluating different fields of application for electricity and hydrogen together with Ludwig-Bölkow-Systemtechnik GmbH on behalf of the German utility RWE AG. The study was presented at the World Hydrogen Energy Conference in Essen on 19 May 2010.

The study pursues the question of where it makes most sense to use electricity or hydrogen as final energy sources in comparison to conventional solutions. Based on Life Cycle Analysis (LCA) and looking at the energy chain from the source to the application, the study focused on aspects of economic efficiency, greenhouse gas emissions and energy efficiency in vehicles. The analyses are valid for Germany and were conducted for the years 2015 and 2030. 

The project leader, Martin Wietschel from Fraunhofer ISI, explains the results as follows: “If regenerative energy sources or those with low CO₂ emissions are used, battery-powered vehicles in particular, but also plug-in hybrids and fuel cell vehicles have clear advantages over conventional cars. Greenhouse gas emissions can be reduced by a factor of four or five compared to cars with combustion engines, even if these are assumed to undergo further efficiency improvements.”

Since the two energy sources electricity and hydrogen and the associated propulsion systems have different features, for example in terms of driving range and speed of refuelling, the results of the study indicate that a situation-dependent use of vehicles with different propulsions is more likely than a single solution which meets all the requirements. For example, battery-electric vehicles show significant advantages at present compared to other alternative drive systems in small cars such as commuters’ second cars. In the segment of mid-size cars, plug-in hybrids are currently the most competitive of the alternative drive systems together with fuel cell cars. In comparison to battery-electric cars they have a longer driving range and the refuelling times are not an obstacle. As far as buses are concerned, hydrogen buses are most likely to achieve a breakthrough compared to today’s propulsion concepts. These offer clear advantages in their life cycle assessment compared to conventional buses, especially in built-up areas with high local emissions.

Economic efficiency represents the biggest challenge at the moment to the use of both energy sources. This is strongly dominated by the propulsion system, the battery or the fuel cell, respectively. Based on today’s figures, there has to be sharp drop in the costs for both technologies: For battery-electric cars by a factor of three and even more than this for fuel cells.

“Up to now, second to fourth generation fuel cell vehicles are being driven as demonstration vehicles with the corresponding practical experience. This experience is still missing for electric vehicles powered by lithium-ion batteries. Especially the lifespan of the battery and the associated impacts on their economic efficiency represent a not inconsiderable risk,” as Wietschel points out. Which direction the development will take also depends on which experiences are made with battery-electric vehicles in the next few years and which technology leaps can be made.

The study can be downloaded here.

The Fraunhofer Institute for Systems and Innovation Research ISI analyzes the framework conditions for innovations. We explore the short- and long-term developments of innovation processes and the societal impacts of new technologies and services. On this basis, we provide our clients from industry, politics and science with policy recommendations and perspectives for key decisions. Our expertise lies in a broad scientific competence as well as an inter-disciplinary and systemic research approach.