In order to reduce emissions in freight transport, the first obvious step is to shift goods from road to rail, but the potentials here are limited and solutions are also required for road transport. Especially busy trunk roads could be alleviated in terms of emissions by overhead catenary systems, which have undergone continuous further development in recent years. Hybrid catenary trucks are powered by electricity from overhead lines while driving and can also drive off electrified roads using power from a smaller battery or a secondary powertrain system. Whether the technology will manage a breakthrough depends on its economic viability and its environmental impact - these were examined in studies by the Fraunhofer ISI, the Oeko Institut, the ifeu and others, as were possible expansion scenarios and policy instruments. All the insights gained are summarized in a new Policy Brief, which was compiled in the context of the BOLD project (Begleitforschung Oberleitungs-Lkw in Deutschland (Accompanying Research for Overhead Line Trucks in Germany)).

Overhead line technology can be economically viable

The Policy Brief makes it clear that when entering the mass market, overhead line trucks will be cheaper than diesel trucks from a user perspective due to significant future cost reductions. At present, and without considering infrastructure costs, the total costs for owning and using a catenary truck are still slightly higher than for a diesel truck.

The deployment of overhead line infrastructure should focus on important s. Due to the high capacity use of certain routes - 65 percent of long-distance truck transport is concentrated on about 4,000 kilometers of highway, which corresponds to a third of the German highway network - it makes sense to construct an overhead line network between important logistics hubs such as between Hamburg and the Ruhr region (A1) or Hamburg and Kassel (A7). This would involve investments of about ten billion euros over a period of about ten years. Part of the revenue from a truck toll based on CO₂ would be sufficient to finance this.

Road freight CO₂ emissions reduced by one fifth

Dr. Patrick Plötz, head of the Business Unit Energy Economics at Fraunhofer ISI and co-author of the Policy Brief, indicates the large potential of overhead line technology for saving CO₂: "The utilization phase is decisive as far as the greenhouse gas balance is concerned, because vehicle production and construction of the overhead line infrastructure are practically negligible in comparison. Compared with diesel trucks, battery hybrid catenary trucks will emit about half as much CO₂ per kilometer in 2030 - using the German electricity mix." Even diesel-hybrid catenary trucks could cut CO₂ emissions by a quarter.

Overall, the overhead line technology could reduce the transport-related emissions of CO₂ by two to four million tonnes per year by 2030 and by up to twelve million tonnes in the long term. This means that the overhead line technology could reduce the emissions from road freight transport as a whole by about 20 percent. The additional electricity required plays only a minor role, even if the system were to be fully expanded.

Early political action is required

The Policy Brief identifies three aspects that are decisive for the successful introduction of catenary trucks to the market: Economic vehicle operation, an existing basic infrastructure, and an attractive range of vehicles. Due to existing incentives such as premiums and toll exemptions for electric trucks, the political focus should be on constructing infrastructure. Government coordination and pre-financing are particularly important here. A toll based on CO₂ could ensure a high share of electric driving while avoiding free rider effects. Direct incentives for the vehicles should be limited to the market introduction phase.

In addition, a market for overhead line trucks can only develop if truck manufacturers provide an appropriate range of vehicles, which politics should also support, for instance, through early international cooperation. Alongside the range of new catenary trucks, retrofitting trucks with electric powertrains is also conceivable.

The Fraunhofer Institute for Systems and Innovation Research ISI analyzes the origins and impacts of innovations. We research the short- and long-term developments of innovation processes and the impacts of new technologies and services on society. On this basis, we are able to provide our clients from industry, politics and science with recommendations for action and perspectives for key decisions. Our expertise is founded on our scientific competence as well as an interdisciplinary and systemic research approach.