Technology Collaboration Programme


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Task 12

Heavy-Duty Hybrid Vehicles

Objective of Task

Task 12 aimed to report on the current status of the heavy-duty hybrid vehicles “playing field”. The status report focused on the available and emerging hybrid vehicle technologies and the current and expected state of the market.

To collect and organise the required information, three subtasks were defined.

Subtask 1: The first technology-oriented subtask aims at structuring the information on heavy-duty hybrid vehicle components, systems, and configurations. This subtask identifies and illustrates the technical requirements, especially highlighting where they are different from light-duty requirements, the available technologies and their characteristics, and the system integration requirements. Additionally, there is a focus on powertrain configurations (topologies) and powertrain strategies for high efficiency and low emissions.

Subtask 2: The second market-oriented subtask targets collecting market information on heavy-duty hybrid vehicles. The current market of existing hybrid prototypes and standard vehicles needs to be investigated. The information gathering will focus on the applied technology, as well as the costs and its merits in meeting customer expectations. In this way it complements the first subtask. This subtask will increase the insights into the applications where heavy-duty hybrids have been an effective solution and can thus provide essential information for future hybrid vehicle deployment projects. The lessons learned will not only focus on the technical barriers to overcome but also on the required framework (training of mechanics, support, etc.) for successful project implementations. To address the potential of heavy-duty hybrid vehicles it is useful to identify niche applications that may benefit to a great extent from hybridisation.

Subtask 3: The third dissemination-oriented subtask involves collecting and disseminating general information and promoting the Task 12 objectives and results to a broad range of stakeholders. This will be done by setting up a dedicated website, preparing papers, giving presentations at relevant conferences, and keeping up contact with relevant platforms by sharing information on heavy-duty hybrid developments.

working method

The Operating Agent organized two expert meetings per year, predominantly in participating countries. Each meeting tried to include a technical visit to the participant’s facilities and/or other interesting projects or events. This allowed the local participant to illustrate its capabilities and infrastructure in the field of heavy-duty hybrid vehicle technology.

A subtask leader was designated for each of the three main objectives to coordinate the progress of their subtasks and complete the respective reports.

  1. Subtask I – National Renewable Energy Laboratory, U.S.,
  2. Subtask II – NL Agency, the Netherlands,
  3. Subtask III – VITO, Belgium.


Eight expert meetings were undertaken during the task period.

results of task 12

Combining the expert meetings with a local workshop, conference, or company visit has brought a lot of added value and information to Task 12.

The first expert meeting in 2007 in San Diego was combined with a heavy-duty hybrid vehicle workshop with some key speakers from the U.S. One of the other expert meetings in 2008 was held in South Bend, Indiana, U.S., in conjunction with the Hybrid Truck User Forum (HTUF) 2008. HTUF is a multi-year, user-driven program to accelerate the commercialization of medium- and heavy-duty hybrid technologies in the U.S. It is operated by CALSTART in partnership with the U.S. Army’s National Automotive Center (NAC) (more info:

The expert meeting in 2009 took place at the National Renewable Energy Laboratory (NREL) that is the primary U.S. laboratory for renewable energy and energy efficiency research and development (R&D). NREL’s mission and strategy are focused on advancing the U.S. Department of Energy’s and U.S. energy goals. Their areas span from understanding renewable resources for energy, to the conversion of these resources to renewable electricity and fuels, and ultimately to the use of renewable electricity and fuels in homes, commercial buildings, and vehicles. It was again confirmed during the visit that NREL has a lot of experience from a research perspective, which has been of valuable input for the Task 12 final report.

Along with input from the R&D and government side, input from industry was crucial for a good overview on the latest trends in heavy-duty hybrid vehicles. As a result, Task 12 was very pleased with the contribution from Switzerland’s designated Task representative, HESS AG. The company began in 1882 with the production of buses and utility vehicles and has been in family ownership for 5 generations. Together with its international licensees, HESS currently produces around 2,400 buses a year. HESS experience ranges from buses to trolleybuses, up to city buses in standard and hybrid versions (see figure 1). Their headquarters in Bellach employs around 260 personnel.

results of task 12

Figure 1 HESS AG hybrid bus, Luxembourg – 2009. (Photo courtesy of HESS AG.)

results of task 12

Figure 2 Attendees at the final Task 12 experts meeting held in October 2010 toured the HESS factory in Bellach, CH. From left to right: Alex Naef (CEO of HESS), Arie Brouwer (The Netherlands), Carlo Mol (Belgium), Jussi Suomela (Finland), Teemu Lehmuspelto (Finland), and Hans-Jörg Gisler (Technical Manager, HESS AG). (Photo courtesy of Solothurner Zeitung.)

The final expert meeting took place in October 2010 at HESS AG headquarters (see figure 2). This location choice enabled attendees to a visit the HESS factory, but the prime focus was the completion of the final report. All collected information was organized from the different subtasks’ reports and will be aggregated into one final report. It can be concluded that the market of heavy-duty hybrid vehicles is growing from a prototype phase into more of a demonstration/commercial phase. Market activities indicate increasing developments in all categories of heavy-duty hybrid vehicles: trucks, buses and mobile work machines. The final report was presented to the HEV TCP Executive Committee in November 2011 at its 35th meeting in Lisbon, Portugal.

Other dissemination events included:

  • March 19, 2010: Presentation at the “Move it” Expo (Genk, Belgium)
  • November 9, 2010: Paper and Presentation at the Electric Vehicle Symposium (EVS-25) “Trends and insight in heavy-duty vehicle electrification” (Shenzhen, China)
  • December 1, 2010: Presentation at the Conference “New Horizons for Urban Traffic” (Luzern, Switzerland)