Project CHIC: Enhancing fuel cell urban bus technology

Posted: 10 June 2015 | | No comments yet

Today, urban areas are increasingly concerned with air and noise pollution – a large part of which is caused by transport. In parallel, our societies are facing growing mobility needs. Cities have been actively searching for alternative solutions to provide their population with efficient, environmentally-friendly and comfortable public transport systems. In this time of changing mobility behaviours, London, Oslo, Milan, Bolzano and the Swiss canton of Aargau have added new buses to their fleet. ‘Hydrogen bus’, ‘autobus ad idrogeno’, ‘Brennstoffzellenbus’, ‘hydrogenbuss’ – you may have already seen those signs on your streets: those buses all have something in common, they are all part of CHIC1, the Clean Hydrogen in European Cities project. Kerstin K. Müller – CHIC Coordinator, explains more.


A fuel cell bus in operation on Bozen/Bolzano

A snapshot of the CHIC project

CHIC is the largest European trial of fuel cell buses. All-in-all, more than 50 fuel cell buses are being deployed in cities across Europe and in Canada, along with hydrogen refuelling stations. The project, which started in 2010, involves 23 partners from eight countries. This initiative exists thanks to the European Fuel Cells and Hydrogen Joint Undertaking (FCH JU), a public private partnership supporting the uptake of fuel cell and hydrogen energy technologies across Europe. By proving that fuel cell electric buses can offer a functional solution against conventional engines, this project helps European cities decarbonise their public transport fleets and reduce noise pollution.

New bus – new engine

To understand this project, we have first to understand what fuel cell buses are. Fuel cell buses are a kind of electric bus; indeed, they share many components with battery electric buses and use electric motors rather than traditional engines for propulsion. However, rather than storing energy in large batteries, fuel cell buses use compressed hydrogen as fuel and use an on-board fuel cell to generate electricity which powers the electric motor. This device uses hydrogen and oxygen to generate electricity through an electro-chemical process producing only water and heat as by-products.

Modern fuel cell electric buses in general additionally have a small battery or super capacitors. These devices improve the performance of the fuel cell and overall energy efficiency of the vehicle, for example they boost the acceleration and allow recuperation of braking energy. Apart from that, the bus structure and the other non-electric components of the bus are the same as those in conventional buses.

Fuel cell buses matter

Lately, the bus industry has been investing in this technology and bus operators and transport authorities such as ATM, Hochbahn, PostBus, Ruter, RVK, STA and Transport for London (TfL) have decided to be part of the CHIC project. Why?

Local authorities have been struggling with the growing challenge of air pollution. Indeed, in the past few years – and especially in the springtime – the maximum alert threshold for particulate matter and nitrogen dioxide has been reached and exceeded in most major European cities. In this context, diesel buses will certainly not remain the only option in the future. Several major cities with ambitious clean air targets are looking at alternative, cleaner drivetrains.

CHIC is offering a solution to this challenge: fuel cell buses have zero tailpipe emissions at point of use, and are quieter than conventional diesel vehicles. Furthermore, the buses are comfortable for passengers and drivers, offering reduced vibrations and a smooth ride. In city centres, which are each year more polluted and noisier, as well as in cities increasingly promoting public transport, fuel cell buses are an excellent choice.

Emissions targets proposed for London’s Ultra-Low Emission Zone will mean that even the most efficient diesel buses will not meet the required standards as a minimum, double-decker buses will need to use hybrid technology, while single-deck buses will have to be zero emission (at point of use), which implies a choice between two options: battery electric buses or fuel cell electric buses. In Oslo, the bus fleet will be low carbon as of 2020. Also, Hamburg has recently inaugurated the bus ‘innovation line 109’ – the first of its kind across Europe – which is testing low carbon and ultra-low carbon vehicles, and has indicated its intention to purchase only emission-free buses from 2020.

CHIC – results of the demonstration

In total, 36 fuel cell buses are currently in daily operations on European streets. Their range exceeds 250km, with up to a 400km range demonstrated in some sites. This means that there is no need for the buses to return to depots during the day to be refuelled. Furthermore, the buses have the potential to offer the same level of operation as a conventional bus, with daily operation of up to 18 hours. Research conducted during the project has also outlined the efficiency of hydrogen as a fuel: with an average of 8kg of hydrogen/100km, the buses have proven to be above 10% more energy efficient than a conventional diesel bus on a tank-to-wheel basis (findings for 12m buses).

But of course, even the most innovative and efficient engine is useless with an empty tank: in each of the CHIC cities, a new hydrogen refuelling station has been built. In the majority of the cities involved in the project, hydrogen is generated on-site from renewable sources; the carbon emissions are negligible along the well-to-wheel energy chain. In those cases, hydrogen is produced by using electricity to ‘split’ water into hydrogen and oxygen through a process called electrolysis. The hydrogen refuelling stations have shown very high levels of availability, up to 98%, and the buses are able to be filled in less than 10 minutes, which is close to the refuelling times of conventional buses.

A work in progress

As is the case for all innovative technologies, the first steps are a moment to test and experiment. One may not expect the technology to be 100% mature. There is a transition period, in which technical issues are being identified and as with all new technologies, the time for finding solutions is longer than one can expect for a technology tested for a long time. CHIC is bringing fuel cell buses close to commercialisation, which also means identifying potential and effective shortcomings, and prepare the market introduction of the next bus generation. Among the main challenges identified, the issue of the availability of the buses is being tackled: failure of some components and late delivery of spare parts have been proven to be problematic in the past. This can be explained as the supply chain is still immature, and is expected to be solved with an increase in scale in the sector. The project had also to take into account the importance of the specific training needed for the staff: electrical skills are to be developed on top of mechanical skills. This is similar to the training required for staff working on other electric drivetrains. Therefore a sufficient amount of training should be foreseen when planning such a project.

Thanks to an efficient collaboration between industrial partners and bus operators, a large majority of the issues have been resolved during the first phase of the project, and the bus availability now reaches the project’s target levels of 85%. To showcase bus industry engagement in this technology, five large bus manufacturers (VDL, EvoBus, Van Hool, APTS and Solaris) signed a letter of understanding on 12 November 2014, in which they expressed their readiness and willingness to deploy some 500 fuel cell buses by 2020. This is a strong sign that the bus manufacturers will ensure that the vehicles developed will be as reliable as other alternative powertrains – and even better.

A worthy cost

The second major challenge is the purchasing cost. While the price of a fuel cell bus has halved during the timeframe of the project, fuel cell buses are still hardly competitive at this stage. Further cost reductions are forecasted as being the main driver for full market penetration in the coming years. In recent years, global car manufacturers have announced the mass market introduction of fuel cell cars. Some car models are already available on the market, while other manufacturers have announced release of vehicles in the years to come. A FCH JU study is currently investigating how this could impact the price of buses. However, cost reductions will mainly be achieved through increase of volume in the sector, which is planned under the Fuel Cell Bus Commercialisation Strategy.

Led by the European Fuel Cells and Hydrogen Joint Undertaking, this strategy plans the deployment of many hundreds of buses across Europe by 2020. To this aim, a coalition gathering the bus industry, infrastructure providers, hydrogen/technology providers, public transport operators and cities has been established. At the time of writing this article, it is expected that some 30 cities will strongly affirm their engagement in purchasing up to around 500 new fuel cell buses by signing a letter of understanding at a major EU transport event during summer 2015. Thus the cities are symbolically replying to the letter signed by the bus manufacturers last November. The letter will be handed over to the European Commissioner for Transport Violeta Bulc at the ‘Connecting Europe, TEN T Days’, to be held in Riga on 22-23 June 2015.

Next steps – when will we see fuel cell buses on all European streets?

The CHIC project will continue with demonstration of the vehicles until the end of December 2016. Cities are currently assessing the opportunity to continue operating the fuel cell buses after this date and to add further fuel cell buses to their current bus fleet. For instance, TfL has already planned to add two fuel cell buses to its fleet as part of the 3Emotion project.

The next generation of FCH JU-funded projects have indeed started since the inception of CHIC, increasing the number of fuel cell buses to 80 in Europe by the end of 2016: 20 fuel cell buses are being deployed as part of the European projects High V.LO-City and HyTransit in San Remo (Italy – five buses), Antwerp (Belgium – five buses) and in Aberdeen (United Kingdom – 10 buses). The project 3Emotion, launched in January 2015, will see, in addition to the two buses in London, 19 more fuel cell buses in Cherbourg (France), Rotterdam/South Holland (the Netherlands), Rome (Italy), and Antwerp (Belgium). Fuel cell buses can also be funded via other sources: Stuttgart and Karlsruhe (Germany) benefit from the co-financing of the German National Innovation Programme Hydrogen and Fuel Cell Technology (NIP) as part of the Clean Energy Partnership (CEP).

Today, fuel cell buses are offering a solid zero local emission alternative to conventional buses, directly addressing cities’ air pollution concerns and supporting them in decarbonising their fleets. Projects such as CHIC and its followers are helping this technology to develop so that it will be possible, in the future, to not only breathe better in cities partnering in such projects, but throughout Europe. 



CHIC project demonstration sites

  • Aargau, Switzerland
  • Berlin, Germany
  • Bolzano, Italy/Bozen, Germany
  • Cologne, Germany
  • Hamburg, Germany
  • London, UK
  • Milan, Italy
  • Oslo, Norway
  • Whistler, Canada


Kerstin K. Müller joined Daimler Buses EvoBus GmbH in October 2014. She is responsible for the coordination of the international fuel cell bus affairs and also took over the coordination of the EU-funded project CHIC. Kerstin has over 30 years of professional experience in the automotive business mainly as Marketing and Sales Manager.