Q: Please can you kindly explain your role and involvement with batteries/hybrid rail vehicles?
Peter Dearman (PD): I have worked in railway electrification in the UK, Europe and internationally for more than 40 years. Helping to develop the approach to traction decarbonisation has allowed me to form a view on the place of batteries in a net-zero railway.
Karl Watts (KW): As Group President of Rail Operations UK, one of my principal responsibilities is to determine the Group’s strategic direction, including our traction strategy. In 2018, our traction strategy detailed the need to procure new locomotives to replace our existing fleet. My experience of working with many types of locomotives throughout my working life, allied to my understanding of new traction technologies, armed me with the knowledge to determine the operating and performance requirements for our new locomotive…a locomotive which had to be fit for the future. The technical specification, originally drafted in 2018 by Stadler, included, for the first time in the history of UK mainline locomotive operation, the employment of batteries for traction. I have been working with Stadler for the last four years refining the new class 93 tri-mode locomotive specification which enters service in 2023.
Simon Jarrett (SJ): I am the Engineering Assurance and Development Manager for Chiltern Railways. Chiltern Railways has been working on trials of Hybrid Conversions for it’s Diesel Multiple Unit fleet for the past four years in response to the Decarbonisation Challenge for the rail industry and to address increasing concerns from stakeholders at the impact of diesel fumes on health. Chiltern Railways is the last diesel-only operator into central London.
Mikel Maiz (MM): I used to define product roadmaps in the field of traction powertrains, including energy storage technology (e.g. lithium-ion batteries), presently my contribution to railways comprises the development of the rolling stock modernisation business within CAF Group. From 'make or buy' decisions in the past to evaluating the rationale of reinvesting in rolling stock at mid-life, my professional background has let me develop a strategic thinking mindset.
Q: In your opinion, what are the three biggest challenges when it comes to battery/hybrid technology implementation in rail?
PD: 1) Battery and battery charging technology is not yet matched to the wider expectations of society.
2) There is a real danger that gambling on that technology advance results in the objective to decarbonise being undermined.
3) Technologies around conventional electrification, hydrogen and batteries are in some quarters seen as in competition. That clouds decision making and will ultimately prevent progress.
KW: Whilst battery powered trains have been around for decades (British Rail introduced a battery powered multiple unit train in 1958), advancements in battery technology have made them more viable for use on trains.
However, batteries have their share of challenges.
Firstly weight. Traction batteries are heavy, both in terms of the basic chemical medium used and the cooling medium required to disperse heat. Furthermore, when used as a part of a traction package, the demanding duty cycle (the number of times the battery is recharged and discharged) means that some form of recharging system needs to be present on the vehicle (although this does not apply to vehicles used for short journeys or shunting where fixed recharging installations are provided). Batteries cannot produce their own energy, they can only store it when charged from another source and it is the provision of this source, normally some form of diesel alternator set, which adds to the weight of the vehicle.
Secondly cost. The demanding duty cycle will degrade performance and impact on battery life. Traction batteries remain expensive and therefore replacement adds significant cost to the whole life maintenance cost of the vehicle. Diesel engines can last many decades, batteries between five and ten years.
Thirdly efficiency. When used as part of a bi-mode or tri-mode traction package, whichever traction power is not being used can be regarded as 'dead' weight. This does not help traction unit efficiency as energy is being consumed just to move this dead weight. This can be over significant distances.
SJ: The challenges are:
a. Cost & Business Case – The capital cost is large and does not present an easy case for investment.
b. Timescales – The development and roll out timescales are long, although now that solutions are becoming commercially available this is reducing.
c. Battery Fire Hazard – The batteries used present a challenge for the management of fire risk. This is becoming clearer in the case of road vehicles and will read across to rail vehicles.
MM: State-of-art. As battery and other alternative technologies keep evolving, boundaries of decarbonisation expand accordingly. However, so far these technologies have not been proven to replace completely conventional (emission based) concepts in non-electrified routes.
Regulatory uncertainty. Future regulatory guidelines are likely to affect existing operational requirements and consequently rolling stock specifications (e.g. zero-emission mode in high exposure areas). But, how will they evolve over the following years and which specifications shall OEMs consider from now on?
Low relevance. Far from desired, railways does not always represent a significant market to develop key technologies to the next stage. Hence, railways should not stand alone on the decarbonisation challenge, but aligned with those sectors acting as technology drivers.
Q: How are these challenges being overcome?
PD: R&D is very much in evidence around the industry. Co-ordination of that R&D effort with clear objectives remains somewhat illusive but only by settling on a structured plan can logical progress be made.
KW: Battery technology is progressing. There is significant global activity aimed at addressing these challenges and we’re already witnessing batteries which are lighter, more efficient and have extended life cycles. New materials are being explored, both as the basic chemical element and for cooling.
SJ: a. Cost & Business Case – We are working with suppliers and funders to develop the business case considering the wider benefits of diesel free operation in urban areas.
b. Timescales – The development timescales are reducing now that commercial solutions are available.
c. Battery Fire Hazard – The solutions to this hazard are being established as they become more widely used.
MM: The railway sector has analysed the limits of technology to fully understand how new regulations and operating requirements should be implemented, evaluating the financial and operational impact. Next steps seems to be crucial to align the rolling stock modernisation plan with the upcoming decarbonising policies and guidelines.
Q: What are the developments in discontinuous electrification and how are these being integrated in the main network?
PD: There are some early thoughts on the use of discontinuous electrification. Advantage can be leveraged if a balanced approach is pursued. The viability of such bi-mode operation will depend on being able to size the battery optimally, battery running past 'dead sections' of a relatively short distance is a different proposition to running for significant distance on batteries. The charging energy must also be factored in to the wired lines, and resolving and quantifying that energy demand is crucial to the traction fixed supply design.
KW: Firstly, we have to consider what we mean by discontinuous electrification (DE). One could argue that we already have this on the Great Western and North Eastern mainlines. Bi-mode units operating over these routes utilise their bi-mode capability depending on whether a particular part of the route is electrified or not.
If we mean a route which has been electrified throughout with small gaps in the OLE which fall into the 'too difficult basket', then this is something else…and something which does not appear to be planned.
Full electrification is the most efficient way to electrify a route. DE is a less viable and less efficient way to achieve electrification. DE has its challenges too depending on where and at what frequency the 'gaps' are. These include the need to employ less efficient bi-mode traction, operational risks, e.g. pantograph mismanagement, and power supply.
Q: Why do you feel it is important for rail operators and rolling stock manufacturers to attend the event?
PD: There is a long road ahead to define the role of battery vehicles in the post 2050 UK economy. Both road and rail will use the technology to some extent. Without a plan optimal solutions will not emerge, without consensus a plan will not emerge. This event is part of the journey allowing engineers to broaden their understanding of the complex and diverse issues involved and to foster that consensus.
KW: Only 42% of our network is electrified. Therefore, on the route to decarbonisation, alternative traction power sources need to be employed. Batteries offer one of these alternatives. Furthermore, batteries will become a solution to ensure we meet social obligations in delivering a 'quiet railway'. Batteries will therefore become an integral part of train operations in the coming years and it is important for us all to understand their role in the future, including their capabilities and limitations.
SJ: The whole industry is being challenged to improve its environmental performance and work towards the elimination of diesel traction. This event will discuss the stepping stones towards this ambition in a constrained cost environment.
MM: It will certainly address the key elements to consider in their mid-term strategic plan resulting from the decarbonisation trends. Participation shall contribute to a better understanding of the logical steps towards railway decarbonisation.
Batteries included: The challenges of adopting battery and hybrid technology in the rail industry will be taking place as a live online seminar on 4 May 2022.
Join this seminar to:
- Learn more about the role hybrid and battery powered vehicles will play in resolving the environmental, noise pollution and health implications facing the industry
- Gain insight into challenges of upgrading existing railway vehicles to become hybrid or battery powered and how these are being managed
- Understand the considerations necessary for introducing new railway vehicles that are hybrid or battery powered
- Discuss the operational implications of adopting alternative traction systems
- Grasp the importance of a whole system mindset to maximise the benefits of introducing hybrid powered railway vehicles, including how these can complement increased electrification
- Find out more about the role the UK supply chain can play to support the growth and adoption of these new technologies and how you could fit into that
To book your place, please visit the event website.