Dance with electrical traction for urban buses: the case of Leipzig

Battery bus in Leipzig | © Egor Muleev

During an urban festival “Viva Mexico!” that took place at the Lindenau bus depot in 2008, one trolleybus and one hybrid bus were on display, as a showcase of future public transport modernisation. This initiative came in parallel with the rearrangement of services due to the opening of the city railway tunnel in 2009 that led to the closure of tram line 9 (between Leipzig and Markleeberg). Released capacities of electrical infrastructure influenced the idea to electrify bus lines by implementing trolleybus service. To put it simply, trolleybus is a bus with the same technology for traction as tram, metro and rail transport in general, used for decades. 

To electrify bus line 60, authorities considered the substitution of diesel buses by classical trolleybuses and commissioned a feasibility study (unavailable online). For bus line 70, a positive feasibility study for an implementation of in-motion charging technology was published in 2013, right after the Fourth International Trolleybus Conference in Leipzig. However, in 2021 the local public transport company received a first batch of 21 battery buses, with 17 more to be delivered in 2022. Such a switch shows that competition between technologies took place. Moreover, we did not find any available references to reports or at least discussions on that topic in local press, among activists or initiated with the help of a city council. We hope to disentangle some basic assumptions of “sustainable” transportation policy such as practical response to climate issues and renovation of the public transport fleet. So the central question is why the local transport company chose battery buses instead of trolleybuses?

Due to the limited availability of data on the decision-making process, even the technical underpinnings for favouring battery buses over trolleybuses are uncertain. Our initial hypothesis was that battery buses provide an easiest and fastest way to electrify the fleet in a city (primarily due to the absence of overhead wires) that promises good political outcomes. We studied official documents and conducted a series of interviews with officials, employees of the industrial sector, academics and local activists. We start with a historical overview, then provide a brief introduction into different local transport-related strategies and then outline three narratives gained from interviews. As our work shows, technological and PR issues are only the tip of the iceberg.

Historical overview

The 2013 report called “Reference Guide on Trolleybus-Tram Network Use” has 2 logos on its front page: LVB and Trolley project. LVB (Leipziger Verkehrsbetriebe) is the municipal public transport operator that runs buses and trams in the city. Trolley project was a group of dedicated specialists from European cities with trolleybuses in operation, and representatives from manufacturing facilities. This community engaged in a specific lobbying agenda focused on trolleybus technology. The study suggests to make use of overhead wires for fuelling an electrical motor, instead of equipping a bus with batteries for the same purpose. The group was active between 2010 and 2013, and LVB was also a member of this network. 

In the report, specialists compared 18m long buses with various power units in operation on route number 70 in Leipzig. After scrutinising 16 parameters from transport capacity to environmental friendliness, authors highlighted that in-motion charged trolleybuses with batteries were the best option: 

“It is recommended to retrofit Line 70 for the operation of electric bus. Four line sections are equipped with overhead contact lines, whereas the remaining line sections are operated by way of energy storage units on board of the vehicles. Additional charging points at the terminals are not needed” (p. 123)

The idea was to use available capacities of the existing electrical equipment to build up overhead wires for in-motion charged trolleybuses. These vehicles could carry small batteries on board that allow them to ride in autonomous mode for short distances. Back in 2008, only Rome and Zurich used this technology, but by 2019 almost all trolleybus cities have used this opportunity to expand the service area. Recently, officials in Prague even decided to build new overhead wires for in-motion charged trolleybuses from scratch. However, the opposite examples also take place that show that it is not a common strategy for trolleybus-equipped cities worldwide.     

According to the local press, the trolleybus restoration project faced the necessity of an automatic plug-in system to cross junctions of tram and trolley wires. In theory it was a solution to avoid the complicated construction of wired intersections. Automatic plug-in system allows lowering trolleybus’ poles and cross junctions with tram wires in autonomous mode. To address this issue, among others, the SKORPION project was launched in 2013. SKORPION means abbreviation of (partly) German words like Electricity, Power, Overhead wires, Recuperation, Plug-In, Innovation, Ecology and Sustainability (Strom, Kraft, Oberleitung, Rekuperation, Plug-In, Innovation, Oekologisch, Nachhaltig). LVB participated in a collaborative project with two German research institutes. The first one, the University of Applied Science from Zwickau, focused on sophisticated engineering solutions for the automatic plug-in system. This invention was tested in Eberswalde in autumn 2015.

A test truck for an automatic plug-in system, Zwickau, 2015 | Source: Westsächsische Hochschule Zwickau

The second, Fraunhofer IVI Institute from Dresden studied ridership with the help of mathematical modelling. Earlier on, the same institute contributed to hybrid bus studies. In parallel with the SCORPION project in 2013, LVB launched a research project with the same funding line called “Ebus Batterfly”. The focus was shifted to another technology: battery driven electric buses with technical support from the same Dresden-based scientific partner.

Two years later, a fast charging facility for batteries appeared at the terminal stop in Connewitz. Three years later, the first  battery bus started operation on route 89. According to the press release, LVB had to receive the second battery bus, with almost two times powerful batteries just a couple months later. 5 years after the initial idea, in 2018, the head of LVB’ technical department said that the battery bus feasibility study and test runs are finished. 

The official paper stated that LVB “proved” technical and economical ability to operate battery buses with suggested overall costs of “about 32,2 Mln. €”: three times higher in comparison with diesel buses. Interestingly, the substitution of diesel buses by battery buses on three lines suggested a reduction of CO2 by 2623 tonnes and NOx by 10,3 tonnes annually. This states the precise appraisal of costs required to reduce the negative environmental impact from 38 same class diesel buses. The delivery for the first batch of battery buses was planned for 2020. The referenced document is only an annotation of a broad report that covered economical and engineering issues, but is unavailable. 

Timeline of electrical bus introduction in Leipzig | Source: local media, feasibility study

According to a project manager’s presentation, as for 2022, 21 battery buses are already delivered, three charging stations are in operation, the depot capacity s being extended to accommodate 50 battery buses, as well as the necessary charging infrastructure, five new charging stations are in the process of installation, and 17 articulated battery buses will be delivered by 2022. In line with the efforts on „green“ public transport since 2008, 18 hybrid buses started their operation in Leipzig, as well as 62 diesel buses. 

Municipal strategies

The review of 14 strategic documents between 2003 and 2019 was aimed to address the issue of bus fleet renovation in response to climate issues awareness. Different departments of city administration and LVB itself developed these strategies. Each document mentions that the city’s financial capacities were very limited. At the same time the framing of the plans’ aims is imprecise and non-binding. Also mostly all technological suggestions are made to increase customer numbers, and address ecological challenges.

The first climate-aware topics were mentioned in the beginning of the 1990-s. However, all proposed measures failed to meet the set goals (City Development Plan 2003 (Stadtentwicklungsplan 2003); Plan for Decrease of Air Pollution 2005 (Luftreinhalteplan 2005); Public Transport Plan 2006 (Nahverkehrsplan 2006)). In respect to urban transportation and buses in particular, the idea of hybrid technology emerged in 2004 (Climate Protection Program (Klimaschutzprogramm)). Moreover, reviewed documents highlighted that available means are scarce and therefore the economic feasibility of the public transport sector needs to be improved by “using all the potentials for saving” (Nahverkehrsplan, 2006). Even though hybrid buses were subsidised, no additional costs are mentioned.

An additional narrative emerged in 2012 in the LVB strategy document Fokus 25. In comparison to municipal documents, it was unique and novel in its rhetoric as it pictures the company’s new philosophy as a “switch from a transportation service towards a mobility service provider” (p. 8). LVB even goes a step further and calls it a “paradigm shift” which should be characterised by disproportionate performance enhancement (p. 8). This transformation implies the company to leave the narrative of passenger transportation by “understanding the customer’s mobility desires” (p. 9). In order to do so they picture “innovation activities” as a central aspect in getting public recognition. By innovation activities they mean modern conveyances, digital media and smart cooperation that constitute an attractive offer for customers (p. 20). In that regard authors refer to electromobility by modernising the fleet of vehicles. What brings us back to the prior narratives is the lack of money for implementing the plans. They explicitly say that this new strategy has a “profound impact on the […] capital intensive fleet of vehicles” (pp. 13). Therefore a lot depends on public funds of different actors aside from the local level. 

In 2018, the Integrated City Development Plan (Integriertes Stadtentwicklungskonzept) proposed  a selection of measures the City of Leipzig is willing to apply in order to decrease CO2 emissions in the upcoming decade. Therefore it formulates an opinion on sustainable urban development and specifically looks into the public transport sector. The general idea ascribes the central role of future public transport to electro mobility calling it its “backbone”. Within the next year, all buses, trams and carsharing offers should rely on battery based electric traction. The Clear Air Plan (Luftreinhalteplan 2018) calls for the modernisation of the bus fleet as a necessity, and “an extraordinary example for innovation, progress and preservation”. The 2019 Public Transport Plan goes in the same direction. Following its agenda, in 2030 the entire(!) public transport sector will be electrically powered. 

The 2003 City Development Plan mentions Leipzig’s membership within the “climate alliance”. This organisation consists of cities, municipalities and counties that set the goal to decrease their carbon emission by 10% every five years. To do so their suggestion for the public transport sector was to purchase hybrid buses and by that renovating their fleets. In the current City Development Plan 2015, they refer to this point as they are considering the reduction of distress for the environment by introducing battery and hybrid buses to Leipzig’s route network. This document served as a base for the Mobility Strategy (Mobilitätsstrategie 2030) published in 2017. It is important to mention that over the 30 years of operation the programs consistently failed to achieve stated climate goals.

The Mobility Strategy 2030 proposes six potential strategies. With regards to actual votes of the city council in choosing one out of six, only the “Sustainability Scenario” has been reviewed by officials. This vision aims to increase the share of public transport, bicycles, pedestrians in overall modal split to 70%. In 2018 it was 60%. For LVB the goal is to increase passenger numbers to 220 million. In 2019 this number was 152 million while in 2021 dropped to 103 million. This increase in public transport ridership should be facilitated through an improvement of LVB’s choice of products. In order to do so, new vehicles need to be purchased. However,  this path is also dependent on public funding to make it economically attractive. 

Even though it was voted for, the “Sustainability Scenario” lacks implementation techniques, argues “Eco-Lions” (Ökolöwe), a communal activist group. This is mostly due to communal tight purses, and an unwillingness to invest, respectively. The objectives are shifted into the future as an “mandate for an investigation” which will not be implemented before 2025. Ökolöwe identifies this behaviour as a “keep going” approach (weiter so) under the cover of the “Sustainability Scenario”. Doing so, the LVB will not reach its obligation of increasing the public transport share to 23% of the entire modal split in 2025 which was already defined in City Development Plan 2015. Moreover neither the Mobility Strategy nor the Public Transport Plan 2019 or even Integrated City Development Plan 2030 define any standard for the LVB regarding climate and environment protection. LVB can independently execute any action regarding the bus fleet renovation. Also the status as a limited liability company suggests an opportunity to avoid city councils orders. This coincides with one of our interviews where an LVB expert pointed out that “LVB does not need the city council” in order to decide the company’s agenda.

Narratives of renovation the fleet

After the scrutiny of available media resources and bureaucrat programs, we conducted a series of interviews with employees of the LVB and ex-participants of Trolleyproject with rather an industrial background, engineers, academics, as well as local activists. In sum we talked with 10 experts and spent almost 20 hours on it. Also we have one written response. 

According to the results of this data, a number of explanations arose. The first narrative focuses on technical issues. In German practice all initiations in fleet renovation had to satisfy the following procedure: 

  1. Idea;
  2. Feasibility report;
  3. Test run;
  4. Appraisals;
  5. Plans and negotiations;
  6. Purchasing;
  7. Delivery. 

As for trolleybuses this process stuck at the second stage in 2013-2014 nonetheless the initial idea arose around 2008. The thought behind the idea of the (re)implementation of trolleybuses (because this transport mode operated in Leipzig till 1975) was to use the already existing power supply system from trams, one LVB official stated which was involved in this process. Additionally he pointed out that beside these technical reasons the city council urged LVB to drastically reduce not only CO2-emissions but also noise emissions. Therefore the reasons for a possible trolleybus network were technically and politically contingent.

Also all developments are not only the vehicle but also the issue of available space for storage and maintenance, educated staff, and financial sources. According to a high-ranked employee of LVB, trolleybuses had a number of problems with satisfying these criteria. Also the issue of intersections between tram and trolleybus overhead wires was highlighted in the same talk as a crucial one. Back in 2010-s the industry was somehow unable to provide a suitable solution for the issue of tram and trolleybus intersections. This fact led to the initiation of technical research in Zwickau on the automatic plug-in system. Last but not least, wires are “ugly” and therefore this technical detail contributed a lot to the aesthetic setting of officials. Another person we interviewed from the local transport company stressed this fact as central. Because of that, he said, the overarching goal was to keep the wire sections to an absolute minimum and only on where they could be attached to already built infrastructure. However, this solution which would have been part of the collaboration was not liked by city officials which in the end said they would rather have a route network where there are no new wires included.

Tram wires at Adler intersection in Leipzig | © Egor Muleev

Nonetheless the idea of emission free public transport appeared in 2008, the argument on the technical inability of trolleybuses to substitute diesel fleet is used as relevant even for today. This statement however was objected to by the other involved person. He made clear that it would have been technically actionable to have a partial trolleybus network. Beside the aforementioned aesthetical reasons the lack of patience for the SKORPION project to develop was another matter. Additionally the little chance of subsidies for the infrastructural challenges of a potential new network was crucial for the projects failing. Nonetheless the project was accompanied with the feasibility study and technical results, it was closed for further developments. However, engineers from Zwickau found another financial source and finished their project on an automatic plug-in system in 2021. 

The second narrative insists on political issues. Nonetheless climate awareness showed up in the late 1980-s, it faced a number of challenges that limited the performance of implementation. One of the main obstacles was and still is the financial dependence of local transport operator companies from external funding. Obviously there are a bunch of procedures that move the implementation of “sustainability” forward but requires a proper bureaucratic framework of reaching these goals. It took years. At the same time, brand new marketing efforts around public transport have been heating the electrical, battery-focused response to climate issues. 

In that respect this “loop” of agenda suggests the process of bureaucratic response to the climate agenda. Public transport operators to some extent are forced to particular solutions which are available on the market. This availability is also a matter of specific agreements that push a technology forward. Battery equipped electric vehicles are the most famous and supported “green” machines during the last years. In the light of this simple observation the influence of producers became obvious. In that regard an LVB official mentioned the Green Vehicle Directive by the EU. He pointed out that its narrow definition of what is sustainable and what isn’t leads to the circumstance that most transport companies are confronted with little variety in their opportunities in terms of a sustainable fleet renovation.

In line with this statement one can see the idea of lobbying that was highlighted numerous times in our talks with trolleybus proponents based in Germany, Austria, Poland and Czech Republic. According to their view, battery buses are expensive but “modern” and “hot” technology that celebrates a lot of hype around it. Industrial policies as well and different weights of players on the market actually shape urban public transport. The introduction of battery buses promises great marketing support, prestige and nice pictures of high-ranked officials. The issues of proper economic appraisals and climate care are sidelined. To some extent cities are forced to buy battery buses.  

City mayor, top management of a transport company, project manager from a transport research institute and a driver at the opening ceremony of the battery bus test operation, Leipzig, 2016 | Source: SAENA

The last argument has an economical underpinning. According to a number of responses from our interviews, trolleybus introduction is “too expensive”. However, this argument has been made with respect to the 2022 situation, while the feasibility report (from 2013) stated the opposite. 


With reference to the 2022, a 18-metre long articulated battery bus costs 720 thousand Euro, while the same length trolleybus with batteries is much more expensive, with ca. 1 mln Euro. Indeed, in 2019, the German city of Solingen paid about 900.000 EUR for one 18m in-motion charging trolleybus. This purchase had specific conditions with 60% coverage for additional costs. “Additional” is estimated in comparison with the cost of diesel buses. Leipzig had an even more advantageous deal. A special offer with government support covered 80% of additional expenses for battery buses and 40% of costs for charging infrastructure.

Despite these high co-funding shares, an LVB official shared that they “did not just buy the bus”. In addition to the purchased buses, charging infrastructure had to be built from scratch. Therefore, a process started where several bus routes were considered for a potential conversion to battery traction, as the depot was not re-developed before mid 2022. The renovation had to accommodate continuous service for the remaining buses. The depot costs had to be covered by LVB themselves, as the maintenance will too. Once the charging stations and buses are purchased the operator won’t receive additional funding either for the maintenance or for new batteries. Therefore, the LVB negotiated a guaranteed runtime of 1.000.000 km before battery replacement. If the buses do not manage to do so, then VDL, the bus manufacturer, will be obliged to pay for a new battery. Additionally, LVB is exposed to changing electricity prices that are more than uncertain right now.

Referring to the question why battery buses became so popular in a comparably short period of time, despite so many uncertainties and “secret” surveys (like feasibility studies or test run results), the LVB official drew a broad framework on the funding situation for battery buses in Europe and Germany. He said that around 2013, the bus market in Europe changed remarkably. New guidelines for a more sustainable public transport and potential fines for not fulfilling them led to EU member states subsidising alternative technologies. In Germany, he said, the combination with the Dieselgate scandal, and the uneasy transformation process of the automobile industry away from combustion engines, led to an unprecedented dynamic. Within a short period of time, a multitude of new funding pots evolved, which turned the LVB focus primarily on battery buses. Additionally he explained LVB’s leaning towards battery buses with the failure of the hybrid buses launch in the years before. The fleet failed considerably as the desired saving of fuel did not work out as one of our respondents explained.


A dance with electrical traction is still continuing. In the same manner in 2019 the feasibility report for Berlin’s district Spandau recommended the substitution of diesel buses by trolleybuses. Nowadays Berlin has the biggest battery bus fleet in Germany. It seems like at least in Germany, a “free” market provides a very limited variety of “sustainable” options. Transportation issues are not only a bottom up motto but a particular bureaucratic structure that forces cities to be climate-sensitive in a very specific and almost a single way. Technology and PR are therefore only a tip of the iceberg with very complicated and intricate interrelations between formal and informal relationships, ordinances, requirements, policy goals, lobbying, etc. The most important part is that not only passengers and citizens are unable to shape the agenda, even a local government has very limited leverages to develop and follow their own vision. Transformations become a very contested field but it is invisible for a general public and these tensions are shifted to orchestrating the origins and destinations of financial flows rather than something else. In that respect the influence of big manufacturers and powerful financial groups is dominant, nonetheless they have almost no chance to use a particular transportation system that they shape according to their own interest. At the same time the contribution of each participant to that process is very visible on streets.  

This study was made during the internship of BA student Jonathan Wich within the CoMoDe project that is part of the Mobilities and Migration Research Group at the IfL.

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