• Intelligent electric vehicle charge management for Public Transport 4.0

    Depot management and smart grids

Worldwide, public transport is recording growing passenger numbers. More and more people are using bus, TRAM and underground – especially in cities. At the same time, air and noise pollution is increasing in cities around the world. This is forcing public transport companies to retrofit in the long term and to switch to alternative drive technologies.

As a result, in many locations, test vehicles and new technologies are being tested for their suitability on innovation lines. In a few cities, the first concrete plans for a consistent transition to electric or hydrogen have already been decided. In addition to the use of reliable vehicles, this project also means a shift in operational procedures and, in turn, the use of new technologies in order to make vehicles available for operation at the depot the next morning.

Electromobility – an alternative with history

In light of the current debate, anyone who has never studied the history of electromobility could quickly get the impression that a completely new technology is being promoted. But this impression is deceptive. As early as the turn of the 20th century, tens of thousands of electronically driven vehicles were whizzing through the world‘s cities. Here, public transport companies were early adopters of electrical drive. Before the beginning of the First World War, there were eleven large taxi companies in Berlin, whose more than 550 vehicles were powered only by electricity.

However, although there was even a small electric car boom in the USA around 1900, the „clean“ vehicles were unable to hold their ground against gasoline engines, mainly due to the problems of unsatisfactory battery technology and the associated problems of range and charging, which have persisted into the 21st century.

Clean technologies put to the test

Battery bus at Hamburger Hochbahn AG.
Battery bus at Hamburger Hochbahn AG.

Today, alternative drives, including electromobility, have once again moved into the focus of interest. Both air and noise pollution, especially in large cities, has triggered a new development boom in the automotive industry towards emission-free drives, forcing the operators of public transport companies to orient on sustainable technologies in the medium term.

For example, in Stuttgart, where several times a year measurements exceed the limits for fine dust pollution, there are already plans for the creation of a comprehensive concept for alternative drive public transport.

Hamburg is one of the cities where, besides the need resulting from environmental pollution, the government has already promised its necessary support in order to consistently work toward emission-free vehicles and in this way to serve as a model throughout both Germany and Europe. Irrespective of concrete implementation plans, in many cities, electric and hydrogen vehicles from various manufacturers are now being used in trials, albeit primarily on single lines or routes.

The challenge of charge management and energy supply

Here, it has been shown that charging electric vehicles is still an issue, the solution to which currently has various approaches. Some well-known manufacturers and transport companies are counting on charging at stops along the route or at the final stops. In light of the number of stops in the network and the resulting infrastructure and administrative costs that would be required, it soon becomes clear that this solution cannot be the right approach for regular operation across an entire fleet.

In addition, current tests have shown that, with the battery technology now available, more than 50% of existing routes can already be driven in most public transport companies – for which depot charging alone is sufficient. Considering that battery technology is developing rapidly, more range improvements can be expected in the short to medium term.

Charge management in depots – and controlling the power supply, where it can quickly come to power feeds of 10-110KV – plays a central role in this context, for which proven solutions already exist. For example, with practice-tested refueling optimisation in conjunction with the Smart Grid module for grid feed-in from the PSI division electrical energy, the depot management system PSItraffic/DMS meets the essential requirements for solving these task without complicated interfaces.

While PSItraffic ensures that all journeys can be carried out with vehicles, the energy module acquires the necessary power at the required time and at the best conditions. In this way, the two technologies combine expertise in public transport processes and knowledge of the processes relating to the supply of energy, and can thus make a decisive contribution to transitioning the test phase with electric vehicles into regular operation.

It is not yet clear whether a single technology, such as electric or hydrogen, can be successful in the public transport sector and determine the future market, or whether the parallel use of various technologies will prove itself in the way that this is already common in electricity generation.

Here, conventional power plants, wind farms and solar power systems exist side-by-side – with PSI Smart Grid as a demand-oriented control tool. Combining this with depot management is therefore in no way new territory, but rather only the transfer to another industry.

Refitting in stages

There is no doubt that a transition to alternative drives is also – or perhaps especially – unavoidable for public transport. In light of the great efforts and investments which must be made to enable the comprehensive use of such vehicles, successive conversion of the fleets using existing optimisation tools makes sense. The stepby- step refitting in particular creates room to manoeuvre and to manage the enormous infrastructure construction, to develop the necessary expertise for maintenance and repairs of the new technologies, and to make investments in new systems and tools in economically feasible „bites“.

Anyone familiar with alternative drive technologies knows that they were playing an important role long before the triumph of the gasoline engine. Today, all stakeholders face the challenge of consistently developing these technologies and boldly implementing them to protect the environment and our finite energy resources. Concerns regarding range or charging problems have long been eliminated, and practical software systems have been brought to market that help to solve and optimise the issues associated with using „clean“ fleets.

As it did so many years ago, public transport can play a decisive role in the world‘s cities in the use of alternative drive vehicles.

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PSI Transcom GmbH
Torsten Vogel
General Manager