PSI Blog

Smart Software Supports the Transition to E-Mobility

21/02/2019 - Energy, Artificial Intelligence, Transport

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Mobility plays a decisive role in economic prosperity. At the same time, it becomes important to make mobility sustainable. While vehicles running solely on electricity were considered exotic transportation in the past, there is now a clear trend towards e-mobility. In course of this trend, the coupling of the charging station infrastructure and the electric grid is becoming increasingly important.

Diesel-gate and numerous headlines about global warming are triggering accelerated rethinking towards emission-free drive systems and renewable energy generation. Cities and municipalities are  receiving millions of Euros of public funds for research and development projects to research the technologies for integration of electric mobility and distribution grids.

At the same time, public transportation fleets are electrified while the public and private charging station infrastructure is expanded. The objective "Green cities" has clearly been set in Germany.

Grid integration of e-mobility

In addition to improving battery technology and unifying communication standards, the challenge of including millions of electric vehicles and the associated charging station infrastructure in the grid planning is moving into focus.

The increased energy demand must be integrated in the distribution grids which are already subject to fluctuations due to the infeed of renewable energies. In addition, an increasing number of heat pumps and cogeneration plants must be considered as well.

In course of the e-mobility trend, the coupling of the charging station infrastructure and the electric grid is becoming increasingly important.

The increased energy demand must be integrated in the distribution grids which are already subject to fluctuations due to the infeed of renewable energies. In addition, an increasing number of heat pumps and cogeneration plants must be considered as well.

Since the physical expansion of the distribution grid is difficult due to structural and economic reasons, intelligent solutions must be developed, tested, and realized.

Software solutions support e-mobility

Already today, PSI supports this mobility transition by developing intelligent cross-platform hardware and software solutions for load and charging management as well as hierarchical decentralized grid management. Together with well-known development partners and customers, comprehensive solution concepts for various infrastructure areas are developed, used in live operations, and continuously enhanced step by step based on the obtained practical expertise. 

Focused integration of know-how in network control systems, network technology, and public transportation achieves maximum benefits for the customers. In addition to customer-specific solutions, modular standard solutions are developed which are characterized by high degree of scalability, operational security, and future-proof design.

Increasing challenges for grid operators

The expansion of electric mobility occurs in public transportation, transportation of goods, large company fleets, and depots and involves different grid voltage levels which require different solution concepts.

In depots, the challenge is to change the depot management systems from mostly diesel-fueled vehicles to emission-free electric vehicles. For example, charging electric vehicles requires much more time than conventional refueling.

The route profile, the loading, and in particular the air conditioning affect the energy consumption of electric vehicles significantly more than that of conventional vehicles operating with fossil fuel. Therefore, reliable consumption forecasts and comprehensive fleet monitoring are an absolute necessity.

Communication with different protocols between the Smart Power/Smart Load Module, vehicles, and charging stations which are connected to the grid. This allows to monitor and control the charging infrastructure. Source: PSI
Communication with different protocols between the Smart Power/Smart Load Module, vehicles, and charging stations which are connected to the grid. This allows to monitor and control the charging infrastructure. Source: PSI

Ensuring grid stability is essential

From the grid point of view, a large number of simultaneously charging vehicles in the depot can quickly result in overloaded transformers or substations. Even a medium-sized depot consumes a double-digit number of megawatts. The connection to the grid is on the medium or high voltage level.

The PSI control system module Smart Power/Smart Load continuously monitors the electric grid. In case of possible overloads, individual consumers are regulated down in order to ensure grid stability. For this purpose, Smart Power continuously and bi-directionally communicates with the charging station infrastructure, the vehicles, and the PSI depot management system.

Operational priorities for charging individual vehicles are sent to the control system in order to ensure an optimal operational schedule with always sufficiently charged vehicles. PSI provides the necessary communication technology with the appropriate hardware components and protocol converters. The concept includes ongoing data exchange with the downstream distribution grid operators in order to provide primary and secondary control power and to optimize consumption of low-cost electricity. This results in significant cost savings for the participating fleet operator.

Together with the Hamburger Hochbahn AG as one of the technology leaders in public transportation, PSI is currently implementing a load and charging management system for bus depots for secure and optimized charging.

Intelligent load management for low voltage grids

Large depots which are separate from the public system require large amounts of power; however, in public areas such as parking structures and for smaller corporate fleets, an increasing number of small and medium size charging stations are installed which are connected to the low voltage grid.

Since simultaneously charging of a relatively small number of vehicles may result in an overload of a low voltage bay, the charging must be monitored and controlled with regard to the locally installed grid capacity. This requires communication with the vehicles as well as local intelligent load management in the secondary substations. Here the hierarchical decentralized grid management system of PSI is used which has already been proven in several pilot projects since 2015.

Charging station and vehicle communication with the Smart Telecontrol Unit. Source: PSI
Charging station and vehicle communication with the Smart Telecontrol Unit. Source: PSI

The on-site components with remote control system functions continuously communicate with the central grid control system of the grid operator and transmit only the main sum variables and indications. The operational regulation of the low voltage grid is performed autonomously on-site in the secondary substations.

The charging powers and charging times can be individually adapted based on the current grid state and the customer preferences. Local renewable energy infeeds as well as available battery storage are used for decentralized energy generation and provide increased flexibility to the consumers.

PSI participates in the ALigN (Expansion of charging infrastructure by special grid support) research project in Aachen, Germany for development of appropriate solution concepts by providing hardware and software solutions.

Residential charging is the greatest challenge

More than fifty percent of all vehicles are charged in residential households. The greatest challenge for the grid operators is to obtain an accurate overview of the locations and capacities of the installed charging stations. This requires introduction of uniform and mandatory registration of charging stations. Reliable wide-area technology for bi-directional communication between residential households and grid operators must also be developed.

The objective is the integration of residential households in existing distribution grids based on customer preferences in order to improve grid operations. This requires intelligent communication, control, and measurement technologies as well as interoperability standards between manufacturers and grid operators.

Good prospects for an inter-connected mobile future

All listed areas require development of secure and intelligent systems. Based on its long-term know-how in the areas intelligent grid management and depot management optimization including load and charging management modules, PSI provides the basis for visionary steps into an inter-connected, mobile and emission-free future.

Andreas Gorks

Division Manager Municipal Utilities
PSI Software AG, Division Electrical Energy

agorks@psi.de

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