The Altdorfer Flexmarkt (ALF)

Figure 1The Altdorfer Flexmarkt (ALF) is a concept for using the flexibility available in the distribution network. DSOs can use ALF as an operational planning tool to react flexibly in response to forecasted network congestion, reducing their dependence upon emergency measures for congestion management. By tapping local flexibility potentials, grids can be better utilized and feed-in and consumption peaks can be reduced. This allows more renewable energy and new consumers to be integrated into the grid, without having to expand the grid to the "last kilowatt" or regularly curtail renewable energy through feed-in management. In this way, ALF makes an active contribution to achieving the goals of energy system transformation.

ALF serves as an interface between grid operators and flexibility in the network. This ensures a cost-optimized, secure, and reliable use of flexibility.

Flexibility providers represent owners, operators, and marketers of flexibility options, and can offer their flexibility on the provided platform. Flexibility options include both controllable generation and consumption units, as well as storage facilities that can be switched on and off by an external signal. By keeping registration and participation simple, ALF’s design encourages even small flexibility options to make a contribution to the transformation of the energy system. PV systems, heat pumps, electric vehicles, and storage systems such as night storage heaters or home batteries are all examples of flexibility options well suited to be a part of ALF.


Functions of the Altdorfer Flexmarkt

ALF offers a market-based method for the prevention of bottlenecks in the distribution network. 

Flexibility providers place so-called flexibility offers on the platform, or add their flexibility option to the market pool if they themselves do not actively market their system. This offers flexibility providers new revenue potential. Additional incentives for flexibility providers to participate on the platform include alternative marketing opportunities and shorter payback periods from this additional income, as well as an active contribution to energy system transformation at relatively low effort. The low entry hurdle to participation ensures that for even small players can realize these benefits.

While there are many types of flexibility providers, intially there will only be one type of flexibility consumer: the network operator. To prevent a bottleneck in their network, they inform the ALF platform of how much flexibility they require. 

When the flexibility consumer determines a need for flexibility, their flexibility demand also includes the specific location of the congestion. ALF then matches the flexibility demand with the flexibility offers and determines which flexibility providers will be activated. In addition, the network operator has set limits on the platform to prevent flexibility calls that resolve one network bottleneck from causing another bottleneck. (see figure 1).



Schematic basic concept of the Altdorfer Flexmarkt and interaction of flexibility option and flexibility consumer

Figure 1: Schematic basic concept of the Altdorfer Flexmarkt and interaction of flexibility option and flexibility consumer

Further information can be found in the concept paper of the Altdorfer Flexmarkt.


Concept paper of the Altdorfer Flexmarkt

Figure 2: Concept paper of the Altdorfer Flexmarkt


Platform interface

ALF offers all participants an easy-to-use interface.

The registration process of the flexibility provider initially takes place via the user interface or platform interface and requires the specification of personal contact data.

To register a flexibility option, the flexibility provider creates a new unit by selecting the unit type using the platform interface. The following flexibility options can be selected:

  • Photovoltaic plant
  • Heat pump
  • Electric vehicle
  • Battery storage (both house storage and larger battery storage systems)
  • Wind turbine
  • Electric storage heater or night storage heater
  • CHP plant, e. g. combined heat and power unit
  • Hydropower Plant
  • Industry / trade and comerce consumers

The next step is to provide general information about the flexibility option before submitting asset-specific technical data. The input query is kept as simple as possible. Figure 3 shows an example of the process a flexibility provider uses to register a flexibility option on the platform.

 User interface for registering a flexibility option on ALF

Figure 3: User interface for registering a flexibility option on ALF


Field test in Altdorf near Landshut

ALF will be implemented and tested together with test persons in a field test in the network area of Bayernwerk in Markt Altdorf near Landshut and the surrounding area (see Figure 4). The participation activities focus on the municipality of Altdorf, the demonstration of the Altdorfer Flexmarkt also includes the surrounding region, as this is also supplied by the same substation.


 Projekt region Altdorf near Landshut and surroundings as well as the installes renewable energy plants

Figure 4: Project region Altdorf near Landshut and surroundings as well as the installed renewable energy plants (State: End of 2016)


Target group

Owners and operators of so-called flexibility options, i.e. controllable energy generation and consumption plants, as explained above.



The C/sells project has been running since the beginning of 2017. C/sells has been active in Altdorf since mid-2018, for example with a stand at the market festival and various information events such as the Altdorf citizens' dialogue. The field test started in October 2019 and is planned to run for at least 6 months.


Technical connection

For the transmission of switching signals and the logging of metering data, ALF will build upon the rollout of intelligent measuring systems (smart meters) planned by the Federal Government. In this process your conventional electricity meter will be replaced by a modern digital measuring system. When participating in ALF, this system will be expanded to include a so-called smart meter gateway and a control box. This will allow both switching signals and metering data to be transmitted safely and reliably to authorised parties. Further information about smart meters can be found (in German) here.


Participation work on site

The participation of the citizens of Altdorf is decisive for the successful implementation of the project. This is why they have been specifically included since the beginning of the project. This outreach work takes place in close cooperation with the SmartGrids BW, which, among other things, carry out the participation activities in C/sells (further information at An information stand at the market festival and posters on roadside utility boxes first attracted the public’s attention in 2018. The C/sells team is also in regular contact with the mayor of Altdorf, the local council and the Working Group for Energy. The highlight so far was the citizens' dialogue on 7 March 2019, during which almost 40 citizens discussed ALF with employees of the FfE and Bayernwerk. The exchange with interested citizens is particularly valuable for the project team, which is why further events are also planned during the field trial. In addition, newsletters and social media will be used to share current developments in the project.


Project C/sells

Csells LogoOver the course of the project C/sells, ALF will be implemented through the Forschungstelle für Energiewirtschaft e.V. in cooperation with Bayernwerk. These partners seek to learn valuable lessons about the energy system of the future and the roles different parties involved in this system will play. By working together, the project partners and the residents of Altdorf are taking the transformation of the energy system into their own hands actively shaping the Energiewende. The results are intended to be a model solution that can be scaled up for widespread implementation as a long-term cornerstone of the energy system.


Förderung und Projektpartner

SINTEG BMWI KoppellogoThe activites described here are part of C/sells, a joint project carried out as part of the Federal Ministry for Economic Affairs and Energy (BMWi) funding program "Smart Energy Showcase - Digital Agenda for the Energy Transition" (SINTEG – funding code 03SIN121). In addition to support from the BMWi, the FfE  receives financial and practical support for its work within C/sells from Bayernwerk AG, Intel Deutschland GmbH, and the Stadtwerke Augsburg Netze GmbH. These partners will evaluate the results of the project to determine the potential for implementation within their service areas.



14 BAG logo   15 SWA Netze logo 16 intel logo 




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