EEBUS presents flexible power limitation

The EEBus Initiative e.V. is an independent association whose members predominantly comprise leading European manufacturers from the fields of e-mobility, energy management, renewable energy, metering, heating, smart home, and connected building technology. On behalf of its members, the association develops the open EEBUS standard - the global language for energy in the Internet of Things. This standard aims to enable storage-capable devices and systems, from e-mobility to heating systems to household appliances, to communicate manufacturer-independently about the efficient, grid-compatible use of energy. All developed specifications are internationally standardized and freely accessible.

As the electrification of vehicles and building technology increases, energy shortages are becoming increasingly likely: Trials show that properties can interact with the grid in a relieving manner through standardized information exchange. For example, e-cars should mitigate load and generation peaks by adjusting their charging power, acting as flexible energy storage and consumers. The holistic solution envisions bidirectional communication from the grid level through smart meter gateways (SMGW) at the grid connection to the corresponding energy management systems (EMS) and connected devices. This way, devices can be operated in an energy-optimized manner and with virtually no loss of comfort during energy shortages.

The standardized EEBUS communication is used between the smart meter gateway, the energy management systems, and devices such as charging stations or heat pumps. The EMS knows the flexible consumers and manages them within the framework of the grid's specifications. Alternatively, the energy management system can also use market incentives such as price tables for the most cost-effective operation.

During an EU and US test event, the communication between the grid and e-cars was successfully tested: Production vehicles and prototypes from leading manufacturers were adjusted in their charging power via openADR and IEC 61850 based on performance requirements. For EEBUS, this represents another step towards becoming the globally used language for energy.

A leading German manufacturer's smart meter gateway - Theben AG - was also integrated into the communication chain: Theben developed a communication module that implements the grid's specifications into the EEBUS standard and vice versa, and can report consumption forecasts and flexibilities collectively to the grid via SMGW.

"The integration of the charging infrastructure via EEBUS through the smart meter gateway shows the direction we are heading," says Ruwen Konzelmann, Head of the Smart Energy Business Unit at Theben AG. Konzelmann adds:

 "We are following the cross-sector standardization strategy published by the Federal Ministry for Economic Affairs and Energy and the Federal Office for Information Security according to the Act on the Digitization of the Energy Transition (GDEW)."

Comprehensive pilot projects demonstrate practical viability in the grid

The German SINTEG projects (standing for "Smart Energy Showcase") demonstrate the practical viability of these approaches. Andreas Weigand, C/sells project leader at Stadtwerke München, explains:

"As a metropolitan grid operator, we depend on such tools. We will not be able to reinforce and relaid all lines for the expansion of electromobility. Therefore, we are testing the concept of the "digital grid connection" to see how we can integrate the property into dynamic load management and send a performance limitation in the event of a possible overload of the street segment. It's like on a highway where speed is reduced in case of an impending traffic collapse. We also use EEBUS as a standard for energetic networking."

Why flexible connections for households will become the standard

For the grid-compatible control of flexible consumers such as the e-car, the principle of "peak smoothing" is currently being introduced into legislation. A study commissioned by the Federal Ministry for Economic Affairs and Energy, carried out by the Aachen Office for Energy Economics and Technical Planning (BET), recommends splitting the grid connection capacity for each building into two parts in the future: The unconditional and the conditional connecting power. Dr. Wolfgang Zander, general representative of BET, explains:

 "One part should always be unconditionally and unrestrictedly at the consumer's disposal. It covers the usual classic consumptions. Normal, inflexible household customers would therefore not be disadvantaged. However, for the second part, the grid operator should be allowed to limit the withdrawal power available for flexible facilities both in terms of time and extent when the grid reaches its capacity limits."

The recommendations of BET form the basis for the revision of §14a of the Act on the Digitalization of the Energy Transition (GDEW), which is set to enter legislation in the summer of 2020. The involved manufacturers are already preparing for this, as Ruwen Konzelmann from Theben AG summarizes:

"With our solution based on EEBUS, we are already enabling the necessary, cross-sector information exchange between distribution networks, Smart Meter Gateways, and EMS with flexible consumers in the home."

This is because the Smart Meter Gateway provides a highly secure, anonymous communication channel for this purpose.

What does this mean?

The energy supply is caught between two challenges: On the one hand, all consumers should communicate via a uniform standard to avoid overloading the power grid, and on the other hand, all of this should take place anonymously and securely. This is where EEBUS comes in, coordinating a uniform communication standard that remains secure. Initial practical tests in municipalities like Munich have proven to be promising.