Direct sale of PV electricity

At the headquarters of the Wilhelm & Willhalm event technology group in Aschheim near Munich, a high-performance photovoltaic system was integrated into a modern energy management system. The project's goal was the professional direct sale of the generated solar power on the German electricity exchange, with Next Kraftwerke GmbH acting as the control center.

The core technical challenge lay in the reliable connection of the M-TEC inverters to the Loxone Miniserver and the secure transmission of all energy-related data to the Next Kraftwerke control center.

A particular challenge was that both the energy management system and the control center operate as master systems. This meant that direct standard communication was not possible. At the same time, high requirements for data security, stability, and future viability had to be met.

The implementation was realized through a consistent, structured communication architecture:

-Modbus TCP for direct communication between the Loxone Miniserver and the inverters
-Secure OpenVPN connection to the control center for external data transmission
-Use of a gateway to couple two master systems

In addition, the definition and coordination of custom Modbus registers were implemented in cooperation with Next Kraftwerke.
This architecture enables stable, bidirectional data provision of all relevant power and status values for direct sale.

The system is successfully connected to the grid and fully integrated into direct sale. The solution stands out due to:

-High cost efficiency compared to proprietary or specialized interface solutions
-Manufacturer independence – applicable to different inverter types
-Scalability for future expansions
-Secure and reliable data communication between building automation and the energy industry

This project demonstrates how building automation and energy technology can intelligently merge – enabling maximum transparency, efficiency, and economic viability in the operation of modern energy systems.