APG Ernsthofen Substation: Modernization on Track, New Regional Control Center Now Operational

Located in the Amstetten district of Lower Austria, the Ernsthofen substation is one of the largest and most critical grid nodes in APG’s transmission network, where national and regional transmission lines converge.

The substation plays a central role in supplying electricity to large parts of Lower Austria and Upper Austria, including the regions of Amstetten, Steyr, and Wels, as well as central Upper Austria and the Linz industrial area with its steel production facilities. In addition, the substation is a key element for Austria’s security of supply and in the nationwide transmission of renewable energy along the country’s east-west axis. The expansion of the Ernsthofen substation will also create additional grid capacity for regional businesses and industry, including data centers and energy storage facilities, thereby further strengthening the region as an economic hub.

Given that parts of the facility date back to the 1940s, extensive modernization is necessary to ensure a secure and reliable electricity supply for decades to come while improving the integration of renewable energy sources.

Modernization progressing according to plan

The large-scale project, which began in 2017, consists of three phases. The modernization of the 110-kV facility was completed at the end of 2022.

The complete overhaul of the 220-kV switchyard—covering an area of 71,000 square meters, equivalent to around ten soccer fields—is currently in full progress. The modernization is being carried out while maintaining ongoing operations through extensive temporary 220-kV infrastructure measures. Construction phase 1 was completed in 2025. Phase 2 began in the same year and is scheduled for completion by 2027, while phase 3 will run from 2027 to 2029.

“The large-scale modernization of the 220-kV switchyard is a logistical masterpiece,” emphasizes Gerhard Christiner, Spokesperson for the Executive Board of Austrian Power Grid (APG). “Due to the extensive construction work, approximately 22,000 square meters of additional space are required for temporary installations, a container village, and storage areas. In addition, around 30,000 cubic meters of concrete, 110,000 cubic meters of earthworks, and 1,400 tons of steel are being used. Thanks to the substation’s direct rail connection, the transport of portal frames—including steel support structures—as well as the delivery of transformers could be carried out in an environmentally friendly manner. All modernization work is progressing according to plan and remains fully on schedule.”

The megaproject also includes the installation of three new 220/110-kV large-scale transformers, which form the heart of the substation. These transformers connect APG’s nationwide extra-high-voltage transmission grid with the regional distribution network and help prevent grid bottlenecks through targeted power-flow management. All three transformers have already been delivered and installed. Together with the seven existing transformers, a total of ten high-performance transformers will ensure a secure electricity supply for the region and for Austria as a whole once the project is completed.

Completion of the overall modernization project is scheduled for 2029.

Commissioning of the new regional APG control center

Austria’s electricity system is centrally managed through APG’s “Power Grid Control” center in Vienna. All operational information from the Austrian transmission grid is collected and processed there. The control center serves as the command, monitoring, and coordination hub for the operation of the nationwide grid, focusing on system stability and international interconnection, and therefore represents the nerve center of Austria’s electricity supply. From Vienna, the transmission system is continuously monitored—including voltages, currents, frequencies, and switching states—while faults and irregularities are detected at an early stage. Grid operations are coordinated centrally, including the switching of lines, transformers, and substations, as well as operational adjustments to maintain a stable and reliable electricity system.

In addition to the central control center in Vienna, APG operates four regional control centers across Austria. These facilities ensure secure, digital, and efficient multi-level grid management while providing redundancy and local operational capabilities to further strengthen supply reliability. The fully digitalized regional control centers complement the central control center by facilitating faster response times and making grid operations more efficient and resilient. They are responsible for managing individual grid regions and thereby relieve the central control center. At the same time, they also serve as critical operational hubs during crises affecting the power system.

One of these four regional APG control centers is located at the Ernsthofen substation. The center is directly connected to local substations, facilitating rapid intervention in the event of disruptions, informed decision-making based on regional expertise, and efficient coordination of maintenance, modifications, and switching operations - —an advantage during regional load fluctuations or modification work. The Ernsthofen regional control center manages approximately 700 control components throughout the region. The previous control room, which had reached the end of its operational life, has now been completely rebuilt, fully digitalized, and upgraded to the latest technological standards. The new system has already been successfully commissioned.

“The replacement of the regional control room at the Ernsthofen substation was a remarkable achievement, as the transition to the new systems was carried out seamlessly during live operation,” emphasizes Gerhard Christiner. “I would like to congratulate everyone involved on the successful commissioning. The modern APG regional control center is equipped with state-of-the-art technology and creates the foundation for safe, stable, and efficient grid operations well into the future.”

About Austrian Power Grid (APG)

As independent transmission system operator Austrian Power Grid (APG) is in charge of ensuring the security of the electricity supply in Austria. With our high-performance and digital electricity infrastructure and the use of state-of-the-art technologies we integrate renewable energies and reduce the dependency on electricity imports, we are the platform for the electricity market, and we provide access to reasonably priced electricity and thus create the basis for Austria as supply-secure and future-oriented industrial and business location and place to live. The APG grid totals a length of about 3,500 km and is operated, maintained, and continuously adapted to the increasing challenges of the electrification of businesses, industry, and society by a team of approximately 1,000 specialists. 67 substations are distributed all over Austria and the majority is operated remotely. Thanks to our committed employees Austria had a security of supply of 99.99 percent also in 2025 and thus ranks among the top countries worldwide. Our investments of 680 million euros in 2026 (2025: 595 Mio., 2024: 440 million euros, 2023: 490 million euros) are a motor for the Austrian economy and a crucial factor in reaching Austria’s climate and energy targets. Until 2035 APG will invest a total of approximately 9 billion euros in grid expansion and renovation projects.