TE-TO Osijek, Croatia: Lower CO₂ and energy savings

The TE-TO Osijek power station, a combined heat and power (CHP) plant in eastern Osijek, Croatia, has served the region for over a century under the ownership of Hrvatska elektroprivreda d.d. (HEP Group). This facility plays a vital role in generating electricity and producing thermal energy for city heating and industrial processes, delivering at least 95 megawatts of power.

Facing challenges with unreliable hot water circulation pumps that caused costly downtime, the plant adopted advanced variable speed electric drives, leading to significant energy efficiency gains, reduced CO₂ emissions, and improved system reliability for a more sustainable energy future.

The TE-TO Osijek power station faced a critical challenge. Specifically, the management of three hot water circulation pumps within the central heating system proved to be unreliable due to frequent breakdowns and difficult maintenance. Downtime and repairs led to increased costs and operational inefficiencies. By using frequency-regulated electric motor drives in thermal power plants, significant energy savings can be achieved at the same time carbon dioxide emissions can be reduced.

In addition to the above generally accepted practice of replacing part of unregulated electric drives with regulated ones, there is also a tendency to replace old engines with low energy utilization by highly efficient modern engines with a high energy class often classified according to IEC standards.

Hrvatska elektroprivreda d.d. (HEP Group) decided to install a frequency-regulated electric motor to operate the circulation pump in the central heating system of the city of Osijek to enhance plant reliability and reduce maintenance burdens.

Siemens Energy stepped in to address the challenge. After assessing the theoretical savings potential and conducting an on-site analysis of TE-TO Osijek’s entire drive train, Siemens Energy devised a concrete optimization concept. The obsolete and inefficient hardware was replaced, and a high-quality variable speed drive was implemented. This solution not only improved reliability but also achieved significant energy savings. Siemens Energy ensured a seamless replacement process, from project planning to commissioning, and continued to provide ongoing service support.

• Energy savings of 2,289 MWh in just three heating periods
• Reduced CO₂ emissions of 800 - 1200 tons per season of central heating
• Increased operational reliability of the electric drive of the hot water pumps and the entire hot water system
• Return on Investment in just 4 years

The upgrades used demonstrate TE-TO Osijek's commitment to improving energy efficiency and to reducing emissions. The partnership between Siemens Energy and TE-TO Osijek laid the groundwork for reliable and efficient heating in the region.