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The "PB 1-3 Replacement" Project

In the second half of November 2018, the founder, GEN energija d.o.o., got the consent to build a new PB 7 gas block in Brestanica. This is the continuation of the PB 1-3 Replacement project, the second part of Phase 1, which includes the installation of another replacement gas generator with the power of 40-70 MW. In the building where the turbine and generator of the sixth gas generator are located, the space and infrastructure for the seventh gas aggregate are ready.

Reasons for the replacement of PB 1-3
The PB 1 - 3 gas blocks are more than 40 years old and as such at the end of their technical life-span. These blocks are extremely flexible and robust and allow start-up from de-energised state (black start), island operation, and power supply of the Posavje and Dolenjska area. They also provide for the supply of urgent own use of Krško in the event of a turbulence or breakdown of the Slovenian power system and the reserve power for the implementation of the tertiary regulation.
Despite their careful operation, regular maintenance and a relatively low number of operating hours, their technical life-span is inevitably coming to an end. Technical characteristics correspond its age, meaning it has a very low efficiency and relatively high emissions and noise. An extension of service life-span is difficult to achieve due to the problems with the supply of spare parts, lack of support for individual systems, and cost-ineffective complete renewal of gas blocks. Above all, the replacement of the existing gas blocks needs to be carried out in order to ensure a high level of availability and reliability of start-ups which contributes to the reliability of electricity supply to consumers throughout Slovenia, and also for ecological reasons, because a 40-year-old technology no longer meets modern standards of environmental protection. 

Start of the project
After obtaining the consent from the founder, the implementation of the investment in the new PB 7 gas block was approached by preparing and executing a public procurement for LOT 1 which includes the supply and installation of the main technological equipment (gas turbine, generator, chimney, and diesel electric generator for the implementation of the dark start) with corresponding construction works. In 2019 follows the preparation and implementation of two public procurement contracts, namely for LOT 2 - technological electrical equipment (transformers, high voltage cables) and LOT 3 - auxiliary technological equipment (fuel supply...). The start of construction works is planned as well.

The project is expected to be completed in the second half of 2020.

Investment value
The estimated investment value of the PB 7 gas block amounts to EUR 26.45 million.

Technical characteristics
The predicted power of the new gas block is within the 40 - 70 MW range. Technical characteristics are required in accordance with BAT which means that the efficiency of the gas turbine will exceed 36%, NO emissionsX will be below 50 mg/m3 for ZP fuel, or less than 86 mg/m3 for KOEL fuel. The gas block has the possibility of operating on both types of fuel. The new gas block will enable start-up from the requirement to full power in less than 12 minutes which meets the criteria of ENTSO-E and SOPO (ELES), related to the provision of tertiary reserves. The required initial reliability of the new PB will be higher than 98% and the required availability higher than 97%. As with the existing PB 1-3 gas blocks, one of the main technical characteristics of the new gas blocks will be the start-up option from the de-energised state with the possibility of island operation for the needs of providing the necessary own use of Krško and island operation for the needs of the power supply of Posavje, Dolenjska and Zasavje.

Model of new GT units (on the left)