Polish power grids are becoming the “bottleneck” of energy transition. The “More RES in the Grid” report by PWEA and Lublin University of Technology presents twelve recommendations for increasing transmission capacity of the Polish grid and connecting new wind and PV sources. Implementation of low-cost solutions would optimise the existing grid infrastructure, enabling a substantial growth in RES investments in the next years and a decrease in the number of refused grid connections. 

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Recommendations presented in the “More RES in the Grid” report constitute a response to increased pressure on adjustments to Poland’s energy mix required by ambitious EU targets as well as the need to become independent from imported fuels. Today’s RES investments are a step towards transition to exclusively domestic resources in the long term. Unofficially, in its update to Energy Policy of Poland by 2040 (EPP2040), which currently is being prepared, the Government plans to substantially increase the share of renewable energy sources, which may reach as much as 57 percent of energy production. Therefore, it is apparent that challenges stemming from connection of new RES to the grid are substantial.

“Our need and want for an increasing volume of RES in the national power system is beyond discussion. However, today the bottleneck for green energy development is the grid infrastructure, which, in my opinion, has not received due attention these years. Power grids face great challenges and need for a change, which require long-term and multi-directional investments at an unprecedented scale,” Rafał Gawin, President of the Energy Regulatory Office emphasized in the report.

Polish Wind Energy Association and Lublin University of Technology decided to identify the key barriers to grid connection of renewable sources. The authors of the “More RES in the Grid” report proposed an investment-free and low-investment methods to increase connection capacity of the Polish power system that could be rapidly implemented and bring substantial results at a relatively short notice. The presented solutions will allow for parallel investments without substantial time pressure, enabling connection of large new capacity within a relatively short time on the basis of regulatory and administrative solutions.

The experts emphasize the need to update strategic governmental documents describing the pace and scale of energy transition, including EPP2040. The publication also stresses the need for harmonisation of notification schemes and methodologies for determining connection capacity in generally accepted practices. The authors claim information chaos, which precludes an unambiguous determination of connection capacity of the 110 kV transmission grid.

Another issue affecting the connection of new capacity is the interpretation of overhead line loading, for as much as 5-10% overload does not result in a threat to the security of the grid, where currently even 0.5% disqualifies a connection. A similar issue applies to the increase in temperature capacity of the lines — an increase from 60°C to 80°C is the simplest and least expensive method to increase transmission capacity. Therefore, old overhead lines exhibit a substantial reserve both in terms of temperature and conductor stress.

Issues with connection of new generation units is clearly apparent in particular in the recent years. On the basis of the ERO data, in 2020–21 only the largest DSOs issued more that 5 thousand refusals to issue grid connection conditions for 20 GW of capacity. “One of recommended solutions is to implement financial incentives for DSOs. The scheme is to foster more rational assessment of connection capacity and promote investments in the development of grid infrastructure,” said one of the authors of the report, Professor Piotr Kacejko from Lublin University of Technology.

“Obviously, it is necessary to modernise grid infrastructure and build new connections. However, to increase connection capacity of the Polish power system in the context of aspirations for a dynamic RES growth immediate action of PSE S.A., DSOs and the Polish Government is also required. The increase in the capacity of grid infrastructure should be at the core and a starting point for a broadly construed energy transition,” emphasised Janusz Gajowiecki, President of the Polish Wind Energy Association.

In the “More RES in the Grid” report the experts also address the need for grid infrastructure sharing, in particular by wind and PV sources (so-called cable pooling) and emphasize the creation of a legal framework for direct line solutions, necessary for and expected by energy-intensive sectors in particular.

“We believe that the report will become an impulse for discussion on the necessary changes to transmission and distribution grids, and our analyses will contribute to optimisation of grid connection conditions in the next years,” PWEA President added.

12 Methods to Increase Connection Capacity of the Polish Power System:

1. Urgent verification of strategic governmental documents, including Energy Policy of Poland by 2040 (increased pace of energy transition).
2. Harmonisation of methodology for determination of grid connection possibilities for sources and publication thereof in a regulation-ranked document.
3. Harmonisation of a scheme for notifying applicants about currently available connection capacity in the 110 kV transmission grid.
4. Interpretation of results of flow analyses and the resulting line loading compliant with metrology standards and physical basics of conductor heating.
5. Legal regulation of acceptable tolerances in interpretation of calculation results preceding the issuance of a decision on grid connection conditions to take into account the approximate nature of such calculations.
6. Elimination of investment barriers with respect to effective increase in line loading to 80°C and development of plans to eliminate lines with design temperature of 40°C.
7. Implementation of a concept for grid infrastructure sharing between different RES technologies — “cable pooling”.
8. Implementation of regulations enabling large-scale use of direct lines.
9. Implementation of financial incentives for DSOs to reduce the number of refusals to connect RES to the grid.
10. Implementation of a scheme reducing RES electricity production both in case of a global balance excess and local surplus causing periodic overload of lines or voltage levels exceeding allowable thresholds.
11. Modification and more flexibility of connection criteria for medium voltage lines coupled with the use of RES installation control capacity.
12. Improvement of low voltage grid operating conditions — decrease in the number of prosumer installations switched online.