Past years development is moving fast with respect to Hybrid Power Plant especially with batteries as storage units and with their rapid evolution it is becoming increasingly beneficial to incorporate large battery systems both as a stand-alone system in the power grid and inside hybrid power plants. A status is evaluated and gap analysis is investigated to design a Hybrid Power Plant with respect to dynamical performance and current operational requirements. Does every production unit or storage facility need to comply with connection requirements on its own or does it make sense to regard the facility as one whole plant? What about overplanting – where sizing of the power plant module exceeds more than 10% of the exchange capacity? New legislation regarding overplanting is submitted recently from Danish TSO Energinet in December 2025.

This article is intended to explore and map these uncertainties on a high-level basis from known and developed technologies such as wind, solar and battery storage systems. It is intended to update status from a previous paper presented at WISO 2023. The paper will investigate, map, and evaluate the status of grid connection regulations in the sense of what is available already, how required needs for regulations are covered, and what is needed for further improvement. The work leading to these findings and conclusions is a part of the IEA Wind Task 50 Hybrid Power Plants – funded by EUDP.

Hybrid Power Plants (HPP) using two or more RE technologies often in combination with a storage solution, is a growing industry – in size, applicability, and availability. The individual producing components still have their own grid code connection requirements and standards, as well-proven from many years of experience. As previously described, strong considerations point to set recommendations as to control and test the HPP as one unit and solely evaluating the plant at its grid connection point. Thereby benefitting from the advantages of the technologies supporting each other to meet the requirements. And new legislation is coming. Especially regarding storage units both as stand-alone and included in hybrid power plants, new legislation has been submitted from Danish Energinet last edition arriving May 2025. Typical HPP design including wind turbines and PV-modules may be rated from a summation of the different component´s ratings. This maximized operation may require voltage support requested in the form of e.g., capacitor banks, or statcoms. Alternatively, HPP control design could include PQ/QV-capacities from various technologies as for example storage units, which play a key role together with inverter-based technology, in meeting the requirements at the PCC. Regarding HPP sizing and operation, new legislation has been submitted from Danish Energinet concerning transmission connected plants operating the power plant by limiting the exchange power at the connection agreement but operation with more production and loading behind the meter. Thus, allowing for overplanting of the power plant. The present article will review status and formulate recommendations for coming grid connection regulations of HPP.

Some key points: Should the plant physically installed capacity be regulated or limited according to the connection agreement? How should the short circuit power at PCC from an HPP when the plant includes more installed capacity than the allowed exchange capacity be determined? Should requirements differ according to technology type and size?