Regulation of the Minister of Climate and Environment on the specific conditions for the operation of the power system [1] introduced two “agricultural institutions”:

• Photovoltaic Farms (par. 2 sec. 4)
• Wind Farms (par. 2 sec. 5)

which constitute an example of unnecessary regulation dictated by the belief that every rectangle, which is a square, must be named a square by law, even if the squareness of that rectangle is actually insignificant. No problem, we can make it significant by creating separate requirements and/or privileges for squares, which by becoming acquired rights or technical obligations, will perpetuate the pathological state of “impossibilism” of geometric (or rather energy) transformation.
Let’s quote the definitions and consider what is what in this conceptual puzzle. Both wind and photovoltaic farms are linked by a definitional core, which I have bolded:

Photovoltaic Farm – a power park module using solar radiation energy to generate electricity, connected to the grid at a single connection point

Wind farm similarly – uses wind energy. Importantly, in both cases, the legislator indicates that these are power park modules – so it is worth quoting the relevant definition from art. 2 sec. 17 of Regulation 2016/631 [2]:

Power Park Module: a unit or a set of units generating electricity, which is connected to the grid in a non-synchronous manner or through power electronics, and which also has a single connection point to the transmission system, distribution system, including a closed distribution system, or HVDC system

As can be seen in the definition of PPM (Power Park Module), there is nothing that indicates categorization based on primary energy (wind, solar), but again there is a single connection point. Therefore, the farm has a connection point to a square. Maybe we will find something in the definition of Power Generating Unit (PGU)? Such a definition (unfortunately) does not directly appear in the Network Codes [2], but was presented as part of the recommendations for amendments to the NC RfG by ACER, art. 2 (74) [3]:

‘Power generating unit’ or ‘PGU’ means an aggregation of components converting a primary source of energy into electricity at the terminals of a unit generating electricity, which is synchronously connected to the network or which is either non-synchronously connected to the network or connected through power electronics.

Author’s translation:
Power Generating Unit (PGU): An aggregation of components connected to the grid (directly or indirectly) in a synchronous, non-synchronous, or through power electronics manner, which converts primary energy (source) into electricity available at the (common) terminals of this unit.

This definition indeed mentions primary energy, but unfortunately not in the manner implied by the national legislator in the system regulation [1]. The separation of the aggregation of components (aggregation of components) remains in the realm of project decisions and does not have to be related to the primary energy source. This means that at the level of a single PGU, it is possible to separate a working aggregation of components converting energy from several different primary energy sources.

Example:

A Power Park Module (PPM) consists of two PGUs connected at a single point to the operator’s network. The first PGU is a hybrid aggregation of components generating energy from “sun,” “water,” and “biogas,” exporting power from a single hybrid converter with a capacity of 5 MVA. The second PGU consists of a double wind turbine exporting power from a single power electronics converter with a capacity of 12 MVA. Additionally, the Power Park Module includes two energy storage systems 2MW/4MWh and one heat storage 1MW/50MWh, as well as a power electronics VSC compensator with a capacity of 5 MVA (+/- 5 Mvar) and flexible load in the form of an electrolyzer with a capacity of 0-5 MW. The Power Park Module declares a net achievable capacity at the switch point (Pmax) at the level of 5 MW with a connection capacity of 5.2 MW, 100% of the energy introduced to the grid comes from renewable sources, and the connection capacity utilization factor is 90% (41,000 MWh/year).

The criterion for separating PGU in this case is practically the regulation capability provided at the interfaces of two power electronics converters, which were separately certified and can be jointly managed from a single supervisory controller. This approach is harmonized with the procedures resulting from NC RfG [5]. Recognizing the remaining components (energy storages, compensators, flexible load) as part of PGM results from the subordination of their operation to the parameters declared (commitments) by the Power Park Module – in other words, they operate dependently on the PGU aggregation within the PPM.

Of course, there can be more criteria for separating PGU, and one of them could be the type of primary energy (so-called “technology”), but the most important conclusion of my lengthy analysis is the statement that “it does not have to be so”.

In this way, we managed to expose the weakness of the “farmers’” definitions, which, although recognizing that within the Power Park Module there may be units generating energy (in whole or in part) from “wind” or “sun,” confuse the rectangle (power park module) with the square (farm…).

Example:

A Power Park Module is modified by expanding it with: two PGUs and an energy storage. As a result of the modification, the Power Park Module includes basic generation installations (NC RfG art. 2 (8)) utilizing both solar radiation energy and wind energy. The net achievable capacity of the modified Power Park Module has not changed, thus the capabilities derived from Pmax also remain unchanged.

Implications arising from “farm-categorization” in the form of a Q&A session:

• System Operator: Was it a Photovoltaic Power Park Module before the modification?
• Power Generating Facility Owner: But in the NC there is no such categorization, it was simply a Power Park Module – it was connected and tested as such.
• SO: In Polish law, you need to specify whether it was a wind farm, photovoltaic farm, or another power park module, which has not yet been defined in the regulation.
• PGFO: Does this change the obligations of the Power Generating Facility Owner in any way?
• SO: Not really, but it helps us to forecast generation, estimate energy production costs in a given source, create correction factors for the availability of a given “technology,” and calculate seasonal loads in the system.
• PGFO: But does this change anything in my relationship with the SO? It is still a Power Park Module, it has the same capabilities, it is controlled from a single SCADA interface of the SO. It is simply a black box operating within the Pmin – Pmax range, providing technical capabilities to fulfill agreed commitments.
• SO: We need to know this because it is required by the system regulation.
• PGFO: Okay, before modernization it was a photovoltaic farm, but now there are also two wind turbines and an energy storage.
• SO: In that case, these are two Power Park Modules – one photovoltaic farm and one wind farm.
• PGFO: And the storage?
• SO: According to the NC RfG, storage is not a source.
• PGFO: Clearly – an independent storage is not a source, but in this case, it works as a component of the Power Park Module, the entire facility is connected at one point and controlled from a single interface, so it should be treated as one Power Park Module.
• SO: No, because these are two power park modules – wind and photovoltaic, one of them can be supported by the storage.
• PGFO: What does supported mean? The storage affects the technical capabilities of the Power Park Module as a whole according to the project assumptions, resulting in changes to Pmin and corrections to the operational plans declared for one PPE.
• SO: Support is not defined, but in practice, we prohibit your graphical unit from providing services in the direction of intake on the balancing market.
• PGFO: Why?
• SO: We did not foresee such a possibility for wind or photovoltaic power park modules.
• PGFO: But there is no such thing in the regulation establishing guidelines for balancing (2017/2195)!
• SO: But it is in the national system regulation, if you want to fully use the energy storage, you must aggregate all this… First, however, both Power Park Modules must be tested for compliance with NC RfG.
• PGFO: But wasn’t the purpose of introducing the definitions of Power Park Module and Synchronous Power Generating Module to eliminate all unnecessary subcategories that could lead to discrimination of certain technical solutions?
• SO: Possible, but our habits are different, maybe someday we will change that.
• PGFO: Wasn’t their purpose also to replace the arbitrary assessment of the nominal parameters of individual devices with universal net quantities verified at the connection point?
• SO: Possible, but we are used to assessing nominal and gross parameters.
• PGFO: I propose not to perpetuate your habits in key documents related to Energy Law and leave them in impermanent acts, such as the RES Act.
• SO: Too late, they are already included in the Balancing Conditions [4], System Regulation [1], and partly in the Energy Law, through the use of the definition of installed electrical capacity, for some Generating Units consisting of RES Installations.
• PGFO: Consisting of RES Installations in whole or in part?
• SO: Give it a rest…

Summary
The RfG network code [2] was supposed to make everyone’s life easier by introducing a new paradigm for categorizing sources connected to the power system. A Power Generating Module is a black box connected at a single point to the distribution or transmission grid. This box must be able to perform the required capabilities for remote and automatic regulation, allowing it to ultimately provide services on the technical market. In Poland, this black box must be labeled as a Farm (…), described in the finest details (dedicated annexes to WP PV, FW), and configured to provide flexibility services before these services are priced. Sometimes it is difficult to see the difference between confirming the capability to provide a service (e.g. voltage stabilization) and its (free) provision as part of better or worse documented interventions.

[1] Regulation of the Minister of Climate and Environment of March 22, 2023, on the specific conditions for the operation of the power system LINK

[2] COMMISSION REGULATION (EU) 2016/631 of April 14, 2016, establishing a network code on requirements for grid connection of generators LINK

[3] ACER Recommendation 03-2023 on reasoned proposals for amendments to the network codes on requirements for grid connection of generators and on demand connection LINK

[4] Balancing Conditions LINK

[5] General Guidance On Compliance Verification – Compliance Testing And Use Of Equipment Certificates LINK